Fix some errors in async prefetching in FilePrefetchBuffer (#9734 )

Summary: In ReadOption `async_io` which prefetches the data asynchronously, db_bench and db_stress runs were failing because wrong data was prefetched which resulted in Error: Checksum mismatched. Wrong data was copied because capacity was less than actual size needed. It has been fixed in this PR. Since there are two separate methods for async and sync prefetching, these changes are in async prefetching methods and any changes would not effect normal prefetching. I ran the regressions to make sure normal prefetching is fine. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9734 Test Plan: 1. CircleCI jobs 2. Ran db_bench ``` . /db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 -async_io=1 -adaptive_readahead=1 ``` 3. Ran db_stress test ``` export CRASH_TEST_EXT_ARGS=" --async_io=1 --adaptive_readahead=1" make crash_test -j ``` 4. Run regressions for async_io disabled. Old flow without any async changes: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.0 Date: Thu Mar 17 13:11:34 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] seekrandom : 483618.390 micros/op 2 ops/sec; 338.9 MB/s (249 of 249 found) ``` With async prefetching changes and async_io disabled to make sure in normal prefetching there is no regression. ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 --async_io=0 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.1 Date: Wed Mar 23 15:56:37 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] seekrandom : 481819.816 micros/op 2 ops/sec; 340.2 MB/s (250 of 250 found) ``` Reviewed By: riversand963 Differential Revision: D35058471 Pulled By: akankshamahajan15 fbshipit-source-id: 9233a1e6d97cea0c7a8111bfb9e8ac3251c341ce
Tidy up HISTORY.md for 7.1.0
2026-07-07 22:55:23 +08:00 · 2022-03-25 18:31:10 -07:00 · 2022-03-23 16:38:06 -07:00 · 2022-03-23 15:42:35 -07:00 · 2022-03-23 15:00:14 -07:00 · 2022-03-21 19:48:41 -07:00
725 changed files with 55837 additions and 22109 deletions
@@ -1,54 +0,0 @@
-#! /bin/bash
-
-# Work around issue with parallel make output causing random error, as in
-# make[1]: write error: stdout
-# Probably due to a kernel bug:
-#   https://bugs.launchpad.net/ubuntu/+source/linux-signed/+bug/1814393
-# Seems to affect image ubuntu-1604:201903-01 and ubuntu-1604:202004-01
-
-cd "$(dirname $0)"
-
-if [ ! -x cat_ignore_eagain.out ]; then
-    cc -x c -o cat_ignore_eagain.out - << EOF
-#include <unistd.h>
-#include <errno.h>
-#include <stdio.h>
-int main() {
-    int n, m, p;
-    char buf[1024];
-    for (;;) {
-        n = read(STDIN_FILENO, buf, 1024);
-        if (n > 0 && n <= 1024) {
-            for (m = 0; m < n;) {
-                p = write(STDOUT_FILENO, buf + m, n - m);
-                if (p < 0) {
-                    if (errno == EAGAIN) {
-                        // ignore but pause a bit
-                        usleep(100);
-                    } else {
-                        perror("write failed");
-                        return 42;
-                    }
-                } else {
-                    m += p;
-                }
-            }
-        } else if (n < 0) {
-            if (errno == EAGAIN) {
-                // ignore but pause a bit
-                usleep(100);
-            } else {
-                // Some non-ignorable error
-                perror("read failed");
-                return 43;
-            }
-        } else {
-            // EOF
-            return 0;
-        }
-    }
-}
-EOF
-fi
-
-exec ./cat_ignore_eagain.out
@@ -10,13 +10,6 @@ aliases:
    only_for_branches: main

 commands:
-  install-pyenv-on-macos:
-    steps:
-      - run:
-          name: Install pyenv on macos
-          command: |
-            HOMEBREW_NO_AUTO_UPDATE=1 brew install pyenv
-
  install-cmake-on-macos:
    steps:
      - run:
@@ -24,6 +17,13 @@ commands:
          command: |
            HOMEBREW_NO_AUTO_UPDATE=1 brew install cmake

+  install-jdk8-on-macos:
+    steps:
+      - run:
+          name: Install JDK 8 on macos
+          command: |
+            brew install --cask adoptopenjdk/openjdk/adoptopenjdk8
+
  increase-max-open-files-on-macos:
    steps:
      - run:
@@ -34,29 +34,26 @@ commands:
            sudo launchctl limit maxfiles 1048576

  pre-steps:
-    parameters:
-      python-version:
-        default: "3.5.9"
-        type: string
    steps:
      - checkout
-      - run: pyenv install --skip-existing <<parameters.python-version>>
-      - run: pyenv global <<parameters.python-version>>
      - run:
          name: Setup Environment Variables
          command: |
            echo "export GTEST_THROW_ON_FAILURE=0" >> $BASH_ENV
            echo "export GTEST_OUTPUT=\"xml:/tmp/test-results/\"" >> $BASH_ENV
            echo "export SKIP_FORMAT_BUCK_CHECKS=1" >> $BASH_ENV
-            echo "export PRINT_PARALLEL_OUTPUTS=1" >> $BASH_ENV
            echo "export GTEST_COLOR=1" >> $BASH_ENV
            echo "export CTEST_OUTPUT_ON_FAILURE=1" >> $BASH_ENV
            echo "export CTEST_TEST_TIMEOUT=300" >> $BASH_ENV
+            echo "export ZLIB_DOWNLOAD_BASE=https://rocksdb-deps.s3.us-west-2.amazonaws.com/pkgs/zlib" >> $BASH_ENV
+            echo "export BZIP2_DOWNLOAD_BASE=https://rocksdb-deps.s3.us-west-2.amazonaws.com/pkgs/bzip2" >> $BASH_ENV
+            echo "export SNAPPY_DOWNLOAD_BASE=https://rocksdb-deps.s3.us-west-2.amazonaws.com/pkgs/snappy" >> $BASH_ENV
+            echo "export LZ4_DOWNLOAD_BASE=https://rocksdb-deps.s3.us-west-2.amazonaws.com/pkgs/lz4" >> $BASH_ENV
+            echo "export ZSTD_DOWNLOAD_BASE=https://rocksdb-deps.s3.us-west-2.amazonaws.com/pkgs/zstd" >> $BASH_ENV

  pre-steps-macos:
      steps:
-        - pre-steps:
-            python-version: "3.6.0"
+        - pre-steps

  post-steps:
    steps:
@@ -79,11 +76,23 @@ commands:
      - run:
          name: Install Clang 10
          command: |
-            echo "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main" | sudo tee -a /etc/apt/sources.list
-            echo "deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main" | sudo tee -a /etc/apt/sources.list
+            wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+            echo "deb http://apt.llvm.org/focal/ llvm-toolchain-focal-10 main" | sudo tee -a /etc/apt/sources.list
+            echo "deb-src http://apt.llvm.org/focal/ llvm-toolchain-focal-10 main" | sudo tee -a /etc/apt/sources.list
            echo "APT::Acquire::Retries \"10\";" | sudo tee -a /etc/apt/apt.conf.d/80-retries # llvm.org unreliable
            sudo apt-get update -y && sudo apt-get install -y clang-10

+  install-clang-13:
+    steps:
+      - run:
+          name: Install Clang 13
+          command: |
+            echo "deb http://apt.llvm.org/focal/ llvm-toolchain-focal-13 main" | sudo tee -a /etc/apt/sources.list
+            echo "deb-src http://apt.llvm.org/focal/ llvm-toolchain-focal-13 main" | sudo tee -a /etc/apt/sources.list
+            echo "APT::Acquire::Retries \"10\";" | sudo tee -a /etc/apt/apt.conf.d/80-retries # llvm.org unreliable
+            wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key|sudo apt-key add -
+            sudo apt-get update -y && sudo apt-get install -y clang-13
+
  install-gflags:
    steps:
      - run:
@@ -93,7 +102,7 @@ commands:

  install-benchmark:
    steps:
-      - run: # currently doesn't support ubuntu-1604 which doesn't have libbenchmark package, user can still install by building it youself
+      - run:
          name: Install benchmark
          command: |
            sudo apt-get update -y && sudo apt-get install -y libbenchmark-dev
@@ -128,6 +137,21 @@ commands:
          command: |
            sudo apt-get update -y && sudo apt-get install -y libsnappy-dev zlib1g-dev libbz2-dev liblz4-dev libzstd-dev

+  install-libprotobuf-mutator:
+    steps:
+      - run:
+          name: Install libprotobuf-mutator libs
+          command: |
+            git clone --single-branch --branch master --depth 1 git@github.com:google/libprotobuf-mutator.git ~/libprotobuf-mutator
+            cd ~/libprotobuf-mutator && mkdir build && cd build
+            cmake .. -GNinja -DCMAKE_C_COMPILER=clang-13 -DCMAKE_CXX_COMPILER=clang++-13 -DCMAKE_BUILD_TYPE=Release -DLIB_PROTO_MUTATOR_DOWNLOAD_PROTOBUF=ON
+            ninja && sudo ninja install
+      - run:
+          name: Setup environment variables
+          command: |
+            echo "export PKG_CONFIG_PATH=/usr/local/OFF/:~/libprotobuf-mutator/build/external.protobuf/lib/pkgconfig/" >> $BASH_ENV
+            echo "export PROTOC_BIN=~/libprotobuf-mutator/build/external.protobuf/bin/protoc" >> $BASH_ENV
+
 executors:
  windows-2xlarge:
    machine:
@@ -138,194 +162,226 @@ executors:
 jobs:
  build-macos:
    macos:
-      xcode: 11.3.0
+      xcode: 12.5.1
    resource_class: large
+    environment:
+      ROCKSDB_DISABLE_JEMALLOC: 1 # jemalloc cause env_test hang, disable it for now
    steps:
      - increase-max-open-files-on-macos
-      - install-pyenv-on-macos
      - install-gflags-on-macos
      - pre-steps-macos
-      - run: ulimit -S -n 1048576 && OPT=-DCIRCLECI make V=1 J=32 -j32 check | .circleci/cat_ignore_eagain
+      - run: ulimit -S -n 1048576 && OPT=-DCIRCLECI make V=1 J=32 -j32 all
      - post-steps

  build-macos-cmake:
    macos:
-      xcode: 11.3.0
+      xcode: 12.5.1
    resource_class: large
+    parameters:
+      run_even_tests:
+        description: run even or odd tests, used to split tests to 2 groups
+        type: boolean
+        default: true
    steps:
      - increase-max-open-files-on-macos
-      - install-pyenv-on-macos
      - install-cmake-on-macos
      - install-gflags-on-macos
      - pre-steps-macos
-      - run: ulimit -S -n 1048576 && (mkdir build && cd build && cmake -DWITH_GFLAGS=1 .. && make V=1 -j32 && ctest -j10) | .circleci/cat_ignore_eagain
+      - run:
+          name: "cmake generate project file"
+          command: ulimit -S -n 1048576 && mkdir build && cd build && cmake -DWITH_GFLAGS=1 ..
+      - run:
+          name: "Build tests"
+          command: cd build && make V=1 -j32
+      - when:
+          condition: << parameters.run_even_tests >>
+          steps:
+            - run:
+                name: "Run even tests"
+                command: ulimit -S -n 1048576 && cd build && ctest -j32 -I 0,,2
+      - when:
+          condition:
+            not: << parameters.run_even_tests >>
+          steps:
+            - run:
+                name: "Run odd tests"
+                command: ulimit -S -n 1048576 && cd build && ctest -j32 -I 1,,2
      - post-steps

  build-linux:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
    steps:
      - pre-steps
      - install-gflags
-      - run: make V=1 J=32 -j32 check | .circleci/cat_ignore_eagain
-      - post-steps
-
-  build-linux-mem-env:
-    machine:
-      image: ubuntu-1604:202104-01
-    resource_class: 2xlarge
-    steps:
-      - pre-steps
-      - install-gflags
-      - run: MEM_ENV=1 make V=1 J=32 -j32 check | .circleci/cat_ignore_eagain
+      - run: make V=1 J=32 -j32 check
      - post-steps

  build-linux-encrypted-env:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
    steps:
      - pre-steps
      - install-gflags
-      - run: ENCRYPTED_ENV=1 make V=1 J=32 -j32 check | .circleci/cat_ignore_eagain
+      - run: ENCRYPTED_ENV=1 make V=1 J=32 -j32 check
      - post-steps

  build-linux-shared_lib-alt_namespace-status_checked:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
    steps:
      - pre-steps
      - install-gflags
-      - run: ASSERT_STATUS_CHECKED=1 TEST_UINT128_COMPAT=1 ROCKSDB_MODIFY_NPHASH=1 LIB_MODE=shared OPT="-DROCKSDB_NAMESPACE=alternative_rocksdb_ns" make V=1 -j32 check | .circleci/cat_ignore_eagain
+      - run: ASSERT_STATUS_CHECKED=1 TEST_UINT128_COMPAT=1 ROCKSDB_MODIFY_NPHASH=1 LIB_MODE=shared OPT="-DROCKSDB_NAMESPACE=alternative_rocksdb_ns" make V=1 -j32 check
      - post-steps

  build-linux-release:
    machine:
-      image: ubuntu-1604:202104-01
-    resource_class: large
+      image: ubuntu-2004:202111-02
+    resource_class: 2xlarge
    steps:
      - checkout # check out the code in the project directory
-      - run: make V=1 -j8 release | .circleci/cat_ignore_eagain
+      - run: make V=1 -j32 release
      - run: if ./db_stress --version; then false; else true; fi # ensure without gflags
      - install-gflags
-      - run: make V=1 -j8 release | .circleci/cat_ignore_eagain
+      - run: make V=1 -j32 release
      - run: ./db_stress --version # ensure with gflags
      - post-steps

  build-linux-release-rtti:
    machine:
-      image: ubuntu-1604:201903-01
-    resource_class: large
+      image: ubuntu-2004:202111-02
+    resource_class: xlarge
    steps:
      - checkout # check out the code in the project directory
      - run: make clean
-      - run: USE_RTTI=1 DEBUG_LEVEL=0 make V=1 -j8 static_lib tools db_bench | .circleci/cat_ignore_eagain
+      - run: USE_RTTI=1 DEBUG_LEVEL=0 make V=1 -j16 static_lib tools db_bench
      - run: if ./db_stress --version; then false; else true; fi # ensure without gflags
      - run: sudo apt-get update -y && sudo apt-get install -y libgflags-dev
      - run: make clean
-      - run: USE_RTTI=1 DEBUG_LEVEL=0 make V=1 -j8 static_lib tools db_bench | .circleci/cat_ignore_eagain
+      - run: USE_RTTI=1 DEBUG_LEVEL=0 make V=1 -j16 static_lib tools db_bench
      - run: ./db_stress --version # ensure with gflags

  build-linux-lite:
    machine:
-      image: ubuntu-1604:202104-01
-    resource_class: 2xlarge
+      image: ubuntu-2004:202111-02
+    resource_class: large
    steps:
      - pre-steps
      - install-gflags
-      - run: LITE=1 make V=1 J=32 -j32 check | .circleci/cat_ignore_eagain
+      - run: LITE=1 make V=1 J=8 -j8 check
      - post-steps

  build-linux-lite-release:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: large
    steps:
      - checkout # check out the code in the project directory
-      - run: LITE=1 make V=1 -j8 release | .circleci/cat_ignore_eagain
+      - run: LITE=1 make V=1 -j8 release
      - run: if ./db_stress --version; then false; else true; fi # ensure without gflags
      - install-gflags
-      - run: LITE=1 make V=1 -j8 release | .circleci/cat_ignore_eagain
+      - run: LITE=1 make V=1 -j8 release
      - run: ./db_stress --version # ensure with gflags
      - post-steps

  build-linux-clang-no_test_run:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: xlarge
    steps:
      - checkout # check out the code in the project directory
      - run: sudo apt-get update -y && sudo apt-get install -y clang libgflags-dev libtbb-dev
-      - run: CC=clang CXX=clang++ USE_CLANG=1 PORTABLE=1 make V=1 -j16 all | .circleci/cat_ignore_eagain
+      - run: CC=clang CXX=clang++ USE_CLANG=1 PORTABLE=1 make V=1 -j16 all
      - post-steps

  build-linux-clang10-asan:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
    steps:
      - pre-steps
      - install-gflags
      - install-clang-10
-      - run: COMPILE_WITH_ASAN=1 CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 check | .circleci/cat_ignore_eagain # aligned new doesn't work for reason we haven't figured out
+      - run: ASAN_OPTIONS=detect_stack_use_after_return=1 COMPILE_WITH_ASAN=1 CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 check # aligned new doesn't work for reason we haven't figured out
      - post-steps

  build-linux-clang10-mini-tsan:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
+    # find test list by `make list_all_tests`
+    parameters:
+      start_test:
+        default: ""
+        type: string
+      end_test:
+        default: ""
+        type: string
    steps:
      - pre-steps
      - install-gflags
      - install-clang-10
-      - run: COMPILE_WITH_TSAN=1 CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 check | .circleci/cat_ignore_eagain # aligned new doesn't work for reason we haven't figured out.
+      - install-gtest-parallel
+      - run:
+          name: "Build unit tests"
+          command: |
+            echo "env: $(env)"
+            ROCKSDBTESTS_START=<<parameters.start_test>> ROCKSDBTESTS_END=<<parameters.end_test>> ROCKSDBTESTS_SUBSET_TESTS_TO_FILE=/tmp/test_list COMPILE_WITH_TSAN=1 CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 --output-sync=target build_subset_tests
+      - run:
+          name: "Run unit tests in parallel"
+          command: |
+            sed -i 's/[[:space:]]*$//; s/ / \.\//g; s/.*/.\/&/' /tmp/test_list
+            cat /tmp/test_list
+            gtest-parallel $(</tmp/test_list) --output_dir=/tmp | cat  # pipe to cat to continuously output status on circleci UI. Otherwise, no status will be printed while the job is running.
      - post-steps

  build-linux-clang10-ubsan:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
    steps:
      - pre-steps
      - install-gflags
      - install-clang-10
-      - run: COMPILE_WITH_UBSAN=1 OPT="-fsanitize-blacklist=.circleci/ubsan_suppression_list.txt" CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 ubsan_check | .circleci/cat_ignore_eagain # aligned new doesn't work for reason we haven't figured out
+      - run: COMPILE_WITH_UBSAN=1 OPT="-fsanitize-blacklist=.circleci/ubsan_suppression_list.txt" CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 ubsan_check # aligned new doesn't work for reason we haven't figured out
      - post-steps

  build-linux-clang10-clang-analyze:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
    steps:
      - pre-steps
      - install-gflags
      - install-clang-10
      - run: sudo apt-get update -y && sudo apt-get install -y clang-tools-10
-      - run: CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 CLANG_ANALYZER="/usr/bin/clang++-10" CLANG_SCAN_BUILD=scan-build-10 USE_CLANG=1 make V=1 -j32 analyze | .circleci/cat_ignore_eagain # aligned new doesn't work for reason we haven't figured out. For unknown, reason passing "clang++-10" as CLANG_ANALYZER doesn't work, and we need a full path.
+      - run: CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 CLANG_ANALYZER="/usr/bin/clang++-10" CLANG_SCAN_BUILD=scan-build-10 USE_CLANG=1 make V=1 -j32 analyze # aligned new doesn't work for reason we haven't figured out. For unknown, reason passing "clang++-10" as CLANG_ANALYZER doesn't work, and we need a full path.
      - post-steps

  build-linux-cmake:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
    steps:
      - pre-steps
      - install-gflags
      - upgrade-cmake
-      - run: (mkdir build && cd build && cmake -DWITH_GFLAGS=1 .. && make V=1 -j20 && ctest -j20) | .circleci/cat_ignore_eagain
+      - run: (mkdir build && cd build && cmake -DWITH_GFLAGS=1 .. && make V=1 -j20 && ctest -j20)
      - post-steps

  build-linux-cmake-ubuntu-20:
    machine:
-      image: ubuntu-2004:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
    steps:
      - pre-steps
      - install-gflags
      - install-benchmark
-      - run: (mkdir build && cd build && cmake -DWITH_GFLAGS=1 -DWITH_BENCHMARK=1 .. && make V=1 -j20 && ctest -j20 && make microbench) | .circleci/cat_ignore_eagain
+      - run: (mkdir build && cd build && cmake -DWITH_GFLAGS=1 -DWITH_BENCHMARK=1 .. && make V=1 -j20 && ctest -j20)
      - post-steps

  build-linux-unity-and-headers:
@@ -335,69 +391,82 @@ jobs:
    steps:
      - checkout # check out the code in the project directory
      - run: apt-get update -y && apt-get install -y libgflags-dev
-      - run: TEST_TMPDIR=/dev/shm && make V=1 -j8 unity_test | .circleci/cat_ignore_eagain
-      - run: make V=1 -j8 -k check-headers | .circleci/cat_ignore_eagain # could be moved to a different build
+      - run: TEST_TMPDIR=/dev/shm && make V=1 -j8 unity_test
+      - run: make V=1 -j8 -k check-headers # could be moved to a different build
      - post-steps

-  build-linux-gcc-4_8-no_test_run:
+  build-linux-gcc-7:
    machine:
-      image: ubuntu-1604:202104-01
-    resource_class: large
+      image: ubuntu-2004:202111-02
+    resource_class: 2xlarge
    steps:
      - pre-steps
-      - run: sudo apt-get update -y && sudo apt-get install gcc-4.8 g++-4.8 libgflags-dev
-      - run: CC=gcc-4.8 CXX=g++-4.8 V=1 SKIP_LINK=1 make -j8 all | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
+      - run: sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get update -y && sudo apt-get install gcc-7 g++-7 libgflags-dev
+      - run: CC=gcc-7 CXX=g++-7 V=1 make -j32 check
      - post-steps

  build-linux-gcc-8-no_test_run:
    machine:
-      image: ubuntu-2004:202010-01
-    resource_class: large
+      image: ubuntu-2004:202111-02
+    resource_class: xlarge
    steps:
      - pre-steps
-      - run: sudo apt-get update -y && sudo apt-get install gcc-8 g++-8 libgflags-dev
-      - run: CC=gcc-8 CXX=g++-8 V=1 SKIP_LINK=1 make -j8 all | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
-      - post-steps
-
-  build-linux-gcc-9-no_test_run:
-    machine:
-      image: ubuntu-2004:202010-01
-    resource_class: large
-    steps:
-      - pre-steps
-      - run: sudo apt-get update -y && sudo apt-get install gcc-9 g++-9 libgflags-dev
-      - run: CC=gcc-9 CXX=g++-9 V=1 SKIP_LINK=1 make -j8 all | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
+      - run: sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get update -y && sudo apt-get install gcc-8 g++-8 libgflags-dev
+      - run: CC=gcc-8 CXX=g++-8 V=1 make -j16 all
      - post-steps

  build-linux-gcc-10-cxx20-no_test_run:
    machine:
-      image: ubuntu-2004:202010-01
+      image: ubuntu-2004:202111-02
    resource_class: xlarge
    steps:
      - pre-steps
      - run: sudo apt-get update -y && sudo apt-get install gcc-10 g++-10 libgflags-dev
-      - run: CC=gcc-10 CXX=g++-10 V=1 SKIP_LINK=1 ROCKSDB_CXX_STANDARD=c++20 make -j16 all | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
+      - run: CC=gcc-10 CXX=g++-10 V=1 ROCKSDB_CXX_STANDARD=c++20 make -j16 all
      - post-steps

  build-linux-gcc-11-no_test_run:
    machine:
-      image: ubuntu-2004:202010-01
-    resource_class: xlarge
-    steps:
-      - pre-steps
-      - run: sudo apt-get update -y && sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get install gcc-11 g++-11 libgflags-dev
-      - run: CC=gcc-11 CXX=g++-11 V=1 SKIP_LINK=1 make -j16 all | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
-      - post-steps
-
-  # This job is only to make sure the microbench tests are able to run, the benchmark result is not meaningful as the CI host is changing.
-  build-linux-microbench:
-    machine:
-      image: ubuntu-2004:202010-01
+      image: ubuntu-2004:202111-02
    resource_class: xlarge
    steps:
      - pre-steps
      - install-benchmark
-      - run: DEBUG_LEVEL=0 make microbench | .circleci/cat_ignore_eagain
+      - run: sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get update -y && sudo apt-get install gcc-11 g++-11 libgflags-dev
+      - run: CC=gcc-11 CXX=g++-11 V=1 make -j16 all microbench
+      - post-steps
+
+  build-linux-clang-13-no_test_run:
+    machine:
+      image: ubuntu-2004:202111-02
+    resource_class: xlarge
+    steps:
+      - pre-steps
+      - install-clang-13
+      - install-benchmark
+      - run: CC=clang-13 CXX=clang++-13 USE_CLANG=1 make -j16 all microbench
+      - post-steps
+
+  # This job is only to make sure the microbench tests are able to run, the benchmark result is not meaningful as the CI host is changing.
+  build-linux-run-microbench:
+    machine:
+      image: ubuntu-2004:202111-02
+    resource_class: 2xlarge
+    steps:
+      - pre-steps
+      - install-benchmark
+      - run: DEBUG_LEVEL=0 make -j32 run_microbench
+      - post-steps
+
+  build-linux-mini-crashtest:
+    machine:
+      image: ubuntu-2004:202111-02
+    resource_class: large
+    steps:
+      - pre-steps
+      - install-gflags
+      - install-compression-libs
+      - run: make V=1 -j8 CRASH_TEST_EXT_ARGS=--duration=960 blackbox_crash_test_with_atomic_flush
      - post-steps

  build-windows:
@@ -470,7 +539,7 @@ jobs:

  build-linux-java:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: large
    environment:
      JAVA_HOME: /usr/lib/jvm/java-1.8.0-openjdk-amd64
@@ -486,15 +555,15 @@ jobs:
            which javac && javac -version
      - run:
          name: "Build RocksDBJava Shared Library"
-          command: make V=1 J=8 -j8 rocksdbjava | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 rocksdbjava
      - run:
          name: "Test RocksDBJava"
-          command: make V=1 J=8 -j8 jtest | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 jtest
      - post-steps

  build-linux-java-static:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: large
    environment:
      JAVA_HOME: /usr/lib/jvm/java-1.8.0-openjdk-amd64
@@ -510,19 +579,20 @@ jobs:
            which javac && javac -version
      - run:
          name: "Build RocksDBJava Static Library"
-          command: make V=1 J=8 -j8 rocksdbjavastatic | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 rocksdbjavastatic
      - post-steps

  build-macos-java:
    macos:
-      xcode: 11.3.0
-    resource_class: medium
+      xcode: 12.5.1
+    resource_class: large
    environment:
      JAVA_HOME: /Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home
+      ROCKSDB_DISABLE_JEMALLOC: 1 # jemalloc causes java 8 crash
    steps:
      - increase-max-open-files-on-macos
-      - install-pyenv-on-macos
      - install-gflags-on-macos
+      - install-jdk8-on-macos
      - pre-steps-macos
      - run:
          name: "Set Java Environment"
@@ -533,23 +603,23 @@ jobs:
            which javac && javac -version
      - run:
          name: "Build RocksDBJava Shared Library"
-          command: make V=1 J=8 -j8 rocksdbjava | .circleci/cat_ignore_eagain
+          command: make V=1 J=16 -j16 rocksdbjava
      - run:
          name: "Test RocksDBJava"
-          command: make V=1 J=8 -j8 jtest | .circleci/cat_ignore_eagain
+          command: make V=1 J=16 -j16 jtest
      - post-steps

  build-macos-java-static:
    macos:
-      xcode: 11.3.0
-    resource_class: medium
+      xcode: 12.5.1
+    resource_class: large
    environment:
      JAVA_HOME: /Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home
    steps:
      - increase-max-open-files-on-macos
-      - install-pyenv-on-macos
      - install-gflags-on-macos
      - install-cmake-on-macos
+      - install-jdk8-on-macos
      - pre-steps-macos
      - run:
          name: "Set Java Environment"
@@ -559,13 +629,37 @@ jobs:
            which java && java -version
            which javac && javac -version
      - run:
-          name: "Build RocksDBJava Static Library"
-          command: make V=1 J=8 -j8 rocksdbjavastatic | .circleci/cat_ignore_eagain
+          name: "Build RocksDBJava x86 and ARM Static Libraries"
+          command: make V=1 J=16 -j16 rocksdbjavastaticosx
+      - post-steps
+
+  build-macos-java-static-universal:
+    macos:
+      xcode: 12.5.1
+    resource_class: large
+    environment:
+      JAVA_HOME: /Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home
+    steps:
+      - increase-max-open-files-on-macos
+      - install-gflags-on-macos
+      - install-cmake-on-macos
+      - install-jdk8-on-macos
+      - pre-steps-macos
+      - run:
+          name: "Set Java Environment"
+          command: |
+            echo "JAVA_HOME=${JAVA_HOME}"
+            echo 'export PATH=$JAVA_HOME/bin:$PATH' >> $BASH_ENV
+            which java && java -version
+            which javac && javac -version
+      - run:
+          name: "Build RocksDBJava Universal Binary Static Library"
+          command: make V=1 J=16 -j16 rocksdbjavastaticosx_ub
      - post-steps

  build-examples:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: large
    steps:
      - pre-steps
@@ -573,13 +667,13 @@ jobs:
      - run:
          name: "Build examples"
          command: |
-            OPT=-DTRAVIS V=1 make -j4 static_lib && cd examples && make -j4 | ../.circleci/cat_ignore_eagain
+            OPT=-DTRAVIS V=1 make -j4 static_lib && cd examples && make -j4
      - post-steps

  build-cmake-mingw:
    machine:
-      image: ubuntu-1604:202104-01
-    resource_class: 2xlarge
+      image: ubuntu-2004:202111-02
+    resource_class: large
    steps:
      - pre-steps
      - install-gflags
@@ -601,57 +695,39 @@ jobs:

  build-linux-non-shm:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
-    parameters:
-      start_test:
-        default: ""
-        type: string
-      end_test:
-        default: ""
-        type: string
+    environment:
+      TEST_TMPDIR: /tmp/rocksdb_test_tmp
    steps:
      - pre-steps
      - install-gflags
-      - install-gtest-parallel
-      - run:
-          name: "Build unit tests"
-          command: |
-            echo "env: $(env)"
-            echo "** done env"
-            ROCKSDBTESTS_START=<<parameters.start_test>> ROCKSDBTESTS_END=<<parameters.end_test>> ROCKSDBTESTS_SUBSET_TESTS_TO_FILE=/tmp/test_list make V=1 -j32 --output-sync=target build_subset_tests
-      - run:
-          name: "Run unit tests in parallel"
-          command: |
-            sed -i 's/[[:space:]]*$//; s/ / \.\//g; s/.*/.\/&/' /tmp/test_list
-            cat /tmp/test_list
-            export TEST_TMPDIR=/tmp/rocksdb_test_tmp
-            gtest-parallel $(</tmp/test_list) --output_dir=/tmp | cat  # pipe to cat to continuously output status on circleci UI. Otherwise, no status will be printed while the job is running.
+      - run: make V=1 -j32 check
      - post-steps

  build-linux-arm-test-full:
    machine:
-      image: ubuntu-2004:202101-01
+      image: ubuntu-2004:202111-02
    resource_class: arm.large
    steps:
      - pre-steps
      - install-gflags
-      - run: make V=1 J=4 -j4 check | .circleci/cat_ignore_eagain
+      - run: make V=1 J=4 -j4 check
      - post-steps

  build-linux-arm:
    machine:
-      image: ubuntu-2004:202101-01
+      image: ubuntu-2004:202111-02
    resource_class: arm.large
    steps:
      - pre-steps
      - install-gflags
-      - run: ROCKSDBTESTS_PLATFORM_DEPENDENT=only make V=1 J=4 -j4 all_but_some_tests check_some | .circleci/cat_ignore_eagain
+      - run: ROCKSDBTESTS_PLATFORM_DEPENDENT=only make V=1 J=4 -j4 all_but_some_tests check_some
      - post-steps

  build-linux-arm-cmake-no_test_run:
    machine:
-      image: ubuntu-2004:202101-01
+      image: ubuntu-2004:202111-02
    resource_class: arm.large
    environment:
      JAVA_HOME: /usr/lib/jvm/java-8-openjdk-arm64
@@ -684,7 +760,7 @@ jobs:

  build-format-compatible:
    machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
    resource_class: 2xlarge
    steps:
      - pre-steps
@@ -699,6 +775,23 @@ jobs:
            tools/check_format_compatible.sh
      - post-steps

+  build-fuzzers:
+    machine:
+      image: ubuntu-2004:202111-02
+    resource_class: large
+    steps:
+      - pre-steps
+      - install-clang-13
+      - run: sudo apt-get update -y && sudo apt-get install -y cmake ninja-build binutils liblzma-dev libz-dev pkg-config autoconf libtool
+      - install-libprotobuf-mutator
+      - run:
+          name: "Build rocksdb lib"
+          command: CC=clang-13 CXX=clang++-13 USE_CLANG=1 make -j4 static_lib
+      - run:
+          name: "Build fuzzers"
+          command: cd fuzz && make sst_file_writer_fuzzer db_fuzzer db_map_fuzzer
+      - post-steps
+
 workflows:
  version: 2
  build-linux:
@@ -708,9 +801,6 @@ workflows:
    jobs:
      - build-linux-cmake
      - build-linux-cmake-ubuntu-20
-  build-linux-mem-env:
-    jobs:
-      - build-linux-mem-env
  build-linux-encrypted-env:
    jobs:
      - build-linux-encrypted-env
@@ -734,7 +824,12 @@ workflows:
      - build-linux-clang10-asan
  build-linux-clang10-mini-tsan:
    jobs:
-      - build-linux-clang10-mini-tsan
+      - build-linux-clang10-mini-tsan:
+          start_test: ""
+          end_test: "env_test"
+      - build-linux-clang10-mini-tsan:
+          start_test: "env_test"
+          end_test: ""
  build-linux-clang10-ubsan:
    jobs:
      - build-linux-clang10-ubsan
@@ -744,6 +839,9 @@ workflows:
  build-linux-unity-and-headers:
    jobs:
      - build-linux-unity-and-headers
+  build-linux-mini-crashtest:
+    jobs:
+      - build-linux-mini-crashtest
  build-windows-vs2019:
    jobs:
      - build-windows:
@@ -765,47 +863,35 @@ workflows:
      - build-linux-java-static
      - build-macos-java
      - build-macos-java-static
+      - build-macos-java-static-universal
  build-examples:
    jobs:
      - build-examples
-  build-linux-non-shm:
-    jobs:
-      - build-linux-non-shm:
-          start_test: ""
-          end_test: "db_options_test" # make sure unique in src.mk
-      - build-linux-non-shm:
-          start_test: "db_options_test" # make sure unique in src.mk
-          end_test: "filename_test" # make sure unique in src.mk
-      - build-linux-non-shm:
-          start_test: "filename_test" # make sure unique in src.mk
-          end_test: "statistics_test" # make sure unique in src.mk
-      - build-linux-non-shm:
-          start_test: "statistics_test" # make sure unique in src.mk
-          end_test: ""
  build-linux-compilers-no_test_run:
    jobs:
      - build-linux-clang-no_test_run
-      - build-linux-gcc-4_8-no_test_run
+      - build-linux-clang-13-no_test_run
+      - build-linux-gcc-7
      - build-linux-gcc-8-no_test_run
-      - build-linux-gcc-9-no_test_run
      - build-linux-gcc-10-cxx20-no_test_run
      - build-linux-gcc-11-no_test_run
      - build-linux-arm-cmake-no_test_run
  build-macos:
    jobs:
      - build-macos
-  build-macos-cmake:
-    jobs:
-      - build-macos-cmake
+      - build-macos-cmake:
+          run_even_tests: true
+      - build-macos-cmake:
+          run_even_tests: false
  build-cmake-mingw:
    jobs:
      - build-cmake-mingw
  build-linux-arm:
    jobs:
      - build-linux-arm
-  build-microbench:
+  build-fuzzers:
    jobs:
-      - build-linux-microbench
+      - build-fuzzers
  nightly:
    triggers:
      - schedule:
@@ -817,3 +903,5 @@ workflows:
    jobs:
      - build-format-compatible
      - build-linux-arm-test-full
+      - build-linux-run-microbench
+      - build-linux-non-shm
@@ -32,7 +32,7 @@ jobs:
    - name: Download clang-format-diff.py
      uses: wei/wget@v1
      with:
-        args: https://raw.githubusercontent.com/llvm/llvm-project/main/clang/tools/clang-format/clang-format-diff.py
+        args: https://raw.githubusercontent.com/llvm/llvm-project/release/12.x/clang/tools/clang-format/clang-format-diff.py

    - name: Check format
      run: VERBOSE_CHECK=1 make check-format
@@ -5,6 +5,7 @@ os:
 arch:
  - arm64
  - ppc64le
+  - s390x
 compiler:
  - clang
  - gcc
@@ -42,23 +43,18 @@ env:
  - JOB_NAME=cmake-gcc9 # 3-5 minutes
  - JOB_NAME=cmake-gcc9-c++20 # 3-5 minutes
  - JOB_NAME=cmake-mingw # 3 minutes
-  - JOB_NAME=make-gcc4.8
-  - JOB_NAME=status_checked

 matrix:
  exclude:
  - os : linux
    arch: arm64
    env: JOB_NAME=cmake-mingw
-  - os : linux
-    arch: arm64
-    env: JOB_NAME=make-gcc4.8
  - os: linux
    arch: ppc64le
    env: JOB_NAME=cmake-mingw
  - os: linux
-    arch: ppc64le
-    env: JOB_NAME=make-gcc4.8
+    arch: s390x
+    env: JOB_NAME=cmake-mingw
  - os: linux
    compiler: clang
  - if: type = pull_request AND commit_message !~ /FULL_CI/
@@ -73,6 +69,10 @@ matrix:
    os: linux
    arch: ppc64le
    env: TEST_GROUP=1
+  - if: type = pull_request AND commit_message !~ /FULL_CI/
+    os: linux
+    arch: s390x
+    env: TEST_GROUP=1
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os : linux
    arch: arm64
@@ -81,6 +81,10 @@ matrix:
    os: linux
    arch: ppc64le
    env: TEST_GROUP=2
+  - if: type = pull_request AND commit_message !~ /FULL_CI/
+    os: linux
+    arch: s390x
+    env: TEST_GROUP=2
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os : linux
    arch: arm64
@@ -89,6 +93,10 @@ matrix:
    os: linux
    arch: ppc64le
    env: TEST_GROUP=3
+  - if: type = pull_request AND commit_message !~ /FULL_CI/
+    os: linux
+    arch: s390x
+    env: TEST_GROUP=3
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os : linux
    arch: arm64
@@ -97,6 +105,10 @@ matrix:
    os: linux
    arch: ppc64le
    env: TEST_GROUP=4
+  - if: type = pull_request AND commit_message !~ /FULL_CI/
+    os: linux
+    arch: s390x
+    env: TEST_GROUP=4
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os : linux
    arch: arm64
@@ -109,6 +121,10 @@ matrix:
    os: linux
    arch: ppc64le
    env: JOB_NAME=java_test
+  - if: type = pull_request AND commit_message !~ /FULL_CI/ AND commit_message !~ /java/
+    os: linux
+    arch: s390x
+    env: JOB_NAME=java_test
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os : linux
    arch: arm64
@@ -117,6 +133,10 @@ matrix:
    os: linux
    arch: ppc64le
    env: JOB_NAME=lite_build
+  - if: type = pull_request AND commit_message !~ /FULL_CI/
+    os: linux
+    arch: s390x
+    env: JOB_NAME=lite_build
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os : linux
    arch: arm64
@@ -125,6 +145,10 @@ matrix:
    os: linux
    arch: ppc64le
    env: JOB_NAME=examples
+  - if: type = pull_request AND commit_message !~ /FULL_CI/
+    os: linux
+    arch: s390x
+    env: JOB_NAME=examples
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os : linux
    arch: arm64
@@ -133,6 +157,10 @@ matrix:
    os: linux
    arch: ppc64le
    env: JOB_NAME=cmake-gcc8
+  - if: type = pull_request AND commit_message !~ /FULL_CI/
+    os: linux
+    arch: s390x
+    env: JOB_NAME=cmake-gcc8
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os : linux
    arch: arm64
@@ -141,6 +169,10 @@ matrix:
    os: linux
    arch: ppc64le
    env: JOB_NAME=cmake-gcc9
+  - if: type = pull_request AND commit_message !~ /FULL_CI/
+    os: linux
+    arch: s390x
+    env: JOB_NAME=cmake-gcc9
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os : linux
    arch: arm64
@@ -149,16 +181,13 @@ matrix:
    os: linux
    arch: ppc64le
    env: JOB_NAME=cmake-gcc9-c++20
-  - if: type = pull_request AND commit_message !~ /FULL_CI/
-    os : linux
-    arch: arm64
-    env: JOB_NAME=status_checked
  - if: type = pull_request AND commit_message !~ /FULL_CI/
    os: linux
-    arch: ppc64le
-    env: JOB_NAME=status_checked
+    arch: s390x
+    env: JOB_NAME=cmake-gcc9-c++20

 install:
+  -  CC=gcc-7 && CXX=g++-7
  - if [ "${JOB_NAME}" == cmake-gcc8 ]; then
      sudo apt-get install -y g++-8 || exit $?;
      CC=gcc-8 && CXX=g++-8;
@@ -170,9 +199,8 @@ install:
  - if [ "${JOB_NAME}" == cmake-mingw ]; then
      sudo apt-get install -y mingw-w64 || exit $?;
    fi
-  - if [ "${JOB_NAME}" == make-gcc4.8 ]; then
-      sudo apt-get install -y g++-4.8 || exit $?;
-      CC=gcc-4.8 && CXX=g++-4.8;
+  - if [ "${CXX}" == "g++-7" ]; then
+      sudo apt-get install -y g++-7 || exit $?;
    fi
  - |
    if [[ "${JOB_NAME}" == cmake* ]]; then
@@ -202,21 +230,25 @@ before_script:
 script:
  - date; ${CXX} --version
  - if [ `command -v ccache` ]; then ccache -C; fi
+  - export MK_PARALLEL=4;
+    if [[ "$TRAVIS_CPU_ARCH" == s390x ]]; then
+      export MK_PARALLEL=1;
+    fi
  - case $TEST_GROUP in
    platform_dependent)
-      OPT=-DTRAVIS LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=only make -j4 all_but_some_tests check_some
+      OPT=-DTRAVIS LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=only make -j$MK_PARALLEL all_but_some_tests check_some
      ;;
    1)
-      OPT=-DTRAVIS LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=exclude ROCKSDBTESTS_END=backupable_db_test make -j4 check_some
+      OPT=-DTRAVIS LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=exclude ROCKSDBTESTS_END=backupable_db_test make -j$MK_PARALLEL check_some
      ;;
    2)
-      OPT="-DTRAVIS -DROCKSDB_NAMESPACE=alternative_rocksdb_ns" LIB_MODE=shared V=1 make -j4 tools && OPT="-DTRAVIS -DROCKSDB_NAMESPACE=alternative_rocksdb_ns" LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=exclude ROCKSDBTESTS_START=backupable_db_test ROCKSDBTESTS_END=db_universal_compaction_test make -j4 check_some
+      OPT="-DTRAVIS -DROCKSDB_NAMESPACE=alternative_rocksdb_ns" LIB_MODE=shared V=1 make -j$MK_PARALLEL tools && OPT="-DTRAVIS -DROCKSDB_NAMESPACE=alternative_rocksdb_ns" LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=exclude ROCKSDBTESTS_START=backupable_db_test ROCKSDBTESTS_END=db_universal_compaction_test make -j$MK_PARALLEL check_some
      ;;
    3)
-      OPT=-DTRAVIS LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=exclude ROCKSDBTESTS_START=db_universal_compaction_test ROCKSDBTESTS_END=table_properties_collector_test make -j4 check_some
+      OPT=-DTRAVIS LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=exclude ROCKSDBTESTS_START=db_universal_compaction_test ROCKSDBTESTS_END=table_properties_collector_test make -j$MK_PARALLEL check_some
      ;;
    4)
-      OPT=-DTRAVIS LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=exclude ROCKSDBTESTS_START=table_properties_collector_test make -j4 check_some
+      OPT=-DTRAVIS LIB_MODE=shared V=1 ROCKSDBTESTS_PLATFORM_DEPENDENT=exclude ROCKSDBTESTS_START=table_properties_collector_test make -j$MK_PARALLEL check_some
      ;;
    esac
  - case $JOB_NAME in
@@ -224,10 +256,10 @@ script:
      OPT=-DTRAVIS LIB_MODE=shared V=1 make rocksdbjava jtest
      ;;
    lite_build)
-      OPT='-DTRAVIS -DROCKSDB_LITE' LIB_MODE=shared V=1 make -j4 all
+      OPT='-DTRAVIS -DROCKSDB_LITE' LIB_MODE=shared V=1 make -j$MK_PARALLEL all
      ;;
    examples)
-      OPT=-DTRAVIS LIB_MODE=shared V=1 make -j4 static_lib && cd examples && make -j4
+      OPT=-DTRAVIS LIB_MODE=shared V=1 make -j$MK_PARALLEL static_lib && cd examples && make -j$MK_PARALLEL
      ;;
    cmake-mingw)
      sudo update-alternatives --set x86_64-w64-mingw32-g++ /usr/bin/x86_64-w64-mingw32-g++-posix;
@@ -240,13 +272,7 @@ script:
          ;;
      esac

-      mkdir build && cd build && cmake -DCMAKE_BUILD_TYPE=Release -DWITH_TESTS=0 -DWITH_GFLAGS=0 -DWITH_BENCHMARK_TOOLS=0 -DWITH_TOOLS=0 -DWITH_CORE_TOOLS=1 .. && make -j4 && cd  .. && rm -rf build && mkdir build && cd build && cmake -DJNI=1 .. -DCMAKE_BUILD_TYPE=Release $OPT && make -j4 rocksdb rocksdbjni
-      ;;
-    make-gcc4.8)
-      OPT=-DTRAVIS LIB_MODE=shared V=1 SKIP_LINK=1 make -j4 all && [ "Linking broken because libgflags compiled with newer ABI" ]
-      ;;
-    status_checked)
-      OPT=-DTRAVIS LIB_MODE=shared V=1 ASSERT_STATUS_CHECKED=1 make -j4 check_some
+      mkdir build && cd build && cmake -DCMAKE_BUILD_TYPE=Release -DWITH_TESTS=0 -DWITH_GFLAGS=0 -DWITH_BENCHMARK_TOOLS=0 -DWITH_TOOLS=0 -DWITH_CORE_TOOLS=1 .. && make -j$MK_PARALLEL && cd  .. && rm -rf build && mkdir build && cd build && cmake -DJNI=1 .. -DCMAKE_BUILD_TYPE=Release $OPT && make -j$MK_PARALLEL rocksdb rocksdbjni
      ;;
    esac
 notifications:
@@ -14,7 +14,7 @@
 #        cd build
 # 3. Run cmake to generate project files for Windows, add more options to enable required third-party libraries.
 #    See thirdparty.inc for more information.
-#        sample command: cmake -G "Visual Studio 15 Win64" -DCMAKE_BUILD_TYPE=Release -DWITH_GFLAGS=1 -DWITH_SNAPPY=1 -DWITH_JEMALLOC=1 -DWITH_JNI=1 ..
+#        sample command: cmake -G "Visual Studio 16 2019" -DCMAKE_BUILD_TYPE=Release -DWITH_GFLAGS=1 -DWITH_SNAPPY=1 -DWITH_JEMALLOC=1 -DWITH_JNI=1 ..
 # 4. Then build the project in debug mode (you may want to add /m[:<N>] flag to run msbuild in <N> parallel threads
 #                                          or simply /m to use all avail cores)
 #        msbuild rocksdb.sln
@@ -27,7 +27,7 @@
 #
 # Linux:
 #
-# 1. Install a recent toolchain such as devtoolset-3 if you're on a older distro. C++11 required.
+# 1. Install a recent toolchain if you're on a older distro. C++17 required (GCC >= 7, Clang >= 5)
 # 2. mkdir build; cd build
 # 3. cmake ..
 # 4. make -j
@@ -92,7 +92,7 @@ else()
 endif()

 if( NOT DEFINED CMAKE_CXX_STANDARD )
-  set(CMAKE_CXX_STANDARD 11)
+  set(CMAKE_CXX_STANDARD 17)
 endif()

 include(CMakeDependentOption)
@@ -219,7 +219,7 @@ if(MSVC)
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FC /d2Zi+ /W4 /wd4127 /wd4800 /wd4996 /wd4351 /wd4100 /wd4204 /wd4324")
 else()
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -W -Wextra -Wall -pthread")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-compare -Wshadow -Wno-unused-parameter -Wno-unused-variable -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers -Wno-strict-aliasing")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-compare -Wshadow -Wno-unused-parameter -Wno-unused-variable -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers -Wno-strict-aliasing -Wno-invalid-offsetof")
  if(CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64")
    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wstrict-prototypes")
  endif()
@@ -267,6 +267,13 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "arm64|aarch64|AARCH64")
  endif(HAS_ARMV8_CRC)
 endif(CMAKE_SYSTEM_PROCESSOR MATCHES "arm64|aarch64|AARCH64")

+if(CMAKE_SYSTEM_PROCESSOR MATCHES "s390x")
+  CHECK_C_COMPILER_FLAG("-march=native" HAS_S390X_MARCH_NATIVE)
+  if(HAS_S390X_MARCH_NATIVE)
+    message(STATUS " HAS_S390X_MARCH_NATIVE yes")
+  endif(HAS_S390X_MARCH_NATIVE)
+endif(CMAKE_SYSTEM_PROCESSOR MATCHES "s390x")
+
 option(PORTABLE "build a portable binary" OFF)
 option(FORCE_SSE42 "force building with SSE4.2, even when PORTABLE=ON" OFF)
 option(FORCE_AVX "force building with AVX, even when PORTABLE=ON" OFF)
@@ -292,12 +299,17 @@ if(PORTABLE)
    if(FORCE_AVX2)
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mavx2 -mbmi -mlzcnt")
    endif()
+    if(CMAKE_SYSTEM_PROCESSOR MATCHES "^s390x")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=z196")
+    endif()
  endif()
 else()
  if(MSVC)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /arch:AVX2")
  else()
-    if(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "^(powerpc|ppc)64" AND NOT HAS_ARMV8_CRC)
+    if(CMAKE_SYSTEM_PROCESSOR MATCHES "^s390x" AND NOT HAS_S390X_MARCH_NATIVE)
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=z196")
+    elseif(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "^(powerpc|ppc)64" AND NOT HAS_ARMV8_CRC)
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native")
    endif()
  endif()
@@ -309,7 +321,8 @@ if(NOT MSVC)
  set(CMAKE_REQUIRED_FLAGS "-msse4.2 -mpclmul")
 endif()

-CHECK_CXX_SOURCE_COMPILES("
+if (NOT PORTABLE OR FORCE_SSE42)
+  CHECK_CXX_SOURCE_COMPILES("
 #include <cstdint>
 #include <nmmintrin.h>
 #include <wmmintrin.h>
@@ -321,16 +334,17 @@ int main() {
  auto d = _mm_cvtsi128_si64(c);
 }
 " HAVE_SSE42)
-if(HAVE_SSE42)
-  add_definitions(-DHAVE_SSE42)
-  add_definitions(-DHAVE_PCLMUL)
-elseif(FORCE_SSE42)
-  message(FATAL_ERROR "FORCE_SSE42=ON but unable to compile with SSE4.2 enabled")
+  if(HAVE_SSE42)
+    add_definitions(-DHAVE_SSE42)
+    add_definitions(-DHAVE_PCLMUL)
+  elseif(FORCE_SSE42)
+    message(FATAL_ERROR "FORCE_SSE42=ON but unable to compile with SSE4.2 enabled")
+  endif()
 endif()

 # Check if -latomic is required or not
 if (NOT MSVC)
-  set(CMAKE_REQUIRED_FLAGS "--std=c++11")
+  set(CMAKE_REQUIRED_FLAGS "--std=c++17")
  CHECK_CXX_SOURCE_COMPILES("
 #include <atomic>
 std::atomic<uint64_t> x(0);
@@ -340,43 +354,25 @@ int main() {
  return 0;
 }
 " BUILTIN_ATOMIC)
-if (NOT BUILTIN_ATOMIC)
-  #TODO: Check if -latomic exists
-  list(APPEND THIRDPARTY_LIBS atomic)
-endif()
+  if (NOT BUILTIN_ATOMIC)
+    #TODO: Check if -latomic exists
+    list(APPEND THIRDPARTY_LIBS atomic)
+  endif()
 endif()

 if (WITH_LIBURING)
-  set(CMAKE_REQUIRED_FLAGS "-luring")
-  CHECK_CXX_SOURCE_COMPILES("
-#include <liburing.h>
-int main() {
-  struct io_uring ring;
-  io_uring_queue_init(1, &ring, 0);
-  return 0;
-}
-" HAS_LIBURING)
-  if (HAS_LIBURING)
+  find_package(uring)
+  if (uring_FOUND)
    add_definitions(-DROCKSDB_IOURING_PRESENT)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -luring")
+    list(APPEND THIRDPARTY_LIBS uring::uring)
  endif()
 endif()

 # Reset the required flags
 set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})

-CHECK_CXX_SOURCE_COMPILES("
-#if defined(_MSC_VER) && !defined(__thread)
-#define __thread __declspec(thread)
-#endif
-int main() {
-  static __thread int tls;
-  (void)tls;
-}
-" HAVE_THREAD_LOCAL)
-if(HAVE_THREAD_LOCAL)
-  add_definitions(-DROCKSDB_SUPPORT_THREAD_LOCAL)
-endif()
+# thread_local is part of C++11 and later (TODO: clean up this define)
+add_definitions(-DROCKSDB_SUPPORT_THREAD_LOCAL)

 option(WITH_IOSTATS_CONTEXT "Enable IO stats context" ON)
 if (NOT WITH_IOSTATS_CONTEXT)
@@ -409,7 +405,7 @@ endif()

 option(WITH_TSAN "build with TSAN" OFF)
 if(WITH_TSAN)
-  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fsanitize=thread -pie")
+  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fsanitize=thread -Wl,-pie")
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=thread -fPIC")
  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=thread -fPIC")
  if(WITH_JEMALLOC)
@@ -612,6 +608,11 @@ if(HAVE_AUXV_GETAUXVAL)
  add_definitions(-DROCKSDB_AUXV_GETAUXVAL_PRESENT)
 endif()

+check_cxx_symbol_exists(F_FULLFSYNC "fcntl.h" HAVE_FULLFSYNC)
+if(HAVE_FULLFSYNC)
+  add_definitions(-DHAVE_FULLFSYNC)
+endif()
+
 include_directories(${PROJECT_SOURCE_DIR})
 include_directories(${PROJECT_SOURCE_DIR}/include)
 if(WITH_FOLLY_DISTRIBUTED_MUTEX)
@@ -624,9 +625,11 @@ find_package(Threads REQUIRED)
 set(SOURCES
        cache/cache.cc
        cache/cache_entry_roles.cc
+        cache/cache_key.cc
        cache/cache_reservation_manager.cc
        cache/clock_cache.cc
        cache/lru_cache.cc
+        cache/lru_secondary_cache.cc
        cache/sharded_cache.cc
        db/arena_wrapped_db_iter.cc
        db/blob/blob_fetcher.cc
@@ -640,6 +643,7 @@ set(SOURCES
        db/blob/blob_log_format.cc
        db/blob/blob_log_sequential_reader.cc
        db/blob/blob_log_writer.cc
+        db/blob/prefetch_buffer_collection.cc
        db/builder.cc
        db/c.cc
        db/column_family.cc
@@ -708,7 +712,6 @@ set(SOURCES
        env/env.cc
        env/env_chroot.cc
        env/env_encryption.cc
-        env/env_hdfs.cc
        env/file_system.cc
        env/file_system_tracer.cc
        env/fs_remap.cc
@@ -732,6 +735,7 @@ set(SOURCES
        memory/concurrent_arena.cc
        memory/jemalloc_nodump_allocator.cc
        memory/memkind_kmem_allocator.cc
+        memory/memory_allocator.cc
        memtable/alloc_tracker.cc
        memtable/hash_linklist_rep.cc
        memtable/hash_skiplist_rep.cc
@@ -828,6 +832,7 @@ set(SOURCES
        util/coding.cc
        util/compaction_job_stats_impl.cc
        util/comparator.cc
+        util/compression.cc
        util/compression_context_cache.cc
        util/concurrent_task_limiter_impl.cc
        util/crc32c.cc
@@ -837,7 +842,6 @@ set(SOURCES
        util/random.cc
        util/rate_limiter.cc
        util/ribbon_config.cc
-        util/regex.cc
        util/slice.cc
        util/file_checksum_helper.cc
        util/status.cc
@@ -860,11 +864,13 @@ set(SOURCES
        utilities/checkpoint/checkpoint_impl.cc
        utilities/compaction_filters.cc
        utilities/compaction_filters/remove_emptyvalue_compactionfilter.cc
+        utilities/counted_fs.cc
        utilities/debug.cc
        utilities/env_mirror.cc
        utilities/env_timed.cc
        utilities/fault_injection_env.cc
        utilities/fault_injection_fs.cc
+        utilities/fault_injection_secondary_cache.cc
        utilities/leveldb_options/leveldb_options.cc
        utilities/memory/memory_util.cc
        utilities/merge_operators.cc
@@ -924,6 +930,31 @@ list(APPEND SOURCES
  utilities/transactions/lock/range/range_tree/lib/util/dbt.cc
  utilities/transactions/lock/range/range_tree/lib/util/memarena.cc)

+message(STATUS "ROCKSDB_PLUGINS: ${ROCKSDB_PLUGINS}")
+if ( ROCKSDB_PLUGINS )
+  string(REPLACE " " ";" PLUGINS ${ROCKSDB_PLUGINS})
+  foreach (plugin ${PLUGINS})
+    add_subdirectory("plugin/${plugin}")
+    foreach (src ${${plugin}_SOURCES})
+      list(APPEND SOURCES plugin/${plugin}/${src})
+      set_source_files_properties(
+        plugin/${plugin}/${src}
+        PROPERTIES COMPILE_FLAGS "${${plugin}_COMPILE_FLAGS}")
+    endforeach()
+    foreach (path ${${plugin}_INCLUDE_PATHS})
+      include_directories(${path})
+    endforeach()
+    foreach (lib ${${plugin}_LIBS})
+      list(APPEND THIRDPARTY_LIBS ${lib})
+    endforeach()
+    foreach (link_path ${${plugin}_LINK_PATHS})
+      link_directories(AFTER ${link_path})
+    endforeach()
+    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${${plugin}_CMAKE_SHARED_LINKER_FLAGS}")
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${${plugin}_CMAKE_EXE_LINKER_FLAGS}")
+  endforeach()
+endif()
+
 if(HAVE_SSE42 AND NOT MSVC)
  set_source_files_properties(
    util/crc32c.cc
@@ -981,12 +1012,6 @@ set(ROCKSDB_SHARED_LIB rocksdb-shared${ARTIFACT_SUFFIX})

 option(ROCKSDB_BUILD_SHARED "Build shared versions of the RocksDB libraries" ON)

-option(WITH_LIBRADOS "Build with librados" OFF)
-if(WITH_LIBRADOS)
-  list(APPEND SOURCES
-    utilities/env_librados.cc)
-  list(APPEND THIRDPARTY_LIBS rados)
-endif()

 if(WIN32)
  set(SYSTEM_LIBS ${SYSTEM_LIBS} shlwapi.lib rpcrt4.lib)
@@ -1133,6 +1158,7 @@ if(WITH_TESTS)
        cache/cache_reservation_manager_test.cc
        cache/cache_test.cc
        cache/lru_cache_test.cc
+        cache/lru_secondary_cache_test.cc
        db/blob/blob_counting_iterator_test.cc
        db/blob/blob_file_addition_test.cc
        db/blob/blob_file_builder_test.cc
@@ -1161,6 +1187,7 @@ if(WITH_TESTS)
        db/db_compaction_filter_test.cc
        db/db_compaction_test.cc
        db/db_dynamic_level_test.cc
+        db/db_encryption_test.cc
        db/db_flush_test.cc
        db/db_inplace_update_test.cc
        db/db_io_failure_test.cc
@@ -1175,6 +1202,7 @@ if(WITH_TESTS)
        db/db_options_test.cc
        db/db_properties_test.cc
        db/db_range_del_test.cc
+        db/db_rate_limiter_test.cc
        db/db_secondary_test.cc
        db/db_sst_test.cc
        db/db_statistics_test.cc
@@ -1186,6 +1214,7 @@ if(WITH_TESTS)
        db/db_universal_compaction_test.cc
        db/db_wal_test.cc
        db/db_with_timestamp_compaction_test.cc
+        db/db_write_buffer_manager_test.cc
        db/db_write_test.cc
        db/dbformat_test.cc
        db/deletefile_test.cc
@@ -1197,6 +1226,7 @@ if(WITH_TESTS)
        db/file_indexer_test.cc
        db/filename_test.cc
        db/flush_job_test.cc
+        db/import_column_family_test.cc
        db/listener_test.cc
        db/log_test.cc
        db/manual_compaction_test.cc
@@ -1230,7 +1260,7 @@ if(WITH_TESTS)
        logging/env_logger_test.cc
        logging/event_logger_test.cc
        memory/arena_test.cc
-        memory/memkind_kmem_allocator_test.cc
+        memory/memory_allocator_test.cc
        memtable/inlineskiplist_test.cc
        memtable/skiplist_test.cc
        memtable/write_buffer_manager_test.cc
@@ -1292,6 +1322,7 @@ if(WITH_TESTS)
        utilities/cassandra/cassandra_row_merge_test.cc
        utilities/cassandra/cassandra_serialize_test.cc
        utilities/checkpoint/checkpoint_test.cc
+        utilities/env_timed_test.cc
        utilities/memory/memory_test.cc
        utilities/merge_operators/string_append/stringappend_test.cc
        utilities/object_registry_test.cc
@@ -1305,16 +1336,15 @@ if(WITH_TESTS)
        utilities/transactions/optimistic_transaction_test.cc
        utilities/transactions/transaction_test.cc
        utilities/transactions/lock/point/point_lock_manager_test.cc
+        utilities/transactions/write_committed_transaction_ts_test.cc
        utilities/transactions/write_prepared_transaction_test.cc
        utilities/transactions/write_unprepared_transaction_test.cc
        utilities/transactions/lock/range/range_locking_test.cc
        utilities/ttl/ttl_test.cc
+        utilities/util_merge_operators_test.cc
        utilities/write_batch_with_index/write_batch_with_index_test.cc
    )
  endif()
-  if(WITH_LIBRADOS)
-    list(APPEND TESTS utilities/env_librados_test.cc)
-  endif()

  if(WITH_FOLLY_DISTRIBUTED_MUTEX)
    list(APPEND TESTS third-party/folly/folly/synchronization/test/DistributedMutexTest.cpp)
@@ -1354,10 +1384,6 @@ if(WITH_TESTS)
        gtest_discover_tests(${exename} DISCOVERY_TIMEOUT 120)
        add_dependencies(check ${exename}${ARTIFACT_SUFFIX})
      endif()
-      if("${exename}" MATCHES "env_librados_test")
-        # env_librados_test.cc uses librados directly
-        target_link_libraries(${exename}${ARTIFACT_SUFFIX} rados)
-      endif()
  endforeach(sourcefile ${TESTS})

  if(WIN32)
@@ -1,4 +1,4 @@
-# RocksDB default options change log
+# RocksDB default options change log (NO LONGER MAINTAINED)
 ## Unreleased
 * delayed_write_rate takes the rate given by rate_limiter if not specified.

@@ -1,4 +1,235 @@
 # Rocksdb Change Log
+## 7.1.0 (03/23/2022)
+### New Features
+* Allow WriteBatchWithIndex to index a WriteBatch that includes keys with user-defined timestamps. The index itself does not have timestamp.
+* Add support for user-defined timestamps to write-committed transaction without API change. The `TransactionDB` layer APIs do not allow timestamps because we require that all user-defined-timestamps-aware operations go through the `Transaction` APIs.
+* Added BlobDB options to `ldb`
+* `BlockBasedTableOptions::detect_filter_construct_corruption` can now be dynamically configured using `DB::SetOptions`.
+* Automatically recover from retryable read IO errors during backgorund flush/compaction.
+* Experimental support for preserving file Temperatures through backup and restore, and for updating DB metadata for outside changes to file Temperature (`UpdateManifestForFilesState` or `ldb update_manifest --update_temperatures`).
+* Experimental support for async_io in ReadOptions which is used by FilePrefetchBuffer to prefetch some of the data asynchronously,  if reads are sequential and auto readahead is enabled by rocksdb internally.
+
+### Bug Fixes
+* Fixed a major performance bug in which Bloom filters generated by pre-7.0 releases are not read by early 7.0.x releases (and vice-versa) due to changes to FilterPolicy::Name() in #9590. This can severely impact read performance and read I/O on upgrade or downgrade with existing DB, but not data correctness.
+* Fixed a data race on `versions_` between `DBImpl::ResumeImpl()` and threads waiting for recovery to complete (#9496)
+* Fixed a bug caused by race among flush, incoming writes and taking snapshots. Queries to snapshots created with these race condition can return incorrect result, e.g. resurfacing deleted data.
+* Fixed a bug that DB flush uses `options.compression` even `options.compression_per_level` is set.
+* Fixed a bug that DisableManualCompaction may assert when disable an unscheduled manual compaction.
+* Fix a race condition when cancel manual compaction with `DisableManualCompaction`. Also DB close can cancel the manual compaction thread.
+* Fixed a potential timer crash when open close DB concurrently.
+* Fixed a race condition for `alive_log_files_` in non-two-write-queues mode. The race is between the write_thread_ in WriteToWAL() and another thread executing `FindObsoleteFiles()`. The race condition will be caught if `__glibcxx_requires_nonempty` is enabled.
+* Fixed a bug that `Iterator::Refresh()` reads stale keys after DeleteRange() performed.
+* Fixed a race condition when disable and re-enable manual compaction.
+* Fixed automatic error recovery failure in atomic flush.
+* Fixed a race condition when mmaping a WritableFile on POSIX.
+
+### Public API changes
+* Added pure virtual FilterPolicy::CompatibilityName(), which is needed for fixing major performance bug involving FilterPolicy naming in SST metadata without affecting Customizable aspect of FilterPolicy. This change only affects those with their own custom or wrapper FilterPolicy classes.
+* `options.compression_per_level` is dynamically changeable with `SetOptions()`.
+* Added `WriteOptions::rate_limiter_priority`. When set to something other than `Env::IO_TOTAL`, the internal rate limiter (`DBOptions::rate_limiter`) will be charged at the specified priority for writes associated with the API to which the `WriteOptions` was provided. Currently the support covers automatic WAL flushes, which happen during live updates (`Put()`, `Write()`, `Delete()`, etc.) when `WriteOptions::disableWAL == false` and `DBOptions::manual_wal_flush == false`.
+* Add DB::OpenAndTrimHistory API. This API will open DB and trim data to the timestamp specified by trim_ts (The data with timestamp larger than specified trim bound will be removed). This API should only be used at a timestamp-enabled column families recovery. If the column family doesn't have timestamp enabled, this API won't trim any data on that column family. This API is not compatible with avoid_flush_during_recovery option.
+* Remove BlockBasedTableOptions.hash_index_allow_collision which already takes no effect.
+
+## 7.0.0 (02/20/2022)
+### Bug Fixes
+* Fixed a major bug in which batched MultiGet could return old values for keys deleted by DeleteRange when memtable Bloom filter is enabled (memtable_prefix_bloom_size_ratio > 0). (The fix includes a substantial MultiGet performance improvement in the unusual case of both memtable_whole_key_filtering and prefix_extractor.)
+* Fixed more cases of EventListener::OnTableFileCreated called with OK status, file_size==0, and no SST file kept. Now the status is Aborted.
+* Fixed a read-after-free bug in `DB::GetMergeOperands()`.
+* Fix a data loss bug for 2PC write-committed transaction caused by concurrent transaction commit and memtable switch (#9571).
+* Fixed NUM_INDEX_AND_FILTER_BLOCKS_READ_PER_LEVEL, NUM_DATA_BLOCKS_READ_PER_LEVEL, and NUM_SST_READ_PER_LEVEL stats to be reported once per MultiGet batch per level.
+
+### Performance Improvements
+* Mitigated the overhead of building the file location hash table used by the online LSM tree consistency checks, which can improve performance for certain workloads (see #9351).
+* Switched to using a sorted `std::vector` instead of `std::map` for storing the metadata objects for blob files, which can improve performance for certain workloads, especially when the number of blob files is high.
+* DisableManualCompaction() doesn't have to wait scheduled manual compaction to be executed in thread-pool to cancel the job.
+
+### Public API changes
+* Require C++17 compatible compiler (GCC >= 7, Clang >= 5, Visual Studio >= 2017) for compiling RocksDB and any code using RocksDB headers. See #9388.
+* Added `ReadOptions::rate_limiter_priority`. When set to something other than `Env::IO_TOTAL`, the internal rate limiter (`DBOptions::rate_limiter`) will be charged at the specified priority for file reads associated with the API to which the `ReadOptions` was provided.
+* Remove HDFS support from main repo.
+* Remove librados support from main repo.
+* Remove obsolete backupable_db.h and type alias `BackupableDBOptions`. Use backup_engine.h and `BackupEngineOptions`. Similar renamings are in the C and Java APIs.
+* Removed obsolete utility_db.h and `UtilityDB::OpenTtlDB`. Use db_ttl.h and `DBWithTTL::Open`.
+* Remove deprecated API DB::AddFile from main repo.
+* Remove deprecated API ObjectLibrary::Register() and the (now obsolete) Regex public API. Use ObjectLibrary::AddFactory() with PatternEntry instead.
+* Remove deprecated option DBOption::table_cache_remove_scan_count_limit.
+* Remove deprecated API AdvancedColumnFamilyOptions::soft_rate_limit.
+* Remove deprecated API AdvancedColumnFamilyOptions::hard_rate_limit.
+* Remove deprecated API DBOption::base_background_compactions.
+* Remove deprecated API DBOptions::purge_redundant_kvs_while_flush.
+* Remove deprecated overloads of API DB::CompactRange.
+* Remove deprecated option DBOptions::skip_log_error_on_recovery.
+* Remove ReadOptions::iter_start_seqnum which has been deprecated.
+* Remove DBOptions::preserved_deletes and DB::SetPreserveDeletesSequenceNumber().
+* Remove deprecated API AdvancedColumnFamilyOptions::rate_limit_delay_max_milliseconds.
+* Removed timestamp from WriteOptions. Accordingly, added to DB APIs Put, Delete, SingleDelete, etc. accepting an additional argument 'timestamp'. Added Put, Delete, SingleDelete, etc to WriteBatch accepting an additional argument 'timestamp'. Removed WriteBatch::AssignTimestamps(vector<Slice>) API. Renamed WriteBatch::AssignTimestamp() to WriteBatch::UpdateTimestamps() with clarified comments.
+* Changed type of cache buffer passed to `Cache::CreateCallback` from `void*` to `const void*`.
+* Significant updates to FilterPolicy-related APIs and configuration:
+  * Remove public API support for deprecated, inefficient block-based filter (use_block_based_builder=true).
+    * Old code and configuration strings that would enable it now quietly enable full filters instead, though any built-in FilterPolicy can still read block-based filters. This includes changing the longstanding default behavior of the Java API.
+    * Remove deprecated FilterPolicy::CreateFilter() and FilterPolicy::KeyMayMatch()
+    * Remove `rocksdb_filterpolicy_create()` from C API, as the only C API support for custom filter policies is now obsolete.
+    * If temporary memory usage in full filter creation is a problem, consider using partitioned filters, smaller SST files, or setting reserve_table_builder_memory=true.
+  * Remove support for "filter_policy=experimental_ribbon" configuration
+  string. Use something like "filter_policy=ribbonfilter:10" instead.
+  * Allow configuration string like "filter_policy=bloomfilter:10" without
+  bool, to minimize acknowledgement of obsolete block-based filter.
+  * Made FilterPolicy Customizable. Configuration of filter_policy is now accurately saved in OPTIONS file and can be loaded with LoadOptionsFromFile. (Loading an OPTIONS file generated by a previous version only enables reading and using existing filters, not generating new filters. Previously, no filter_policy would be configured from a saved OPTIONS file.)
+  * Change meaning of nullptr return from GetBuilderWithContext() from "use
+    block-based filter" to "generate no filter in this case."
+    * Also, when user specifies bits_per_key < 0.5, we now round this down
+    to "no filter" because we expect a filter with >= 80% FP rate is
+    unlikely to be worth the CPU cost of accessing it (esp with
+    cache_index_and_filter_blocks=1 or partition_filters=1).
+    * bits_per_key >= 0.5 and < 1.0 is still rounded up to 1.0 (for 62% FP
+    rate)
+  * Remove class definitions for FilterBitsBuilder and FilterBitsReader from
+    public API, so these can evolve more easily as implementation details.
+    Custom FilterPolicy can still decide what kind of built-in filter to use
+    under what conditions.
+  * Also removed deprecated functions
+    * FilterPolicy::GetFilterBitsBuilder()
+    * NewExperimentalRibbonFilterPolicy()
+  * Remove default implementations of
+    * FilterPolicy::GetBuilderWithContext()
+* Remove default implementation of Name() from FileSystemWrapper.
+* Rename `SizeApproximationOptions.include_memtabtles` to `SizeApproximationOptions.include_memtables`.
+* Remove deprecated option DBOptions::max_mem_compaction_level.
+* Return Status::InvalidArgument from ObjectRegistry::NewObject if a factory exists but the object ould not be created (returns NotFound if the factory is missing).
+* Remove deprecated overloads of API DB::GetApproximateSizes.
+* Remove deprecated option DBOptions::new_table_reader_for_compaction_inputs.
+* Add Transaction::SetReadTimestampForValidation() and Transaction::SetCommitTimestamp(). Default impl returns NotSupported().
+* Add support for decimal patterns to ObjectLibrary::PatternEntry
+* Remove deprecated remote compaction APIs `CompactionService::Start()` and `CompactionService::WaitForComplete()`. Please use `CompactionService::StartV2()`, `CompactionService::WaitForCompleteV2()` instead, which provides the same information plus extra data like priority, db_id, etc.
+* `ColumnFamilyOptions::OldDefaults` and `DBOptions::OldDefaults` are marked deprecated, as they are no longer maintained.
+* Add subcompaction callback APIs: `OnSubcompactionBegin()` and `OnSubcompactionCompleted()`.
+* Add file Temperature information to `FileOperationInfo` in event listener API.
+* Change the type of SizeApproximationFlags from enum to enum class. Also update the signature of DB::GetApproximateSizes API from uint8_t to SizeApproximationFlags.
+* Add Temperature hints information from RocksDB in API `NewSequentialFile()`. backup and checkpoint operations need to open the source files with `NewSequentialFile()`, which will have the temperature hints. Other operations are not covered.
+
+### Behavior Changes
+* Disallow the combination of DBOptions.use_direct_io_for_flush_and_compaction == true and DBOptions.writable_file_max_buffer_size == 0. This combination can cause WritableFileWriter::Append() to loop forever, and it does not make much sense in direct IO.
+* `ReadOptions::total_order_seek` no longer affects `DB::Get()`. The original motivation for this interaction has been obsolete since RocksDB has been able to detect whether the current prefix extractor is compatible with that used to generate table files, probably RocksDB 5.14.0.
+
+## New Features
+* Introduced an option `BlockBasedTableOptions::detect_filter_construct_corruption` for detecting corruption during Bloom Filter (format_version >= 5) and Ribbon Filter construction.
+* Improved the SstDumpTool to read the comparator from table properties and use it to read the SST File.
+* Extended the column family statistics in the info log so the total amount of garbage in the blob files and the blob file space amplification factor are also logged. Also exposed the blob file space amp via the `rocksdb.blob-stats` DB property.
+* Introduced the API rocksdb_create_dir_if_missing in c.h that calls underlying file system's CreateDirIfMissing API to create the directory.
+* Added last level and non-last level read statistics: `LAST_LEVEL_READ_*`, `NON_LAST_LEVEL_READ_*`.
+* Experimental: Add support for new APIs ReadAsync in FSRandomAccessFile that reads the data asynchronously and Poll API in FileSystem that checks if requested read request has completed or not. ReadAsync takes a callback function. Poll API checks for completion of read IO requests and  should call callback functions to indicate completion of read requests.
+
+## 6.29.0 (01/21/2022)
+Note: The next release will be major release 7.0. See https://github.com/facebook/rocksdb/issues/9390 for more info.
+### Public API change
+* Added values to `TraceFilterType`: `kTraceFilterIteratorSeek`, `kTraceFilterIteratorSeekForPrev`, and `kTraceFilterMultiGet`. They can be set in `TraceOptions` to filter out the operation types after which they are named.
+* Added `TraceOptions::preserve_write_order`. When enabled it  guarantees write records are traced in the same order they are logged to WAL and applied to the DB. By default it is disabled (false) to match the legacy behavior and prevent regression.
+* Made the Env class extend the Customizable class.  Implementations need to be registered with the ObjectRegistry and to implement a Name() method in order to be created via this method.
+* `Options::OldDefaults` is marked deprecated, as it is no longer maintained.
+* Add ObjectLibrary::AddFactory and ObjectLibrary::PatternEntry classes.  This method and associated class are the preferred mechanism for registering factories with the ObjectLibrary going forward.  The ObjectLibrary::Register method, which uses regular expressions and may be problematic, is deprecated and will be in a future release.
+* Changed `BlockBasedTableOptions::block_size` from `size_t` to `uint64_t`.
+* Added API warning against using `Iterator::Refresh()` together with `DB::DeleteRange()`, which are incompatible and have always risked causing the refreshed iterator to return incorrect results.
+* Made `AdvancedColumnFamilyOptions.bottommost_temperature` dynamically changeable with `SetOptions()`.
+
+### Behavior Changes
+* `DB::DestroyColumnFamilyHandle()` will return Status::InvalidArgument() if called with `DB::DefaultColumnFamily()`.
+* On 32-bit platforms, mmap reads are no longer quietly disabled, just discouraged.
+
+### New Features
+* Added `Options::DisableExtraChecks()` that can be used to improve peak write performance by disabling checks that should not be necessary in the absence of software logic errors or CPU+memory hardware errors. (Default options are slowly moving toward some performance overheads for extra correctness checking.)
+
+### Performance Improvements
+* Improved read performance when a prefix extractor is used (Seek, Get, MultiGet), even compared to version 6.25 baseline (see bug fix below), by optimizing the common case of prefix extractor compatible with table file and unchanging.
+
+### Bug Fixes
+* Fix a bug that FlushMemTable may return ok even flush not succeed.
+* Fixed a bug of Sync() and Fsync() not using `fcntl(F_FULLFSYNC)` on OS X and iOS.
+* Fixed a significant performance regression in version 6.26 when a prefix extractor is used on the read path (Seek, Get, MultiGet). (Excessive time was spent in SliceTransform::AsString().)
+* Fixed a race condition in SstFileManagerImpl error recovery code that can cause a crash during process shutdown.
+
+### New Features
+* Added RocksJava support for MacOS universal binary (ARM+x86)
+
+## 6.28.0 (2021-12-17)
+### New Features
+* Introduced 'CommitWithTimestamp' as a new tag. Currently, there is no API for user to trigger a write with this tag to the WAL. This is part of the efforts to support write-commited transactions with user-defined timestamps.
+* Introduce SimulatedHybridFileSystem which can help simulating HDD latency in db_bench. Tiered Storage latency simulation can be enabled using -simulate_hybrid_fs_file (note that it doesn't work if db_bench is interrupted in the middle). -simulate_hdd can also be used to simulate all files on HDD.
+
+### Bug Fixes
+* Fixed a bug in rocksdb automatic implicit prefetching which got broken because of new feature adaptive_readahead and internal prefetching got disabled when iterator moves from one file to next.
+* Fixed a bug in TableOptions.prepopulate_block_cache which causes segmentation fault when used with TableOptions.partition_filters = true and TableOptions.cache_index_and_filter_blocks = true.
+* Fixed a bug affecting custom memtable factories which are not registered with the `ObjectRegistry`. The bug could result in failure to save the OPTIONS file.
+* Fixed a bug causing two duplicate entries to be appended to a file opened in non-direct mode and tracked by `FaultInjectionTestFS`.
+* Fixed a bug in TableOptions.prepopulate_block_cache to support block-based filters also.
+* Block cache keys no longer use `FSRandomAccessFile::GetUniqueId()` (previously used when available), so a filesystem recycling unique ids can no longer lead to incorrect result or crash (#7405). For files generated by RocksDB >= 6.24, the cache keys are stable across DB::Open and DB directory move / copy / import / export / migration, etc. Although collisions are still theoretically possible, they are (a) impossible in many common cases, (b) not dependent on environmental factors, and (c) much less likely than a CPU miscalculation while executing RocksDB.
+* Fixed a bug in C bindings causing iterator to return incorrect result (#9343).
+
+### Behavior Changes
+* MemTableList::TrimHistory now use allocated bytes when max_write_buffer_size_to_maintain > 0(default in TrasactionDB, introduced in PR#5022) Fix #8371.
+
+### Public API change
+* Extend WriteBatch::AssignTimestamp and AssignTimestamps API so that both functions can accept an optional `checker` argument that performs additional checking on timestamp sizes.
+* Introduce a new EventListener callback that will be called upon the end of automatic error recovery.
+* Add IncreaseFullHistoryTsLow API so users can advance each column family's full_history_ts_low seperately.
+* Add GetFullHistoryTsLow API so users can query current full_history_low value of specified column family.
+
+### Performance Improvements
+* Replaced map property `TableProperties::properties_offsets`  with uint64_t property `external_sst_file_global_seqno_offset` to save table properties's memory.
+* Block cache accesses are faster by RocksDB using cache keys of fixed size (16 bytes).
+
+### Java API Changes
+* Removed Java API `TableProperties.getPropertiesOffsets()` as it exposed internal details to external users.
+
+## 6.27.0 (2021-11-19)
+### New Features
+* Added new ChecksumType kXXH3 which is faster than kCRC32c on almost all x86\_64 hardware.
+* Added a new online consistency check for BlobDB which validates that the number/total size of garbage blobs does not exceed the number/total size of all blobs in any given blob file.
+* Provided support for tracking per-sst user-defined timestamp information in MANIFEST.
+* Added new option "adaptive_readahead" in ReadOptions. For iterators, RocksDB does auto-readahead on noticing sequential reads and by enabling this option, readahead_size of current file (if reads are sequential) will be carried forward to next file instead of starting from the scratch at each level (except L0 level files). If reads are not sequential it will fall back to 8KB. This option is applicable only for RocksDB internal prefetch buffer and isn't supported with underlying file system prefetching.
+* Added the read count and read bytes related stats to Statistics for tiered storage hot, warm, and cold file reads.
+* Added an option to dynamically charge an updating estimated memory usage of block-based table building to block cache if block cache available. It currently only includes charging memory usage of constructing (new) Bloom Filter and Ribbon Filter to block cache. To enable this feature, set `BlockBasedTableOptions::reserve_table_builder_memory = true`.
+* Add a new API OnIOError in listener.h that notifies listeners when an IO error occurs during FileSystem operation along with filename, status etc.
+* Added compaction readahead support for blob files to the integrated BlobDB implementation, which can improve compaction performance when the database resides on higher-latency storage like HDDs or remote filesystems. Readahead can be configured using the column family option `blob_compaction_readahead_size`.
+
+### Bug Fixes
+* Prevent a `CompactRange()` with `CompactRangeOptions::change_level == true` from possibly causing corruption to the LSM state (overlapping files within a level) when run in parallel with another manual compaction. Note that setting `force_consistency_checks == true` (the default) would cause the DB to enter read-only mode in this scenario and return `Status::Corruption`, rather than committing any corruption.
+* Fixed a bug in CompactionIterator when write-prepared transaction is used. A released earliest write conflict snapshot may cause assertion failure in dbg mode and unexpected key in opt mode.
+* Fix ticker WRITE_WITH_WAL("rocksdb.write.wal"), this bug is caused by a bad extra `RecordTick(stats_, WRITE_WITH_WAL)` (at 2 place), this fix remove the extra `RecordTick`s and fix the corresponding test case.
+* EventListener::OnTableFileCreated was previously called with OK status and file_size==0 in cases of no SST file contents written (because there was no content to add) and the empty file deleted before calling the listener. Now the status is Aborted.
+* Fixed a bug in CompactionIterator when write-preared transaction is used. Releasing earliest_snapshot during compaction may cause a SingleDelete to be output after a PUT of the same user key whose seq has been zeroed.
+* Added input sanitization on negative bytes passed into `GenericRateLimiter::Request`.
+* Fixed an assertion failure in CompactionIterator when write-prepared transaction is used. We prove that certain operations can lead to a Delete being followed by a SingleDelete (same user key). We can drop the SingleDelete.
+* Fixed a bug of timestamp-based GC which can cause all versions of a key under full_history_ts_low to be dropped. This bug will be triggered when some of the ikeys' timestamps are lower than full_history_ts_low, while others are newer.
+* In some cases outside of the DB read and compaction paths, SST block checksums are now checked where they were not before.
+* Explicitly check for and disallow the `BlockBasedTableOptions` if insertion into one of {`block_cache`, `block_cache_compressed`, `persistent_cache`} can show up in another of these. (RocksDB expects to be able to use the same key for different physical data among tiers.)
+* Users who configured a dedicated thread pool for bottommost compactions by explicitly adding threads to the `Env::Priority::BOTTOM` pool will no longer see RocksDB schedule automatic compactions exceeding the DB's compaction concurrency limit. For details on per-DB compaction concurrency limit, see API docs of `max_background_compactions` and `max_background_jobs`.
+* Fixed a bug of background flush thread picking more memtables to flush and prematurely advancing column family's log_number.
+* Fixed an assertion failure in ManifestTailer.
+* Fixed a bug that could, with WAL enabled, cause backups, checkpoints, and `GetSortedWalFiles()` to fail randomly with an error like `IO error: 001234.log: No such file or directory`
+
+### Behavior Changes
+* `NUM_FILES_IN_SINGLE_COMPACTION` was only counting the first input level files, now it's including all input files.
+* `TransactionUtil::CheckKeyForConflicts` can also perform conflict-checking based on user-defined timestamps in addition to sequence numbers.
+* Removed `GenericRateLimiter`'s minimum refill bytes per period previously enforced.
+
+### Public API change
+* When options.ttl is used with leveled compaction with compactinon priority kMinOverlappingRatio, files exceeding half of TTL value will be prioritized more, so that by the time TTL is reached, fewer extra compactions will be scheduled to clear them up. At the same time, when compacting files with data older than half of TTL, output files may be cut off based on those files' boundaries, in order for the early TTL compaction to work properly.
+* Made FileSystem and RateLimiter extend the Customizable class and added a CreateFromString method.  Implementations need to be registered with the ObjectRegistry and to implement a Name() method in order to be created via this method.
+* Clarified in API comments that RocksDB is not exception safe for callbacks and custom extensions. An exception propagating into RocksDB can lead to undefined behavior, including data loss, unreported corruption, deadlocks, and more.
+* Marked `WriteBufferManager` as `final` because it is not intended for extension.
+* Removed unimportant implementation details from table_properties.h
+* Add API `FSDirectory::FsyncWithDirOptions()`, which provides extra information like directory fsync reason in `DirFsyncOptions`. File system like btrfs is using that to skip directory fsync for creating a new file, or when renaming a file, fsync the target file instead of the directory, which improves the `DB::Open()` speed by ~20%.
+* `DB::Open()` is not going be blocked by obsolete file purge if `DBOptions::avoid_unnecessary_blocking_io` is set to true.
+* In builds where glibc provides `gettid()`, info log ("LOG" file) lines now print a system-wide thread ID from `gettid()` instead of the process-local `pthread_self()`. For all users, the thread ID format is changed from hexadecimal to decimal integer.
+* In builds where glibc provides `pthread_setname_np()`, the background thread names no longer contain an ID suffix. For example, "rocksdb:bottom7" (and all other threads in the `Env::Priority::BOTTOM` pool) are now named "rocksdb:bottom". Previously large thread pools could breach the name size limit (e.g., naming "rocksdb:bottom10" would fail).
+* Deprecating `ReadOptions::iter_start_seqnum` and `DBOptions::preserve_deletes`, please try using user defined timestamp feature instead. The options will be removed in a future release, currently it logs a warning message when using.
+
+### Performance Improvements
+* Released some memory related to filter construction earlier in `BlockBasedTableBuilder` for `FullFilter` and `PartitionedFilter` case (#9070)
+
+### Behavior Changes
+* `NUM_FILES_IN_SINGLE_COMPACTION` was only counting the first input level files, now it's including all input files.
+
 ## 6.26.0 (2021-10-20)
 ### Bug Fixes
 * Fixes a bug in directed IO mode when calling MultiGet() for blobs in the same blob file. The bug is caused by not sorting the blob read requests by file offsets.
@@ -10,6 +241,7 @@
 * Fixed a bug where stalled writes would remain stalled forever after the user calls `WriteBufferManager::SetBufferSize()` with `new_size == 0` to dynamically disable memory limiting.
 * Make `DB::close()` thread-safe.
 * Fix a bug in atomic flush where one bg flush thread will wait forever for a preceding bg flush thread to commit its result to MANIFEST but encounters an error which is mapped to a soft error (DB not stopped).
+* Fix a bug in `BackupEngine` where some internal callers of `GenericRateLimiter::Request()` do not honor `bytes <= GetSingleBurstBytes()`.

 ### New Features
 * Print information about blob files when using "ldb list_live_files_metadata"
@@ -6,7 +6,7 @@ than release mode.

 RocksDB's library should be able to compile without any dependency installed,
 although we recommend installing some compression libraries (see below).
-We do depend on newer gcc/clang with C++11 support.
+We do depend on newer gcc/clang with C++17 support (GCC >= 7, Clang >= 5).

 There are few options when compiling RocksDB:

@@ -47,10 +47,12 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi

 * If you wish to build the RocksJava static target, then cmake is required for building Snappy.

+* If you wish to run microbench (e.g, `make microbench`, `make ribbon_bench` or `cmake -DWITH_BENCHMARK=1`), Google benchmark < 1.6.0 is needed.
+
 ## Supported platforms

 * **Linux - Ubuntu**
-    * Upgrade your gcc to version at least 4.8 to get C++11 support.
+    * Upgrade your gcc to version at least 7 to get C++17 support.
    * Install gflags. First, try: `sudo apt-get install libgflags-dev`
      If this doesn't work and you're using Ubuntu, here's a nice tutorial:
      (http://askubuntu.com/questions/312173/installing-gflags-12-04)
@@ -62,8 +64,7 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
    * Install zstandard: `sudo apt-get install libzstd-dev`.

 * **Linux - CentOS / RHEL**
-    * Upgrade your gcc to version at least 4.8 to get C++11 support:
-      `yum install gcc48-c++`
+    * Upgrade your gcc to version at least 7 to get C++17 support
    * Install gflags:

              git clone https://github.com/gflags/gflags.git
@@ -113,11 +114,11 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
              make && sudo make install

 * **OS X**:
-    * Install latest C++ compiler that supports C++ 11:
+    * Install latest C++ compiler that supports C++ 17:
        * Update XCode:  run `xcode-select --install` (or install it from XCode App's settting).
        * Install via [homebrew](http://brew.sh/).
            * If you're first time developer in MacOS, you still need to run: `xcode-select --install` in your command line.
-            * run `brew tap homebrew/versions; brew install gcc48 --use-llvm` to install gcc 4.8 (or higher).
+            * run `brew tap homebrew/versions; brew install gcc7 --use-llvm` to install gcc 7 (or higher).
    * run `brew install rocksdb`

 * **FreeBSD** (11.01):
@@ -160,7 +161,7 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi

    * Install the dependencies for RocksDB:

-        pkg_add gmake gflags snappy bzip2 lz4 zstd git jdk bash findutils gnuwatch 
+        pkg_add gmake gflags snappy bzip2 lz4 zstd git jdk bash findutils gnuwatch

    * Build RocksDB from source:

@@ -182,13 +183,13 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
 * **Windows**:
  * For building with MS Visual Studio 13 you will need Update 4 installed.
  * Read and follow the instructions at CMakeLists.txt
-  * Or install via [vcpkg](https://github.com/microsoft/vcpkg) 
+  * Or install via [vcpkg](https://github.com/microsoft/vcpkg)
       * run `vcpkg install rocksdb:x64-windows`

 * **AIX 6.1**
    * Install AIX Toolbox rpms with gcc
    * Use these environment variables:
-  
+
             export PORTABLE=1
             export CC=gcc
             export AR="ar -X64"
@@ -199,9 +200,9 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
             export LIBPATH=/opt/freeware/lib
             export JAVA_HOME=/usr/java8_64
             export PATH=/opt/freeware/bin:$PATH
-  
+
 * **Solaris Sparc**
-    * Install GCC 4.8.2 and higher.
+    * Install GCC 7 and higher.
    * Use these environment variables:

             export CC=gcc
@@ -210,4 +211,3 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
             export EXTRA_LDFLAGS=-m64
             export PORTABLE=1
             export PLATFORM_LDFLAGS="-static-libstdc++ -static-libgcc"
-
@@ -8,11 +8,7 @@

 BASH_EXISTS := $(shell which bash)
 SHELL := $(shell which bash)
-# Default to python3. Some distros like CentOS 8 do not have `python`.
-ifeq ($(origin PYTHON), undefined)
-	PYTHON := $(shell which python3 || which python || echo python3)
-endif
-export PYTHON
+include python.mk

 CLEAN_FILES = # deliberately empty, so we can append below.
 CFLAGS += ${EXTRA_CFLAGS}
@@ -134,12 +130,6 @@ CFLAGS +=  -DHAVE_POWER8
 HAVE_POWER8=1
 endif

-ifeq (,$(shell $(CXX) -fsyntax-only -march=armv8-a+crc+crypto -xc /dev/null 2>&1))
-CXXFLAGS += -march=armv8-a+crc+crypto
-CFLAGS += -march=armv8-a+crc+crypto
-ARMCRC_SOURCE=1
-endif
-
 # if we're compiling for shared libraries, add the shared flags
 ifeq ($(LIB_MODE),shared)
 CXXFLAGS += $(PLATFORM_SHARED_CFLAGS) -DROCKSDB_DLL
@@ -220,13 +210,8 @@ am__v_AR_ = $(am__v_AR_$(AM_DEFAULT_VERBOSITY))
 am__v_AR_0 = @echo "  AR      " $@;
 am__v_AR_1 =

-ifdef ROCKSDB_USE_LIBRADOS
-LIB_SOURCES += utilities/env_librados.cc
-LDFLAGS += -lrados
-endif
-
 AM_LINK = $(AM_V_CCLD)$(CXX) -L. $(patsubst lib%.a, -l%, $(patsubst lib%.$(PLATFORM_SHARED_EXT), -l%, $^)) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
-AM_SHARE = $(AM_V_CCLD) $(CXX) $(PLATFORM_SHARED_LDFLAGS)$@ -L. $(patsubst lib%.$(PLATFORM_SHARED_EXT), -l%, $^) $(LDFLAGS) -o $@
+AM_SHARE = $(AM_V_CCLD) $(CXX) $(PLATFORM_SHARED_LDFLAGS)$@ -L. $(patsubst lib%.$(PLATFORM_SHARED_EXT), -l%, $^) $(EXEC_LDFLAGS) $(LDFLAGS) -o $@

 # Detect what platform we're building on.
 # Export some common variables that might have been passed as Make variables
@@ -240,6 +225,7 @@ dummy := $(shell (export ROCKSDB_ROOT="$(CURDIR)"; \
                  export PORTABLE="$(PORTABLE)"; \
                  export ROCKSDB_NO_FBCODE="$(ROCKSDB_NO_FBCODE)"; \
                  export USE_CLANG="$(USE_CLANG)"; \
+                  export LIB_MODE="$(LIB_MODE)"; \
                  "$(CURDIR)/build_tools/build_detect_platform" "$(CURDIR)/make_config.mk"))
 # this file is generated by the previous line to set build flags and sources
 include make_config.mk
@@ -248,7 +234,40 @@ ROCKSDB_PLUGIN_MKS = $(foreach plugin, $(ROCKSDB_PLUGINS), plugin/$(plugin)/*.mk
 include $(ROCKSDB_PLUGIN_MKS)
 ROCKSDB_PLUGIN_SOURCES = $(foreach plugin, $(ROCKSDB_PLUGINS), $(foreach source, $($(plugin)_SOURCES), plugin/$(plugin)/$(source)))
 ROCKSDB_PLUGIN_HEADERS = $(foreach plugin, $(ROCKSDB_PLUGINS), $(foreach header, $($(plugin)_HEADERS), plugin/$(plugin)/$(header)))
-PLATFORM_LDFLAGS += $(foreach plugin, $(ROCKSDB_PLUGINS), $($(plugin)_LDFLAGS))
+ROCKSDB_PLUGIN_PKGCONFIG_REQUIRES = $(foreach plugin, $(ROCKSDB_PLUGINS), $($(plugin)_PKGCONFIG_REQUIRES))
+CXXFLAGS += $(foreach plugin, $(ROCKSDB_PLUGINS), $($(plugin)_CXXFLAGS))
+
+# Patch up the link flags for JNI from the plugins
+ROCKSDB_PLUGIN_LDFLAGS = $(foreach plugin, $(ROCKSDB_PLUGINS), $($(plugin)_LDFLAGS))
+PLATFORM_LDFLAGS += $(ROCKSDB_PLUGIN_LDFLAGS)
+JAVA_LDFLAGS += $(ROCKSDB_PLUGIN_LDFLAGS)
+JAVA_STATIC_LDFLAGS += $(ROCKSDB_PLUGIN_LDFLAGS)
+
+# Patch up the list of java native sources with files from the plugins
+ROCKSDB_PLUGIN_JNI_NATIVE_SOURCES = $(foreach plugin, $(ROCKSDB_PLUGINS), $(foreach source, $($(plugin)_JNI_NATIVE_SOURCES), plugin/$(plugin)/$(source)))
+ALL_JNI_NATIVE_SOURCES = $(JNI_NATIVE_SOURCES) $(ROCKSDB_PLUGIN_JNI_NATIVE_SOURCES)
+ROCKSDB_PLUGIN_JNI_CXX_INCLUDEFLAGS = $(foreach plugin, $(ROCKSDB_PLUGINS), -I./plugin/$(plugin))
+
+ifneq ($(strip $(ROCKSDB_PLUGIN_PKGCONFIG_REQUIRES)),)
+LDFLAGS := $(LDFLAGS) $(shell pkg-config --libs $(ROCKSDB_PLUGIN_PKGCONFIG_REQUIRES))
+ifneq ($(.SHELLSTATUS),0)
+$(error pkg-config failed)
+endif
+CXXFLAGS := $(CXXFLAGS) $(shell pkg-config --cflags $(ROCKSDB_PLUGIN_PKGCONFIG_REQUIRES))
+ifneq ($(.SHELLSTATUS),0)
+$(error pkg-config failed)
+endif
+endif
+
+CXXFLAGS += $(ARCHFLAG)
+
+ifeq (,$(shell $(CXX) -fsyntax-only -march=armv8-a+crc+crypto -xc /dev/null 2>&1))
+ifneq ($(PLATFORM),OS_MACOSX)
+CXXFLAGS += -march=armv8-a+crc+crypto
+CFLAGS += -march=armv8-a+crc+crypto
+ARMCRC_SOURCE=1
+endif
+endif

 export JAVAC_ARGS
 CLEAN_FILES += make_config.mk rocksdb.pc
@@ -299,12 +318,32 @@ ifeq ($(LIB_MODE),shared)
 EXEC_LDFLAGS += -Wl,-rpath -Wl,'$$ORIGIN'
 endif

+ifeq ($(PLATFORM), OS_MACOSX)
+ifeq ($(ARCHFLAG), -arch arm64)
+ifneq ($(MACHINE), arm64)
+# If we're building on a non-arm64 machine but targeting arm64 Mac, we need to disable
+# linking with jemalloc (as it won't be arm64-compatible) and remove some other options
+# set during platform detection
+DISABLE_JEMALLOC=1
+PLATFORM_CFLAGS := $(filter-out -march=native -DHAVE_SSE42 -DHAVE_AVX2, $(PLATFORM_CFLAGS))
+PLATFORM_CXXFLAGS := $(filter-out -march=native -DHAVE_SSE42 -DHAVE_AVX2, $(PLATFORM_CXXFLAGS))
+endif
+endif
+endif
+
 # ASAN doesn't work well with jemalloc. If we're compiling with ASAN, we should use regular malloc.
 ifdef COMPILE_WITH_ASAN
 	DISABLE_JEMALLOC=1
 	EXEC_LDFLAGS += -fsanitize=address
 	PLATFORM_CCFLAGS += -fsanitize=address
 	PLATFORM_CXXFLAGS += -fsanitize=address
+ifeq ($(LIB_MODE),shared)
+ifdef USE_CLANG
+# Fix false ODR violation; see https://github.com/google/sanitizers/issues/1017
+	EXEC_LDFLAGS += -mllvm -asan-use-private-alias=1
+	PLATFORM_CXXFLAGS += -mllvm -asan-use-private-alias=1
+endif
+endif
 endif

 # TSAN doesn't work well with jemalloc. If we're compiling with TSAN, we should use regular malloc.
@@ -468,6 +507,11 @@ endif
 CFLAGS += $(C_WARNING_FLAGS) $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CCFLAGS) $(OPT)
 CXXFLAGS += $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CXXFLAGS) $(OPT) -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers

+# Allow offsetof to work on non-standard layout types. Some compiler could
+# completely reject our usage of offsetof, but we will solve that when it
+# happens.
+CXXFLAGS += -Wno-invalid-offsetof
+
 LDFLAGS += $(PLATFORM_LDFLAGS)

 LIB_OBJECTS = $(patsubst %.cc, $(OBJ_DIR)/%.o, $(LIB_SOURCES))
@@ -507,6 +551,7 @@ STRESS_OBJECTS =  $(patsubst %.cc, $(OBJ_DIR)/%.o, $(STRESS_LIB_SOURCES))
 ALL_SOURCES  = $(filter-out util/build_version.cc, $(LIB_SOURCES)) $(TEST_LIB_SOURCES) $(MOCK_LIB_SOURCES) $(GTEST_DIR)/gtest/gtest-all.cc
 ALL_SOURCES += $(TOOL_LIB_SOURCES) $(BENCH_LIB_SOURCES) $(CACHE_BENCH_LIB_SOURCES) $(ANALYZER_LIB_SOURCES) $(STRESS_LIB_SOURCES)
 ALL_SOURCES += $(TEST_MAIN_SOURCES) $(TOOL_MAIN_SOURCES) $(BENCH_MAIN_SOURCES)
+ALL_SOURCES += $(ROCKSDB_PLUGIN_SOURCES)

 TESTS = $(patsubst %.cc, %, $(notdir $(TEST_MAIN_SOURCES)))
 TESTS += $(patsubst %.c, %, $(notdir $(TEST_MAIN_SOURCES_C)))
@@ -520,9 +565,9 @@ endif
 # dependencies
 ifneq ($(filter check-headers, $(MAKECMDGOALS)),)
 # TODO: add/support JNI headers
-	DEV_HEADER_DIRS := $(sort include/ hdfs/ $(dir $(ALL_SOURCES)))
+	DEV_HEADER_DIRS := $(sort include/ $(dir $(ALL_SOURCES)))
 # Some headers like in port/ are platform-specific
-	DEV_HEADERS := $(shell $(FIND) $(DEV_HEADER_DIRS) -type f -name '*.h' | egrep -v 'port/|plugin/|lua/|range_tree/|tools/rdb/db_wrapper.h|include/rocksdb/utilities/env_librados.h')
+	DEV_HEADERS := $(shell $(FIND) $(DEV_HEADER_DIRS) -type f -name '*.h' | egrep -v 'port/|plugin/|lua/|range_tree/')
 else
 	DEV_HEADERS :=
 endif
@@ -541,28 +586,29 @@ check-headers: $(HEADER_OK_FILES)

 # options_settable_test doesn't pass with UBSAN as we use hack in the test
 ifdef COMPILE_WITH_UBSAN
-        TESTS := $(shell echo $(TESTS) | sed 's/\boptions_settable_test\b//g')
+TESTS := $(shell echo $(TESTS) | sed 's/\boptions_settable_test\b//g')
 endif
 ifdef ASSERT_STATUS_CHECKED
-	# TODO: finish fixing all tests to pass this check
-	TESTS_FAILING_ASC = \
-		c_test \
-		db_test \
-		env_test \
-		range_locking_test \
-		testutil_test \
+# TODO: finish fixing all tests to pass this check
+TESTS_FAILING_ASC = \
+	c_test \
+	env_test \
+	range_locking_test \
+	testutil_test \

-	# Since we have very few ASC exclusions left, excluding them from
-	# the build is the most convenient way to exclude them from testing
-	TESTS := $(filter-out $(TESTS_FAILING_ASC),$(TESTS))
+# Since we have very few ASC exclusions left, excluding them from
+# the build is the most convenient way to exclude them from testing
+TESTS := $(filter-out $(TESTS_FAILING_ASC),$(TESTS))
 endif

 ROCKSDBTESTS_SUBSET ?= $(TESTS)

+# c_test - doesn't use gtest
 # env_test - suspicious use of test::TmpDir
 # deletefile_test - serial because it generates giant temporary files in
 #   its various tests. Parallel can fill up your /dev/shm
 NON_PARALLEL_TEST = \
+	c_test \
 	env_test \
 	deletefile_test \

@@ -743,7 +789,9 @@ endif  # PLATFORM_SHARED_EXT
 	blackbox_crash_test_with_atomic_flush whitebox_crash_test_with_atomic_flush  \
 	blackbox_crash_test_with_txn whitebox_crash_test_with_txn \
 	blackbox_crash_test_with_best_efforts_recovery \
-	blackbox_crash_test_with_ts whitebox_crash_test_with_ts
+	blackbox_crash_test_with_ts whitebox_crash_test_with_ts \
+	blackbox_crash_test_with_multiops_wc_txn \
+	blackbox_crash_test_with_multiops_wp_txn


 all: $(LIBRARY) $(BENCHMARKS) tools tools_lib test_libs $(TESTS)
@@ -765,6 +813,8 @@ test_libs: $(TEST_LIBS)
 benchmarks: $(BENCHMARKS)

 microbench: $(MICROBENCHS)
+
+run_microbench: $(MICROBENCHS)
 	for t in $(MICROBENCHS); do echo "===== Running benchmark $$t (`date`)"; ./$$t || exit 1; done;

 dbg: $(LIBRARY) $(BENCHMARKS) tools $(TESTS)
@@ -820,17 +870,14 @@ endif

 parallel_tests = $(patsubst %,parallel_%,$(PARALLEL_TEST))
 .PHONY: gen_parallel_tests $(parallel_tests)
-$(parallel_tests): $(PARALLEL_TEST)
+$(parallel_tests):
 	$(AM_V_at)TEST_BINARY=$(patsubst parallel_%,%,$@); \
  TEST_NAMES=` \
-    ./$$TEST_BINARY --gtest_list_tests \
-    | perl -n \
-      -e 's/ *\#.*//;' \
-      -e '/^(\s*)(\S+)/; !$$1 and do {$$p=$$2; break};'	\
-      -e 'print qq! $$p$$2!'`; \
+    (./$$TEST_BINARY --gtest_list_tests || echo "  $${TEST_BINARY}__list_tests_failure") \
+    | awk '/^[^ ]/ { prefix = $$1 } /^[ ]/ { print prefix $$1 }'`; \
+	echo "  Generating parallel test scripts for $$TEST_BINARY"; \
 	for TEST_NAME in $$TEST_NAMES; do \
 		TEST_SCRIPT=t/run-$$TEST_BINARY-$${TEST_NAME//\//-}; \
-		echo "  GEN     " $$TEST_SCRIPT; \
    printf '%s\n' \
      '#!/bin/sh' \
      "d=\$(TMPD)$$TEST_SCRIPT" \
@@ -862,7 +909,7 @@ gen_parallel_tests:
 # 107.816 PASS t/DBTest.EncodeDecompressedBlockSizeTest
 #
 slow_test_regexp = \
-	^.*SnapshotConcurrentAccessTest.*$$|^.*SeqAdvanceConcurrentTest.*$$|^t/run-table_test-HarnessTest.Randomized$$|^t/run-db_test-.*(?:FileCreationRandomFailure|EncodeDecompressedBlockSizeTest)$$|^.*RecoverFromCorruptedWALWithoutFlush$$
+	^.*MySQLStyleTransactionTest.*$$|^.*SnapshotConcurrentAccessTest.*$$|^.*SeqAdvanceConcurrentTest.*$$|^t/run-table_test-HarnessTest.Randomized$$|^t/run-db_test-.*(?:FileCreationRandomFailure|EncodeDecompressedBlockSizeTest)$$|^.*RecoverFromCorruptedWALWithoutFlush$$
 prioritize_long_running_tests =						\
  perl -pe 's,($(slow_test_regexp)),100 $$1,'				\
    | sort -k1,1gr							\
@@ -877,12 +924,18 @@ J ?= 100%

 # Use this regexp to select the subset of tests whose names match.
 tests-regexp = .
-EXCLUDE_TESTS_REGEX ?= "^$"
+EXCLUDE_TESTS_REGEX ?= "^$$"

 ifeq ($(PRINT_PARALLEL_OUTPUTS), 1)
-	parallel_com = '{}'
+	parallel_redir =
+else ifeq ($(QUIET_PARALLEL_TESTS), 1)
+	parallel_redir = >& t/$(test_log_prefix)log-{/}
 else
-	parallel_com = '{} >& t/log-{/}'
+# Default: print failure output only, as it happens
+# Note: gnu_parallel --eta is now always used, but has been modified to provide
+# only infrequent updates when not connected to a terminal. (CircleCI will
+# kill a job if no output for 10min.)
+	parallel_redir = >& t/$(test_log_prefix)log-{/} || bash -c "cat t/$(test_log_prefix)log-{/}; exit $$?"
 endif

 .PHONY: check_0
@@ -891,7 +944,6 @@ check_0:
 	printf '%s\n' ''						\
 	  'To monitor subtest <duration,pass/fail,name>,'		\
 	  '  run "make watch-log" in a separate window' '';		\
-	test -t 1 && eta=--eta || eta=; \
 	{ \
 		printf './%s\n' $(filter-out $(PARALLEL_TEST),$(TESTS)); \
 		find t -name 'run-*' -print; \
@@ -899,7 +951,7 @@ check_0:
 	  | $(prioritize_long_running_tests)				\
 	  | grep -E '$(tests-regexp)'					\
 	  | grep -E -v '$(EXCLUDE_TESTS_REGEX)'					\
-	  | build_tools/gnu_parallel -j$(J) --plain --joblog=LOG $$eta --gnu  $(parallel_com) ; \
+	  | build_tools/gnu_parallel -j$(J) --plain --joblog=LOG --eta --gnu '{} $(parallel_redir)' ; \
 	parallel_retcode=$$? ; \
 	awk '{ if ($$7 != 0 || $$8 != 0) { if ($$7 == "Exitval") { h = $$0; } else { if (!f) print h; print; f = 1 } } } END { if(f) exit 1; }' < LOG ; \
 	awk_retcode=$$?; \
@@ -908,12 +960,12 @@ check_0:
 valgrind-exclude-regexp = InlineSkipTest.ConcurrentInsert|TransactionStressTest.DeadlockStress|DBCompactionTest.SuggestCompactRangeNoTwoLevel0Compactions|BackupableDBTest.RateLimiting|DBTest.CloseSpeedup|DBTest.ThreadStatusFlush|DBTest.RateLimitingTest|DBTest.EncodeDecompressedBlockSizeTest|FaultInjectionTest.UninstalledCompaction|HarnessTest.Randomized|ExternalSSTFileTest.CompactDuringAddFileRandom|ExternalSSTFileTest.IngestFileWithGlobalSeqnoRandomized|MySQLStyleTransactionTest.TransactionStressTest

 .PHONY: valgrind_check_0
+valgrind_check_0: test_log_prefix := valgrind_
 valgrind_check_0:
 	$(AM_V_GEN)export TEST_TMPDIR=$(TMPD);				\
 	printf '%s\n' ''						\
 	  'To monitor subtest <duration,pass/fail,name>,'		\
 	  '  run "make watch-log" in a separate window' '';		\
-	test -t 1 && eta=--eta || eta=;					\
 	{								\
 	  printf './%s\n' $(filter-out $(PARALLEL_TEST) %skiplist_test options_settable_test, $(TESTS));		\
 	  find t -name 'run-*' -print; \
@@ -921,9 +973,9 @@ valgrind_check_0:
 	  | $(prioritize_long_running_tests)				\
 	  | grep -E '$(tests-regexp)'					\
 	  | grep -E -v '$(valgrind-exclude-regexp)'					\
-	  | build_tools/gnu_parallel -j$(J) --plain --joblog=LOG $$eta --gnu \
-	  '(if [[ "{}" == "./"* ]] ; then $(DRIVER) {}; else {}; fi) ' \
-	  '>& t/valgrind_log-{/}'
+	  | build_tools/gnu_parallel -j$(J) --plain --joblog=LOG --eta --gnu \
+	  '(if [[ "{}" == "./"* ]] ; then $(DRIVER) {}; else {}; fi) \
+	  $(parallel_redir)' \

 CLEAN_FILES += t LOG $(TMPD)

@@ -977,80 +1029,34 @@ check_some: $(ROCKSDBTESTS_SUBSET)
 ldb_tests: ldb
 	$(PYTHON) tools/ldb_test.py

-crash_test: whitebox_crash_test blackbox_crash_test
-
-crash_test_with_atomic_flush: whitebox_crash_test_with_atomic_flush blackbox_crash_test_with_atomic_flush
-
-crash_test_with_txn: whitebox_crash_test_with_txn blackbox_crash_test_with_txn
-
-crash_test_with_best_efforts_recovery: blackbox_crash_test_with_best_efforts_recovery
-
-crash_test_with_ts: whitebox_crash_test_with_ts blackbox_crash_test_with_ts
-
-blackbox_crash_test: db_stress
-	$(PYTHON) -u tools/db_crashtest.py --simple blackbox $(CRASH_TEST_EXT_ARGS)
-	$(PYTHON) -u tools/db_crashtest.py blackbox $(CRASH_TEST_EXT_ARGS)
-
-blackbox_crash_test_with_atomic_flush: db_stress
-	$(PYTHON) -u tools/db_crashtest.py --cf_consistency blackbox $(CRASH_TEST_EXT_ARGS)
-
-blackbox_crash_test_with_txn: db_stress
-	$(PYTHON) -u tools/db_crashtest.py --txn blackbox $(CRASH_TEST_EXT_ARGS)
-
-blackbox_crash_test_with_best_efforts_recovery: db_stress
-	$(PYTHON) -u tools/db_crashtest.py --test_best_efforts_recovery blackbox $(CRASH_TEST_EXT_ARGS)
-
-blackbox_crash_test_with_ts: db_stress
-	$(PYTHON) -u tools/db_crashtest.py --enable_ts blackbox $(CRASH_TEST_EXT_ARGS)
-
-ifeq ($(CRASH_TEST_KILL_ODD),)
-  CRASH_TEST_KILL_ODD=888887
-endif
-
-whitebox_crash_test: db_stress
-	$(PYTHON) -u tools/db_crashtest.py --simple whitebox --random_kill_odd \
-      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
-	$(PYTHON) -u tools/db_crashtest.py whitebox  --random_kill_odd \
-      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
-
-whitebox_crash_test_with_atomic_flush: db_stress
-	$(PYTHON) -u tools/db_crashtest.py --cf_consistency whitebox  --random_kill_odd \
-      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
-
-whitebox_crash_test_with_txn: db_stress
-	$(PYTHON) -u tools/db_crashtest.py --txn whitebox --random_kill_odd \
-      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
-
-whitebox_crash_test_with_ts: db_stress
-	$(PYTHON) -u tools/db_crashtest.py --enable_ts whitebox --random_kill_odd \
-      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
+include crash_test.mk

 asan_check: clean
-	COMPILE_WITH_ASAN=1 $(MAKE) check -j32
+	ASAN_OPTIONS=detect_stack_use_after_return=1 COMPILE_WITH_ASAN=1 $(MAKE) check -j32
 	$(MAKE) clean

 asan_crash_test: clean
-	COMPILE_WITH_ASAN=1 $(MAKE) crash_test
+	ASAN_OPTIONS=detect_stack_use_after_return=1 COMPILE_WITH_ASAN=1 $(MAKE) crash_test
 	$(MAKE) clean

 whitebox_asan_crash_test: clean
-	COMPILE_WITH_ASAN=1 $(MAKE) whitebox_crash_test
+	ASAN_OPTIONS=detect_stack_use_after_return=1 COMPILE_WITH_ASAN=1 $(MAKE) whitebox_crash_test
 	$(MAKE) clean

 blackbox_asan_crash_test: clean
-	COMPILE_WITH_ASAN=1 $(MAKE) blackbox_crash_test
+	ASAN_OPTIONS=detect_stack_use_after_return=1 COMPILE_WITH_ASAN=1 $(MAKE) blackbox_crash_test
 	$(MAKE) clean

 asan_crash_test_with_atomic_flush: clean
-	COMPILE_WITH_ASAN=1 $(MAKE) crash_test_with_atomic_flush
+	ASAN_OPTIONS=detect_stack_use_after_return=1 COMPILE_WITH_ASAN=1 $(MAKE) crash_test_with_atomic_flush
 	$(MAKE) clean

 asan_crash_test_with_txn: clean
-	COMPILE_WITH_ASAN=1 $(MAKE) crash_test_with_txn
+	ASAN_OPTIONS=detect_stack_use_after_return=1 COMPILE_WITH_ASAN=1 $(MAKE) crash_test_with_txn
 	$(MAKE) clean

 asan_crash_test_with_best_efforts_recovery: clean
-	COMPILE_WITH_ASAN=1 $(MAKE) crash_test_with_best_efforts_recovery
+	ASAN_OPTIONS=detect_stack_use_after_return=1 COMPILE_WITH_ASAN=1 $(MAKE) crash_test_with_best_efforts_recovery
 	$(MAKE) clean

 ubsan_check: clean
@@ -1173,7 +1179,7 @@ analyze_incremental:
 	$(CLANG_SCAN_BUILD) --use-analyzer=$(CLANG_ANALYZER) \
 		--use-c++=$(CXX) --use-cc=$(CC) --status-bugs \
 		-o $(CURDIR)/scan_build_report \
-		$(MAKE) dbg
+		$(MAKE) SKIP_LINK=1 dbg

 CLEAN_FILES += unity.cc
 unity.cc: Makefile util/build_version.cc.in
@@ -1326,7 +1332,7 @@ db_repl_stress: $(OBJ_DIR)/tools/db_repl_stress.o $(LIBRARY)
 arena_test: $(OBJ_DIR)/memory/arena_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

-memkind_kmem_allocator_test: memory/memkind_kmem_allocator_test.o $(TEST_LIBRARY) $(LIBRARY)
+memory_allocator_test: memory/memory_allocator_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

 autovector_test: $(OBJ_DIR)/util/autovector_test.o $(TEST_LIBRARY) $(LIBRARY)
@@ -1479,6 +1485,9 @@ db_options_test: $(OBJ_DIR)/db/db_options_test.o $(TEST_LIBRARY) $(LIBRARY)
 db_range_del_test: $(OBJ_DIR)/db/db_range_del_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

+db_rate_limiter_test: $(OBJ_DIR)/db/db_rate_limiter_test.o $(TEST_LIBRARY) $(LIBRARY)
+	$(AM_LINK)
+
 db_sst_test: $(OBJ_DIR)/db/db_sst_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

@@ -1560,11 +1569,6 @@ env_mirror_test: $(OBJ_DIR)/utilities/env_mirror_test.o $(TEST_LIBRARY) $(LIBRAR
 env_timed_test: $(OBJ_DIR)/utilities/env_timed_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

-ifdef ROCKSDB_USE_LIBRADOS
-env_librados_test: $(OBJ_DIR)/utilities/env_librados_test.o $(TEST_LIBRARY) $(LIBRARY)
-	$(AM_LINK)
-endif
-
 object_registry_test: $(OBJ_DIR)/utilities/object_registry_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

@@ -1802,6 +1806,9 @@ point_lock_manager_test: utilities/transactions/lock/point/point_lock_manager_te
 transaction_test: $(OBJ_DIR)/utilities/transactions/transaction_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

+write_committed_transaction_ts_test: $(OBJ_DIR)/utilities/transactions/write_committed_transaction_ts_test.o $(TEST_LIBRARY) $(LIBRARY)
+	$(AM_LINK)
+
 write_prepared_transaction_test: $(OBJ_DIR)/utilities/transactions/write_prepared_transaction_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

@@ -1835,6 +1842,9 @@ statistics_test: $(OBJ_DIR)/monitoring/statistics_test.o $(TEST_LIBRARY) $(LIBRA
 stats_history_test: $(OBJ_DIR)/monitoring/stats_history_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

+lru_secondary_cache_test: $(OBJ_DIR)/cache/lru_secondary_cache_test.o $(TEST_LIBRARY) $(LIBRARY)
+	$(AM_LINK)
+
 lru_cache_test: $(OBJ_DIR)/cache/lru_cache_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)

@@ -1925,6 +1935,9 @@ clipping_iterator_test: $(OBJ_DIR)/db/compaction/clipping_iterator_test.o $(TEST
 ribbon_bench: $(OBJ_DIR)/microbench/ribbon_bench.o $(LIBRARY)
 	$(AM_LINK)

+db_basic_bench: $(OBJ_DIR)/microbench/db_basic_bench.o $(LIBRARY)
+	$(AM_LINK)
+
 cache_reservation_manager_test: $(OBJ_DIR)/cache/cache_reservation_manager_test.o $(TEST_LIBRARY) $(LIBRARY)
 	$(AM_LINK)
 #-------------------------------------------------
@@ -1985,6 +1998,7 @@ gen-pc:
 	-echo 'Libs: -L$${libdir} $(EXEC_LDFLAGS) -lrocksdb' >> rocksdb.pc
 	-echo 'Libs.private: $(PLATFORM_LDFLAGS)' >> rocksdb.pc
 	-echo 'Cflags: -I$${includedir} $(PLATFORM_CXXFLAGS)' >> rocksdb.pc
+	-echo 'Requires: $(subst ",,$(ROCKSDB_PLUGIN_PKGCONFIG_REQUIRES))' >> rocksdb.pc

 #-------------------------------------------------

@@ -1992,12 +2006,11 @@ gen-pc:
 # ---------------------------------------------------------------------------
 # Jni stuff
 # ---------------------------------------------------------------------------
-
 JAVA_INCLUDE = -I$(JAVA_HOME)/include/ -I$(JAVA_HOME)/include/linux
 ifeq ($(PLATFORM), OS_SOLARIS)
 	ARCH := $(shell isainfo -b)
 else ifeq ($(PLATFORM), OS_OPENBSD)
-	ifneq (,$(filter amd64 ppc64 ppc64le arm64 aarch64 sparc64, $(MACHINE)))
+	ifneq (,$(filter amd64 ppc64 ppc64le s390x arm64 aarch64 sparc64, $(MACHINE)))
 		ARCH := 64
 	else
 		ARCH := 32
@@ -2017,11 +2030,13 @@ ifneq ($(origin JNI_LIBC), undefined)
  JNI_LIBC_POSTFIX = -$(JNI_LIBC)
 endif

-ifneq (,$(filter ppc% arm64 aarch64 sparc64, $(MACHINE)))
+ifeq (,$(ROCKSDBJNILIB))
+ifneq (,$(filter ppc% s390x arm64 aarch64 sparc64, $(MACHINE)))
 	ROCKSDBJNILIB = librocksdbjni-linux-$(MACHINE)$(JNI_LIBC_POSTFIX).so
 else
 	ROCKSDBJNILIB = librocksdbjni-linux$(ARCH)$(JNI_LIBC_POSTFIX).so
 endif
+endif
 ROCKSDB_JAVA_VERSION ?= $(ROCKSDB_MAJOR).$(ROCKSDB_MINOR).$(ROCKSDB_PATCH)
 ROCKSDB_JAR = rocksdbjni-$(ROCKSDB_JAVA_VERSION)-linux$(ARCH)$(JNI_LIBC_POSTFIX).jar
 ROCKSDB_JAR_ALL = rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar
@@ -2047,7 +2062,15 @@ ZSTD_DOWNLOAD_BASE ?= https://github.com/facebook/zstd/archive
 CURL_SSL_OPTS ?= --tlsv1

 ifeq ($(PLATFORM), OS_MACOSX)
+ifeq (,$(findstring librocksdbjni-osx,$(ROCKSDBJNILIB)))
+ifeq ($(MACHINE),arm64)
+	ROCKSDBJNILIB = librocksdbjni-osx-arm64.jnilib
+else ifeq ($(MACHINE),x86_64)
+	ROCKSDBJNILIB = librocksdbjni-osx-x86_64.jnilib
+else
 	ROCKSDBJNILIB = librocksdbjni-osx.jnilib
+endif
+endif
 	ROCKSDB_JAR = rocksdbjni-$(ROCKSDB_JAVA_VERSION)-osx.jar
 	SHA256_CMD = openssl sha256 -r
 ifneq ("$(wildcard $(JAVA_HOME)/include/darwin)","")
@@ -2056,6 +2079,7 @@ else
 	JAVA_INCLUDE = -I/System/Library/Frameworks/JavaVM.framework/Headers/
 endif
 endif
+
 ifeq ($(PLATFORM), OS_FREEBSD)
 	JAVA_INCLUDE = -I$(JAVA_HOME)/include -I$(JAVA_HOME)/include/freebsd
 	ROCKSDBJNILIB = librocksdbjni-freebsd$(ARCH).so
@@ -2090,7 +2114,11 @@ zlib-$(ZLIB_VER).tar.gz:
 libz.a: zlib-$(ZLIB_VER).tar.gz
 	-rm -rf zlib-$(ZLIB_VER)
 	tar xvzf zlib-$(ZLIB_VER).tar.gz
-	cd zlib-$(ZLIB_VER) && CFLAGS='-fPIC ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' ./configure --static && $(MAKE)
+	if [ -n"$(ARCHFLAG)" ]; then \
+		cd zlib-$(ZLIB_VER) && CFLAGS='-fPIC ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' ./configure --static --archs="$(ARCHFLAG)" && $(MAKE);  \
+	else \
+		cd zlib-$(ZLIB_VER) && CFLAGS='-fPIC ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' ./configure --static && $(MAKE);  \
+	fi
 	cp zlib-$(ZLIB_VER)/libz.a .

 bzip2-$(BZIP2_VER).tar.gz:
@@ -2104,7 +2132,7 @@ bzip2-$(BZIP2_VER).tar.gz:
 libbz2.a: bzip2-$(BZIP2_VER).tar.gz
 	-rm -rf bzip2-$(BZIP2_VER)
 	tar xvzf bzip2-$(BZIP2_VER).tar.gz
-	cd bzip2-$(BZIP2_VER) && $(MAKE) CFLAGS='-fPIC -O2 -g -D_FILE_OFFSET_BITS=64 ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' AR='ar ${EXTRA_ARFLAGS}'
+	cd bzip2-$(BZIP2_VER) && $(MAKE) CFLAGS='-fPIC -O2 -g -D_FILE_OFFSET_BITS=64 $(ARCHFLAG) ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' AR='ar ${EXTRA_ARFLAGS}' libbz2.a
 	cp bzip2-$(BZIP2_VER)/libbz2.a .

 snappy-$(SNAPPY_VER).tar.gz:
@@ -2119,7 +2147,7 @@ libsnappy.a: snappy-$(SNAPPY_VER).tar.gz
 	-rm -rf snappy-$(SNAPPY_VER)
 	tar xvzf snappy-$(SNAPPY_VER).tar.gz
 	mkdir snappy-$(SNAPPY_VER)/build
-	cd snappy-$(SNAPPY_VER)/build && CFLAGS='${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' CXXFLAGS='${JAVA_STATIC_DEPS_CXXFLAGS} ${EXTRA_CXXFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' cmake -DCMAKE_POSITION_INDEPENDENT_CODE=ON ${PLATFORM_CMAKE_FLAGS} .. && $(MAKE) ${SNAPPY_MAKE_TARGET}
+	cd snappy-$(SNAPPY_VER)/build && CFLAGS='$(ARCHFLAG) ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' CXXFLAGS='$(ARCHFLAG) ${JAVA_STATIC_DEPS_CXXFLAGS} ${EXTRA_CXXFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' cmake -DCMAKE_POSITION_INDEPENDENT_CODE=ON ${PLATFORM_CMAKE_FLAGS} .. && $(MAKE) ${SNAPPY_MAKE_TARGET}
 	cp snappy-$(SNAPPY_VER)/build/libsnappy.a .

 lz4-$(LZ4_VER).tar.gz:
@@ -2133,7 +2161,7 @@ lz4-$(LZ4_VER).tar.gz:
 liblz4.a: lz4-$(LZ4_VER).tar.gz
 	-rm -rf lz4-$(LZ4_VER)
 	tar xvzf lz4-$(LZ4_VER).tar.gz
-	cd lz4-$(LZ4_VER)/lib && $(MAKE) CFLAGS='-fPIC -O2 ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' all
+	cd lz4-$(LZ4_VER)/lib && $(MAKE) CFLAGS='-fPIC -O2 $(ARCHFLAG) ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' all
 	cp lz4-$(LZ4_VER)/lib/liblz4.a .

 zstd-$(ZSTD_VER).tar.gz:
@@ -2147,7 +2175,7 @@ zstd-$(ZSTD_VER).tar.gz:
 libzstd.a: zstd-$(ZSTD_VER).tar.gz
 	-rm -rf zstd-$(ZSTD_VER)
 	tar xvzf zstd-$(ZSTD_VER).tar.gz
-	cd zstd-$(ZSTD_VER)/lib && DESTDIR=. PREFIX= $(MAKE) CFLAGS='-fPIC -O2 ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' libzstd.a
+	cd zstd-$(ZSTD_VER)/lib && DESTDIR=. PREFIX= $(MAKE) CFLAGS='-fPIC -O2 $(ARCHFLAG) ${JAVA_STATIC_DEPS_CCFLAGS} ${EXTRA_CFLAGS}' LDFLAGS='${JAVA_STATIC_DEPS_LDFLAGS} ${EXTRA_LDFLAGS}' libzstd.a
 	cp zstd-$(ZSTD_VER)/lib/libzstd.a .

 # A version of each $(LIB_OBJECTS) compiled with -fPIC and a fixed set of static compression libraries
@@ -2169,41 +2197,82 @@ endif
 	$(MAKE) rocksdbjavastatic_deps
 	$(MAKE) rocksdbjavastatic_libobjects
 	$(MAKE) rocksdbjavastatic_javalib
+	$(MAKE) rocksdbjava_jar

+rocksdbjavastaticosx: rocksdbjavastaticosx_archs
+	cd java; $(JAR_CMD)  -cf target/$(ROCKSDB_JAR) HISTORY*.md
+	cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR) librocksdbjni-osx-x86_64.jnilib librocksdbjni-osx-arm64.jnilib
+	cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
+	openssl sha1 java/target/$(ROCKSDB_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR).sha1
+
+rocksdbjavastaticosx_ub: rocksdbjavastaticosx_archs
+	cd java/target; lipo -create -output librocksdbjni-osx.jnilib librocksdbjni-osx-x86_64.jnilib librocksdbjni-osx-arm64.jnilib
+	cd java; $(JAR_CMD)  -cf target/$(ROCKSDB_JAR) HISTORY*.md
+	cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR) librocksdbjni-osx.jnilib
+	cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
+	openssl sha1 java/target/$(ROCKSDB_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR).sha1
+
+rocksdbjavastaticosx_archs:
+	$(MAKE) rocksdbjavastaticosx_arch_x86_64
+	$(MAKE) rocksdbjavastaticosx_arch_arm64
+
+rocksdbjavastaticosx_arch_%:
+ifeq ($(JAVA_HOME),)
+	$(error JAVA_HOME is not set)
+endif
+	$(MAKE) clean-ext-libraries-bin
+	$(MAKE) clean-rocks
+	ARCHFLAG="-arch $*" $(MAKE) rocksdbjavastatic_deps
+	ARCHFLAG="-arch $*" $(MAKE) rocksdbjavastatic_libobjects
+	ARCHFLAG="-arch $*" ROCKSDBJNILIB="librocksdbjni-osx-$*.jnilib" $(MAKE) rocksdbjavastatic_javalib
+
+ifeq ($(JAR_CMD),)
+ifneq ($(JAVA_HOME),)
+JAR_CMD := $(JAVA_HOME)/bin/jar
+else
+JAR_CMD := jar
+endif
+endif
 rocksdbjavastatic_javalib:
 	cd java; SHA256_CMD='$(SHA256_CMD)' $(MAKE) javalib
 	rm -f java/target/$(ROCKSDBJNILIB)
 	$(CXX) $(CXXFLAGS) -I./java/. $(JAVA_INCLUDE) -shared -fPIC \
-	  -o ./java/target/$(ROCKSDBJNILIB) $(JNI_NATIVE_SOURCES) \
+	  -o ./java/target/$(ROCKSDBJNILIB) $(ALL_JNI_NATIVE_SOURCES) \
 	  $(LIB_OBJECTS) $(COVERAGEFLAGS) \
 	  $(JAVA_COMPRESSIONS) $(JAVA_STATIC_LDFLAGS)
 	cd java/target;if [ "$(DEBUG_LEVEL)" == "0" ]; then \
 		strip $(STRIPFLAGS) $(ROCKSDBJNILIB); \
 	fi
-	cd java;jar -cf target/$(ROCKSDB_JAR) HISTORY*.md
-	cd java/target;jar -uf $(ROCKSDB_JAR) $(ROCKSDBJNILIB)
-	cd java/target/classes;jar -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
-	cd java/target/apidocs;jar -cf ../$(ROCKSDB_JAVADOCS_JAR) *
-	cd java/src/main/java;jar -cf ../../../target/$(ROCKSDB_SOURCES_JAR) org
+
+rocksdbjava_jar:
+	cd java; $(JAR_CMD)  -cf target/$(ROCKSDB_JAR) HISTORY*.md
+	cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR) $(ROCKSDBJNILIB)
+	cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
 	openssl sha1 java/target/$(ROCKSDB_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR).sha1
+
+rocksdbjava_javadocs_jar:
+	cd java/target/apidocs; $(JAR_CMD) -cf ../$(ROCKSDB_JAVADOCS_JAR) *
 	openssl sha1 java/target/$(ROCKSDB_JAVADOCS_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAVADOCS_JAR).sha1
+
+rocksdbjava_sources_jar:
+	cd java/src/main/java; $(JAR_CMD) -cf ../../../target/$(ROCKSDB_SOURCES_JAR) org
 	openssl sha1 java/target/$(ROCKSDB_SOURCES_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_SOURCES_JAR).sha1

 rocksdbjavastatic_deps: $(JAVA_COMPRESSIONS)

 rocksdbjavastatic_libobjects: $(LIB_OBJECTS)

-rocksdbjavastaticrelease: rocksdbjavastatic
+rocksdbjavastaticrelease: rocksdbjavastaticosx rocksdbjava_javadocs_jar rocksdbjava_sources_jar
 	cd java/crossbuild && (vagrant destroy -f || true) && vagrant up linux32 && vagrant halt linux32 && vagrant up linux64 && vagrant halt linux64 && vagrant up linux64-musl && vagrant halt linux64-musl
-	cd java;jar -cf target/$(ROCKSDB_JAR_ALL) HISTORY*.md
-	cd java/target;jar -uf $(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
-	cd java/target/classes;jar -uf ../$(ROCKSDB_JAR_ALL) org/rocksdb/*.class org/rocksdb/util/*.class
+	cd java; $(JAR_CMD) -cf target/$(ROCKSDB_JAR_ALL) HISTORY*.md
+	cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
+	cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR_ALL) org/rocksdb/*.class org/rocksdb/util/*.class
 	openssl sha1 java/target/$(ROCKSDB_JAR_ALL) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR_ALL).sha1

-rocksdbjavastaticreleasedocker: rocksdbjavastatic rocksdbjavastaticdockerx86 rocksdbjavastaticdockerx86_64 rocksdbjavastaticdockerx86musl rocksdbjavastaticdockerx86_64musl
-	cd java;jar -cf target/$(ROCKSDB_JAR_ALL) HISTORY*.md
-	cd java/target;jar -uf $(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
-	cd java/target/classes;jar -uf ../$(ROCKSDB_JAR_ALL) org/rocksdb/*.class org/rocksdb/util/*.class
+rocksdbjavastaticreleasedocker: rocksdbjavastaticosx rocksdbjavastaticdockerx86 rocksdbjavastaticdockerx86_64 rocksdbjavastaticdockerx86musl rocksdbjavastaticdockerx86_64musl rocksdbjava_javadocs_jar rocksdbjava_sources_jar
+	cd java; $(JAR_CMD) -cf target/$(ROCKSDB_JAR_ALL) HISTORY*.md
+	cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
+	cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR_ALL) org/rocksdb/*.class org/rocksdb/util/*.class
 	openssl sha1 java/target/$(ROCKSDB_JAR_ALL) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR_ALL).sha1

 rocksdbjavastaticdockerx86:
@@ -2222,40 +2291,54 @@ rocksdbjavastaticdockerarm64v8:
 	mkdir -p java/target
 	docker run --rm --name rocksdb_linux_arm64v8-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:centos7_arm64v8-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh

+rocksdbjavastaticdockers390x:
+	mkdir -p java/target
+	docker run --rm --name rocksdb_linux_s390x-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:ubuntu18_s390x-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+
 rocksdbjavastaticdockerx86musl:
 	mkdir -p java/target
-	docker run --rm --name rocksdb_linux_x86-musl-be --platform linux/386 --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_x86-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+	docker run --rm --name rocksdb_linux_x86-musl-be --platform linux/386 --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_x86-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh

 rocksdbjavastaticdockerx86_64musl:
 	mkdir -p java/target
-	docker run --rm --name rocksdb_linux_x64-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_x64-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+	docker run --rm --name rocksdb_linux_x64-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_x64-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh

 rocksdbjavastaticdockerppc64lemusl:
 	mkdir -p java/target
-	docker run --rm --name rocksdb_linux_ppc64le-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_ppc64le-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+	docker run --rm --name rocksdb_linux_ppc64le-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_ppc64le-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh

 rocksdbjavastaticdockerarm64v8musl:
 	mkdir -p java/target
-	docker run --rm --name rocksdb_linux_arm64v8-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_arm64v8-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+	docker run --rm --name rocksdb_linux_arm64v8-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_arm64v8-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh
+
+rocksdbjavastaticdockers390xmusl:
+	mkdir -p java/target
+	docker run --rm --name rocksdb_linux_s390x-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_s390x-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh

 rocksdbjavastaticpublish: rocksdbjavastaticrelease rocksdbjavastaticpublishcentral

 rocksdbjavastaticpublishdocker: rocksdbjavastaticreleasedocker rocksdbjavastaticpublishcentral

+ROCKSDB_JAVA_RELEASE_CLASSIFIERS = javadoc sources linux64 linux32 linux64-musl linux32-musl osx win64
+
 rocksdbjavastaticpublishcentral: rocksdbjavageneratepom
-	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-javadoc.jar -Dclassifier=javadoc
-	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-sources.jar -Dclassifier=sources
-	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-linux64.jar -Dclassifier=linux64
-	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-linux32.jar -Dclassifier=linux32
-	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-linux64-musl.jar -Dclassifier=linux64-musl
-	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-linux32-musl.jar -Dclassifier=linux32-musl
-	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-osx.jar -Dclassifier=osx
-	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-win64.jar -Dclassifier=win64
 	mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar
+	$(foreach classifier, $(ROCKSDB_JAVA_RELEASE_CLASSIFIERS), mvn gpg:sign-and-deploy-file -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ -DrepositoryId=sonatype-nexus-staging -DpomFile=java/pom.xml -Dfile=java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar -Dclassifier=$(classifier);)

 rocksdbjavageneratepom:
 	cd java;cat pom.xml.template | sed 's/\$${ROCKSDB_JAVA_VERSION}/$(ROCKSDB_JAVA_VERSION)/' > pom.xml

+rocksdbjavastaticnexusbundlejar: rocksdbjavageneratepom
+	openssl sha1 -r java/pom.xml | awk '{  print $$1 }' > java/target/pom.xml.sha1
+	openssl sha1 -r java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar | awk '{  print $$1 }' > java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar.sha1
+	$(foreach classifier, $(ROCKSDB_JAVA_RELEASE_CLASSIFIERS), openssl sha1 -r java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar | awk '{  print $$1 }' > java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar.sha1;)
+	gpg --yes --output java/target/pom.xml.asc -ab java/pom.xml
+	gpg --yes -ab java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar
+	$(foreach classifier, $(ROCKSDB_JAVA_RELEASE_CLASSIFIERS), gpg --yes -ab java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar;)
+	$(JAR_CMD) cvf java/target/nexus-bundle-rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar -C java pom.xml -C java/target pom.xml.sha1 -C java/target pom.xml.asc -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar.sha1 -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar.asc
+	$(foreach classifier, $(ROCKSDB_JAVA_RELEASE_CLASSIFIERS), $(JAR_CMD) uf java/target/nexus-bundle-rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar.sha1 -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar.asc;)
+
+
 # A version of each $(LIBOBJECTS) compiled with -fPIC

 jl/%.o: %.cc
@@ -2267,10 +2350,10 @@ ifeq ($(JAVA_HOME),)
 endif
 	$(AM_V_GEN)cd java; SHA256_CMD='$(SHA256_CMD)' $(MAKE) javalib;
 	$(AM_V_at)rm -f ./java/target/$(ROCKSDBJNILIB)
-	$(AM_V_at)$(CXX) $(CXXFLAGS) -I./java/. $(JAVA_INCLUDE) -shared -fPIC -o ./java/target/$(ROCKSDBJNILIB) $(JNI_NATIVE_SOURCES) $(LIB_OBJECTS) $(JAVA_LDFLAGS) $(COVERAGEFLAGS)
-	$(AM_V_at)cd java;jar -cf target/$(ROCKSDB_JAR) HISTORY*.md
-	$(AM_V_at)cd java/target;jar -uf $(ROCKSDB_JAR) $(ROCKSDBJNILIB)
-	$(AM_V_at)cd java/target/classes;jar -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
+	$(AM_V_at)$(CXX) $(CXXFLAGS) -I./java/. -I./java/rocksjni $(JAVA_INCLUDE) $(ROCKSDB_PLUGIN_JNI_CXX_INCLUDEFLAGS) -shared -fPIC -o ./java/target/$(ROCKSDBJNILIB) $(ALL_JNI_NATIVE_SOURCES) $(LIB_OBJECTS) $(JAVA_LDFLAGS) $(COVERAGEFLAGS)
+	$(AM_V_at)cd java; $(JAR_CMD) -cf target/$(ROCKSDB_JAR) HISTORY*.md
+	$(AM_V_at)cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR) $(ROCKSDBJNILIB)
+	$(AM_V_at)cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
 	$(AM_V_at)openssl sha1 java/target/$(ROCKSDB_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR).sha1

 jclean:
@@ -2389,6 +2472,9 @@ endif
 build_subset_tests: $(ROCKSDBTESTS_SUBSET)
 	$(AM_V_GEN)if [ -n "$${ROCKSDBTESTS_SUBSET_TESTS_TO_FILE}" ]; then echo "$(ROCKSDBTESTS_SUBSET)" > "$${ROCKSDBTESTS_SUBSET_TESTS_TO_FILE}"; else echo "$(ROCKSDBTESTS_SUBSET)"; fi

+list_all_tests:
+	echo "$(ROCKSDBTESTS_SUBSET)"
+
 # Remove the rules for which dependencies should not be generated and see if any are left.
 #If so, include the dependencies; if not, do not include the dependency files
 ROCKS_DEP_RULES=$(filter-out clean format check-format check-buck-targets check-headers check-sources jclean jtest package analyze tags rocksdbjavastatic% unity.% unity_test, $(MAKECMDGOALS))
@@ -1,4 +1,6 @@
 This is the list of all known third-party plugins for RocksDB. If something is missing, please open a pull request to add it.

 * [Dedupfs](https://github.com/ajkr/dedupfs): an example for plugin developers to reference
+* [HDFS](https://github.com/riversand963/rocksdb-hdfs-env): an Env used for interacting with HDFS. Migrated from main RocksDB repo
 * [ZenFS](https://github.com/westerndigitalcorporation/zenfs): a file system for zoned block devices
+* [RADOS](https://github.com/riversand963/rocksdb-rados-env): an Env used for interacting with RADOS. Migrated from RocksDB main repo.
@@ -25,7 +25,7 @@ The public interface is in `include/`.  Callers should not include or
 rely on the details of any other header files in this package.  Those
 internal APIs may be changed without warning.

-Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/ and https://rocksdb.slack.com/
+Questions and discussions are welcome on the [RocksDB Developers Public](https://www.facebook.com/groups/rocksdb.dev/) Facebook group and [email list](https://groups.google.com/g/rocksdb) on Google Groups.

 ## License

@@ -121,6 +121,8 @@ LzLabs is using RocksDB as a storage engine in their multi-database distributed
 ## Kafka
 [Kafka](https://kafka.apache.org/) is an open-source distributed event streaming platform, it uses RocksDB to store state in Kafka Streams: https://www.confluent.io/blog/how-to-tune-rocksdb-kafka-streams-state-stores-performance/.

+## Solana Labs
+[Solana](https://github.com/solana-labs/solana) is a fast, secure, scalable, and decentralized blockchain.  It uses RocksDB as the underlying storage for its ledger store.
+
 ## Others
 More databases using RocksDB can be found at [dbdb.io](https://dbdb.io/browse?embeds=rocksdb).
-
@@ -1,77 +0,0 @@
-version: 1.0.{build}
-
-image: Visual Studio 2019
-
-environment:
-  JAVA_HOME: C:\Program Files\Java\jdk1.8.0
-  THIRDPARTY_HOME: $(APPVEYOR_BUILD_FOLDER)\thirdparty
-  SNAPPY_HOME: $(THIRDPARTY_HOME)\snappy-1.1.7
-  SNAPPY_INCLUDE: $(SNAPPY_HOME);$(SNAPPY_HOME)\build
-  SNAPPY_LIB_DEBUG: $(SNAPPY_HOME)\build\Debug\snappy.lib
-  SNAPPY_LIB_RELEASE: $(SNAPPY_HOME)\build\Release\snappy.lib
-  LZ4_HOME: $(THIRDPARTY_HOME)\lz4-1.8.3
-  LZ4_INCLUDE: $(LZ4_HOME)\lib
-  LZ4_LIB_DEBUG: $(LZ4_HOME)\visual\VS2010\bin\x64_Debug\liblz4_static.lib
-  LZ4_LIB_RELEASE: $(LZ4_HOME)\visual\VS2010\bin\x64_Release\liblz4_static.lib
-  ZSTD_HOME: $(THIRDPARTY_HOME)\zstd-1.4.0
-  ZSTD_INCLUDE: $(ZSTD_HOME)\lib;$(ZSTD_HOME)\lib\dictBuilder
-  ZSTD_LIB_DEBUG: $(ZSTD_HOME)\build\VS2010\bin\x64_Debug\libzstd_static.lib
-  ZSTD_LIB_RELEASE: $(ZSTD_HOME)\build\VS2010\bin\x64_Release\libzstd_static.lib
-  matrix:
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      CMAKE_GENERATOR: Visual Studio 14 Win64
-      DEV_ENV: C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\devenv.com
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      CMAKE_GENERATOR: Visual Studio 15 Win64
-      DEV_ENV: C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\devenv.com
-
-install:
-  - md %THIRDPARTY_HOME%
-  - echo "Building Snappy dependency..."
-  - cd %THIRDPARTY_HOME%
-  - curl --fail --silent --show-error --output snappy-1.1.7.zip --location https://github.com/google/snappy/archive/1.1.7.zip
-  - unzip snappy-1.1.7.zip
-  - cd snappy-1.1.7
-  - mkdir build
-  - cd build
-  - if DEFINED CMAKE_PLATEFORM_NAME (set "PLATEFORM_OPT=-A %CMAKE_PLATEFORM_NAME%")
-  - cmake .. -G "%CMAKE_GENERATOR%" %PLATEFORM_OPT%
-  - msbuild Snappy.sln /p:Configuration=Debug /p:Platform=x64
-  - msbuild Snappy.sln /p:Configuration=Release /p:Platform=x64
-  - echo "Building LZ4 dependency..."
-  - cd %THIRDPARTY_HOME%
-  - curl --fail --silent --show-error --output lz4-1.8.3.zip --location https://github.com/lz4/lz4/archive/v1.8.3.zip
-  - unzip lz4-1.8.3.zip
-  - cd lz4-1.8.3\visual\VS2010
-  - ps: $CMD="$Env:DEV_ENV"; & $CMD lz4.sln /upgrade
-  - msbuild lz4.sln /p:Configuration=Debug /p:Platform=x64
-  - msbuild lz4.sln /p:Configuration=Release /p:Platform=x64
-  - echo "Building ZStd dependency..."
-  - cd %THIRDPARTY_HOME%
-  - curl --fail --silent --show-error --output zstd-1.4.0.zip --location https://github.com/facebook/zstd/archive/v1.4.0.zip
-  - unzip zstd-1.4.0.zip
-  - cd zstd-1.4.0\build\VS2010
-  - ps: $CMD="$Env:DEV_ENV"; & $CMD zstd.sln /upgrade
-  - msbuild zstd.sln /p:Configuration=Debug /p:Platform=x64
-  - msbuild zstd.sln /p:Configuration=Release /p:Platform=x64
-
-before_build:
-  - md %APPVEYOR_BUILD_FOLDER%\build
-  - cd %APPVEYOR_BUILD_FOLDER%\build
-  - if DEFINED CMAKE_PLATEFORM_NAME (set "PLATEFORM_OPT=-A %CMAKE_PLATEFORM_NAME%")
-  - cmake .. -G "%CMAKE_GENERATOR%" %PLATEFORM_OPT% %CMAKE_OPT% -DCMAKE_BUILD_TYPE=Debug -DOPTDBG=1 -DPORTABLE=1 -DSNAPPY=1 -DLZ4=1 -DZSTD=1 -DXPRESS=1 -DJNI=1 -DWITH_ALL_TESTS=0
-  - cd ..
-
-build:
-  project: build\rocksdb.sln
-  parallel: true
-  verbosity: normal
-
-test:
-
-test_script:
-  - ps: build_tools\run_ci_db_test.ps1 -SuiteRun db_basic_test,env_basic_test -Concurrency 8
-
-on_failure:
-  - cmd: 7z a build-failed.zip %APPVEYOR_BUILD_FOLDER%\build\ && appveyor PushArtifact build-failed.zip
-
@@ -163,9 +163,8 @@ def generate_targets(repo_path, deps_map):
        src_mk.get("EXP_LIB_SOURCES", []) +
        src_mk.get("ANALYZER_LIB_SOURCES", []),
        [":rocksdb_lib"],
-        extra_external_deps=""" + [
-        ("googletest", None, "gtest"),
-    ]""")
+        extra_test_libs=True
+        )
    # rocksdb_tools_lib
    TARGETS.add_library(
        "rocksdb_tools_lib",
@@ -184,12 +183,19 @@ def generate_targets(repo_path, deps_map):
        src_mk.get("ANALYZER_LIB_SOURCES", [])
        + src_mk.get('STRESS_LIB_SOURCES', [])
        + ["test_util/testutil.cc"])
-
+    # bench binaries
+    for src in src_mk.get("MICROBENCH_SOURCES", []):
+        name =  src.rsplit('/',1)[1].split('.')[0] if '/' in src else src.split('.')[0]
+        TARGETS.add_binary(
+            name,
+            [src],
+            [],
+            extra_bench_libs=True
+            )
    print("Extra dependencies:\n{0}".format(json.dumps(deps_map)))

    # Dictionary test executable name -> relative source file path
    test_source_map = {}
-    print(src_mk)

    # c_test.c is added through TARGETS.add_c_test(). If there
    # are more than one .c test file, we need to extend
@@ -200,6 +206,42 @@ def generate_targets(repo_path, deps_map):
            return False
    TARGETS.add_c_test()

+    try:
+        with open(f"{repo_path}/buckifier/bench.json") as json_file:
+            fast_fancy_bench_config_list = json.load(json_file)
+            for config_dict in fast_fancy_bench_config_list:
+                clean_benchmarks = {}
+                benchmarks = config_dict['benchmarks']
+                for binary, benchmark_dict in benchmarks.items():
+                    clean_benchmarks[binary] = {}
+                    for benchmark, overloaded_metric_list in benchmark_dict.items():
+                        clean_benchmarks[binary][benchmark] = []
+                        for metric in overloaded_metric_list:
+                            if not isinstance(metric, dict):
+                                clean_benchmarks[binary][benchmark].append(metric)
+                TARGETS.add_fancy_bench_config(config_dict['name'], clean_benchmarks, False, config_dict['expected_runtime_one_iter'], config_dict['sl_iterations'], config_dict['regression_threshold'])
+
+        with open(f"{repo_path}/buckifier/bench-slow.json") as json_file:
+            slow_fancy_bench_config_list = json.load(json_file)
+            for config_dict in slow_fancy_bench_config_list:
+                clean_benchmarks = {}
+                benchmarks = config_dict['benchmarks']
+                for binary, benchmark_dict in benchmarks.items():
+                    clean_benchmarks[binary] = {}
+                    for benchmark, overloaded_metric_list in benchmark_dict.items():
+                        clean_benchmarks[binary][benchmark] = []
+                        for metric in overloaded_metric_list:
+                            if not isinstance(metric, dict):
+                                clean_benchmarks[binary][benchmark].append(metric)
+            for config_dict in slow_fancy_bench_config_list:
+                TARGETS.add_fancy_bench_config(config_dict['name']+"_slow", clean_benchmarks, True, config_dict['expected_runtime_one_iter'], config_dict['sl_iterations'], config_dict['regression_threshold'])
+    # it is better servicelab experiments break
+    # than rocksdb github ci
+    except Exception:
+        pass
+
+    TARGETS.add_test_header()
+
    for test_src in src_mk.get("TEST_MAIN_SOURCES", []):
        test = test_src.split('.c')[0].strip().split('/')[-1].strip()
        test_source_map[test] = test_src
@@ -213,17 +255,21 @@ def generate_targets(repo_path, deps_map):

            test_target_name = \
                test if not target_alias else test + "_" + target_alias
-            TARGETS.register_test(
-                test_target_name,
-                test_src,
-                test not in non_parallel_tests,
-                json.dumps(deps['extra_deps']),
-                json.dumps(deps['extra_compiler_flags']))

            if test in _EXPORTED_TEST_LIBS:
                test_library = "%s_lib" % test_target_name
-                TARGETS.add_library(test_library, [test_src], [":rocksdb_test_lib"])
-    TARGETS.flush_tests()
+                TARGETS.add_library(test_library, [test_src], deps=[":rocksdb_test_lib"], extra_test_libs=True)
+                TARGETS.register_test(
+                    test_target_name,
+                    test_src,
+                    deps = json.dumps(deps['extra_deps'] + [':'+test_library]),
+                    extra_compiler_flags = json.dumps(deps['extra_compiler_flags']))
+            else:
+                TARGETS.register_test(
+                    test_target_name,
+                    test_src,
+                    deps = json.dumps(deps['extra_deps'] + [":rocksdb_test_lib"] ),
+                    extra_compiler_flags = json.dumps(deps['extra_compiler_flags']))

    print(ColorString.info("Generated TARGETS Summary:"))
    print(ColorString.info("- %d libs" % TARGETS.total_lib))
@@ -10,6 +10,7 @@ except ImportError:
    from __builtin__ import object
    from __builtin__ import str
 import targets_cfg
+import pprint

 def pretty_list(lst, indent=8):
    if lst is None or len(lst) == 0:
@@ -40,85 +41,73 @@ class TARGETSBuilder(object):
        self.targets_file.close()

    def add_library(self, name, srcs, deps=None, headers=None,
-                    extra_external_deps="", link_whole=False):
-        headers_attr_prefix = ""
-        if headers is None:
-            headers_attr_prefix = "auto_"
-            headers = "AutoHeaders.RECURSIVE_GLOB"
-        else:
+                    extra_external_deps="", link_whole=False,
+                     external_dependencies=None, extra_test_libs=False):
+        if headers is not None:
            headers = "[" + pretty_list(headers) + "]"
        self.targets_file.write(targets_cfg.library_template.format(
            name=name,
            srcs=pretty_list(srcs),
-            headers_attr_prefix=headers_attr_prefix,
            headers=headers,
            deps=pretty_list(deps),
            extra_external_deps=extra_external_deps,
-            link_whole=link_whole).encode("utf-8"))
+            link_whole=link_whole,
+            external_dependencies=pretty_list(external_dependencies),
+            extra_test_libs=extra_test_libs
+            ).encode("utf-8"))
        self.total_lib = self.total_lib + 1

-    def add_rocksdb_library(self, name, srcs, headers=None):
-        headers_attr_prefix = ""
-        if headers is None:
-            headers_attr_prefix = "auto_"
-            headers = "AutoHeaders.RECURSIVE_GLOB"
-        else:
+    def add_rocksdb_library(self, name, srcs, headers=None,
+                            external_dependencies=None):
+        if headers is not None:
            headers = "[" + pretty_list(headers) + "]"
        self.targets_file.write(targets_cfg.rocksdb_library_template.format(
            name=name,
            srcs=pretty_list(srcs),
-            headers_attr_prefix=headers_attr_prefix,
-            headers=headers).encode("utf-8"))
+            headers=headers,
+            external_dependencies=pretty_list(external_dependencies)
+            ).encode("utf-8")
+            )
        self.total_lib = self.total_lib + 1

-    def add_binary(self, name, srcs, deps=None):
+    def add_binary(self, name, srcs, deps=None, extra_preprocessor_flags=None,extra_bench_libs=False):
        self.targets_file.write(targets_cfg.binary_template.format(
            name=name,
            srcs=pretty_list(srcs),
-            deps=pretty_list(deps)).encode("utf-8"))
+            deps=pretty_list(deps),
+            extra_preprocessor_flags=pretty_list(extra_preprocessor_flags),
+            extra_bench_libs=extra_bench_libs,
+            ).encode("utf-8"))
        self.total_bin = self.total_bin + 1

    def add_c_test(self):
        self.targets_file.write(b"""
-cpp_binary(
-    name = "c_test_bin",
-    srcs = ["db/c_test.c"],
-    arch_preprocessor_flags = ROCKSDB_ARCH_PREPROCESSOR_FLAGS,
-    os_preprocessor_flags = ROCKSDB_OS_PREPROCESSOR_FLAGS,
-    compiler_flags = ROCKSDB_COMPILER_FLAGS,
-    preprocessor_flags = ROCKSDB_PREPROCESSOR_FLAGS,
-    include_paths = ROCKSDB_INCLUDE_PATHS,
-    deps = [":rocksdb_test_lib"],
-) if not is_opt_mode else None
-
-custom_unittest(
-    name = "c_test",
-    command = [
-        native.package_name() + "/buckifier/rocks_test_runner.sh",
-        "$(location :{})".format("c_test_bin"),
-    ],
-    type = "simple",
-) if not is_opt_mode else None
+add_c_test_wrapper()
 """)

+    def add_test_header(self):
+        self.targets_file.write(b"""
+        # Generate a test rule for each entry in ROCKS_TESTS
+        # Do not build the tests in opt mode, since SyncPoint and other test code
+        # will not be included.
+""")
+
+    def add_fancy_bench_config(self, name, bench_config, slow, expected_runtime, sl_iterations, regression_threshold):
+        self.targets_file.write(targets_cfg.fancy_bench_template.format(
+                    name=name,
+                    bench_config=pprint.pformat(bench_config),
+                    slow=slow,
+                    expected_runtime=expected_runtime,
+                    sl_iterations=sl_iterations,
+                    regression_threshold=regression_threshold
+                    ).encode("utf-8"))
+
    def register_test(self,
                      test_name,
                      src,
-                      is_parallel,
-                      extra_deps,
+                      deps,
                      extra_compiler_flags):
-        exec_mode = "serial"
-        if is_parallel:
-            exec_mode = "parallel"
-        self.tests_cfg += targets_cfg.test_cfg_template % (
-            test_name,
-            str(src),
-            str(exec_mode),
-            extra_deps,
-            extra_compiler_flags)

+        self.targets_file.write(targets_cfg.unittests_template.format(test_name=test_name,test_cc=str(src),deps=deps,
+            extra_compiler_flags=extra_compiler_flags).encode("utf-8"))
        self.total_test = self.total_test + 1
-
-    def flush_tests(self):
-        self.targets_file.write(targets_cfg.unittests_template.format(tests=self.tests_cfg).encode("utf-8"))
-        self.tests_cfg = ""
@@ -11,210 +11,36 @@ rocksdb_target_header_template = \
 # This file is a Facebook-specific integration for buck builds, so can
 # only be validated by Facebook employees.
 #
-load("@fbcode_macros//build_defs:auto_headers.bzl", "AutoHeaders")
-load("@fbcode_macros//build_defs:cpp_library.bzl", "cpp_library")
-load(":defs.bzl", "test_binary")
+# @noautodeps @nocodemods
+load("//rocks/buckifier:defs.bzl", "cpp_library_wrapper","rocks_cpp_library_wrapper","cpp_binary_wrapper","cpp_unittest_wrapper","fancy_bench_wrapper","add_c_test_wrapper")

-REPO_PATH = package_name() + "/"
-
-ROCKSDB_COMPILER_FLAGS_0 = [
-    "-fno-builtin-memcmp",
-    # Needed to compile in fbcode
-    "-Wno-expansion-to-defined",
-    # Added missing flags from output of build_detect_platform
-    "-Wnarrowing",
-    "-DROCKSDB_NO_DYNAMIC_EXTENSION",
-]
-
-ROCKSDB_EXTERNAL_DEPS = [
-    ("bzip2", None, "bz2"),
-    ("snappy", None, "snappy"),
-    ("zlib", None, "z"),
-    ("gflags", None, "gflags"),
-    ("lz4", None, "lz4"),
-    ("zstd", None, "zstd"),
-]
-
-ROCKSDB_OS_DEPS_0 = [
-    (
-        "linux",
-        ["third-party//numa:numa", "third-party//liburing:uring", "third-party//tbb:tbb"],
-    ),
-    (
-        "macos",
-        ["third-party//tbb:tbb"],
-    ),
-]
-
-ROCKSDB_OS_PREPROCESSOR_FLAGS_0 = [
-    (
-        "linux",
-        [
-            "-DOS_LINUX",
-            "-DROCKSDB_FALLOCATE_PRESENT",
-            "-DROCKSDB_MALLOC_USABLE_SIZE",
-            "-DROCKSDB_PTHREAD_ADAPTIVE_MUTEX",
-            "-DROCKSDB_RANGESYNC_PRESENT",
-            "-DROCKSDB_SCHED_GETCPU_PRESENT",
-            "-DROCKSDB_IOURING_PRESENT",
-            "-DHAVE_SSE42",
-            "-DLIBURING",
-            "-DNUMA",
-            "-DROCKSDB_PLATFORM_POSIX",
-            "-DROCKSDB_LIB_IO_POSIX",
-            "-DTBB",
-        ],
-    ),
-    (
-        "macos",
-        [
-            "-DOS_MACOSX",
-            "-DROCKSDB_PLATFORM_POSIX",
-            "-DROCKSDB_LIB_IO_POSIX",
-            "-DTBB",
-        ],
-    ),
-    (
-        "windows",
-        [ "-DOS_WIN", "-DWIN32", "-D_MBCS", "-DWIN64", "-DNOMINMAX" ]
-    ),
-]
-
-ROCKSDB_PREPROCESSOR_FLAGS = [
-    "-DROCKSDB_SUPPORT_THREAD_LOCAL",
-
-    # Flags to enable libs we include
-    "-DSNAPPY",
-    "-DZLIB",
-    "-DBZIP2",
-    "-DLZ4",
-    "-DZSTD",
-    "-DZSTD_STATIC_LINKING_ONLY",
-    "-DGFLAGS=gflags",
-
-    # Added missing flags from output of build_detect_platform
-    "-DROCKSDB_BACKTRACE",
-]
-
-# Directories with files for #include
-ROCKSDB_INCLUDE_PATHS = [
-    "",
-    "include",
-]
-
-ROCKSDB_ARCH_PREPROCESSOR_FLAGS = {{
-    "x86_64": [
-        "-DHAVE_PCLMUL",
-    ],
-}}
-
-build_mode = read_config("fbcode", "build_mode")
-
-is_opt_mode = build_mode.startswith("opt")
-
-# -DNDEBUG is added by default in opt mode in fbcode. But adding it twice
-# doesn't harm and avoid forgetting to add it.
-ROCKSDB_COMPILER_FLAGS = ROCKSDB_COMPILER_FLAGS_0 + (["-DNDEBUG"] if is_opt_mode else [])
-
-sanitizer = read_config("fbcode", "sanitizer")
-
-# Do not enable jemalloc if sanitizer presents. RocksDB will further detect
-# whether the binary is linked with jemalloc at runtime.
-ROCKSDB_OS_PREPROCESSOR_FLAGS = ROCKSDB_OS_PREPROCESSOR_FLAGS_0 + ([(
-    "linux",
-    ["-DROCKSDB_JEMALLOC"],
-)] if sanitizer == "" else [])
-
-ROCKSDB_OS_DEPS = ROCKSDB_OS_DEPS_0 + ([(
-    "linux",
-    ["third-party//jemalloc:headers"],
-)] if sanitizer == "" else [])
-
-ROCKSDB_LIB_DEPS = [
-    ":rocksdb_lib",
-    ":rocksdb_test_lib",
-] if not is_opt_mode else [":rocksdb_lib"]
 """


 library_template = """
-cpp_library(
-    name = "{name}",
-    srcs = [{srcs}],
-    {headers_attr_prefix}headers = {headers},
-    arch_preprocessor_flags = ROCKSDB_ARCH_PREPROCESSOR_FLAGS,
-    compiler_flags = ROCKSDB_COMPILER_FLAGS,
-    os_deps = ROCKSDB_OS_DEPS,
-    os_preprocessor_flags = ROCKSDB_OS_PREPROCESSOR_FLAGS,
-    preprocessor_flags = ROCKSDB_PREPROCESSOR_FLAGS,
-    include_paths = ROCKSDB_INCLUDE_PATHS,
-    deps = [{deps}],
-    external_deps = ROCKSDB_EXTERNAL_DEPS{extra_external_deps},
-    link_whole = {link_whole},
-)
+cpp_library_wrapper(name="{name}", srcs=[{srcs}], deps=[{deps}], headers={headers}, link_whole={link_whole}, extra_test_libs={extra_test_libs})
 """

 rocksdb_library_template = """
-cpp_library(
-    name = "{name}",
-    srcs = [{srcs}],
-    {headers_attr_prefix}headers = {headers},
-    arch_preprocessor_flags = ROCKSDB_ARCH_PREPROCESSOR_FLAGS,
-    compiler_flags = ROCKSDB_COMPILER_FLAGS,
-    os_deps = ROCKSDB_OS_DEPS,
-    os_preprocessor_flags = ROCKSDB_OS_PREPROCESSOR_FLAGS,
-    preprocessor_flags = ROCKSDB_PREPROCESSOR_FLAGS,
-    include_paths = ROCKSDB_INCLUDE_PATHS,
-    deps = ROCKSDB_LIB_DEPS,
-    external_deps = ROCKSDB_EXTERNAL_DEPS,
-)
+rocks_cpp_library_wrapper(name="{name}", srcs=[{srcs}], headers={headers})
+
 """

+
+
 binary_template = """
-cpp_binary(
-    name = "{name}",
-    srcs = [{srcs}],
-    arch_preprocessor_flags = ROCKSDB_ARCH_PREPROCESSOR_FLAGS,
-    compiler_flags = ROCKSDB_COMPILER_FLAGS,
-    preprocessor_flags = ROCKSDB_PREPROCESSOR_FLAGS,
-    include_paths = ROCKSDB_INCLUDE_PATHS,
-    deps = [{deps}],
-    external_deps = ROCKSDB_EXTERNAL_DEPS,
-)
-"""
-
-test_cfg_template = """    [
-        "%s",
-        "%s",
-        "%s",
-        %s,
-        %s,
-    ],
+cpp_binary_wrapper(name="{name}", srcs=[{srcs}], deps=[{deps}], extra_preprocessor_flags=[{extra_preprocessor_flags}], extra_bench_libs={extra_bench_libs})
 """

 unittests_template = """
-# [test_name, test_src, test_type, extra_deps, extra_compiler_flags]
-ROCKS_TESTS = [
-{tests}]
+cpp_unittest_wrapper(name="{test_name}",
+            srcs=["{test_cc}"],
+            deps={deps},
+            extra_compiler_flags={extra_compiler_flags})
+
+"""
+
+fancy_bench_template = """
+fancy_bench_wrapper(suite_name="{name}", binary_to_bench_to_metric_list_map={bench_config}, slow={slow}, expected_runtime={expected_runtime}, sl_iterations={sl_iterations}, regression_threshold={regression_threshold})

-# Generate a test rule for each entry in ROCKS_TESTS
-# Do not build the tests in opt mode, since SyncPoint and other test code
-# will not be included.
-[
-    cpp_unittest(
-        name = test_name,
-        srcs = [test_cc],
-        arch_preprocessor_flags = ROCKSDB_ARCH_PREPROCESSOR_FLAGS,
-        os_preprocessor_flags = ROCKSDB_OS_PREPROCESSOR_FLAGS,
-        compiler_flags = ROCKSDB_COMPILER_FLAGS + extra_compiler_flags,
-        preprocessor_flags = ROCKSDB_PREPROCESSOR_FLAGS,
-        include_paths = ROCKSDB_INCLUDE_PATHS,
-        deps = [":rocksdb_test_lib"] + extra_deps,
-        external_deps = ROCKSDB_EXTERNAL_DEPS + [
-            ("googletest", None, "gtest"),
-        ],
-    )
-    for test_name, test_cc, parallelism, extra_deps, extra_compiler_flags in ROCKS_TESTS
-    if not is_opt_mode
-]
 """
@@ -45,11 +45,11 @@ if test -z "$OUTPUT"; then
  exit 1
 fi

-# we depend on C++11, but should be compatible with newer standards
+# we depend on C++17, but should be compatible with newer standards
 if [ "$ROCKSDB_CXX_STANDARD" ]; then
  PLATFORM_CXXFLAGS="-std=$ROCKSDB_CXX_STANDARD"
 else
-  PLATFORM_CXXFLAGS="-std=c++11"
+  PLATFORM_CXXFLAGS="-std=c++17"
 fi

 # we currently depend on POSIX platform
@@ -58,8 +58,11 @@ COMMON_FLAGS="-DROCKSDB_PLATFORM_POSIX -DROCKSDB_LIB_IO_POSIX"
 # Default to fbcode gcc on internal fb machines
 if [ -z "$ROCKSDB_NO_FBCODE" -a -d /mnt/gvfs/third-party ]; then
    FBCODE_BUILD="true"
-    # If we're compiling with TSAN we need pic build
+    # If we're compiling with TSAN or shared lib, we need pic build
    PIC_BUILD=$COMPILE_WITH_TSAN
+    if [ "$LIB_MODE" == "shared" ]; then
+      PIC_BUILD=1
+    fi
    if [ -n "$ROCKSDB_FBCODE_BUILD_WITH_481" ]; then
      # we need this to build with MySQL. Don't use for other purposes.
      source "$PWD/build_tools/fbcode_config4.8.1.sh"
@@ -176,7 +179,7 @@ case "$TARGET_OS" in
        fi
        if test "$ROCKSDB_USE_IO_URING" -ne 0; then
            # check for liburing
-            $CXX $PLATFORM_CXXFLAGS -x c++ - -luring -o /dev/null 2>/dev/null  <<EOF
+            $CXX $PLATFORM_CXXFLAGS -x c++ - -luring -o test.o 2>/dev/null  <<EOF
              #include <liburing.h>
              int main() {
                struct io_uring ring;
@@ -271,7 +274,7 @@ esac
 PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS ${CXXFLAGS}"
 JAVA_LDFLAGS="$PLATFORM_LDFLAGS"
 JAVA_STATIC_LDFLAGS="$PLATFORM_LDFLAGS"
-JAVAC_ARGS="-source 7"
+JAVAC_ARGS="-source 8"

 if [ "$CROSS_COMPILE" = "true" -o "$FBCODE_BUILD" = "true" ]; then
    # Cross-compiling; do not try any compilation tests.
@@ -284,7 +287,7 @@ if [ "$CROSS_COMPILE" = "true" -o "$FBCODE_BUILD" = "true" ]; then
 else
    if ! test $ROCKSDB_DISABLE_FALLOCATE; then
        # Test whether fallocate is available
-        $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <fcntl.h>
          #include <linux/falloc.h>
          int main() {
@@ -300,7 +303,7 @@ EOF
    if ! test $ROCKSDB_DISABLE_SNAPPY; then
        # Test whether Snappy library is installed
        # http://code.google.com/p/snappy/
-        $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <snappy.h>
          int main() {}
 EOF
@@ -315,7 +318,7 @@ EOF
        # Test whether gflags library is installed
        # http://gflags.github.io/gflags/
        # check if the namespace is gflags
-        if $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null << EOF
+        if $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null << EOF
          #include <gflags/gflags.h>
          using namespace GFLAGS_NAMESPACE;
          int main() {}
@@ -324,7 +327,7 @@ EOF
          COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS=1"
          PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lgflags"
        # check if namespace is gflags
-        elif $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null << EOF
+        elif $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null << EOF
            #include <gflags/gflags.h>
            using namespace gflags;
            int main() {}
@@ -333,7 +336,7 @@ EOF
          COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS=1 -DGFLAGS_NAMESPACE=gflags"
          PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lgflags"
        # check if namespace is google
-        elif $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null << EOF
+        elif $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null << EOF
            #include <gflags/gflags.h>
            using namespace google;
            int main() {}
@@ -346,7 +349,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_ZLIB; then
        # Test whether zlib library is installed
-        $CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <zlib.h>
          int main() {}
 EOF
@@ -359,7 +362,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_BZIP; then
        # Test whether bzip library is installed
-        $CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <bzlib.h>
          int main() {}
 EOF
@@ -372,7 +375,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_LZ4; then
        # Test whether lz4 library is installed
-        $CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <lz4.h>
          #include <lz4hc.h>
          int main() {}
@@ -399,7 +402,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_NUMA; then
        # Test whether numa is available
-        $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null -lnuma 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o -lnuma 2>/dev/null  <<EOF
          #include <numa.h>
          #include <numaif.h>
          int main() {}
@@ -413,7 +416,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_TBB; then
        # Test whether tbb is available
-        $CXX $PLATFORM_CXXFLAGS $LDFLAGS -x c++ - -o /dev/null -ltbb 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS $LDFLAGS -x c++ - -o test.o -ltbb 2>/dev/null  <<EOF
          #include <tbb/tbb.h>
          int main() {}
 EOF
@@ -426,7 +429,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_JEMALLOC; then
        # Test whether jemalloc is available
-        if echo 'int main() {}' | $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null -ljemalloc \
+        if echo 'int main() {}' | $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o -ljemalloc \
          2>/dev/null; then
            # This will enable some preprocessor identifiers in the Makefile
            JEMALLOC=1
@@ -447,7 +450,7 @@ EOF
    fi
    if ! test $JEMALLOC && ! test $ROCKSDB_DISABLE_TCMALLOC; then
        # jemalloc is not available. Let's try tcmalloc
-        if echo 'int main() {}' | $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null \
+        if echo 'int main() {}' | $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o \
          -ltcmalloc 2>/dev/null; then
            PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -ltcmalloc"
            JAVA_LDFLAGS="$JAVA_LDFLAGS -ltcmalloc"
@@ -456,7 +459,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_MALLOC_USABLE_SIZE; then
        # Test whether malloc_usable_size is available
-        $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <malloc.h>
          int main() {
            size_t res = malloc_usable_size(0);
@@ -471,7 +474,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_MEMKIND; then
        # Test whether memkind library is installed
-        $CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -lmemkind -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -lmemkind -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <memkind.h>
          int main() {
            memkind_malloc(MEMKIND_DAX_KMEM, 1024);
@@ -487,7 +490,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_PTHREAD_MUTEX_ADAPTIVE_NP; then
        # Test whether PTHREAD_MUTEX_ADAPTIVE_NP mutex type is available
-        $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <pthread.h>
          int main() {
            int x = PTHREAD_MUTEX_ADAPTIVE_NP;
@@ -502,7 +505,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_BACKTRACE; then
        # Test whether backtrace is available
-        $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <execinfo.h>
          int main() {
            void* frames[1];
@@ -514,7 +517,7 @@ EOF
            COMMON_FLAGS="$COMMON_FLAGS -DROCKSDB_BACKTRACE"
        else
            # Test whether execinfo library is installed
-            $CXX $PLATFORM_CXXFLAGS -lexecinfo -x c++ - -o /dev/null 2>/dev/null  <<EOF
+            $CXX $PLATFORM_CXXFLAGS -lexecinfo -x c++ - -o test.o 2>/dev/null  <<EOF
              #include <execinfo.h>
              int main() {
                void* frames[1];
@@ -531,7 +534,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_PG; then
        # Test if -pg is supported
-        $CXX $PLATFORM_CXXFLAGS -pg -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -pg -x c++ - -o test.o 2>/dev/null  <<EOF
          int main() {
            return 0;
          }
@@ -543,7 +546,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_SYNC_FILE_RANGE; then
        # Test whether sync_file_range is supported for compatibility with an old glibc
-        $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <fcntl.h>
          int main() {
            int fd = open("/dev/null", 0);
@@ -557,7 +560,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_SCHED_GETCPU; then
        # Test whether sched_getcpu is supported
-        $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <sched.h>
          int main() {
            int cpuid = sched_getcpu();
@@ -571,7 +574,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_AUXV_GETAUXVAL; then
        # Test whether getauxval is supported
-        $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+        $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o 2>/dev/null  <<EOF
          #include <sys/auxv.h>
          int main() {
            uint64_t auxv = getauxval(AT_HWCAP);
@@ -585,7 +588,7 @@ EOF

    if ! test $ROCKSDB_DISABLE_ALIGNED_NEW; then
        # Test whether c++17 aligned-new is supported
-        $CXX $PLATFORM_CXXFLAGS -faligned-new -x c++ - -o /dev/null 2>/dev/null <<EOF
+        $CXX $PLATFORM_CXXFLAGS -faligned-new -x c++ - -o test.o 2>/dev/null <<EOF
            struct alignas(1024) t {int a;};
            int main() {}
 EOF
@@ -609,7 +612,7 @@ fi
 # -Wshorten-64-to-32 breaks compilation on FreeBSD aarch64 and i386
 if ! { [ "$TARGET_OS" = FreeBSD ] && [ "$TARGET_ARCHITECTURE" = arm64 -o "$TARGET_ARCHITECTURE" = i386 ]; }; then
  # Test whether -Wshorten-64-to-32 is available
-  $CXX $PLATFORM_CXXFLAGS -x c++ - -o /dev/null -Wshorten-64-to-32 2>/dev/null  <<EOF
+  $CXX $PLATFORM_CXXFLAGS -x c++ - -o test.o -Wshorten-64-to-32 2>/dev/null  <<EOF
    int main() {}
 EOF
  if [ "$?" = 0 ]; then
@@ -617,34 +620,27 @@ EOF
  fi
 fi

-# shall we use HDFS?
-
-if test "$USE_HDFS"; then
-  if test -z "$JAVA_HOME"; then
-    echo "JAVA_HOME has to be set for HDFS usage." >&2
-    exit 1
-  fi
-  HDFS_CCFLAGS="$HDFS_CCFLAGS -I$JAVA_HOME/include -I$JAVA_HOME/include/linux -DUSE_HDFS -I$HADOOP_HOME/include"
-  HDFS_LDFLAGS="$HDFS_LDFLAGS -lhdfs -L$JAVA_HOME/jre/lib/amd64 -L$HADOOP_HOME/lib/native"
-  HDFS_LDFLAGS="$HDFS_LDFLAGS -L$JAVA_HOME/jre/lib/amd64/server -L$GLIBC_RUNTIME_PATH/lib"
-  HDFS_LDFLAGS="$HDFS_LDFLAGS -ldl -lverify -ljava -ljvm"
-  COMMON_FLAGS="$COMMON_FLAGS $HDFS_CCFLAGS"
-  PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS $HDFS_LDFLAGS"
-  JAVA_LDFLAGS="$JAVA_LDFLAGS $HDFS_LDFLAGS"
-fi
-
 if test "0$PORTABLE" -eq 0; then
  if test -n "`echo $TARGET_ARCHITECTURE | grep ^ppc64`"; then
    # Tune for this POWER processor, treating '+' models as base models
    POWER=`LD_SHOW_AUXV=1 /bin/true | grep AT_PLATFORM | grep -E -o power[0-9]+`
    COMMON_FLAGS="$COMMON_FLAGS -mcpu=$POWER -mtune=$POWER "
-  elif test -n "`echo $TARGET_ARCHITECTURE | grep ^s390x`"; then
-    COMMON_FLAGS="$COMMON_FLAGS -march=z10 "
  elif test -n "`echo $TARGET_ARCHITECTURE | grep -e^arm -e^aarch64`"; then
    # TODO: Handle this with approprite options.
    COMMON_FLAGS="$COMMON_FLAGS"
  elif test -n "`echo $TARGET_ARCHITECTURE | grep ^aarch64`"; then
    COMMON_FLAGS="$COMMON_FLAGS"
+  elif test -n "`echo $TARGET_ARCHITECTURE | grep ^s390x`"; then
+    if echo 'int main() {}' | $CXX $PLATFORM_CXXFLAGS -x c++ \
+      -march=native - -o /dev/null 2>/dev/null; then
+      COMMON_FLAGS="$COMMON_FLAGS -march=native "
+    else
+      COMMON_FLAGS="$COMMON_FLAGS -march=z196 "
+    fi
+    COMMON_FLAGS="$COMMON_FLAGS"
+  elif test -n "`echo $TARGET_ARCHITECTURE | grep ^riscv64`"; then
+    RISC_ISA=$(cat /proc/cpuinfo | grep isa | head -1 | cut --delimiter=: -f 2 | cut -b 2-)
+    COMMON_FLAGS="$COMMON_FLAGS -march=${RISC_ISA}"
  elif [ "$TARGET_OS" == "IOS" ]; then
    COMMON_FLAGS="$COMMON_FLAGS"
  elif [ "$TARGET_OS" == "AIX" ] || [ "$TARGET_OS" == "SunOS" ]; then
@@ -661,11 +657,21 @@ else
    TRY_SSE_ETC="1"
  fi

+  if test -n "`echo $TARGET_ARCHITECTURE | grep ^s390x`"; then
+    COMMON_FLAGS="$COMMON_FLAGS -march=z196 "
+  fi
+
+  if test -n "`echo $TARGET_ARCHITECTURE | grep ^riscv64`"; then
+    RISC_ISA=$(cat /proc/cpuinfo | grep isa | head -1 | cut --delimiter=: -f 2 | cut -b 2-)
+    COMMON_FLAGS="$COMMON_FLAGS -march=${RISC_ISA}"
+  fi
+
  if [[ "${PLATFORM}" == "OS_MACOSX" ]]; then
    # For portability compile for macOS 10.12 (2016) or newer
    COMMON_FLAGS="$COMMON_FLAGS -mmacosx-version-min=10.12"
    PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -mmacosx-version-min=10.12"
-    PLATFORM_SHARED_LDFLAGS="$PLATFORM_SHARED_LDFLAGS -mmacosx-version-min=10.12"
+    # -mmacosx-version-min must come first here.
+    PLATFORM_SHARED_LDFLAGS="-mmacosx-version-min=10.12 $PLATFORM_SHARED_LDFLAGS"
    PLATFORM_CMAKE_FLAGS="-DCMAKE_OSX_DEPLOYMENT_TARGET=10.12"
    JAVA_STATIC_DEPS_COMMON_FLAGS="-mmacosx-version-min=10.12"
    JAVA_STATIC_DEPS_LDFLAGS="$JAVA_STATIC_DEPS_COMMON_FLAGS"
@@ -712,7 +718,7 @@ if test "$TRY_SSE_ETC"; then
  TRY_LZCNT="-mlzcnt"
 fi

-$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_SSE42 -x c++ - -o /dev/null 2>/dev/null <<EOF
+$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_SSE42 -x c++ - -o test.o 2>/dev/null <<EOF
  #include <cstdint>
  #include <nmmintrin.h>
  int main() {
@@ -726,7 +732,7 @@ elif test "$USE_SSE"; then
  echo "warning: USE_SSE specified but compiler could not use SSE intrinsics, disabling" >&2
 fi

-$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_PCLMUL -x c++ - -o /dev/null 2>/dev/null <<EOF
+$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_PCLMUL -x c++ - -o test.o 2>/dev/null <<EOF
  #include <cstdint>
  #include <wmmintrin.h>
  int main() {
@@ -743,7 +749,7 @@ elif test "$USE_SSE"; then
  echo "warning: USE_SSE specified but compiler could not use PCLMUL intrinsics, disabling" >&2
 fi

-$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_AVX2 -x c++ - -o /dev/null 2>/dev/null <<EOF
+$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_AVX2 -x c++ - -o test.o 2>/dev/null <<EOF
  #include <cstdint>
  #include <immintrin.h>
  int main() {
@@ -758,7 +764,7 @@ elif test "$USE_SSE"; then
  echo "warning: USE_SSE specified but compiler could not use AVX2 intrinsics, disabling" >&2
 fi

-$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_BMI -x c++ - -o /dev/null 2>/dev/null <<EOF
+$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_BMI -x c++ - -o test.o 2>/dev/null <<EOF
  #include <cstdint>
  #include <immintrin.h>
  int main(int argc, char *argv[]) {
@@ -772,7 +778,7 @@ elif test "$USE_SSE"; then
  echo "warning: USE_SSE specified but compiler could not use BMI intrinsics, disabling" >&2
 fi

-$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_LZCNT -x c++ - -o /dev/null 2>/dev/null <<EOF
+$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS $TRY_LZCNT -x c++ - -o test.o 2>/dev/null <<EOF
  #include <cstdint>
  #include <immintrin.h>
  int main(int argc, char *argv[]) {
@@ -786,7 +792,7 @@ elif test "$USE_SSE"; then
  echo "warning: USE_SSE specified but compiler could not use LZCNT intrinsics, disabling" >&2
 fi

-$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -x c++ - -o /dev/null 2>/dev/null <<EOF
+$CXX $PLATFORM_CXXFLAGS $COMMON_FLAGS -x c++ - -o test.o 2>/dev/null <<EOF
  #include <cstdint>
  int main() {
    uint64_t a = 0xffffFFFFffffFFFF;
@@ -799,31 +805,15 @@ if [ "$?" = 0 ]; then
  COMMON_FLAGS="$COMMON_FLAGS -DHAVE_UINT128_EXTENSION"
 fi

-# iOS doesn't support thread-local storage, but this check would erroneously
-# succeed because the cross-compiler flags are added by the Makefile, not this
-# script.
-if [ "$PLATFORM" != IOS ]; then
-  $CXX $COMMON_FLAGS -x c++ - -o /dev/null 2>/dev/null <<EOF
-  #if defined(_MSC_VER) && !defined(__thread)
-  #define __thread __declspec(thread)
-  #endif
-  int main() {
-    static __thread int tls;
-    (void)tls;
-  }
-EOF
-  if [ "$?" = 0 ]; then
-    COMMON_FLAGS="$COMMON_FLAGS -DROCKSDB_SUPPORT_THREAD_LOCAL"
-  fi
-fi
-
+# thread_local is part of C++11 and later (TODO: clean up this define)
+COMMON_FLAGS="$COMMON_FLAGS -DROCKSDB_SUPPORT_THREAD_LOCAL"

 if [ "$FBCODE_BUILD" != "true" -a "$PLATFORM" = OS_LINUX ]; then
  $CXX $COMMON_FLAGS $PLATFORM_SHARED_CFLAGS -x c++ -c - -o test_dl.o 2>/dev/null <<EOF
  void dummy_func() {}
 EOF
  if [ "$?" = 0 ]; then
-    $CXX $COMMON_FLAGS $PLATFORM_SHARED_LDFLAGS test_dl.o -o /dev/null 2>/dev/null
+    $CXX $COMMON_FLAGS $PLATFORM_SHARED_LDFLAGS test_dl.o -o test.o 2>/dev/null
    if [ "$?" = 0 ]; then
      EXEC_LDFLAGS+="-ldl"
      rm -f test_dl.o
@@ -831,6 +821,20 @@ EOF
  fi
 fi

+# check for F_FULLFSYNC
+$CXX $PLATFORM_CXXFALGS -x c++ - -o test.o 2>/dev/null  <<EOF
+  #include <fcntl.h>
+  int main() {
+    fcntl(0, F_FULLFSYNC);
+    return 0;
+  }
+EOF
+if [ "$?" = 0 ]; then
+  COMMON_FLAGS="$COMMON_FLAGS -DHAVE_FULLFSYNC"
+fi
+
+rm -f test.o test_dl.o
+
 PLATFORM_CCFLAGS="$PLATFORM_CCFLAGS $COMMON_FLAGS"
 PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS $COMMON_FLAGS"

@@ -23,6 +23,14 @@ if [ "$?" != "1" ]; then
  BAD=1
 fi

+git grep 'using namespace' -- ':!build_tools' ':!docs' \
+    ':!third-party/folly/folly/lang/Align.h' \
+    ':!third-party/gtest-1.8.1/fused-src/gtest/gtest.h'
+if [ "$?" != "1" ]; then
+  echo '^^^^ Do not use "using namespace"'
+  BAD=1
+fi
+
 if [ "$BAD" ]; then
  exit 1
 fi
@@ -21,85 +21,63 @@ LIBGCC_LIBS=" -L $LIBGCC_BASE/lib"
 GLIBC_INCLUDE="$GLIBC_BASE/include"
 GLIBC_LIBS=" -L $GLIBC_BASE/lib"

+if test -z $PIC_BUILD; then
+  MAYBE_PIC=
+else
+  MAYBE_PIC=_pic
+fi
+
 # snappy
 SNAPPY_INCLUDE=" -I $SNAPPY_BASE/include/"
-if test -z $PIC_BUILD; then
-  SNAPPY_LIBS=" $SNAPPY_BASE/lib/libsnappy.a"
-else
-  SNAPPY_LIBS=" $SNAPPY_BASE/lib/libsnappy_pic.a"
-fi
+SNAPPY_LIBS=" $SNAPPY_BASE/lib/libsnappy${MAYBE_PIC}.a"
 CFLAGS+=" -DSNAPPY"

-if test -z $PIC_BUILD; then
-  # location of zlib headers and libraries
-  ZLIB_INCLUDE=" -I $ZLIB_BASE/include/"
-  ZLIB_LIBS=" $ZLIB_BASE/lib/libz.a"
-  CFLAGS+=" -DZLIB"
+# location of zlib headers and libraries
+ZLIB_INCLUDE=" -I $ZLIB_BASE/include/"
+ZLIB_LIBS=" $ZLIB_BASE/lib/libz${MAYBE_PIC}.a"
+CFLAGS+=" -DZLIB"

-  # location of bzip headers and libraries
-  BZIP_INCLUDE=" -I $BZIP2_BASE/include/"
-  BZIP_LIBS=" $BZIP2_BASE/lib/libbz2.a"
-  CFLAGS+=" -DBZIP2"
+# location of bzip headers and libraries
+BZIP_INCLUDE=" -I $BZIP2_BASE/include/"
+BZIP_LIBS=" $BZIP2_BASE/lib/libbz2${MAYBE_PIC}.a"
+CFLAGS+=" -DBZIP2"

-  LZ4_INCLUDE=" -I $LZ4_BASE/include/"
-  LZ4_LIBS=" $LZ4_BASE/lib/liblz4.a"
-  CFLAGS+=" -DLZ4"
-fi
+LZ4_INCLUDE=" -I $LZ4_BASE/include/"
+LZ4_LIBS=" $LZ4_BASE/lib/liblz4${MAYBE_PIC}.a"
+CFLAGS+=" -DLZ4"

 ZSTD_INCLUDE=" -I $ZSTD_BASE/include/"
-if test -z $PIC_BUILD; then
-  ZSTD_LIBS=" $ZSTD_BASE/lib/libzstd.a"
-else
-  ZSTD_LIBS=" $ZSTD_BASE/lib/libzstd_pic.a"
-fi
+ZSTD_LIBS=" $ZSTD_BASE/lib/libzstd${MAYBE_PIC}.a"
 CFLAGS+=" -DZSTD"

 # location of gflags headers and libraries
 GFLAGS_INCLUDE=" -I $GFLAGS_BASE/include/"
-if test -z $PIC_BUILD; then
-  GFLAGS_LIBS=" $GFLAGS_BASE/lib/libgflags.a"
-else
-  GFLAGS_LIBS=" $GFLAGS_BASE/lib/libgflags_pic.a"
-fi
+GFLAGS_LIBS=" $GFLAGS_BASE/lib/libgflags${MAYBE_PIC}.a"
 CFLAGS+=" -DGFLAGS=gflags"

 BENCHMARK_INCLUDE=" -I $BENCHMARK_BASE/include/"
-if test -z $PIC_BUILD; then
-  BENCHMARK_LIBS=" $BENCHMARK_BASE/lib/libbenchmark.a"
-else
-  BENCHMARK_LIBS=" $BENCHMARK_BASE/lib/libbenchmark_pic.a"
-fi
+BENCHMARK_LIBS=" $BENCHMARK_BASE/lib/libbenchmark${MAYBE_PIC}.a"

 # location of jemalloc
 JEMALLOC_INCLUDE=" -I $JEMALLOC_BASE/include/"
-JEMALLOC_LIB=" $JEMALLOC_BASE/lib/libjemalloc.a"
+JEMALLOC_LIB=" $JEMALLOC_BASE/lib/libjemalloc${MAYBE_PIC}.a"

-if test -z $PIC_BUILD; then
-  # location of numa
-  NUMA_INCLUDE=" -I $NUMA_BASE/include/"
-  NUMA_LIB=" $NUMA_BASE/lib/libnuma.a"
-  CFLAGS+=" -DNUMA"
+# location of numa
+NUMA_INCLUDE=" -I $NUMA_BASE/include/"
+NUMA_LIB=" $NUMA_BASE/lib/libnuma${MAYBE_PIC}.a"
+CFLAGS+=" -DNUMA"

-  # location of libunwind
-  LIBUNWIND="$LIBUNWIND_BASE/lib/libunwind.a"
-fi
+# location of libunwind
+LIBUNWIND="$LIBUNWIND_BASE/lib/libunwind${MAYBE_PIC}.a"

 # location of TBB
 TBB_INCLUDE=" -isystem $TBB_BASE/include/"
-if test -z $PIC_BUILD; then
-  TBB_LIBS="$TBB_BASE/lib/libtbb.a"
-else
-  TBB_LIBS="$TBB_BASE/lib/libtbb_pic.a"
-fi
+TBB_LIBS="$TBB_BASE/lib/libtbb${MAYBE_PIC}.a"
 CFLAGS+=" -DTBB"

 # location of LIBURING
 LIBURING_INCLUDE=" -isystem $LIBURING_BASE/include/"
-if test -z $PIC_BUILD; then
-  LIBURING_LIBS="$LIBURING_BASE/lib/liburing.a"
-else
-  LIBURING_LIBS="$LIBURING_BASE/lib/liburing_pic.a"
-fi
+LIBURING_LIBS="$LIBURING_BASE/lib/liburing${MAYBE_PIC}.a"
 CFLAGS+=" -DLIBURING"

 test "$USE_SSE" || USE_SSE=1
@@ -127,11 +127,11 @@ uncommitted_code=`git diff HEAD`
 if [ -z "$uncommitted_code" ]
 then
  # Attempt to get name of facebook/rocksdb.git remote.
-  [ "$FORMAT_REMOTE" ] || FORMAT_REMOTE="$(git remote -v | grep 'facebook/rocksdb.git' | head -n 1 | cut -f 1)"
+  [ "$FORMAT_REMOTE" ] || FORMAT_REMOTE="$(LC_ALL=POSIX LANG=POSIX git remote -v | grep 'facebook/rocksdb.git' | head -n 1 | cut -f 1)"
  # Fall back on 'origin' if that fails
  [ "$FORMAT_REMOTE" ] || FORMAT_REMOTE=origin
  # Use main branch from that remote
-  [ "$FORMAT_UPSTREAM" ] || FORMAT_UPSTREAM="$FORMAT_REMOTE/$(git remote show $FORMAT_REMOTE | sed -n '/HEAD branch/s/.*: //p')"
+  [ "$FORMAT_UPSTREAM" ] || FORMAT_UPSTREAM="$FORMAT_REMOTE/$(LC_ALL=POSIX LANG=POSIX git remote show $FORMAT_REMOTE | sed -n '/HEAD branch/s/.*: //p')"
  # Get the common ancestor with that remote branch. Everything after that
  # common ancestor would be considered the contents of a pull request, so
  # should be relevant for formatting fixes.
@@ -1561,6 +1561,7 @@ sub save_stdin_stdout_stderr {
 	::die_bug("Can't dup STDERR: $!");
    open $Global::original_stdin, "<&", "STDIN" or
 	::die_bug("Can't dup STDIN: $!");
+    $Global::is_terminal = (-t $Global::original_stderr) && !$ENV{'CIRCLECI'} && !$ENV{'TRAVIS'};
 }

 sub enough_file_handles {
@@ -1840,12 +1841,17 @@ sub start_another_job {
 }
 }

+$opt::min_progress_interval = 0;
+
 sub init_progress {
    # Uses:
    #   $opt::bar
    # Returns:
    #   list of computers for progress output
    $|=1;
+    if (not $Global::is_terminal) {
+      $opt::min_progress_interval = 30;
+    }
    if($opt::bar) {
 	return("","");
    }
@@ -1870,6 +1876,9 @@ sub drain_job_queue {
    }
    my $last_header="";
    my $sleep = 0.2;
+    my $last_left = 1000000000;
+    my $last_progress_time = 0;
+    my $ps_reported = 0;
    do {
        while($Global::total_running > 0) {
            debug($Global::total_running, "==", scalar
@@ -1880,14 +1889,38 @@ sub drain_job_queue {
 		    close $job->fh(0,"w");
 		}
 	    }
-            if($opt::progress) {
+            # When not connected to terminal, assume CI (e.g. CircleCI). In
+            # that case we want occasional progress output to prevent abort
+            # due to timeout with no output, but we also need to stop sending
+            # progress output if there has been no actual progress, so that
+            # the job can time out appropriately (CirecleCI: 10m) in case of
+            # a hung test. But without special output, it is extremely
+            # annoying to diagnose which test is hung, so we add that using
+            # `ps` below.
+            if($opt::progress and
+               ($Global::is_terminal or (time() - $last_progress_time) >= 30)) {
                my %progress = progress();
                if($last_header ne $progress{'header'}) {
                    print $Global::original_stderr "\n", $progress{'header'}, "\n";
                    $last_header = $progress{'header'};
                }
-                print $Global::original_stderr "\r",$progress{'status'};
-		flush $Global::original_stderr;
+                if ($Global::is_terminal) {
+                    print $Global::original_stderr "\r",$progress{'status'};
+                }
+                if ($last_left > $Global::left) {
+                    if (not $Global::is_terminal) {
+                        print $Global::original_stderr $progress{'status'},"\n";
+                    }
+                    $last_progress_time = time();
+                    $ps_reported = 0;
+                } elsif (not $ps_reported and (time() - $last_progress_time) >= 60) {
+                    # No progress in at least 60 seconds: run ps
+                    print $Global::original_stderr "\n";
+                    system("ps", "-wf");
+                    $ps_reported = 1;
+                }
+                $last_left = $Global::left;
+                flush $Global::original_stderr;
            }
 	    if($Global::total_running < $Global::max_jobs_running
 	       and not $Global::JobQueue->empty()) {
@@ -1921,7 +1954,7 @@ sub drain_job_queue {
 	     not $Global::start_no_new_jobs and not $Global::JobQueue->empty());
    if($opt::progress) {
 	my %progress = progress();
-	print $Global::original_stderr "\r", $progress{'status'}, "\n";
+	print $Global::original_stderr $opt::progress_sep, $progress{'status'}, "\n";
 	flush $Global::original_stderr;
    }
 }
@@ -1954,10 +1987,11 @@ sub progress {
    my $eta = "";
    my ($status,$header)=("","");
    if($opt::eta) {
-	my($total, $completed, $left, $pctcomplete, $avgtime, $this_eta) =
-	    compute_eta();
-	$eta = sprintf("ETA: %ds Left: %d AVG: %.2fs  ",
-		       $this_eta, $left, $avgtime);
+      my($total, $completed, $left, $pctcomplete, $avgtime, $this_eta) =
+        compute_eta();
+      $eta = sprintf("ETA: %ds Left: %d AVG: %.2fs  ",
+        $this_eta, $left, $avgtime);
+      $Global::left = $left;
    }
    my $termcols = terminal_columns();
    my @workers = sort keys %Global::host;
@@ -258,7 +258,6 @@ common_in_mem_args="--db=/dev/shm/rocksdb \
    --value_size=100 \
    --compression_type=none \
    --compression_ratio=1 \
-    --hard_rate_limit=2 \
    --write_buffer_size=134217728 \
    --max_write_buffer_number=4 \
    --level0_file_num_compaction_trigger=8 \
@@ -5,11 +5,14 @@

 #ifdef GFLAGS
 #include <cinttypes>
+#include <cstddef>
 #include <cstdio>
 #include <limits>
+#include <memory>
 #include <set>
 #include <sstream>

+#include "db/db_impl/db_impl.h"
 #include "monitoring/histogram.h"
 #include "port/port.h"
 #include "rocksdb/cache.h"
@@ -18,6 +21,8 @@
 #include "rocksdb/env.h"
 #include "rocksdb/secondary_cache.h"
 #include "rocksdb/system_clock.h"
+#include "rocksdb/table_properties.h"
+#include "table/block_based/block_based_table_reader.h"
 #include "table/block_based/cachable_entry.h"
 #include "util/coding.h"
 #include "util/gflags_compat.h"
@@ -73,6 +78,57 @@ static class std::shared_ptr<ROCKSDB_NAMESPACE::SecondaryCache> secondary_cache;

 DEFINE_bool(use_clock_cache, false, "");

+// ## BEGIN stress_cache_key sub-tool options ##
+// See class StressCacheKey below.
+DEFINE_bool(stress_cache_key, false,
+            "If true, run cache key stress test instead");
+DEFINE_uint32(
+    sck_files_per_day, 2500000,
+    "(-stress_cache_key) Simulated files generated per simulated day");
+// NOTE: Giving each run a specified lifetime, rather than e.g. "until
+// first collision" ensures equal skew from start-up, when collisions are
+// less likely.
+DEFINE_uint32(sck_days_per_run, 90,
+              "(-stress_cache_key) Number of days to simulate in each run");
+// NOTE: The number of observed collisions directly affects the relative
+// accuracy of the predicted probabilities. 15 observations should be well
+// within factor-of-2 accuracy.
+DEFINE_uint32(
+    sck_min_collision, 15,
+    "(-stress_cache_key) Keep running until this many collisions seen");
+// sck_file_size_mb can be thought of as average file size. The simulation is
+// not precise enough to care about the distribution of file sizes; other
+// simulations (https://github.com/pdillinger/unique_id/tree/main/monte_carlo)
+// indicate the distribution only makes a small difference (e.g. < 2x factor)
+DEFINE_uint32(
+    sck_file_size_mb, 32,
+    "(-stress_cache_key) Simulated file size in MiB, for accounting purposes");
+DEFINE_uint32(sck_reopen_nfiles, 100,
+              "(-stress_cache_key) Simulate DB re-open average every n files");
+DEFINE_uint32(sck_restarts_per_day, 24,
+              "(-stress_cache_key) Average simulated process restarts per day "
+              "(across DBs)");
+DEFINE_uint32(
+    sck_db_count, 100,
+    "(-stress_cache_key) Parallel DBs in simulation sharing a block cache");
+DEFINE_uint32(
+    sck_table_bits, 20,
+    "(-stress_cache_key) Log2 number of tracked (live) files (across DBs)");
+// sck_keep_bits being well below full 128 bits amplifies the collision
+// probability so that the true probability can be estimated through observed
+// collisions. (More explanation below.)
+DEFINE_uint32(
+    sck_keep_bits, 50,
+    "(-stress_cache_key) Number of bits to keep from each cache key (<= 64)");
+// sck_randomize is used to validate whether cache key is performing "better
+// than random." Even with this setting, file offsets are not randomized.
+DEFINE_bool(sck_randomize, false,
+            "(-stress_cache_key) Randomize (hash) cache key");
+// See https://github.com/facebook/rocksdb/pull/9058
+DEFINE_bool(sck_footer_unique_id, false,
+            "(-stress_cache_key) Simulate using proposed footer unique id");
+// ## END stress_cache_key sub-tool options ##
+
 namespace ROCKSDB_NAMESPACE {

 class CacheBench;
@@ -220,7 +276,7 @@ class CacheBench {
    if (skewed_) {
      uint64_t max_key = max_key_;
      while (max_key >>= 1) max_log_++;
-      if (max_key > (1u << max_log_)) max_log_++;
+      if (max_key > (static_cast<uint64_t>(1) << max_log_)) max_log_++;
    }

    if (FLAGS_use_clock_cache) {
@@ -380,7 +436,8 @@ class CacheBench {
                 << "Average key size: "
                 << (1.0 * total_key_size / total_entry_count) << "\n"
                 << "Average charge: "
-                 << BytesToHumanString(1.0 * total_charge / total_entry_count)
+                 << BytesToHumanString(static_cast<uint64_t>(
+                        1.0 * total_charge / total_entry_count))
                 << "\n"
                 << "Unique deleters: " << deleters.size() << "\n";
            *stats_report = ostr.str();
@@ -453,8 +510,9 @@ class CacheBench {
      timer.Start();
      Slice key = gen.GetRand(thread->rnd, max_key_, max_log_);
      uint64_t random_op = thread->rnd.Next();
-      Cache::CreateCallback create_cb =
-          [](void* buf, size_t size, void** out_obj, size_t* charge) -> Status {
+      Cache::CreateCallback create_cb = [](const void* buf, size_t size,
+                                           void** out_obj,
+                                           size_t* charge) -> Status {
        *out_obj = reinterpret_cast<void*>(new char[size]);
        memcpy(*out_obj, buf, size);
        *charge = size;
@@ -547,9 +605,303 @@ class CacheBench {
  }
 };

+// cache_bench -stress_cache_key is an independent embedded tool for
+// estimating the probability of CacheKey collisions through simulation.
+// At a high level, it simulates generating SST files over many months,
+// keeping them in the DB and/or cache for some lifetime while staying
+// under resource caps, and checking for any cache key collisions that
+// arise among the set of live files. For efficient simulation, we make
+// some simplifying "pessimistic" assumptions (that only increase the
+// chance of the simulation reporting a collision relative to the chance
+// of collision in practice):
+// * Every generated file has a cache entry for every byte offset in the
+// file (contiguous range of cache keys)
+// * All of every file is cached for its entire lifetime. (Here "lifetime"
+// is technically the union of DB and Cache lifetime, though we only
+// model a generous DB lifetime, where space usage is always maximized.
+// In a effective Cache, lifetime in cache can only substantially exceed
+// lifetime in DB if there is little cache activity; cache activity is
+// required to hit cache key collisions.)
+//
+// It would be possible to track an exact set of cache key ranges for the
+// set of live files, but we would have no hope of observing collisions
+// (overlap in live files) in our simulation. We need to employ some way
+// of amplifying collision probability that allows us to predict the real
+// collision probability by extrapolation from observed collisions. Our
+// basic approach is to reduce each cache key range down to some smaller
+// number of bits, and limiting to bits that are shared over the whole
+// range.  Now we can observe collisions using a set of smaller stripped-down
+// (reduced) cache keys. Let's do some case analysis to understand why this
+// works:
+// * No collision in reduced key - because the reduction is a pure function
+// this implies no collision in the full keys
+// * Collision detected between two reduced keys - either
+//   * The reduction has dropped some structured uniqueness info (from one of
+// session counter or file number; file offsets are never materialized here).
+// This can only artificially inflate the observed and extrapolated collision
+// probabilities. We only have to worry about this in designing the reduction.
+//   * The reduction has preserved all the structured uniqueness in the cache
+// key, which means either
+//     * REJECTED: We have a uniqueness bug in generating cache keys, where
+// structured uniqueness info should have been different but isn't. In such a
+// case, increasing by 1 the number of bits kept after reduction would not
+// reduce observed probabilities by half. (In our observations, the
+// probabilities are reduced approximately by half.)
+//     * ACCEPTED: The lost unstructured uniqueness in the key determines the
+// probability that an observed collision would imply an overlap in ranges.
+// In short, dropping n bits from key would increase collision probability by
+// 2**n, assuming those n bits have full entropy in unstructured uniqueness.
+//
+// But we also have to account for the key ranges based on file size. If file
+// sizes are roughly 2**b offsets, using XOR in 128-bit cache keys for
+// "ranges", we know from other simulations (see
+// https://github.com/pdillinger/unique_id/) that that's roughly equivalent to
+// (less than 2x higher collision probability) using a cache key of size
+// 128 - b bits for the whole file. (This is the only place we make an
+// "optimistic" assumption, which is more than offset by the real
+// implementation stripping off 2 lower bits from block byte offsets for cache
+// keys. The simulation assumes byte offsets, which is net pessimistic.)
+//
+// So to accept the extrapolation as valid, we need to be confident that all
+// "lost" bits, excluding those covered by file offset, are full entropy.
+// Recall that we have assumed (verifiably, safely) that other structured data
+// (file number and session counter) are kept, not lost. Based on the
+// implementation comments for OffsetableCacheKey, the only potential hole here
+// is that we only have ~103 bits of entropy in "all new" session IDs, and in
+// extreme cases, there might be only 1 DB ID. However, because the upper ~39
+// bits of session ID are hashed, the combination of file number and file
+// offset only has to add to 25 bits (or more) to ensure full entropy in
+// unstructured uniqueness lost in the reduction. Typical file size of 32MB
+// suffices (at least for simulation purposes where we assume each file offset
+// occupies a cache key).
+//
+// Example results in comments on OffsetableCacheKey.
+class StressCacheKey {
+ public:
+  void Run() {
+    if (FLAGS_sck_footer_unique_id) {
+      // Proposed footer unique IDs are DB-independent and session-independent
+      // (but process-dependent) which is most easily simulated here by
+      // assuming 1 DB and (later below) no session resets without process
+      // reset.
+      FLAGS_sck_db_count = 1;
+    }
+
+    // Describe the simulated workload
+    uint64_t mb_per_day =
+        uint64_t{FLAGS_sck_files_per_day} * FLAGS_sck_file_size_mb;
+    printf("Total cache or DBs size: %gTiB  Writing %g MiB/s or %gTiB/day\n",
+           FLAGS_sck_file_size_mb / 1024.0 / 1024.0 *
+               std::pow(2.0, FLAGS_sck_table_bits),
+           mb_per_day / 86400.0, mb_per_day / 1024.0 / 1024.0);
+    // For extrapolating probability of any collisions from a number of
+    // observed collisions
+    multiplier_ = std::pow(2.0, 128 - FLAGS_sck_keep_bits) /
+                  (FLAGS_sck_file_size_mb * 1024.0 * 1024.0);
+    printf(
+        "Multiply by %g to correct for simulation losses (but still assume "
+        "whole file cached)\n",
+        multiplier_);
+    restart_nfiles_ = FLAGS_sck_files_per_day / FLAGS_sck_restarts_per_day;
+    double without_ejection =
+        std::pow(1.414214, FLAGS_sck_keep_bits) / FLAGS_sck_files_per_day;
+    // This should be a lower bound for -sck_randomize, usually a terribly
+    // rough lower bound.
+    // If observation is worse than this, then something has gone wrong.
+    printf(
+        "Without ejection, expect random collision after %g days (%g "
+        "corrected)\n",
+        without_ejection, without_ejection * multiplier_);
+    double with_full_table =
+        std::pow(2.0, FLAGS_sck_keep_bits - FLAGS_sck_table_bits) /
+        FLAGS_sck_files_per_day;
+    // This is an alternate lower bound for -sck_randomize, usually pretty
+    // accurate. Our cache keys should usually perform "better than random"
+    // but always no worse. (If observation is substantially worse than this,
+    // then something has gone wrong.)
+    printf(
+        "With ejection and full table, expect random collision after %g "
+        "days (%g corrected)\n",
+        with_full_table, with_full_table * multiplier_);
+    collisions_ = 0;
+
+    // Run until sufficient number of observed collisions.
+    for (int i = 1; collisions_ < FLAGS_sck_min_collision; i++) {
+      RunOnce();
+      if (collisions_ == 0) {
+        printf(
+            "No collisions after %d x %u days                              "
+            "                   \n",
+            i, FLAGS_sck_days_per_run);
+      } else {
+        double est = 1.0 * i * FLAGS_sck_days_per_run / collisions_;
+        printf("%" PRIu64
+               " collisions after %d x %u days, est %g days between (%g "
+               "corrected)        \n",
+               collisions_, i, FLAGS_sck_days_per_run, est, est * multiplier_);
+      }
+    }
+  }
+
+  void RunOnce() {
+    // Re-initialized simulated state
+    const size_t db_count = FLAGS_sck_db_count;
+    dbs_.reset(new TableProperties[db_count]{});
+    const size_t table_mask = (size_t{1} << FLAGS_sck_table_bits) - 1;
+    table_.reset(new uint64_t[table_mask + 1]{});
+    if (FLAGS_sck_keep_bits > 64) {
+      FLAGS_sck_keep_bits = 64;
+    }
+
+    // Details of which bits are dropped in reduction
+    uint32_t shift_away = 64 - FLAGS_sck_keep_bits;
+    // Shift away fewer potential file number bits (b) than potential
+    // session counter bits (a).
+    uint32_t shift_away_b = shift_away / 3;
+    uint32_t shift_away_a = shift_away - shift_away_b;
+
+    process_count_ = 0;
+    session_count_ = 0;
+    ResetProcess();
+
+    Random64 r{std::random_device{}()};
+
+    uint64_t max_file_count =
+        uint64_t{FLAGS_sck_files_per_day} * FLAGS_sck_days_per_run;
+    uint64_t file_size = FLAGS_sck_file_size_mb * uint64_t{1024} * 1024U;
+    uint32_t report_count = 0;
+    uint32_t collisions_this_run = 0;
+    size_t db_i = 0;
+
+    for (uint64_t file_count = 1; file_count <= max_file_count;
+         ++file_count, ++db_i) {
+      // Round-robin through DBs (this faster than %)
+      if (db_i >= db_count) {
+        db_i = 0;
+      }
+      // Any other periodic actions before simulating next file
+      if (!FLAGS_sck_footer_unique_id && r.OneIn(FLAGS_sck_reopen_nfiles)) {
+        ResetSession(db_i);
+      } else if (r.OneIn(restart_nfiles_)) {
+        ResetProcess();
+      }
+      // Simulate next file
+      OffsetableCacheKey ock;
+      dbs_[db_i].orig_file_number += 1;
+      // skip some file numbers for other file kinds, except in footer unique
+      // ID, orig_file_number here tracks process-wide generated SST file
+      // count.
+      if (!FLAGS_sck_footer_unique_id) {
+        dbs_[db_i].orig_file_number += (r.Next() & 3);
+      }
+      bool is_stable;
+      BlockBasedTable::SetupBaseCacheKey(&dbs_[db_i], /* ignored */ "",
+                                         /* ignored */ 42, file_size, &ock,
+                                         &is_stable);
+      assert(is_stable);
+      // Get a representative cache key, which later we analytically generalize
+      // to a range.
+      CacheKey ck = ock.WithOffset(0);
+      uint64_t reduced_key;
+      if (FLAGS_sck_randomize) {
+        reduced_key = GetSliceHash64(ck.AsSlice()) >> shift_away;
+      } else if (FLAGS_sck_footer_unique_id) {
+        // Special case: keep only file number, not session counter
+        uint32_t a = DecodeFixed32(ck.AsSlice().data() + 4) >> shift_away_a;
+        uint32_t b = DecodeFixed32(ck.AsSlice().data() + 12) >> shift_away_b;
+        reduced_key = (uint64_t{a} << 32) + b;
+      } else {
+        // Try to keep file number and session counter (shift away other bits)
+        uint32_t a = DecodeFixed32(ck.AsSlice().data()) << shift_away_a;
+        uint32_t b = DecodeFixed32(ck.AsSlice().data() + 12) >> shift_away_b;
+        reduced_key = (uint64_t{a} << 32) + b;
+      }
+      if (reduced_key == 0) {
+        // Unlikely, but we need to exclude tracking this value because we
+        // use it to mean "empty" in table. This case is OK as long as we
+        // don't hit it often.
+        printf("Hit Zero!                                                  \n");
+        file_count--;
+        continue;
+      }
+      uint64_t h =
+          NPHash64(reinterpret_cast<char*>(&reduced_key), sizeof(reduced_key));
+      // Skew expected lifetimes, for high variance (super-Poisson) variance
+      // in actual lifetimes.
+      size_t pos =
+          std::min(Lower32of64(h) & table_mask, Upper32of64(h) & table_mask);
+      if (table_[pos] == reduced_key) {
+        collisions_this_run++;
+        // Our goal is to predict probability of no collisions, not expected
+        // number of collisions. To make the distinction, we have to get rid
+        // of observing correlated collisions, which this takes care of:
+        ResetProcess();
+      } else {
+        // Replace (end of lifetime for file that was in this slot)
+        table_[pos] = reduced_key;
+      }
+
+      if (++report_count == FLAGS_sck_files_per_day) {
+        report_count = 0;
+        // Estimate fill %
+        size_t incr = table_mask / 1000;
+        size_t sampled_count = 0;
+        for (size_t i = 0; i <= table_mask; i += incr) {
+          if (table_[i] != 0) {
+            sampled_count++;
+          }
+        }
+        // Report
+        printf(
+            "%" PRIu64 " days, %" PRIu64 " proc, %" PRIu64
+            " sess, %u coll, occ %g%%, ejected %g%%   \r",
+            file_count / FLAGS_sck_files_per_day, process_count_,
+            session_count_, collisions_this_run, 100.0 * sampled_count / 1000.0,
+            100.0 * (1.0 - sampled_count / 1000.0 * table_mask / file_count));
+        fflush(stdout);
+      }
+    }
+    collisions_ += collisions_this_run;
+  }
+
+  void ResetSession(size_t i) {
+    dbs_[i].db_session_id = DBImpl::GenerateDbSessionId(nullptr);
+    session_count_++;
+  }
+
+  void ResetProcess() {
+    process_count_++;
+    DBImpl::TEST_ResetDbSessionIdGen();
+    for (size_t i = 0; i < FLAGS_sck_db_count; ++i) {
+      ResetSession(i);
+    }
+    if (FLAGS_sck_footer_unique_id) {
+      // For footer unique ID, this tracks process-wide generated SST file
+      // count.
+      dbs_[0].orig_file_number = 0;
+    }
+  }
+
+ private:
+  // Use db_session_id and orig_file_number from TableProperties
+  std::unique_ptr<TableProperties[]> dbs_;
+  std::unique_ptr<uint64_t[]> table_;
+  uint64_t process_count_ = 0;
+  uint64_t session_count_ = 0;
+  uint64_t collisions_ = 0;
+  uint32_t restart_nfiles_ = 0;
+  double multiplier_ = 0.0;
+};
+
 int cache_bench_tool(int argc, char** argv) {
  ParseCommandLineFlags(&argc, &argv, true);

+  if (FLAGS_stress_cache_key) {
+    // Alternate tool
+    StressCacheKey().Run();
+    return 0;
+  }
+
  if (FLAGS_threads <= 0) {
    fprintf(stderr, "threads number <= 0\n");
    exit(1);
@@ -20,6 +20,7 @@ std::array<const char*, kNumCacheEntryRoles> kCacheEntryRoleToCamelString{{
    "OtherBlock",
    "WriteBuffer",
    "CompressionDictionaryBuildingBuffer",
+    "FilterConstruction",
    "Misc",
 }};

@@ -32,6 +33,7 @@ std::array<const char*, kNumCacheEntryRoles> kCacheEntryRoleToHyphenString{{
    "other-block",
    "write-buffer",
    "compression-dictionary-building-buffer",
+    "filter-construction",
    "misc",
 }};

@@ -7,6 +7,8 @@

 #include <array>
 #include <cstdint>
+#include <memory>
+#include <type_traits>
 #include <unordered_map>

 #include "rocksdb/cache.h"
@@ -34,6 +36,9 @@ enum class CacheEntryRole {
  // BlockBasedTableBuilder reservations to account for
  // compression dictionary building buffer's memory usage
  kCompressionDictionaryBuildingBuffer,
+  // Filter reservations to account for
+  // (new) bloom and ribbon filter construction's memory usage
+  kFilterConstruction,
  // Default bucket, for miscellaneous cache entries. Do not use for
  // entries that could potentially add up to large usage.
  kMisc,
@@ -90,7 +95,9 @@ struct RegisteredDeleter {
  // These have global linkage to help ensure compiler optimizations do not
  // break uniqueness for each <T,R>
  static void Delete(const Slice& /* key */, void* value) {
-    delete static_cast<T*>(value);
+    // Supports T == Something[], unlike delete operator
+    std::default_delete<T>()(
+        static_cast<typename std::remove_extent<T>::type*>(value));
  }
 };

@@ -98,9 +105,9 @@ template <CacheEntryRole R>
 struct RegisteredNoopDeleter {
  RegisteredNoopDeleter() { RegisterCacheDeleterRole(Delete, R); }

-  static void Delete(const Slice& /* key */, void* value) {
-    (void)value;
-    assert(value == nullptr);
+  static void Delete(const Slice& /* key */, void* /* value */) {
+    // Here was `assert(value == nullptr);` but we can also put pointers
+    // to static data in Cache, for testing at least.
  }
 };

@@ -11,6 +11,7 @@
 #include <mutex>

 #include "cache/cache_helpers.h"
+#include "cache/cache_key.h"
 #include "port/lang.h"
 #include "rocksdb/cache.h"
 #include "rocksdb/status.h"
@@ -112,13 +113,7 @@ class CacheEntryStatsCollector {
  // entry in cache until all refs are destroyed.
  static Status GetShared(Cache *cache, SystemClock *clock,
                          std::shared_ptr<CacheEntryStatsCollector> *ptr) {
-    std::array<uint64_t, 3> cache_key_data{
-        {// First 16 bytes == md5 of class name
-         0x7eba5a8fb5437c90U, 0x8ca68c9b11655855U,
-         // Last 8 bytes based on a function pointer to make unique for each
-         // template instantiation
-         reinterpret_cast<uint64_t>(&CacheEntryStatsCollector::GetShared)}};
-    Slice cache_key = GetSlice(&cache_key_data);
+    const Slice &cache_key = GetCacheKey();

    Cache::Handle *h = cache->Lookup(cache_key);
    if (h == nullptr) {
@@ -166,6 +161,13 @@ class CacheEntryStatsCollector {
    delete static_cast<CacheEntryStatsCollector *>(value);
  }

+  static const Slice &GetCacheKey() {
+    // For each template instantiation
+    static CacheKey ckey = CacheKey::CreateUniqueForProcessLifetime();
+    static Slice ckey_slice = ckey.AsSlice();
+    return ckey_slice;
+  }
+
  std::mutex saved_mutex_;
  Stats saved_stats_;

@@ -0,0 +1,344 @@
+//  Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include "cache/cache_key.h"
+
+#include <algorithm>
+#include <atomic>
+
+#include "rocksdb/cache.h"
+#include "table/unique_id_impl.h"
+#include "util/hash.h"
+#include "util/math.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// Value space plan for CacheKey:
+//
+// session_etc64_ | offset_etc64_ | Only generated by
+// ---------------+---------------+------------------------------------------
+//              0 |             0 | Reserved for "empty" CacheKey()
+//              0 |  > 0, < 1<<63 | CreateUniqueForCacheLifetime
+//              0 |      >= 1<<63 | CreateUniqueForProcessLifetime
+//            > 0 |           any | OffsetableCacheKey.WithOffset
+
+CacheKey CacheKey::CreateUniqueForCacheLifetime(Cache *cache) {
+  // +1 so that we can reserve all zeros for "unset" cache key
+  uint64_t id = cache->NewId() + 1;
+  // Ensure we don't collide with CreateUniqueForProcessLifetime
+  assert((id >> 63) == 0U);
+  return CacheKey(0, id);
+}
+
+CacheKey CacheKey::CreateUniqueForProcessLifetime() {
+  // To avoid colliding with CreateUniqueForCacheLifetime, assuming
+  // Cache::NewId counts up from zero, here we count down from UINT64_MAX.
+  // If this ever becomes a point of contention, we could sub-divide the
+  // space and use CoreLocalArray.
+  static std::atomic<uint64_t> counter{UINT64_MAX};
+  uint64_t id = counter.fetch_sub(1, std::memory_order_relaxed);
+  // Ensure we don't collide with CreateUniqueForCacheLifetime
+  assert((id >> 63) == 1U);
+  return CacheKey(0, id);
+}
+
+// Value plan for CacheKeys from OffsetableCacheKey, assuming that
+// db_session_ids are generated from a base_session_id and
+// session_id_counter (by SemiStructuredUniqueIdGen+EncodeSessionId
+// in DBImpl::GenerateDbSessionId):
+//
+// Conceptual inputs:
+//   db_id                   (unstructured, from GenerateRawUniqueId or equiv)
+//                           * could be shared between cloned DBs but rare
+//                           * could be constant, if session id suffices
+//   base_session_id         (unstructured, from GenerateRawUniqueId)
+//   session_id_counter      (structured)
+//                           * usually much smaller than 2**24
+//   file_number             (structured)
+//                           * usually smaller than 2**24
+//   offset_in_file          (structured, might skip lots of values)
+//                           * usually smaller than 2**32
+//   max_offset              determines placement of file_number to prevent
+//                           overlapping with offset
+//
+// Outputs come from bitwise-xor of the constituent pieces, low bits on left:
+//
+// |------------------------- session_etc64 -------------------------|
+// | +++++++++++++++ base_session_id (lower 64 bits) +++++++++++++++ |
+// |-----------------------------------------------------------------|
+// | session_id_counter ...|                                         |
+// |-----------------------------------------------------------------|
+// |                                               | ... file_number |
+// |                                               | overflow & meta |
+// |-----------------------------------------------------------------|
+//
+//
+// |------------------------- offset_etc64 --------------------------|
+// | hash of: ++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
+// |  * base_session_id (upper ~39 bits)                             |
+// |  * db_id (~122 bits entropy)                                    |
+// |-----------------------------------------------------------------|
+// | offset_in_file ............... |                                |
+// |-----------------------------------------------------------------|
+// |                                              | file_number, 0-3 |
+// |                                              | lower bytes      |
+// |-----------------------------------------------------------------|
+//
+// Based on max_offset, a maximal number of bytes 0..3 is chosen for
+// including from lower bits of file_number in offset_etc64. The choice
+// is encoded in two bits of metadata going into session_etc64, though
+// the common case of 3 bytes is encoded as 0 so that session_etc64
+// is unmodified by file_number concerns in the common case.
+//
+// There is nothing preventing "file number overflow & meta" from meeting
+// and overlapping with session_id_counter, but reaching such a case requires
+// an intractable combination of large file offsets (thus at least some large
+// files), large file numbers (thus large number of files generated), and
+// large number of session IDs generated in a single process. A trillion each
+// (2**40) of session ids, offsets, and file numbers comes to 120 bits.
+// With two bits of metadata and byte granularity, this is on the verge of
+// overlap, but even in the overlap case, it doesn't seem likely that
+// a file from billions of files or session ids ago will still be live
+// or cached.
+//
+// In fact, if our SST files are all < 4TB (see
+// BlockBasedTable::kMaxFileSizeStandardEncoding), then SST files generated
+// in a single process are guaranteed to have unique cache keys, unless/until
+// number session ids * max file number = 2**86, e.g. 1 trillion DB::Open in
+// a single process and 64 trillion files generated. Even at that point, to
+// see a collision we would need a miraculous re-synchronization of session
+// id and file number, along with a live file or stale cache entry from
+// trillions of files ago.
+//
+// How https://github.com/pdillinger/unique_id applies here:
+// Every bit of output always includes "unstructured" uniqueness bits and
+// often combines with "structured" uniqueness bits. The "unstructured" bits
+// change infrequently: only when we cannot guarantee our state tracking for
+// "structured" uniqueness hasn't been cloned. Using a static
+// SemiStructuredUniqueIdGen for db_session_ids, this means we only get an
+// "all new" session id when a new process uses RocksDB. (Between processes,
+// we don't know if a DB or other persistent storage has been cloned. We
+// assume that if VM hot cloning is used, subsequently generated SST files
+// do not interact.) Within a process, only the session_lower of the
+// db_session_id changes incrementally ("structured" uniqueness).
+//
+// This basically means that our offsets, counters and file numbers allow us
+// to do somewhat "better than random" (birthday paradox) while in the
+// degenerate case of completely new session for each tiny file, we still
+// have strong uniqueness properties from the birthday paradox, with ~103
+// bit session IDs or up to 128 bits entropy with different DB IDs sharing a
+// cache.
+//
+// More collision probability analysis:
+// Suppose a RocksDB host generates (generously) 2 GB/s (10TB data, 17 DWPD)
+// with average process/session lifetime of (pessimistically) 4 minutes.
+// In 180 days (generous allowable data lifespan), we generate 31 million GB
+// of data, or 2^55 bytes, and 2^16 "all new" session IDs.
+//
+// First, suppose this is in a single DB (lifetime 180 days):
+// 128 bits cache key size
+// - 55 <- ideal size for byte offsets + file numbers
+// -  2 <- bits for offsets and file numbers not exactly powers of two
+// -  2 <- bits for file number encoding metadata
+// +  2 <- bits saved not using byte offsets in BlockBasedTable::GetCacheKey
+// ----
+//   71 <- bits remaining for distinguishing session IDs
+// The probability of a collision in 71 bits of session ID data is less than
+// 1 in 2**(71 - (2 * 16)), or roughly 1 in a trillion. And this assumes all
+// data from the last 180 days is in cache for potential collision, and that
+// cache keys under each session id exhaustively cover the remaining 57 bits
+// while in reality they'll only cover a small fraction of it.
+//
+// Although data could be transferred between hosts, each host has its own
+// cache and we are already assuming a high rate of "all new" session ids.
+// So this doesn't really change the collision calculation. Across a fleet
+// of 1 million, each with <1 in a trillion collision possibility,
+// fleetwide collision probability is <1 in a million.
+//
+// Now suppose we have many DBs per host, say 2**10, with same host-wide write
+// rate and process/session lifetime. File numbers will be ~10 bits smaller
+// and we will have 2**10 times as many session IDs because of simultaneous
+// lifetimes. So now collision chance is less than 1 in 2**(81 - (2 * 26)),
+// or roughly 1 in a billion.
+//
+// Suppose instead we generated random or hashed cache keys for each
+// (compressed) block. For 1KB compressed block size, that is 2^45 cache keys
+// in 180 days. Collision probability is more easily estimated at roughly
+// 1 in 2**(128 - (2 * 45)) or roughly 1 in a trillion (assuming all
+// data from the last 180 days is in cache, but NOT the other assumption
+// for the 1 in a trillion estimate above).
+//
+//
+// Collision probability estimation through simulation:
+// A tool ./cache_bench -stress_cache_key broadly simulates host-wide cache
+// activity over many months, by making some pessimistic simplifying
+// assumptions. See class StressCacheKey in cache_bench_tool.cc for details.
+// Here is some sample output with
+// `./cache_bench -stress_cache_key -sck_keep_bits=40`:
+//
+//   Total cache or DBs size: 32TiB  Writing 925.926 MiB/s or 76.2939TiB/day
+//   Multiply by 9.22337e+18 to correct for simulation losses (but still
+//   assume whole file cached)
+//
+// These come from default settings of 2.5M files per day of 32 MB each, and
+// `-sck_keep_bits=40` means that to represent a single file, we are only
+// keeping 40 bits of the 128-bit (base) cache key.  With file size of 2**25
+// contiguous keys (pessimistic), our simulation is about 2\*\*(128-40-25) or
+// about 9 billion billion times more prone to collision than reality.
+//
+// More default assumptions, relatively pessimistic:
+// * 100 DBs in same process (doesn't matter much)
+// * Re-open DB in same process (new session ID related to old session ID) on
+// average every 100 files generated
+// * Restart process (all new session IDs unrelated to old) 24 times per day
+//
+// After enough data, we get a result at the end (-sck_keep_bits=40):
+//
+//   (keep 40 bits)  17 collisions after 2 x 90 days, est 10.5882 days between
+//                   (9.76592e+19 corrected)
+//
+// If we believe the (pessimistic) simulation and the mathematical
+// extrapolation, we would need to run a billion machines all for 97 billion
+// days to expect a cache key collision. To help verify that our extrapolation
+// ("corrected") is robust, we can make our simulation more precise with
+// `-sck_keep_bits=41` and `42`, which takes more running time to get enough
+// collision data:
+//
+//   (keep 41 bits)  16 collisions after 4 x 90 days, est 22.5 days between
+//                   (1.03763e+20 corrected)
+//   (keep 42 bits)  19 collisions after 10 x 90 days, est 47.3684 days between
+//                   (1.09224e+20 corrected)
+//
+// The extrapolated prediction is very close. If anything, we might have some
+// very small losses of structured data (see class StressCacheKey in
+// cache_bench_tool.cc) leading to more accurate & more attractive prediction
+// with more bits kept.
+//
+// With the `-sck_randomize` option, we can see that typical workloads like
+// above have lower collision probability than "random" cache keys (note:
+// offsets still non-randomized) by a modest amount (roughly 20x less collision
+// prone than random), which should make us reasonably comfortable even in
+// "degenerate" cases (e.g. repeatedly launch a process to generate 1 file
+// with SstFileWriter):
+//
+//   (rand 40 bits) 197 collisions after 1 x 90 days, est 0.456853 days between
+//                  (4.21372e+18 corrected)
+//
+// We can see that with more frequent process restarts (all new session IDs),
+// we get closer to the "random" cache key performance:
+//
+//   (-sck_restarts_per_day=5000): 140 collisions after 1 x 90 days, ...
+//                  (5.92931e+18 corrected)
+//
+// Other tests have been run to validate other conditions behave as expected,
+// never behaving "worse than random" unless we start chopping off structured
+// data.
+//
+//
+// Conclusion: Even in extreme cases, rapidly burning through "all new" IDs
+// that only arise when a new process is started, the chance of any cache key
+// collisions in a giant fleet of machines is negligible. Especially when
+// processes live for hours or days, the chance of a cache key collision is
+// likely more plausibly due to bad hardware than to bad luck in random
+// session ID data. Software defects are surely more likely to cause corruption
+// than both of those.
+//
+// TODO: Nevertheless / regardless, an efficient way to detect (and thus
+// quantify) block cache corruptions, including collisions, should be added.
+OffsetableCacheKey::OffsetableCacheKey(const std::string &db_id,
+                                       const std::string &db_session_id,
+                                       uint64_t file_number,
+                                       uint64_t max_offset) {
+#ifndef NDEBUG
+  max_offset_ = max_offset;
+#endif
+  // Closely related to GetSstInternalUniqueId, but only need 128 bits and
+  // need to include an offset within the file.
+  // See also https://github.com/pdillinger/unique_id for background.
+  uint64_t session_upper = 0;  // Assignment to appease clang-analyze
+  uint64_t session_lower = 0;  // Assignment to appease clang-analyze
+  {
+    Status s = DecodeSessionId(db_session_id, &session_upper, &session_lower);
+    if (!s.ok()) {
+      // A reasonable fallback in case malformed
+      Hash2x64(db_session_id.data(), db_session_id.size(), &session_upper,
+               &session_lower);
+    }
+  }
+
+  // Hash the session upper (~39 bits entropy) and DB id (120+ bits entropy)
+  // for more global uniqueness entropy.
+  // (It is possible that many DBs descended from one common DB id are copied
+  // around and proliferate, in which case session id is critical, but it is
+  // more common for different DBs to have different DB ids.)
+  uint64_t db_hash = Hash64(db_id.data(), db_id.size(), session_upper);
+
+  // This establishes the db+session id part of the cache key.
+  //
+  // Exactly preserve (in common cases; see modifiers below) session lower to
+  // ensure that session ids generated during the same process lifetime are
+  // guaranteed unique.
+  //
+  // We put this first for CommonPrefixSlice(), so that a small-ish set of
+  // cache key prefixes to cover entries relevant to any DB.
+  session_etc64_ = session_lower;
+  // This provides extra entopy in case of different DB id or process
+  // generating a session id, but is also partly/variably obscured by
+  // file_number and offset (see below).
+  offset_etc64_ = db_hash;
+
+  // Into offset_etc64_ we are (eventually) going to pack & xor in an offset and
+  // a file_number, but we might need the file_number to overflow into
+  // session_etc64_. (There must only be one session_etc64_ value per
+  // file, and preferably shared among many files.)
+  //
+  // Figure out how many bytes of file_number we are going to be able to
+  // pack in with max_offset, though our encoding will only support packing
+  // in up to 3 bytes of file_number. (16M file numbers is enough for a new
+  // file number every second for half a year.)
+  int file_number_bytes_in_offset_etc =
+      (63 - FloorLog2(max_offset | 0x100000000U)) / 8;
+  int file_number_bits_in_offset_etc = file_number_bytes_in_offset_etc * 8;
+
+  // Assert two bits of metadata
+  assert(file_number_bytes_in_offset_etc >= 0 &&
+         file_number_bytes_in_offset_etc <= 3);
+  // Assert we couldn't have used a larger allowed number of bytes (shift
+  // would chop off bytes).
+  assert(file_number_bytes_in_offset_etc == 3 ||
+         (max_offset << (file_number_bits_in_offset_etc + 8) >>
+          (file_number_bits_in_offset_etc + 8)) != max_offset);
+
+  uint64_t mask = (uint64_t{1} << (file_number_bits_in_offset_etc)) - 1;
+  // Pack into high bits of etc so that offset can go in low bits of etc
+  // TODO: could be EndianSwapValue?
+  uint64_t offset_etc_modifier = ReverseBits(file_number & mask);
+  assert(offset_etc_modifier << file_number_bits_in_offset_etc == 0U);
+
+  // Overflow and 3 - byte count (likely both zero) go into session_id part
+  uint64_t session_etc_modifier =
+      (file_number >> file_number_bits_in_offset_etc << 2) |
+      static_cast<uint64_t>(3 - file_number_bytes_in_offset_etc);
+  // Packed into high bits to minimize interference with session id counter.
+  session_etc_modifier = ReverseBits(session_etc_modifier);
+
+  // Assert session_id part is only modified in extreme cases
+  assert(session_etc_modifier == 0 || file_number > /*3 bytes*/ 0xffffffU ||
+         max_offset > /*5 bytes*/ 0xffffffffffU);
+
+  // Xor in the modifiers
+  session_etc64_ ^= session_etc_modifier;
+  offset_etc64_ ^= offset_etc_modifier;
+
+  // Although DBImpl guarantees (in recent versions) that session_lower is not
+  // zero, that's not entirely sufficient to guarantee that session_etc64_ is
+  // not zero (so that the 0 case can be used by CacheKey::CreateUnique*)
+  if (session_etc64_ == 0U) {
+    session_etc64_ = session_upper | 1U;
+  }
+  assert(session_etc64_ != 0);
+}
+
+}  // namespace ROCKSDB_NAMESPACE
@@ -0,0 +1,132 @@
+//  Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#include <cstdint>
+
+#include "rocksdb/rocksdb_namespace.h"
+#include "rocksdb/slice.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class Cache;
+
+// A standard holder for fixed-size block cache keys (and for related caches).
+// They are created through one of these, each using its own range of values:
+// * CacheKey::CreateUniqueForCacheLifetime
+// * CacheKey::CreateUniqueForProcessLifetime
+// * Default ctor ("empty" cache key)
+// * OffsetableCacheKey->WithOffset
+//
+// The first two use atomic counters to guarantee uniqueness over the given
+// lifetime and the last uses a form of universally unique identifier for
+// uniqueness with very high probabilty (and guaranteed for files generated
+// during a single process lifetime).
+//
+// CacheKeys are currently used by calling AsSlice() to pass as a key to
+// Cache. For performance, the keys are endianness-dependent (though otherwise
+// portable). (Persistable cache entries are not intended to cross platforms.)
+class CacheKey {
+ public:
+  // For convenience, constructs an "empty" cache key that is never returned
+  // by other means.
+  inline CacheKey() : session_etc64_(), offset_etc64_() {}
+
+  inline bool IsEmpty() const {
+    return (session_etc64_ == 0) & (offset_etc64_ == 0);
+  }
+
+  // Use this cache key as a Slice (byte order is endianness-dependent)
+  inline Slice AsSlice() const {
+    static_assert(sizeof(*this) == 16, "Standardized on 16-byte cache key");
+    assert(!IsEmpty());
+    return Slice(reinterpret_cast<const char *>(this), sizeof(*this));
+  }
+
+  // Create a CacheKey that is unique among others associated with this Cache
+  // instance. Depends on Cache::NewId. This is useful for block cache
+  // "reservations".
+  static CacheKey CreateUniqueForCacheLifetime(Cache *cache);
+
+  // Create a CacheKey that is unique among others for the lifetime of this
+  // process. This is useful for saving in a static data member so that
+  // different DB instances can agree on a cache key for shared entities,
+  // such as for CacheEntryStatsCollector.
+  static CacheKey CreateUniqueForProcessLifetime();
+
+ protected:
+  friend class OffsetableCacheKey;
+  CacheKey(uint64_t session_etc64, uint64_t offset_etc64)
+      : session_etc64_(session_etc64), offset_etc64_(offset_etc64) {}
+  uint64_t session_etc64_;
+  uint64_t offset_etc64_;
+};
+
+// A file-specific generator of cache keys, sometimes referred to as the
+// "base" cache key for a file because all the cache keys for various offsets
+// within the file are computed using simple arithmetic. The basis for the
+// general approach is dicussed here: https://github.com/pdillinger/unique_id
+// Heavily related to GetUniqueIdFromTableProperties.
+//
+// If the db_id, db_session_id, and file_number come from the file's table
+// properties, then the keys will be stable across DB::Open/Close, backup/
+// restore, import/export, etc.
+//
+// This class "is a" CacheKey only privately so that it is not misused as
+// a ready-to-use CacheKey.
+class OffsetableCacheKey : private CacheKey {
+ public:
+  // For convenience, constructs an "empty" cache key that should not be used.
+  inline OffsetableCacheKey() : CacheKey() {}
+
+  // Constructs an OffsetableCacheKey with the given information about a file.
+  // max_offset is based on file size (see WithOffset) and is required here to
+  // choose an appropriate (sub-)encoding. This constructor never generates an
+  // "empty" base key.
+  OffsetableCacheKey(const std::string &db_id, const std::string &db_session_id,
+                     uint64_t file_number, uint64_t max_offset);
+
+  inline bool IsEmpty() const {
+    bool result = session_etc64_ == 0;
+    assert(!(offset_etc64_ > 0 && result));
+    return result;
+  }
+
+  // Construct a CacheKey for an offset within a file, which must be
+  // <= max_offset provided in constructor. An offset is not necessarily a
+  // byte offset if a smaller unique identifier of keyable offsets is used.
+  //
+  // This class was designed to make this hot code extremely fast.
+  inline CacheKey WithOffset(uint64_t offset) const {
+    assert(!IsEmpty());
+    assert(offset <= max_offset_);
+    return CacheKey(session_etc64_, offset_etc64_ ^ offset);
+  }
+
+  // The "common prefix" is a shared prefix for all the returned CacheKeys,
+  // that also happens to usually be the same among many files in the same DB,
+  // so is efficient and highly accurate (not perfectly) for DB-specific cache
+  // dump selection (but not file-specific).
+  static constexpr size_t kCommonPrefixSize = 8;
+  inline Slice CommonPrefixSlice() const {
+    static_assert(sizeof(session_etc64_) == kCommonPrefixSize,
+                  "8 byte common prefix expected");
+    assert(!IsEmpty());
+    assert(&this->session_etc64_ == static_cast<const void *>(this));
+
+    return Slice(reinterpret_cast<const char *>(this), kCommonPrefixSize);
+  }
+
+  // For any max_offset <= this value, the same encoding scheme is guaranteed.
+  static constexpr uint64_t kMaxOffsetStandardEncoding = 0xffffffffffU;
+
+ private:
+#ifndef NDEBUG
+  uint64_t max_offset_ = 0;
+#endif
+};
+
+}  // namespace ROCKSDB_NAMESPACE
@@ -23,11 +23,11 @@
 namespace ROCKSDB_NAMESPACE {
 CacheReservationManager::CacheReservationManager(std::shared_ptr<Cache> cache,
                                                 bool delayed_decrease)
-    : delayed_decrease_(delayed_decrease), cache_allocated_size_(0) {
+    : delayed_decrease_(delayed_decrease),
+      cache_allocated_size_(0),
+      memory_used_(0) {
  assert(cache != nullptr);
  cache_ = cache;
-  std::memset(cache_key_, 0, kCacheKeyPrefixSize + kMaxVarint64Length);
-  EncodeVarint64(cache_key_, cache_->NewId());
 }

 CacheReservationManager::~CacheReservationManager() {
@@ -39,6 +39,7 @@ CacheReservationManager::~CacheReservationManager() {
 template <CacheEntryRole R>
 Status CacheReservationManager::UpdateCacheReservation(
    std::size_t new_mem_used) {
+  memory_used_ = new_mem_used;
  std::size_t cur_cache_allocated_size =
      cache_allocated_size_.load(std::memory_order_relaxed);
  if (new_mem_used == cur_cache_allocated_size) {
@@ -76,6 +77,28 @@ template Status CacheReservationManager::UpdateCacheReservation<
 template Status CacheReservationManager::UpdateCacheReservation<
    CacheEntryRole::kMisc>(std::size_t new_mem_used);

+template <CacheEntryRole R>
+Status CacheReservationManager::MakeCacheReservation(
+    std::size_t incremental_memory_used,
+    std::unique_ptr<CacheReservationHandle<R>>* handle) {
+  assert(handle != nullptr);
+  Status s =
+      UpdateCacheReservation<R>(GetTotalMemoryUsed() + incremental_memory_used);
+  (*handle).reset(new CacheReservationHandle<R>(incremental_memory_used,
+                                                shared_from_this()));
+  return s;
+}
+
+template Status
+CacheReservationManager::MakeCacheReservation<CacheEntryRole::kMisc>(
+    std::size_t incremental_memory_used,
+    std::unique_ptr<CacheReservationHandle<CacheEntryRole::kMisc>>* handle);
+template Status CacheReservationManager::MakeCacheReservation<
+    CacheEntryRole::kFilterConstruction>(
+    std::size_t incremental_memory_used,
+    std::unique_ptr<
+        CacheReservationHandle<CacheEntryRole::kFilterConstruction>>* handle);
+
 template <CacheEntryRole R>
 Status CacheReservationManager::IncreaseCacheReservation(
    std::size_t new_mem_used) {
@@ -118,14 +141,48 @@ std::size_t CacheReservationManager::GetTotalReservedCacheSize() {
  return cache_allocated_size_.load(std::memory_order_relaxed);
 }

+std::size_t CacheReservationManager::GetTotalMemoryUsed() {
+  return memory_used_;
+}
+
 Slice CacheReservationManager::GetNextCacheKey() {
  // Calling this function will have the side-effect of changing the
  // underlying cache_key_ that is shared among other keys generated from this
  // fucntion. Therefore please make sure the previous keys are saved/copied
  // before calling this function.
-  std::memset(cache_key_ + kCacheKeyPrefixSize, 0, kMaxVarint64Length);
-  char* end =
-      EncodeVarint64(cache_key_ + kCacheKeyPrefixSize, next_cache_key_id_++);
-  return Slice(cache_key_, static_cast<std::size_t>(end - cache_key_));
+  cache_key_ = CacheKey::CreateUniqueForCacheLifetime(cache_.get());
+  return cache_key_.AsSlice();
 }
-}  // namespace ROCKSDB_NAMESPACE
+
+template <CacheEntryRole R>
+Cache::DeleterFn CacheReservationManager::TEST_GetNoopDeleterForRole() {
+  return GetNoopDeleterForRole<R>();
+}
+
+template Cache::DeleterFn CacheReservationManager::TEST_GetNoopDeleterForRole<
+    CacheEntryRole::kFilterConstruction>();
+
+template <CacheEntryRole R>
+CacheReservationHandle<R>::CacheReservationHandle(
+    std::size_t incremental_memory_used,
+    std::shared_ptr<CacheReservationManager> cache_res_mgr)
+    : incremental_memory_used_(incremental_memory_used) {
+  assert(cache_res_mgr != nullptr);
+  cache_res_mgr_ = cache_res_mgr;
+}
+
+template <CacheEntryRole R>
+CacheReservationHandle<R>::~CacheReservationHandle() {
+  assert(cache_res_mgr_ != nullptr);
+  assert(cache_res_mgr_->GetTotalMemoryUsed() >= incremental_memory_used_);
+
+  Status s = cache_res_mgr_->UpdateCacheReservation<R>(
+      cache_res_mgr_->GetTotalMemoryUsed() - incremental_memory_used_);
+  s.PermitUncheckedError();
+}
+
+// Explicitly instantiate templates for "CacheEntryRole" values we use.
+// This makes it possible to keep the template definitions in the .cc file.
+template class CacheReservationHandle<CacheEntryRole::kMisc>;
+template class CacheReservationHandle<CacheEntryRole::kFilterConstruction>;
+}  // namespace ROCKSDB_NAMESPACE
@@ -24,10 +24,16 @@

 namespace ROCKSDB_NAMESPACE {

+template <CacheEntryRole R>
+class CacheReservationHandle;
+
 // CacheReservationManager is for reserving cache space for the memory used
 // through inserting/releasing dummy entries in the cache.
-// This class is not thread-safe.
-class CacheReservationManager {
+//
+// This class is NOT thread-safe, except that GetTotalReservedCacheSize()
+// can be called without external synchronization.
+class CacheReservationManager
+    : public std::enable_shared_from_this<CacheReservationManager> {
 public:
  // Construct a CacheReservationManager
  // @param cache The cache where dummy entries are inserted and released for
@@ -52,9 +58,13 @@ class CacheReservationManager {

  template <CacheEntryRole R>

+  // One of the two ways of reserving/releasing cache,
+  // see CacheReservationManager::MakeCacheReservation() for the other.
+  // Use ONLY one of them to prevent unexpected behavior.
+  //
  // Insert and release dummy entries in the cache to
-  // match the size of total dummy entries with the smallest multiple of
-  // kSizeDummyEntry that is greater than or equal to new_mem_used
+  // match the size of total dummy entries with the least multiple of
+  // kSizeDummyEntry greater than or equal to new_mem_used
  //
  // Insert dummy entries if new_memory_used > cache_allocated_size_;
  //
@@ -68,19 +78,86 @@ class CacheReservationManager {
  // is set true.
  //
  // @param new_memory_used The number of bytes used by new memory
+  //        The most recent new_memoy_used passed in will be returned
+  //        in GetTotalMemoryUsed() even when the call return non-ok status.
+  //
+  //        Since the class is NOT thread-safe, external synchronization on the
+  //        order of calling UpdateCacheReservation() is needed if you want
+  //        GetTotalMemoryUsed() indeed returns the latest memory used.
+  //
  // @return On inserting dummy entries, it returns Status::OK() if all dummy
-  // entry insertions succeed. Otherwise, it returns the first non-ok status;
-  // On releasing dummy entries, it always returns Status::OK().
-  // On keeping dummy entries the same, it always returns Status::OK().
+  //         entry insertions succeed.
+  //         Otherwise, it returns the first non-ok status;
+  //         On releasing dummy entries, it always returns Status::OK().
+  //         On keeping dummy entries the same, it always returns Status::OK().
  Status UpdateCacheReservation(std::size_t new_memory_used);
+
+  // One of the two ways of reserving/releasing cache,
+  // see CacheReservationManager::UpdateCacheReservation() for the other.
+  // Use ONLY one of them to prevent unexpected behavior.
+  //
+  // Insert dummy entries in the cache for the incremental memory usage
+  // to match the size of total dummy entries with the least multiple of
+  // kSizeDummyEntry greater than or equal to the total memory used.
+  //
+  // A CacheReservationHandle is returned as an output parameter.
+  // The reserved dummy entries are automatically released on the destruction of
+  // this handle, which achieves better RAII per cache reservation.
+  //
+  // WARNING: Deallocate all the handles of the CacheReservationManager object
+  //          before deallocating the object to prevent unexpected behavior.
+  //
+  // @param incremental_memory_used The number of bytes increased in memory
+  //        usage.
+  //
+  //        Calling GetTotalMemoryUsed() afterward will return the total memory
+  //        increased by this number, even when calling MakeCacheReservation()
+  //        returns non-ok status.
+  //
+  //        Since the class is NOT thread-safe, external synchronization in
+  //        calling MakeCacheReservation() is needed if you want
+  //        GetTotalMemoryUsed() indeed returns the latest memory used.
+  //
+  // @param handle An pointer to std::unique_ptr<CacheReservationHandle<R>> that
+  //        manages the lifetime of the handle and its cache reservation.
+  //
+  // @return It returns Status::OK() if all dummy
+  //         entry insertions succeed.
+  //         Otherwise, it returns the first non-ok status;
+  //
+  // REQUIRES: handle != nullptr
+  // REQUIRES: The CacheReservationManager object is NOT managed by
+  //           std::unique_ptr as CacheReservationHandle needs to
+  //           shares ownership to the CacheReservationManager object.
+  template <CacheEntryRole R>
+  Status MakeCacheReservation(
+      std::size_t incremental_memory_used,
+      std::unique_ptr<CacheReservationHandle<R>> *handle);
+
+  // Return the size of the cache (which is a multiple of kSizeDummyEntry)
+  // successfully reserved by calling UpdateCacheReservation().
+  //
+  // When UpdateCacheReservation() returns non-ok status,
+  // calling GetTotalReservedCacheSize() after that might return a slightly
+  // smaller number than the actual reserved cache size due to
+  // the returned number will always be a multiple of kSizeDummyEntry
+  // and cache full might happen in the middle of inserting a dummy entry.
  std::size_t GetTotalReservedCacheSize();

+  // Return the latest total memory used indicated by the most recent call of
+  // UpdateCacheReservation(std::size_t new_memory_used);
+  std::size_t GetTotalMemoryUsed();
+
+  static constexpr std::size_t GetDummyEntrySize() { return kSizeDummyEntry; }
+
+  // For testing only - it is to help ensure the NoopDeleterForRole<R>
+  // accessed from CacheReservationManager and the one accessed from the test
+  // are from the same translation units
+  template <CacheEntryRole R>
+  static Cache::DeleterFn TEST_GetNoopDeleterForRole();
+
 private:
  static constexpr std::size_t kSizeDummyEntry = 256 * 1024;
-  // The key will be longer than keys for blocks in SST files so they won't
-  // conflict.
-  static const std::size_t kCacheKeyPrefixSize =
-      BlockBasedTable::kMaxCacheKeyPrefixSize + kMaxVarint64Length;

  Slice GetNextCacheKey();
  template <CacheEntryRole R>
@@ -90,9 +167,25 @@ class CacheReservationManager {
  std::shared_ptr<Cache> cache_;
  bool delayed_decrease_;
  std::atomic<std::size_t> cache_allocated_size_;
+  std::size_t memory_used_;
  std::vector<Cache::Handle *> dummy_handles_;
-  std::uint64_t next_cache_key_id_ = 0;
-  // The non-prefix part will be updated according to the ID to use.
-  char cache_key_[kCacheKeyPrefixSize + kMaxVarint64Length];
+  CacheKey cache_key_;
 };
-}  // namespace ROCKSDB_NAMESPACE
+
+// CacheReservationHandle is for managing the lifetime of a cache reservation
+// This class is NOT thread-safe
+template <CacheEntryRole R>
+class CacheReservationHandle {
+ public:
+  // REQUIRES: cache_res_mgr != nullptr
+  explicit CacheReservationHandle(
+      std::size_t incremental_memory_used,
+      std::shared_ptr<CacheReservationManager> cache_res_mgr);
+
+  ~CacheReservationHandle();
+
+ private:
+  std::size_t incremental_memory_used_;
+  std::shared_ptr<CacheReservationManager> cache_res_mgr_;
+};
+}  // namespace ROCKSDB_NAMESPACE
@@ -22,15 +22,13 @@
 namespace ROCKSDB_NAMESPACE {
 class CacheReservationManagerTest : public ::testing::Test {
 protected:
-  static constexpr std::size_t kOneGigabyte = 1024 * 1024 * 1024;
+  static constexpr std::size_t kSizeDummyEntry =
+      CacheReservationManager::GetDummyEntrySize();
+  static constexpr std::size_t kCacheCapacity = 4096 * kSizeDummyEntry;
  static constexpr int kNumShardBits = 0;  // 2^0 shard
-
-  static constexpr std::size_t kSizeDummyEntry = 256 * 1024;
-  static const std::size_t kCacheKeyPrefixSize =
-      BlockBasedTable::kMaxCacheKeyPrefixSize + kMaxVarint64Length;
  static constexpr std::size_t kMetaDataChargeOverhead = 10000;

-  std::shared_ptr<Cache> cache = NewLRUCache(kOneGigabyte, kNumShardBits);
+  std::shared_ptr<Cache> cache = NewLRUCache(kCacheCapacity, kNumShardBits);
  std::unique_ptr<CacheReservationManager> test_cache_rev_mng;

  CacheReservationManagerTest() {
@@ -39,22 +37,6 @@ class CacheReservationManagerTest : public ::testing::Test {
 };

 TEST_F(CacheReservationManagerTest, GenerateCacheKey) {
-  // The first cache reservation manager owning the cache will have
-  // cache->NewId() = 1
-  constexpr std::size_t kCacheNewId = 1;
-  // The first key generated inside of cache reservation manager will have
-  // next_cache_key_id = 0
-  constexpr std::size_t kCacheKeyId = 0;
-
-  char expected_cache_key[kCacheKeyPrefixSize + kMaxVarint64Length];
-  std::memset(expected_cache_key, 0, kCacheKeyPrefixSize + kMaxVarint64Length);
-
-  EncodeVarint64(expected_cache_key, kCacheNewId);
-  char* end =
-      EncodeVarint64(expected_cache_key + kCacheKeyPrefixSize, kCacheKeyId);
-  Slice expected_cache_key_slice(
-      expected_cache_key, static_cast<std::size_t>(end - expected_cache_key));
-
  std::size_t new_mem_used = 1 * kSizeDummyEntry;
  Status s =
      test_cache_rev_mng
@@ -65,7 +47,17 @@ TEST_F(CacheReservationManagerTest, GenerateCacheKey) {
  ASSERT_LT(cache->GetPinnedUsage(),
            1 * kSizeDummyEntry + kMetaDataChargeOverhead);

-  Cache::Handle* handle = cache->Lookup(expected_cache_key_slice);
+  // Next unique Cache key
+  CacheKey ckey = CacheKey::CreateUniqueForCacheLifetime(cache.get());
+  // Back it up to the one used by CRM (using CacheKey implementation details)
+  using PairU64 = std::pair<uint64_t, uint64_t>;
+  auto& ckey_pair = *reinterpret_cast<PairU64*>(&ckey);
+  ckey_pair.second--;
+
+  // Specific key (subject to implementation details)
+  EXPECT_EQ(ckey_pair, PairU64(0, 2));
+
+  Cache::Handle* handle = cache->Lookup(ckey.AsSlice());
  EXPECT_NE(handle, nullptr)
      << "Failed to generate the cache key for the dummy entry correctly";
  // Clean up the returned handle from Lookup() to prevent memory leak
@@ -81,6 +73,7 @@ TEST_F(CacheReservationManagerTest, KeepCacheReservationTheSame) {
  ASSERT_EQ(s, Status::OK());
  ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
            1 * kSizeDummyEntry);
+  ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
  std::size_t initial_pinned_usage = cache->GetPinnedUsage();
  ASSERT_GE(initial_pinned_usage, 1 * kSizeDummyEntry);
  ASSERT_LT(initial_pinned_usage,
@@ -96,6 +89,9 @@ TEST_F(CacheReservationManagerTest, KeepCacheReservationTheSame) {
            1 * kSizeDummyEntry)
      << "Failed to bookkeep correctly when new_mem_used equals to current "
         "cache reservation";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly when new_mem_used "
+         "equals to current cache reservation";
  EXPECT_EQ(cache->GetPinnedUsage(), initial_pinned_usage)
      << "Failed to keep underlying dummy entries the same when new_mem_used "
         "equals to current cache reservation";
@@ -113,6 +109,8 @@ TEST_F(CacheReservationManagerTest,
  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
            2 * kSizeDummyEntry)
      << "Failed to bookkeep cache reservation increase correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry)
      << "Failed to increase underlying dummy entries in cache correctly";
  EXPECT_LT(cache->GetPinnedUsage(),
@@ -132,6 +130,8 @@ TEST_F(CacheReservationManagerTest,
  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
            3 * kSizeDummyEntry)
      << "Failed to bookkeep cache reservation increase correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_GE(cache->GetPinnedUsage(), 3 * kSizeDummyEntry)
      << "Failed to increase underlying dummy entries in cache correctly";
  EXPECT_LT(cache->GetPinnedUsage(),
@@ -141,20 +141,22 @@ TEST_F(CacheReservationManagerTest,

 TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
     IncreaseCacheReservationOnFullCache) {
-  constexpr std::size_t kOneMegabyte = 1024 * 1024;
-  constexpr std::size_t kOneGigabyte = 1024 * 1024 * 1024;
-  constexpr std::size_t kSizeDummyEntry = 256 * 1024;
+  ;
+  constexpr std::size_t kSizeDummyEntry =
+      CacheReservationManager::GetDummyEntrySize();
+  constexpr std::size_t kSmallCacheCapacity = 4 * kSizeDummyEntry;
+  constexpr std::size_t kBigCacheCapacity = 4096 * kSizeDummyEntry;
  constexpr std::size_t kMetaDataChargeOverhead = 10000;

  LRUCacheOptions lo;
-  lo.capacity = kOneMegabyte;
+  lo.capacity = kSmallCacheCapacity;
  lo.num_shard_bits = 0;  // 2^0 shard
  lo.strict_capacity_limit = true;
  std::shared_ptr<Cache> cache = NewLRUCache(lo);
  std::unique_ptr<CacheReservationManager> test_cache_rev_mng(
      new CacheReservationManager(cache));

-  std::size_t new_mem_used = kOneMegabyte + 1;
+  std::size_t new_mem_used = kSmallCacheCapacity + 1;
  Status s =
      test_cache_rev_mng
          ->UpdateCacheReservation<ROCKSDB_NAMESPACE::CacheEntryRole::kMisc>(
@@ -166,18 +168,21 @@ TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
            1 * kSizeDummyEntry)
      << "Failed to bookkeep correctly before cache resevation failure happens "
         "due to full cache";
-  EXPECT_LE(test_cache_rev_mng->GetTotalReservedCacheSize(), kOneMegabyte)
+  EXPECT_LE(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            kSmallCacheCapacity)
      << "Failed to bookkeep correctly (i.e, bookkeep only successful dummy "
         "entry insertions) when encountering cache resevation failure due to "
         "full cache";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
      << "Failed to insert underlying dummy entries correctly when "
         "encountering cache resevation failure due to full cache";
-  EXPECT_LE(cache->GetPinnedUsage(), kOneMegabyte)
+  EXPECT_LE(cache->GetPinnedUsage(), kSmallCacheCapacity)
      << "Failed to insert underlying dummy entries correctly when "
         "encountering cache resevation failure due to full cache";

-  new_mem_used = kOneMegabyte / 2;  // 2 dummy entries
+  new_mem_used = kSmallCacheCapacity / 2;  // 2 dummy entries
  s = test_cache_rev_mng
          ->UpdateCacheReservation<ROCKSDB_NAMESPACE::CacheEntryRole::kMisc>(
              new_mem_used);
@@ -188,6 +193,8 @@ TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
            2 * kSizeDummyEntry)
      << "Failed to bookkeep cache reservation decrease correctly after "
         "encountering cache reservation due to full cache";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry)
      << "Failed to release underlying dummy entries correctly on cache "
         "reservation decrease after encountering cache resevation failure due "
@@ -199,7 +206,7 @@ TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
         "to full cache";

  // Create cache full again for subsequent tests
-  new_mem_used = kOneMegabyte + 1;
+  new_mem_used = kSmallCacheCapacity + 1;
  s = test_cache_rev_mng
          ->UpdateCacheReservation<ROCKSDB_NAMESPACE::CacheEntryRole::kMisc>(
              new_mem_used);
@@ -210,21 +217,24 @@ TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
            1 * kSizeDummyEntry)
      << "Failed to bookkeep correctly before cache resevation failure happens "
         "due to full cache";
-  EXPECT_LE(test_cache_rev_mng->GetTotalReservedCacheSize(), kOneMegabyte)
+  EXPECT_LE(test_cache_rev_mng->GetTotalReservedCacheSize(),
+            kSmallCacheCapacity)
      << "Failed to bookkeep correctly (i.e, bookkeep only successful dummy "
         "entry insertions) when encountering cache resevation failure due to "
         "full cache";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
      << "Failed to insert underlying dummy entries correctly when "
         "encountering cache resevation failure due to full cache";
-  EXPECT_LE(cache->GetPinnedUsage(), kOneMegabyte)
+  EXPECT_LE(cache->GetPinnedUsage(), kSmallCacheCapacity)
      << "Failed to insert underlying dummy entries correctly when "
         "encountering cache resevation failure due to full cache";

  // Increase cache capacity so the previously failed insertion can fully
  // succeed
-  cache->SetCapacity(kOneGigabyte);
-  new_mem_used = kOneMegabyte + 1;
+  cache->SetCapacity(kBigCacheCapacity);
+  new_mem_used = kSmallCacheCapacity + 1;
  s = test_cache_rev_mng
          ->UpdateCacheReservation<ROCKSDB_NAMESPACE::CacheEntryRole::kMisc>(
              new_mem_used);
@@ -235,6 +245,8 @@ TEST(CacheReservationManagerIncreaseReservcationOnFullCacheTest,
            5 * kSizeDummyEntry)
      << "Failed to bookkeep cache reservation increase correctly after "
         "increasing cache capacity and mitigating cache full error";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_GE(cache->GetPinnedUsage(), 5 * kSizeDummyEntry)
      << "Failed to insert underlying dummy entries correctly after increasing "
         "cache capacity and mitigating cache full error";
@@ -254,6 +266,7 @@ TEST_F(CacheReservationManagerTest,
  ASSERT_EQ(s, Status::OK());
  ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
            2 * kSizeDummyEntry);
+  ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
  ASSERT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry);
  ASSERT_LT(cache->GetPinnedUsage(),
            2 * kSizeDummyEntry + kMetaDataChargeOverhead);
@@ -267,6 +280,8 @@ TEST_F(CacheReservationManagerTest,
  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
            1 * kSizeDummyEntry)
      << "Failed to bookkeep cache reservation decrease correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
      << "Failed to decrease underlying dummy entries in cache correctly";
  EXPECT_LT(cache->GetPinnedUsage(),
@@ -284,6 +299,7 @@ TEST_F(CacheReservationManagerTest,
  ASSERT_EQ(s, Status::OK());
  ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
            2 * kSizeDummyEntry);
+  ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
  ASSERT_GE(cache->GetPinnedUsage(), 2 * kSizeDummyEntry);
  ASSERT_LT(cache->GetPinnedUsage(),
            2 * kSizeDummyEntry + kMetaDataChargeOverhead);
@@ -297,6 +313,8 @@ TEST_F(CacheReservationManagerTest,
  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
            1 * kSizeDummyEntry)
      << "Failed to bookkeep cache reservation decrease correctly";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_GE(cache->GetPinnedUsage(), 1 * kSizeDummyEntry)
      << "Failed to decrease underlying dummy entries in cache correctly";
  EXPECT_LT(cache->GetPinnedUsage(),
@@ -306,12 +324,13 @@ TEST_F(CacheReservationManagerTest,

 TEST(CacheReservationManagerWithDelayedDecreaseTest,
     DecreaseCacheReservationWithDelayedDecrease) {
-  constexpr std::size_t kOneGigabyte = 1024 * 1024 * 1024;
-  constexpr std::size_t kSizeDummyEntry = 256 * 1024;
+  constexpr std::size_t kSizeDummyEntry =
+      CacheReservationManager::GetDummyEntrySize();
+  constexpr std::size_t kCacheCapacity = 4096 * kSizeDummyEntry;
  constexpr std::size_t kMetaDataChargeOverhead = 10000;

  LRUCacheOptions lo;
-  lo.capacity = kOneGigabyte;
+  lo.capacity = kCacheCapacity;
  lo.num_shard_bits = 0;
  std::shared_ptr<Cache> cache = NewLRUCache(lo);
  std::unique_ptr<CacheReservationManager> test_cache_rev_mng(
@@ -325,6 +344,7 @@ TEST(CacheReservationManagerWithDelayedDecreaseTest,
  ASSERT_EQ(s, Status::OK());
  ASSERT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(),
            8 * kSizeDummyEntry);
+  ASSERT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used);
  std::size_t initial_pinned_usage = cache->GetPinnedUsage();
  ASSERT_GE(initial_pinned_usage, 8 * kSizeDummyEntry);
  ASSERT_LT(initial_pinned_usage,
@@ -339,6 +359,8 @@ TEST(CacheReservationManagerWithDelayedDecreaseTest,
            8 * kSizeDummyEntry)
      << "Failed to bookkeep correctly when delaying cache reservation "
         "decrease";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_EQ(cache->GetPinnedUsage(), initial_pinned_usage)
      << "Failed to delay decreasing underlying dummy entries in cache";

@@ -351,6 +373,8 @@ TEST(CacheReservationManagerWithDelayedDecreaseTest,
            8 * kSizeDummyEntry)
      << "Failed to bookkeep correctly when delaying cache reservation "
         "decrease";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_EQ(cache->GetPinnedUsage(), initial_pinned_usage)
      << "Failed to delay decreasing underlying dummy entries in cache";

@@ -365,6 +389,8 @@ TEST(CacheReservationManagerWithDelayedDecreaseTest,
            6 * kSizeDummyEntry)
      << "Failed to bookkeep correctly when new_mem_used < "
         "GetTotalReservedCacheSize() * 3 / 4 on delayed decrease mode";
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), new_mem_used)
+      << "Failed to bookkeep the used memory correctly";
  EXPECT_GE(cache->GetPinnedUsage(), 6 * kSizeDummyEntry)
      << "Failed to decrease underlying dummy entries in cache when "
         "new_mem_used < GetTotalReservedCacheSize() * 3 / 4 on delayed "
@@ -378,12 +404,13 @@ TEST(CacheReservationManagerWithDelayedDecreaseTest,

 TEST(CacheReservationManagerDestructorTest,
     ReleaseRemainingDummyEntriesOnDestruction) {
-  constexpr std::size_t kOneGigabyte = 1024 * 1024 * 1024;
-  constexpr std::size_t kSizeDummyEntry = 256 * 1024;
+  constexpr std::size_t kSizeDummyEntry =
+      CacheReservationManager::GetDummyEntrySize();
+  constexpr std::size_t kCacheCapacity = 4096 * kSizeDummyEntry;
  constexpr std::size_t kMetaDataChargeOverhead = 10000;

  LRUCacheOptions lo;
-  lo.capacity = kOneGigabyte;
+  lo.capacity = kCacheCapacity;
  lo.num_shard_bits = 0;
  std::shared_ptr<Cache> cache = NewLRUCache(lo);
  {
@@ -403,9 +430,77 @@ TEST(CacheReservationManagerDestructorTest,
      << "Failed to release remaining underlying dummy entries in cache in "
         "CacheReservationManager's destructor";
 }
+
+TEST(CacheReservationHandleTest, HandleTest) {
+  constexpr std::size_t kOneGigabyte = 1024 * 1024 * 1024;
+  constexpr std::size_t kSizeDummyEntry = 256 * 1024;
+  constexpr std::size_t kMetaDataChargeOverhead = 10000;
+
+  LRUCacheOptions lo;
+  lo.capacity = kOneGigabyte;
+  lo.num_shard_bits = 0;
+  std::shared_ptr<Cache> cache = NewLRUCache(lo);
+
+  std::shared_ptr<CacheReservationManager> test_cache_rev_mng(
+      std::make_shared<CacheReservationManager>(cache));
+
+  std::size_t mem_used = 0;
+  const std::size_t incremental_mem_used_handle_1 = 1 * kSizeDummyEntry;
+  const std::size_t incremental_mem_used_handle_2 = 2 * kSizeDummyEntry;
+  std::unique_ptr<CacheReservationHandle<CacheEntryRole::kMisc>> handle_1,
+      handle_2;
+
+  // To test consecutive CacheReservationManager::MakeCacheReservation works
+  // correctly in terms of returning the handle as well as updating cache
+  // reservation and the latest total memory used
+  Status s = test_cache_rev_mng->MakeCacheReservation<CacheEntryRole::kMisc>(
+      incremental_mem_used_handle_1, &handle_1);
+  mem_used = mem_used + incremental_mem_used_handle_1;
+  ASSERT_EQ(s, Status::OK());
+  EXPECT_TRUE(handle_1 != nullptr);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(), mem_used);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), mem_used);
+  EXPECT_GE(cache->GetPinnedUsage(), mem_used);
+  EXPECT_LT(cache->GetPinnedUsage(), mem_used + kMetaDataChargeOverhead);
+
+  s = test_cache_rev_mng->MakeCacheReservation<CacheEntryRole::kMisc>(
+      incremental_mem_used_handle_2, &handle_2);
+  mem_used = mem_used + incremental_mem_used_handle_2;
+  ASSERT_EQ(s, Status::OK());
+  EXPECT_TRUE(handle_2 != nullptr);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(), mem_used);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), mem_used);
+  EXPECT_GE(cache->GetPinnedUsage(), mem_used);
+  EXPECT_LT(cache->GetPinnedUsage(), mem_used + kMetaDataChargeOverhead);
+
+  // To test CacheReservationHandle::~CacheReservationHandle() works correctly
+  // in releasing the cache reserved for the handle
+  handle_1.reset();
+  EXPECT_TRUE(handle_1 == nullptr);
+  mem_used = mem_used - incremental_mem_used_handle_1;
+  EXPECT_EQ(test_cache_rev_mng->GetTotalReservedCacheSize(), mem_used);
+  EXPECT_EQ(test_cache_rev_mng->GetTotalMemoryUsed(), mem_used);
+  EXPECT_GE(cache->GetPinnedUsage(), mem_used);
+  EXPECT_LT(cache->GetPinnedUsage(), mem_used + kMetaDataChargeOverhead);
+
+  // To test the actual CacheReservationManager object won't be deallocated
+  // as long as there remain handles pointing to it.
+  // We strongly recommend deallocating CacheReservationManager object only
+  // after all its handles are deallocated to keep things easy to reasonate
+  test_cache_rev_mng.reset();
+  EXPECT_GE(cache->GetPinnedUsage(), mem_used);
+  EXPECT_LT(cache->GetPinnedUsage(), mem_used + kMetaDataChargeOverhead);
+
+  handle_2.reset();
+  // The CacheReservationManager object is now deallocated since all the handles
+  // and its original pointer is gone
+  mem_used = mem_used - incremental_mem_used_handle_2;
+  EXPECT_EQ(mem_used, 0);
+  EXPECT_EQ(cache->GetPinnedUsage(), mem_used);
+}
 }  // namespace ROCKSDB_NAMESPACE

 int main(int argc, char** argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
-}
+}
@@ -609,6 +609,9 @@ TEST_P(CacheTest, SetCapacity) {
  for (size_t i = 5; i < 10; i++) {
    cache->Release(handles[i]);
  }
+
+  // Make sure this doesn't crash or upset ASAN/valgrind
+  cache->DisownData();
 }

 TEST_P(LRUCacheTest, SetStrictCapacityLimit) {
@@ -33,11 +33,11 @@ std::shared_ptr<Cache> NewClockCache(
 #ifndef ROCKSDB_USE_RTTI
 #define TBB_USE_EXCEPTIONS 0
 #endif
-#include "tbb/concurrent_hash_map.h"
-
 #include "cache/sharded_cache.h"
+#include "port/lang.h"
 #include "port/malloc.h"
 #include "port/port.h"
+#include "tbb/concurrent_hash_map.h"
 #include "util/autovector.h"
 #include "util/mutexlock.h"

@@ -228,22 +228,22 @@ struct CacheHandle {
 };

 // Key of hash map. We store hash value with the key for convenience.
-struct CacheKey {
+struct ClockCacheKey {
  Slice key;
  uint32_t hash_value;

-  CacheKey() = default;
+  ClockCacheKey() = default;

-  CacheKey(const Slice& k, uint32_t h) {
+  ClockCacheKey(const Slice& k, uint32_t h) {
    key = k;
    hash_value = h;
  }

-  static bool equal(const CacheKey& a, const CacheKey& b) {
+  static bool equal(const ClockCacheKey& a, const ClockCacheKey& b) {
    return a.hash_value == b.hash_value && a.key == b.key;
  }

-  static size_t hash(const CacheKey& a) {
+  static size_t hash(const ClockCacheKey& a) {
    return static_cast<size_t>(a.hash_value);
  }
 };
@@ -260,7 +260,8 @@ struct CleanupContext {
 class ClockCacheShard final : public CacheShard {
 public:
  // Hash map type.
-  using HashTable = tbb::concurrent_hash_map<CacheKey, CacheHandle*, CacheKey>;
+  using HashTable =
+      tbb::concurrent_hash_map<ClockCacheKey, CacheHandle*, ClockCacheKey>;

  ClockCacheShard();
  ~ClockCacheShard() override;
@@ -559,7 +560,7 @@ bool ClockCacheShard::TryEvict(CacheHandle* handle, CleanupContext* context) {
  if (handle->flags.compare_exchange_strong(flags, 0, std::memory_order_acquire,
                                            std::memory_order_relaxed)) {
    bool erased __attribute__((__unused__)) =
-        table_.erase(CacheKey(handle->key, handle->hash));
+        table_.erase(ClockCacheKey(handle->key, handle->hash));
    assert(erased);
    RecycleHandle(handle, context);
    return true;
@@ -656,13 +657,13 @@ CacheHandle* ClockCacheShard::Insert(
  // relative updates (fetch_add, etc).
  handle->flags.store(flags, std::memory_order_relaxed);
  HashTable::accessor accessor;
-  if (table_.find(accessor, CacheKey(key, hash))) {
+  if (table_.find(accessor, ClockCacheKey(key, hash))) {
    *overwritten = true;
    CacheHandle* existing_handle = accessor->second;
    table_.erase(accessor);
    UnsetInCache(existing_handle, context);
  }
-  table_.insert(HashTable::value_type(CacheKey(key, hash), handle));
+  table_.insert(HashTable::value_type(ClockCacheKey(key, hash), handle));
  if (hold_reference) {
    pinned_usage_.fetch_add(total_charge, std::memory_order_relaxed);
  }
@@ -686,7 +687,7 @@ Status ClockCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
  Status s;
  if (out_handle != nullptr) {
    if (handle == nullptr) {
-      s = Status::Incomplete("Insert failed due to LRU cache being full.");
+      s = Status::Incomplete("Insert failed due to CLOCK cache being full.");
    } else {
      *out_handle = reinterpret_cast<Cache::Handle*>(handle);
    }
@@ -701,7 +702,7 @@ Status ClockCacheShard::Insert(const Slice& key, uint32_t hash, void* value,

 Cache::Handle* ClockCacheShard::Lookup(const Slice& key, uint32_t hash) {
  HashTable::const_accessor accessor;
-  if (!table_.find(accessor, CacheKey(key, hash))) {
+  if (!table_.find(accessor, ClockCacheKey(key, hash))) {
    return nullptr;
  }
  CacheHandle* handle = accessor->second;
@@ -746,7 +747,7 @@ bool ClockCacheShard::EraseAndConfirm(const Slice& key, uint32_t hash,
  MutexLock l(&mutex_);
  HashTable::accessor accessor;
  bool erased = false;
-  if (table_.find(accessor, CacheKey(key, hash))) {
+  if (table_.find(accessor, ClockCacheKey(key, hash))) {
    CacheHandle* handle = accessor->second;
    table_.erase(accessor);
    erased = UnsetInCache(handle, context);
@@ -809,9 +810,10 @@ class ClockCache final : public ShardedCache {
  }

  void DisownData() override {
-#ifndef MUST_FREE_HEAP_ALLOCATIONS
-    shards_ = nullptr;
-#endif
+    // Leak data only if that won't generate an ASAN/valgrind warning
+    if (!kMustFreeHeapAllocations) {
+      shards_ = nullptr;
+    }
  }

  void WaitAll(std::vector<Handle*>& /*handles*/) override {}
@@ -15,6 +15,7 @@

 #include "monitoring/perf_context_imp.h"
 #include "monitoring/statistics.h"
+#include "port/lang.h"
 #include "util/mutexlock.h"

 namespace ROCKSDB_NAMESPACE {
@@ -704,11 +705,11 @@ uint32_t LRUCache::GetHash(Handle* handle) const {
 }

 void LRUCache::DisownData() {
-// Do not drop data if compile with ASAN to suppress leak warning.
-#ifndef MUST_FREE_HEAP_ALLOCATIONS
-  shards_ = nullptr;
-  num_shards_ = 0;
-#endif
+  // Leak data only if that won't generate an ASAN/valgrind warning
+  if (!kMustFreeHeapAllocations) {
+    shards_ = nullptr;
+    num_shards_ = 0;
+  }
 }

 size_t LRUCache::TEST_GetLRUSize() {
@@ -8,6 +8,7 @@
 #include <string>
 #include <vector>

+#include "cache/cache_key.h"
 #include "db/db_test_util.h"
 #include "file/sst_file_manager_impl.h"
 #include "port/port.h"
@@ -233,7 +234,10 @@ class TestSecondaryCache : public SecondaryCache {
  void ResetInjectFailure() { inject_failure_ = false; }

  void SetDbSessionId(const std::string& db_session_id) {
-    db_session_id_ = db_session_id;
+    // NOTE: we assume the file is smaller than kMaxFileSizeStandardEncoding
+    // for this to work, but that's safe in a test.
+    auto base = OffsetableCacheKey("unknown", db_session_id, 1, 1);
+    ckey_prefix_ = base.CommonPrefixSlice().ToString();
  }

  Status Insert(const Slice& key, void* value,
@@ -241,7 +245,7 @@ class TestSecondaryCache : public SecondaryCache {
    if (inject_failure_) {
      return Status::Corruption("Insertion Data Corrupted");
    }
-    assert(IsDbSessionIdAsKeyPrefix(key) == true);
+    EXPECT_TRUE(IsDbSessionLowerAsKeyPrefix(key));
    size_t size;
    char* buf;
    Status s;
@@ -317,18 +321,8 @@ class TestSecondaryCache : public SecondaryCache {

  uint32_t num_lookups() { return num_lookups_; }

-  bool IsDbSessionIdAsKeyPrefix(const Slice& key) {
-    if (db_session_id_.size() == 0) {
-      return true;
-    }
-    if (key.size() < 20) {
-      return false;
-    }
-    std::string s_key = key.ToString();
-    if (s_key.substr(0, 20) != db_session_id_) {
-      return false;
-    }
-    return true;
+  bool IsDbSessionLowerAsKeyPrefix(const Slice& key) {
+    return key.starts_with(ckey_prefix_);
  }

 private:
@@ -373,7 +367,7 @@ class TestSecondaryCache : public SecondaryCache {
  uint32_t num_inserts_;
  uint32_t num_lookups_;
  bool inject_failure_;
-  std::string db_session_id_;
+  std::string ckey_prefix_;
  ResultMap result_map_;
 };

@@ -438,8 +432,9 @@ class LRUSecondaryCacheTest : public LRUCacheTest {

  static Cache::CacheItemHelper helper_fail_;

-  Cache::CreateCallback test_item_creator =
-      [&](void* buf, size_t size, void** out_obj, size_t* charge) -> Status {
+  Cache::CreateCallback test_item_creator = [&](const void* buf, size_t size,
+                                                void** out_obj,
+                                                size_t* charge) -> Status {
    if (fail_create_) {
      return Status::NotSupported();
    }
@@ -517,10 +512,12 @@ TEST_F(LRUSecondaryCacheTest, BasicFailTest) {

  Random rnd(301);
  std::string str1 = rnd.RandomString(1020);
-  TestItem* item1 = new TestItem(str1.data(), str1.length());
-  ASSERT_NOK(cache->Insert("k1", item1, nullptr, str1.length()));
-  ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_,
+  auto item1 = std::make_unique<TestItem>(str1.data(), str1.length());
+  ASSERT_TRUE(cache->Insert("k1", item1.get(), nullptr, str1.length())
+                  .IsInvalidArgument());
+  ASSERT_OK(cache->Insert("k1", item1.get(), &LRUSecondaryCacheTest::helper_,
                          str1.length()));
+  item1.release();  // Appease clang-analyze "potential memory leak"

  Cache::Handle* handle;
  handle = cache->Lookup("k2", nullptr, test_item_creator, Cache::Priority::LOW,
@@ -0,0 +1,168 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include "cache/lru_secondary_cache.h"
+
+#include <memory>
+
+#include "memory/memory_allocator.h"
+#include "util/compression.h"
+#include "util/string_util.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+namespace {
+
+void DeletionCallback(const Slice& /*key*/, void* obj) {
+  delete reinterpret_cast<CacheAllocationPtr*>(obj);
+  obj = nullptr;
+}
+
+}  // namespace
+
+LRUSecondaryCache::LRUSecondaryCache(
+    size_t capacity, int num_shard_bits, bool strict_capacity_limit,
+    double high_pri_pool_ratio,
+    std::shared_ptr<MemoryAllocator> memory_allocator, bool use_adaptive_mutex,
+    CacheMetadataChargePolicy metadata_charge_policy,
+    CompressionType compression_type, uint32_t compress_format_version)
+    : cache_options_(capacity, num_shard_bits, strict_capacity_limit,
+                     high_pri_pool_ratio, memory_allocator, use_adaptive_mutex,
+                     metadata_charge_policy, compression_type,
+                     compress_format_version) {
+  cache_ = NewLRUCache(capacity, num_shard_bits, strict_capacity_limit,
+                       high_pri_pool_ratio, memory_allocator,
+                       use_adaptive_mutex, metadata_charge_policy);
+}
+
+LRUSecondaryCache::~LRUSecondaryCache() { cache_.reset(); }
+
+std::unique_ptr<SecondaryCacheResultHandle> LRUSecondaryCache::Lookup(
+    const Slice& key, const Cache::CreateCallback& create_cb, bool /*wait*/) {
+  std::unique_ptr<SecondaryCacheResultHandle> handle;
+  Cache::Handle* lru_handle = cache_->Lookup(key);
+  if (lru_handle == nullptr) {
+    return handle;
+  }
+
+  CacheAllocationPtr* ptr =
+      reinterpret_cast<CacheAllocationPtr*>(cache_->Value(lru_handle));
+  void* value = nullptr;
+  size_t charge = 0;
+  Status s;
+
+  if (cache_options_.compression_type == kNoCompression) {
+    s = create_cb(ptr->get(), cache_->GetCharge(lru_handle), &value, &charge);
+  } else {
+    UncompressionContext uncompression_context(cache_options_.compression_type);
+    UncompressionInfo uncompression_info(uncompression_context,
+                                         UncompressionDict::GetEmptyDict(),
+                                         cache_options_.compression_type);
+
+    size_t uncompressed_size = 0;
+    CacheAllocationPtr uncompressed;
+    uncompressed = UncompressData(
+        uncompression_info, (char*)ptr->get(), cache_->GetCharge(lru_handle),
+        &uncompressed_size, cache_options_.compress_format_version,
+        cache_options_.memory_allocator.get());
+
+    if (!uncompressed) {
+      cache_->Release(lru_handle, true);
+      return handle;
+    }
+    s = create_cb(uncompressed.get(), uncompressed_size, &value, &charge);
+  }
+
+  if (!s.ok()) {
+    cache_->Release(lru_handle, true);
+    return handle;
+  }
+
+  handle.reset(new LRUSecondaryCacheResultHandle(value, charge));
+  cache_->Release(lru_handle);
+  return handle;
+}
+
+Status LRUSecondaryCache::Insert(const Slice& key, void* value,
+                                 const Cache::CacheItemHelper* helper) {
+  size_t size = (*helper->size_cb)(value);
+  CacheAllocationPtr ptr =
+      AllocateBlock(size, cache_options_.memory_allocator.get());
+
+  Status s = (*helper->saveto_cb)(value, 0, size, ptr.get());
+  if (!s.ok()) {
+    return s;
+  }
+  Slice val(ptr.get(), size);
+
+  std::string compressed_val;
+  if (cache_options_.compression_type != kNoCompression) {
+    CompressionOptions compression_opts;
+    CompressionContext compression_context(cache_options_.compression_type);
+    uint64_t sample_for_compression = 0;
+    CompressionInfo compression_info(
+        compression_opts, compression_context, CompressionDict::GetEmptyDict(),
+        cache_options_.compression_type, sample_for_compression);
+
+    bool success =
+        CompressData(val, compression_info,
+                     cache_options_.compress_format_version, &compressed_val);
+
+    if (!success) {
+      return Status::Corruption("Error compressing value.");
+    }
+
+    val = Slice(compressed_val);
+    size = compressed_val.size();
+    ptr = AllocateBlock(size, cache_options_.memory_allocator.get());
+    memcpy(ptr.get(), compressed_val.data(), size);
+  }
+
+  CacheAllocationPtr* buf = new CacheAllocationPtr(std::move(ptr));
+
+  return cache_->Insert(key, buf, size, DeletionCallback);
+}
+
+void LRUSecondaryCache::Erase(const Slice& key) { cache_->Erase(key); }
+
+std::string LRUSecondaryCache::GetPrintableOptions() const {
+  std::string ret;
+  ret.reserve(20000);
+  const int kBufferSize = 200;
+  char buffer[kBufferSize];
+  ret.append(cache_->GetPrintableOptions());
+  snprintf(buffer, kBufferSize, "    compression_type : %s\n",
+           CompressionTypeToString(cache_options_.compression_type).c_str());
+  ret.append(buffer);
+  snprintf(buffer, kBufferSize, "    compression_type : %d\n",
+           cache_options_.compress_format_version);
+  ret.append(buffer);
+  return ret;
+}
+
+std::shared_ptr<SecondaryCache> NewLRUSecondaryCache(
+    size_t capacity, int num_shard_bits, bool strict_capacity_limit,
+    double high_pri_pool_ratio,
+    std::shared_ptr<MemoryAllocator> memory_allocator, bool use_adaptive_mutex,
+    CacheMetadataChargePolicy metadata_charge_policy,
+    CompressionType compression_type, uint32_t compress_format_version) {
+  return std::make_shared<LRUSecondaryCache>(
+      capacity, num_shard_bits, strict_capacity_limit, high_pri_pool_ratio,
+      memory_allocator, use_adaptive_mutex, metadata_charge_policy,
+      compression_type, compress_format_version);
+}
+
+std::shared_ptr<SecondaryCache> NewLRUSecondaryCache(
+    const LRUSecondaryCacheOptions& opts) {
+  // The secondary_cache is disabled for this LRUCache instance.
+  assert(opts.secondary_cache == nullptr);
+  return NewLRUSecondaryCache(
+      opts.capacity, opts.num_shard_bits, opts.strict_capacity_limit,
+      opts.high_pri_pool_ratio, opts.memory_allocator, opts.use_adaptive_mutex,
+      opts.metadata_charge_policy, opts.compression_type,
+      opts.compress_format_version);
+}
+
+}  // namespace ROCKSDB_NAMESPACE
@@ -0,0 +1,85 @@
+// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#include <memory>
+
+#include "cache/lru_cache.h"
+#include "memory/memory_allocator.h"
+#include "rocksdb/secondary_cache.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/status.h"
+#include "util/compression.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class LRUSecondaryCacheResultHandle : public SecondaryCacheResultHandle {
+ public:
+  LRUSecondaryCacheResultHandle(void* value, size_t size)
+      : value_(value), size_(size) {}
+  virtual ~LRUSecondaryCacheResultHandle() override = default;
+
+  LRUSecondaryCacheResultHandle(const LRUSecondaryCacheResultHandle&) = delete;
+  LRUSecondaryCacheResultHandle& operator=(
+      const LRUSecondaryCacheResultHandle&) = delete;
+
+  bool IsReady() override { return true; }
+
+  void Wait() override {}
+
+  void* Value() override { return value_; }
+
+  size_t Size() override { return size_; }
+
+ private:
+  void* value_;
+  size_t size_;
+};
+
+// The LRUSecondaryCache is a concrete implementation of
+// rocksdb::SecondaryCache.
+//
+// Users can also cast a pointer to it and call methods on
+// it directly, especially custom methods that may be added
+// in the future.  For example -
+// std::unique_ptr<rocksdb::SecondaryCache> cache =
+//      NewLRUSecondaryCache(opts);
+// static_cast<LRUSecondaryCache*>(cache.get())->Erase(key);
+
+class LRUSecondaryCache : public SecondaryCache {
+ public:
+  LRUSecondaryCache(
+      size_t capacity, int num_shard_bits, bool strict_capacity_limit,
+      double high_pri_pool_ratio,
+      std::shared_ptr<MemoryAllocator> memory_allocator = nullptr,
+      bool use_adaptive_mutex = kDefaultToAdaptiveMutex,
+      CacheMetadataChargePolicy metadata_charge_policy =
+          kDontChargeCacheMetadata,
+      CompressionType compression_type = CompressionType::kLZ4Compression,
+      uint32_t compress_format_version = 2);
+  virtual ~LRUSecondaryCache() override;
+
+  const char* Name() const override { return "LRUSecondaryCache"; }
+
+  Status Insert(const Slice& key, void* value,
+                const Cache::CacheItemHelper* helper) override;
+
+  std::unique_ptr<SecondaryCacheResultHandle> Lookup(
+      const Slice& key, const Cache::CreateCallback& create_cb,
+      bool /*wait*/) override;
+
+  void Erase(const Slice& key) override;
+
+  void WaitAll(std::vector<SecondaryCacheResultHandle*> /*handles*/) override {}
+
+  std::string GetPrintableOptions() const override;
+
+ private:
+  std::shared_ptr<Cache> cache_;
+  LRUSecondaryCacheOptions cache_options_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE
@@ -0,0 +1,597 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include "cache/lru_secondary_cache.h"
+
+#include <algorithm>
+#include <cstdint>
+
+#include "memory/jemalloc_nodump_allocator.h"
+#include "memory/memory_allocator.h"
+#include "test_util/testharness.h"
+#include "test_util/testutil.h"
+#include "util/compression.h"
+#include "util/random.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class LRUSecondaryCacheTest : public testing::Test {
+ public:
+  LRUSecondaryCacheTest() : fail_create_(false) {}
+  ~LRUSecondaryCacheTest() {}
+
+ protected:
+  class TestItem {
+   public:
+    TestItem(const char* buf, size_t size) : buf_(new char[size]), size_(size) {
+      memcpy(buf_.get(), buf, size);
+    }
+    ~TestItem() {}
+
+    char* Buf() { return buf_.get(); }
+    size_t Size() { return size_; }
+
+   private:
+    std::unique_ptr<char[]> buf_;
+    size_t size_;
+  };
+
+  static size_t SizeCallback(void* obj) {
+    return reinterpret_cast<TestItem*>(obj)->Size();
+  }
+
+  static Status SaveToCallback(void* from_obj, size_t from_offset,
+                               size_t length, void* out) {
+    TestItem* item = reinterpret_cast<TestItem*>(from_obj);
+    const char* buf = item->Buf();
+    EXPECT_EQ(length, item->Size());
+    EXPECT_EQ(from_offset, 0);
+    memcpy(out, buf, length);
+    return Status::OK();
+  }
+
+  static void DeletionCallback(const Slice& /*key*/, void* obj) {
+    delete reinterpret_cast<TestItem*>(obj);
+    obj = nullptr;
+  }
+
+  static Cache::CacheItemHelper helper_;
+
+  static Status SaveToCallbackFail(void* /*obj*/, size_t /*offset*/,
+                                   size_t /*size*/, void* /*out*/) {
+    return Status::NotSupported();
+  }
+
+  static Cache::CacheItemHelper helper_fail_;
+
+  Cache::CreateCallback test_item_creator = [&](const void* buf, size_t size,
+                                                void** out_obj,
+                                                size_t* charge) -> Status {
+    if (fail_create_) {
+      return Status::NotSupported();
+    }
+    *out_obj = reinterpret_cast<void*>(new TestItem((char*)buf, size));
+    *charge = size;
+    return Status::OK();
+  };
+
+  void SetFailCreate(bool fail) { fail_create_ = fail; }
+
+  void BasicTest(bool sec_cache_is_compressed, bool use_jemalloc) {
+    LRUSecondaryCacheOptions opts;
+    opts.capacity = 2048;
+    opts.num_shard_bits = 0;
+    opts.metadata_charge_policy = kDontChargeCacheMetadata;
+
+    if (sec_cache_is_compressed) {
+      if (!LZ4_Supported()) {
+        ROCKSDB_GTEST_SKIP("This test requires LZ4 support.");
+        opts.compression_type = CompressionType::kNoCompression;
+      }
+    } else {
+      opts.compression_type = CompressionType::kNoCompression;
+    }
+
+    if (use_jemalloc) {
+      JemallocAllocatorOptions jopts;
+      std::shared_ptr<MemoryAllocator> allocator;
+      std::string msg;
+      if (JemallocNodumpAllocator::IsSupported(&msg)) {
+        Status s = NewJemallocNodumpAllocator(jopts, &allocator);
+        if (s.ok()) {
+          opts.memory_allocator = allocator;
+        }
+      } else {
+        ROCKSDB_GTEST_BYPASS("JEMALLOC not supported");
+      }
+    }
+    std::shared_ptr<SecondaryCache> cache = NewLRUSecondaryCache(opts);
+
+    // Lookup an non-existent key.
+    std::unique_ptr<SecondaryCacheResultHandle> handle0 =
+        cache->Lookup("k0", test_item_creator, true);
+    ASSERT_EQ(handle0, nullptr);
+
+    Random rnd(301);
+    // Insert and Lookup the first item.
+    std::string str1;
+    test::CompressibleString(&rnd, 0.25, 1000, &str1);
+    TestItem item1(str1.data(), str1.length());
+    ASSERT_OK(cache->Insert("k1", &item1, &LRUSecondaryCacheTest::helper_));
+    std::unique_ptr<SecondaryCacheResultHandle> handle1 =
+        cache->Lookup("k1", test_item_creator, true);
+    ASSERT_NE(handle1, nullptr);
+    // delete reinterpret_cast<TestItem*>(handle1->Value());
+    std::unique_ptr<TestItem> val1 =
+        std::unique_ptr<TestItem>(static_cast<TestItem*>(handle1->Value()));
+    ASSERT_NE(val1, nullptr);
+    ASSERT_EQ(memcmp(val1->Buf(), item1.Buf(), item1.Size()), 0);
+
+    // Insert and Lookup the second item.
+    std::string str2;
+    test::CompressibleString(&rnd, 0.5, 1000, &str2);
+    TestItem item2(str2.data(), str2.length());
+    ASSERT_OK(cache->Insert("k2", &item2, &LRUSecondaryCacheTest::helper_));
+    std::unique_ptr<SecondaryCacheResultHandle> handle2 =
+        cache->Lookup("k2", test_item_creator, true);
+    ASSERT_NE(handle2, nullptr);
+    std::unique_ptr<TestItem> val2 =
+        std::unique_ptr<TestItem>(static_cast<TestItem*>(handle2->Value()));
+    ASSERT_NE(val2, nullptr);
+    ASSERT_EQ(memcmp(val2->Buf(), item2.Buf(), item2.Size()), 0);
+
+    // Lookup the first item again to make sure it is still in the cache.
+    std::unique_ptr<SecondaryCacheResultHandle> handle1_1 =
+        cache->Lookup("k1", test_item_creator, true);
+    ASSERT_NE(handle1_1, nullptr);
+    std::unique_ptr<TestItem> val1_1 =
+        std::unique_ptr<TestItem>(static_cast<TestItem*>(handle1_1->Value()));
+    ASSERT_NE(val1_1, nullptr);
+    ASSERT_EQ(memcmp(val1_1->Buf(), item1.Buf(), item1.Size()), 0);
+
+    std::vector<SecondaryCacheResultHandle*> handles = {handle1.get(),
+                                                        handle2.get()};
+    cache->WaitAll(handles);
+
+    cache->Erase("k1");
+    handle1 = cache->Lookup("k1", test_item_creator, true);
+    ASSERT_EQ(handle1, nullptr);
+
+    cache.reset();
+  }
+
+  void FailsTest(bool sec_cache_is_compressed) {
+    LRUSecondaryCacheOptions secondary_cache_opts;
+    if (sec_cache_is_compressed) {
+      if (!LZ4_Supported()) {
+        ROCKSDB_GTEST_SKIP("This test requires LZ4 support.");
+        secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+      }
+    } else {
+      secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+    }
+
+    secondary_cache_opts.capacity = 1100;
+    secondary_cache_opts.num_shard_bits = 0;
+    secondary_cache_opts.metadata_charge_policy = kDontChargeCacheMetadata;
+    std::shared_ptr<SecondaryCache> cache =
+        NewLRUSecondaryCache(secondary_cache_opts);
+
+    // Insert and Lookup the first item.
+    Random rnd(301);
+    std::string str1(rnd.RandomString(1000));
+    TestItem item1(str1.data(), str1.length());
+    ASSERT_OK(cache->Insert("k1", &item1, &LRUSecondaryCacheTest::helper_));
+    std::unique_ptr<SecondaryCacheResultHandle> handle1 =
+        cache->Lookup("k1", test_item_creator, true);
+    ASSERT_NE(handle1, nullptr);
+    std::unique_ptr<TestItem> val1 =
+        std::unique_ptr<TestItem>(static_cast<TestItem*>(handle1->Value()));
+    ASSERT_NE(val1, nullptr);
+    ASSERT_EQ(memcmp(val1->Buf(), item1.Buf(), item1.Size()), 0);
+
+    // Insert and Lookup the second item.
+    std::string str2(rnd.RandomString(200));
+    TestItem item2(str2.data(), str2.length());
+    // k1 is evicted.
+    ASSERT_OK(cache->Insert("k2", &item2, &LRUSecondaryCacheTest::helper_));
+    std::unique_ptr<SecondaryCacheResultHandle> handle1_1 =
+        cache->Lookup("k1", test_item_creator, true);
+    ASSERT_EQ(handle1_1, nullptr);
+    std::unique_ptr<SecondaryCacheResultHandle> handle2 =
+        cache->Lookup("k2", test_item_creator, true);
+    ASSERT_NE(handle2, nullptr);
+    std::unique_ptr<TestItem> val2 =
+        std::unique_ptr<TestItem>(static_cast<TestItem*>(handle2->Value()));
+    ASSERT_NE(val2, nullptr);
+    ASSERT_EQ(memcmp(val2->Buf(), item2.Buf(), item2.Size()), 0);
+
+    // Create Fails.
+    SetFailCreate(true);
+    std::unique_ptr<SecondaryCacheResultHandle> handle2_1 =
+        cache->Lookup("k2", test_item_creator, true);
+    ASSERT_EQ(handle2_1, nullptr);
+
+    // Save Fails.
+    std::string str3 = rnd.RandomString(10);
+    TestItem item3(str3.data(), str3.length());
+    ASSERT_NOK(
+        cache->Insert("k3", &item3, &LRUSecondaryCacheTest::helper_fail_));
+
+    cache.reset();
+  }
+
+  void BasicIntegrationTest(bool sec_cache_is_compressed) {
+    LRUSecondaryCacheOptions secondary_cache_opts;
+
+    if (sec_cache_is_compressed) {
+      if (!LZ4_Supported()) {
+        ROCKSDB_GTEST_SKIP("This test requires LZ4 support.");
+        secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+      }
+    } else {
+      secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+    }
+
+    secondary_cache_opts.capacity = 2300;
+    secondary_cache_opts.num_shard_bits = 0;
+    secondary_cache_opts.metadata_charge_policy = kDontChargeCacheMetadata;
+    std::shared_ptr<SecondaryCache> secondary_cache =
+        NewLRUSecondaryCache(secondary_cache_opts);
+    LRUCacheOptions lru_cache_opts(1024, 0, false, 0.5, nullptr,
+                                   kDefaultToAdaptiveMutex,
+                                   kDontChargeCacheMetadata);
+    lru_cache_opts.secondary_cache = secondary_cache;
+    std::shared_ptr<Cache> cache = NewLRUCache(lru_cache_opts);
+    std::shared_ptr<Statistics> stats = CreateDBStatistics();
+
+    Random rnd(301);
+
+    std::string str1 = rnd.RandomString(1010);
+    std::string str1_clone{str1};
+    TestItem* item1 = new TestItem(str1.data(), str1.length());
+    ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_,
+                            str1.length()));
+
+    std::string str2 = rnd.RandomString(1020);
+    TestItem* item2 = new TestItem(str2.data(), str2.length());
+    // After Insert, lru cache contains k2 and secondary cache contains k1.
+    ASSERT_OK(cache->Insert("k2", item2, &LRUSecondaryCacheTest::helper_,
+                            str2.length()));
+
+    std::string str3 = rnd.RandomString(1020);
+    TestItem* item3 = new TestItem(str3.data(), str3.length());
+    // After Insert, lru cache contains k3 and secondary cache contains k1 and
+    // k2
+    ASSERT_OK(cache->Insert("k3", item3, &LRUSecondaryCacheTest::helper_,
+                            str3.length()));
+
+    Cache::Handle* handle;
+    handle =
+        cache->Lookup("k3", &LRUSecondaryCacheTest::helper_, test_item_creator,
+                      Cache::Priority::LOW, true, stats.get());
+    ASSERT_NE(handle, nullptr);
+    TestItem* val3 = static_cast<TestItem*>(cache->Value(handle));
+    ASSERT_NE(val3, nullptr);
+    ASSERT_EQ(memcmp(val3->Buf(), item3->Buf(), item3->Size()), 0);
+    cache->Release(handle);
+
+    // Lookup an non-existent key.
+    handle =
+        cache->Lookup("k0", &LRUSecondaryCacheTest::helper_, test_item_creator,
+                      Cache::Priority::LOW, true, stats.get());
+    ASSERT_EQ(handle, nullptr);
+
+    // This Lookup should promote k1 and demote k3, so k2 is evicted from the
+    // secondary cache. The lru cache contains k1 and secondary cache contains
+    // k3. item1 was Free(), so it cannot be compared against the item1.
+    handle =
+        cache->Lookup("k1", &LRUSecondaryCacheTest::helper_, test_item_creator,
+                      Cache::Priority::LOW, true, stats.get());
+    ASSERT_NE(handle, nullptr);
+    TestItem* val1_1 = static_cast<TestItem*>(cache->Value(handle));
+    ASSERT_NE(val1_1, nullptr);
+    ASSERT_EQ(memcmp(val1_1->Buf(), str1_clone.data(), str1_clone.size()), 0);
+    cache->Release(handle);
+
+    handle =
+        cache->Lookup("k2", &LRUSecondaryCacheTest::helper_, test_item_creator,
+                      Cache::Priority::LOW, true, stats.get());
+    ASSERT_EQ(handle, nullptr);
+
+    cache.reset();
+    secondary_cache.reset();
+  }
+
+  void BasicIntegrationFailTest(bool sec_cache_is_compressed) {
+    LRUSecondaryCacheOptions secondary_cache_opts;
+
+    if (sec_cache_is_compressed) {
+      if (!LZ4_Supported()) {
+        ROCKSDB_GTEST_SKIP("This test requires LZ4 support.");
+        secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+      }
+    } else {
+      secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+    }
+
+    secondary_cache_opts.capacity = 2048;
+    secondary_cache_opts.num_shard_bits = 0;
+    secondary_cache_opts.metadata_charge_policy = kDontChargeCacheMetadata;
+    std::shared_ptr<SecondaryCache> secondary_cache =
+        NewLRUSecondaryCache(secondary_cache_opts);
+
+    LRUCacheOptions opts(1024, 0, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
+                         kDontChargeCacheMetadata);
+    opts.secondary_cache = secondary_cache;
+    std::shared_ptr<Cache> cache = NewLRUCache(opts);
+
+    Random rnd(301);
+    std::string str1 = rnd.RandomString(1020);
+    auto item1 =
+        std::unique_ptr<TestItem>(new TestItem(str1.data(), str1.length()));
+    ASSERT_NOK(cache->Insert("k1", item1.get(), nullptr, str1.length()));
+    ASSERT_OK(cache->Insert("k1", item1.get(), &LRUSecondaryCacheTest::helper_,
+                            str1.length()));
+    item1.release();  // Appease clang-analyze "potential memory leak"
+
+    Cache::Handle* handle;
+    handle = cache->Lookup("k2", nullptr, test_item_creator,
+                           Cache::Priority::LOW, true);
+    ASSERT_EQ(handle, nullptr);
+    handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
+                           test_item_creator, Cache::Priority::LOW, false);
+    ASSERT_EQ(handle, nullptr);
+
+    cache.reset();
+    secondary_cache.reset();
+  }
+
+  void IntegrationSaveFailTest(bool sec_cache_is_compressed) {
+    LRUSecondaryCacheOptions secondary_cache_opts;
+
+    if (sec_cache_is_compressed) {
+      if (!LZ4_Supported()) {
+        ROCKSDB_GTEST_SKIP("This test requires LZ4 support.");
+        secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+      }
+    } else {
+      secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+    }
+
+    secondary_cache_opts.capacity = 2048;
+    secondary_cache_opts.num_shard_bits = 0;
+    secondary_cache_opts.metadata_charge_policy = kDontChargeCacheMetadata;
+
+    std::shared_ptr<SecondaryCache> secondary_cache =
+        NewLRUSecondaryCache(secondary_cache_opts);
+
+    LRUCacheOptions opts(1024, 0, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
+                         kDontChargeCacheMetadata);
+    opts.secondary_cache = secondary_cache;
+    std::shared_ptr<Cache> cache = NewLRUCache(opts);
+
+    Random rnd(301);
+    std::string str1 = rnd.RandomString(1020);
+    TestItem* item1 = new TestItem(str1.data(), str1.length());
+    ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_fail_,
+                            str1.length()));
+    std::string str2 = rnd.RandomString(1020);
+    TestItem* item2 = new TestItem(str2.data(), str2.length());
+    // k1 should be demoted to the secondary cache.
+    ASSERT_OK(cache->Insert("k2", item2, &LRUSecondaryCacheTest::helper_fail_,
+                            str2.length()));
+
+    Cache::Handle* handle;
+    handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_fail_,
+                           test_item_creator, Cache::Priority::LOW, true);
+    ASSERT_NE(handle, nullptr);
+    cache->Release(handle);
+    // This lookup should fail, since k1 demotion would have failed
+    handle = cache->Lookup("k1", &LRUSecondaryCacheTest::helper_fail_,
+                           test_item_creator, Cache::Priority::LOW, true);
+    ASSERT_EQ(handle, nullptr);
+    // Since k1 didn't get promoted, k2 should still be in cache
+    handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_fail_,
+                           test_item_creator, Cache::Priority::LOW, true);
+    ASSERT_NE(handle, nullptr);
+    cache->Release(handle);
+
+    cache.reset();
+    secondary_cache.reset();
+  }
+
+  void IntegrationCreateFailTest(bool sec_cache_is_compressed) {
+    LRUSecondaryCacheOptions secondary_cache_opts;
+
+    if (sec_cache_is_compressed) {
+      if (!LZ4_Supported()) {
+        ROCKSDB_GTEST_SKIP("This test requires LZ4 support.");
+        secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+      }
+    } else {
+      secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+    }
+
+    secondary_cache_opts.capacity = 2048;
+    secondary_cache_opts.num_shard_bits = 0;
+    secondary_cache_opts.metadata_charge_policy = kDontChargeCacheMetadata;
+
+    std::shared_ptr<SecondaryCache> secondary_cache =
+        NewLRUSecondaryCache(secondary_cache_opts);
+
+    LRUCacheOptions opts(1024, 0, false, 0.5, nullptr, kDefaultToAdaptiveMutex,
+                         kDontChargeCacheMetadata);
+    opts.secondary_cache = secondary_cache;
+    std::shared_ptr<Cache> cache = NewLRUCache(opts);
+
+    Random rnd(301);
+    std::string str1 = rnd.RandomString(1020);
+    TestItem* item1 = new TestItem(str1.data(), str1.length());
+    ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_,
+                            str1.length()));
+
+    std::string str2 = rnd.RandomString(1020);
+    TestItem* item2 = new TestItem(str2.data(), str2.length());
+    // k1 should be demoted to the secondary cache.
+    ASSERT_OK(cache->Insert("k2", item2, &LRUSecondaryCacheTest::helper_,
+                            str2.length()));
+
+    Cache::Handle* handle;
+    SetFailCreate(true);
+    handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
+                           test_item_creator, Cache::Priority::LOW, true);
+    ASSERT_NE(handle, nullptr);
+    cache->Release(handle);
+    // This lookup should fail, since k1 creation would have failed
+    handle = cache->Lookup("k1", &LRUSecondaryCacheTest::helper_,
+                           test_item_creator, Cache::Priority::LOW, true);
+    ASSERT_EQ(handle, nullptr);
+    // Since k1 didn't get promoted, k2 should still be in cache
+    handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
+                           test_item_creator, Cache::Priority::LOW, true);
+    ASSERT_NE(handle, nullptr);
+    cache->Release(handle);
+
+    cache.reset();
+    secondary_cache.reset();
+  }
+
+  void IntegrationFullCapacityTest(bool sec_cache_is_compressed) {
+    LRUSecondaryCacheOptions secondary_cache_opts;
+
+    if (sec_cache_is_compressed) {
+      if (!LZ4_Supported()) {
+        ROCKSDB_GTEST_SKIP("This test requires LZ4 support.");
+        secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+      }
+    } else {
+      secondary_cache_opts.compression_type = CompressionType::kNoCompression;
+    }
+
+    secondary_cache_opts.capacity = 2048;
+    secondary_cache_opts.num_shard_bits = 0;
+    secondary_cache_opts.metadata_charge_policy = kDontChargeCacheMetadata;
+
+    std::shared_ptr<SecondaryCache> secondary_cache =
+        NewLRUSecondaryCache(secondary_cache_opts);
+
+    LRUCacheOptions opts(1024, 0, /*_strict_capacity_limit=*/true, 0.5, nullptr,
+                         kDefaultToAdaptiveMutex, kDontChargeCacheMetadata);
+    opts.secondary_cache = secondary_cache;
+    std::shared_ptr<Cache> cache = NewLRUCache(opts);
+
+    Random rnd(301);
+    std::string str1 = rnd.RandomString(1020);
+    TestItem* item1 = new TestItem(str1.data(), str1.length());
+    ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_,
+                            str1.length()));
+    std::string str2 = rnd.RandomString(1020);
+    TestItem* item2 = new TestItem(str2.data(), str2.length());
+    // k1 should be demoted to the secondary cache.
+    ASSERT_OK(cache->Insert("k2", item2, &LRUSecondaryCacheTest::helper_,
+                            str2.length()));
+
+    Cache::Handle* handle;
+    handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
+                           test_item_creator, Cache::Priority::LOW, true);
+    ASSERT_NE(handle, nullptr);
+    // k1 promotion should fail due to the block cache being at capacity,
+    // but the lookup should still succeed
+    Cache::Handle* handle2;
+    handle2 = cache->Lookup("k1", &LRUSecondaryCacheTest::helper_,
+                            test_item_creator, Cache::Priority::LOW, true);
+    ASSERT_NE(handle2, nullptr);
+    // Since k1 didn't get inserted, k2 should still be in cache
+    cache->Release(handle);
+    cache->Release(handle2);
+    handle = cache->Lookup("k2", &LRUSecondaryCacheTest::helper_,
+                           test_item_creator, Cache::Priority::LOW, true);
+    ASSERT_NE(handle, nullptr);
+    cache->Release(handle);
+
+    cache.reset();
+    secondary_cache.reset();
+  }
+
+ private:
+  bool fail_create_;
+};
+
+Cache::CacheItemHelper LRUSecondaryCacheTest::helper_(
+    LRUSecondaryCacheTest::SizeCallback, LRUSecondaryCacheTest::SaveToCallback,
+    LRUSecondaryCacheTest::DeletionCallback);
+
+Cache::CacheItemHelper LRUSecondaryCacheTest::helper_fail_(
+    LRUSecondaryCacheTest::SizeCallback,
+    LRUSecondaryCacheTest::SaveToCallbackFail,
+    LRUSecondaryCacheTest::DeletionCallback);
+
+TEST_F(LRUSecondaryCacheTest, BasicTestWithNoCompression) {
+  BasicTest(false, false);
+}
+
+TEST_F(LRUSecondaryCacheTest, BasicTestWithMemoryAllocatorAndNoCompression) {
+  BasicTest(false, true);
+}
+
+TEST_F(LRUSecondaryCacheTest, BasicTestWithCompression) {
+  BasicTest(true, false);
+}
+
+TEST_F(LRUSecondaryCacheTest, BasicTestWithMemoryAllocatorAndCompression) {
+  BasicTest(true, true);
+}
+
+TEST_F(LRUSecondaryCacheTest, FailsTestWithNoCompression) { FailsTest(false); }
+
+TEST_F(LRUSecondaryCacheTest, FailsTestWithCompression) { FailsTest(true); }
+
+TEST_F(LRUSecondaryCacheTest, BasicIntegrationTestWithNoCompression) {
+  BasicIntegrationTest(false);
+}
+
+TEST_F(LRUSecondaryCacheTest, BasicIntegrationTestWithCompression) {
+  BasicIntegrationTest(true);
+}
+
+TEST_F(LRUSecondaryCacheTest, BasicIntegrationFailTestWithNoCompression) {
+  BasicIntegrationFailTest(false);
+}
+
+TEST_F(LRUSecondaryCacheTest, BasicIntegrationFailTestWithCompression) {
+  BasicIntegrationFailTest(true);
+}
+
+TEST_F(LRUSecondaryCacheTest, IntegrationSaveFailTestWithNoCompression) {
+  IntegrationSaveFailTest(false);
+}
+
+TEST_F(LRUSecondaryCacheTest, IntegrationSaveFailTestWithCompression) {
+  IntegrationSaveFailTest(true);
+}
+
+TEST_F(LRUSecondaryCacheTest, IntegrationCreateFailTestWithNoCompression) {
+  IntegrationCreateFailTest(false);
+}
+
+TEST_F(LRUSecondaryCacheTest, IntegrationCreateFailTestWithCompression) {
+  IntegrationCreateFailTest(true);
+}
+
+TEST_F(LRUSecondaryCacheTest, IntegrationFullCapacityTestWithNoCompression) {
+  IntegrationFullCapacityTest(false);
+}
+
+TEST_F(LRUSecondaryCacheTest, IntegrationFullCapacityTestWithCompression) {
+  IntegrationFullCapacityTest(true);
+}
+
+}  // namespace ROCKSDB_NAMESPACE
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
@@ -0,0 +1,26 @@
+# - Find liburing
+#
+# uring_INCLUDE_DIR - Where to find liburing.h
+# uring_LIBRARIES - List of libraries when using uring.
+# uring_FOUND - True if uring found.
+
+find_path(uring_INCLUDE_DIR
+  NAMES liburing.h)
+find_library(uring_LIBRARIES
+  NAMES liburing.a liburing)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(uring
+  DEFAULT_MSG uring_LIBRARIES uring_INCLUDE_DIR)
+
+mark_as_advanced(
+  uring_INCLUDE_DIR
+  uring_LIBRARIES)
+
+if(uring_FOUND AND NOT TARGET uring::uring)
+  add_library(uring::uring UNKNOWN IMPORTED)
+  set_target_properties(uring::uring PROPERTIES
+    INTERFACE_INCLUDE_DIRECTORIES "${uring_INCLUDE_DIR}"
+    IMPORTED_LINK_INTERFACE_LANGUAGES "C"
+    IMPORTED_LOCATION "${uring_LIBRARIES}")
+endif()
@@ -0,0 +1,87 @@
+# This file is used by Meta-internal infrastructure as well as by Makefile
+
+# When included from Makefile, there are rules to build DB_STRESS_CMD. When
+# used directly with `make -f crashtest.mk ...` there will be no rules to
+# build DB_STRESS_CMD so it must exist prior.
+DB_STRESS_CMD?=./db_stress
+
+include python.mk
+
+CRASHTEST_MAKE=$(MAKE) -f crash_test.mk
+CRASHTEST_PY=$(PYTHON) -u tools/db_crashtest.py --stress_cmd=$(DB_STRESS_CMD)
+
+.PHONY: crash_test crash_test_with_atomic_flush crash_test_with_txn \
+	crash_test_with_best_efforts_recovery crash_test_with_ts \
+	blackbox_crash_test blackbox_crash_test_with_atomic_flush \
+	blackbox_crash_test_with_txn blackbox_crash_test_with_ts \
+	blackbox_crash_test_with_best_efforts_recovery \
+	whitebox_crash_test whitebox_crash_test_with_atomic_flush \
+	whitebox_crash_test_with_txn whitebox_crash_test_with_ts \
+	blackbox_crash_test_with_multiops_wc_txn \
+	blackbox_crash_test_with_multiops_wp_txn
+
+crash_test: $(DB_STRESS_CMD)
+# Do not parallelize
+	$(CRASHTEST_MAKE) whitebox_crash_test
+	$(CRASHTEST_MAKE) blackbox_crash_test
+
+crash_test_with_atomic_flush: $(DB_STRESS_CMD)
+# Do not parallelize
+	$(CRASHTEST_MAKE) whitebox_crash_test_with_atomic_flush
+	$(CRASHTEST_MAKE) blackbox_crash_test_with_atomic_flush
+
+crash_test_with_txn: $(DB_STRESS_CMD)
+# Do not parallelize
+	$(CRASHTEST_MAKE) whitebox_crash_test_with_txn
+	$(CRASHTEST_MAKE) blackbox_crash_test_with_txn
+
+crash_test_with_best_efforts_recovery: blackbox_crash_test_with_best_efforts_recovery
+
+crash_test_with_ts: $(DB_STRESS_CMD)
+# Do not parallelize
+	$(CRASHTEST_MAKE) whitebox_crash_test_with_ts
+	$(CRASHTEST_MAKE) blackbox_crash_test_with_ts
+
+blackbox_crash_test: $(DB_STRESS_CMD)
+	$(CRASHTEST_PY) --simple blackbox $(CRASH_TEST_EXT_ARGS)
+	$(CRASHTEST_PY) blackbox $(CRASH_TEST_EXT_ARGS)
+
+blackbox_crash_test_with_atomic_flush: $(DB_STRESS_CMD)
+	$(CRASHTEST_PY) --cf_consistency blackbox $(CRASH_TEST_EXT_ARGS)
+
+blackbox_crash_test_with_txn: $(DB_STRESS_CMD)
+	$(CRASHTEST_PY) --txn blackbox $(CRASH_TEST_EXT_ARGS)
+
+blackbox_crash_test_with_best_efforts_recovery: $(DB_STRESS_CMD)
+	$(CRASHTEST_PY) --test_best_efforts_recovery blackbox $(CRASH_TEST_EXT_ARGS)
+
+blackbox_crash_test_with_ts: $(DB_STRESS_CMD)
+	$(CRASHTEST_PY) --enable_ts blackbox $(CRASH_TEST_EXT_ARGS)
+
+blackbox_crash_test_with_multiops_wc_txn: $(DB_STRESS_CMD)
+	$(PYTHON) -u tools/db_crashtest.py --test_multiops_txn --write_policy write_committed blackbox $(CRASH_TEST_EXT_ARGS)
+
+blackbox_crash_test_with_multiops_wp_txn: $(DB_STRESS_CMD)
+	$(PYTHON) -u tools/db_crashtest.py --test_multiops_txn --write_policy write_prepared blackbox $(CRASH_TEST_EXT_ARGS)
+
+ifeq ($(CRASH_TEST_KILL_ODD),)
+  CRASH_TEST_KILL_ODD=888887
+endif
+
+whitebox_crash_test: $(DB_STRESS_CMD)
+	$(CRASHTEST_PY) --simple whitebox --random_kill_odd \
+      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
+	$(CRASHTEST_PY) whitebox  --random_kill_odd \
+      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
+
+whitebox_crash_test_with_atomic_flush: $(DB_STRESS_CMD)
+	$(CRASHTEST_PY) --cf_consistency whitebox  --random_kill_odd \
+      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
+
+whitebox_crash_test_with_txn: $(DB_STRESS_CMD)
+	$(CRASHTEST_PY) --txn whitebox --random_kill_odd \
+      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
+
+whitebox_crash_test_with_ts: $(DB_STRESS_CMD)
+	$(CRASHTEST_PY) --enable_ts whitebox --random_kill_odd \
+      $(CRASH_TEST_KILL_ODD) $(CRASH_TEST_EXT_ARGS)
@@ -58,30 +58,55 @@ Status ArenaWrappedDBIter::Refresh() {
  uint64_t cur_sv_number = cfd_->GetSuperVersionNumber();
  TEST_SYNC_POINT("ArenaWrappedDBIter::Refresh:1");
  TEST_SYNC_POINT("ArenaWrappedDBIter::Refresh:2");
-  if (sv_number_ != cur_sv_number) {
-    Env* env = db_iter_->env();
-    db_iter_->~DBIter();
-    arena_.~Arena();
-    new (&arena_) Arena();
+  while (true) {
+    if (sv_number_ != cur_sv_number) {
+      Env* env = db_iter_->env();
+      db_iter_->~DBIter();
+      arena_.~Arena();
+      new (&arena_) Arena();

-    SuperVersion* sv = cfd_->GetReferencedSuperVersion(db_impl_);
-    SequenceNumber latest_seq = db_impl_->GetLatestSequenceNumber();
-    if (read_callback_) {
-      read_callback_->Refresh(latest_seq);
+      SuperVersion* sv = cfd_->GetReferencedSuperVersion(db_impl_);
+      SequenceNumber latest_seq = db_impl_->GetLatestSequenceNumber();
+      if (read_callback_) {
+        read_callback_->Refresh(latest_seq);
+      }
+      Init(env, read_options_, *(cfd_->ioptions()), sv->mutable_cf_options,
+           sv->current, latest_seq,
+           sv->mutable_cf_options.max_sequential_skip_in_iterations,
+           cur_sv_number, read_callback_, db_impl_, cfd_, expose_blob_index_,
+           allow_refresh_);
+
+      InternalIterator* internal_iter = db_impl_->NewInternalIterator(
+          read_options_, cfd_, sv, &arena_, db_iter_->GetRangeDelAggregator(),
+          latest_seq, /* allow_unprepared_value */ true);
+      SetIterUnderDBIter(internal_iter);
+      break;
+    } else {
+      SequenceNumber latest_seq = db_impl_->GetLatestSequenceNumber();
+      // Refresh range-tombstones in MemTable
+      if (!read_options_.ignore_range_deletions) {
+        SuperVersion* sv = cfd_->GetThreadLocalSuperVersion(db_impl_);
+        ReadRangeDelAggregator* range_del_agg =
+            db_iter_->GetRangeDelAggregator();
+        std::unique_ptr<FragmentedRangeTombstoneIterator> range_del_iter;
+        range_del_iter.reset(
+            sv->mem->NewRangeTombstoneIterator(read_options_, latest_seq));
+        range_del_agg->AddTombstones(std::move(range_del_iter));
+        cfd_->ReturnThreadLocalSuperVersion(sv);
+      }
+      // Refresh latest sequence number
+      db_iter_->set_sequence(latest_seq);
+      db_iter_->set_valid(false);
+      // Check again if the latest super version number is changed
+      uint64_t latest_sv_number = cfd_->GetSuperVersionNumber();
+      if (latest_sv_number != cur_sv_number) {
+        // If the super version number is changed after refreshing,
+        // fallback to Re-Init the InternalIterator
+        cur_sv_number = latest_sv_number;
+        continue;
+      }
+      break;
    }
-    Init(env, read_options_, *(cfd_->ioptions()), sv->mutable_cf_options,
-         sv->current, latest_seq,
-         sv->mutable_cf_options.max_sequential_skip_in_iterations,
-         cur_sv_number, read_callback_, db_impl_, cfd_, expose_blob_index_,
-         allow_refresh_);
-
-    InternalIterator* internal_iter = db_impl_->NewInternalIterator(
-        read_options_, cfd_, sv, &arena_, db_iter_->GetRangeDelAggregator(),
-        latest_seq, /* allow_unprepared_value */ true);
-    SetIterUnderDBIter(internal_iter);
-  } else {
-    db_iter_->set_sequence(db_impl_->GetLatestSequenceNumber());
-    db_iter_->set_valid(false);
  }
  return Status::OK();
 }
@@ -9,14 +9,26 @@

 namespace ROCKSDB_NAMESPACE {

-Status BlobFetcher::FetchBlob(const Slice& user_key, const Slice& blob_index,
-                              PinnableSlice* blob_value) {
-  Status s;
+Status BlobFetcher::FetchBlob(const Slice& user_key,
+                              const Slice& blob_index_slice,
+                              FilePrefetchBuffer* prefetch_buffer,
+                              PinnableSlice* blob_value,
+                              uint64_t* bytes_read) const {
  assert(version_);
-  constexpr uint64_t* bytes_read = nullptr;
-  s = version_->GetBlob(read_options_, user_key, blob_index, blob_value,
-                        bytes_read);
-  return s;
+
+  return version_->GetBlob(read_options_, user_key, blob_index_slice,
+                           prefetch_buffer, blob_value, bytes_read);
 }

-}  // namespace ROCKSDB_NAMESPACE
+Status BlobFetcher::FetchBlob(const Slice& user_key,
+                              const BlobIndex& blob_index,
+                              FilePrefetchBuffer* prefetch_buffer,
+                              PinnableSlice* blob_value,
+                              uint64_t* bytes_read) const {
+  assert(version_);
+
+  return version_->GetBlob(read_options_, user_key, blob_index, prefetch_buffer,
+                           blob_value, bytes_read);
+}
+
+}  // namespace ROCKSDB_NAMESPACE
@@ -9,18 +9,29 @@
 #include "rocksdb/status.h"

 namespace ROCKSDB_NAMESPACE {
-class Version;

+class Version;
+class Slice;
+class FilePrefetchBuffer;
+class PinnableSlice;
+class BlobIndex;
+
+// A thin wrapper around the blob retrieval functionality of Version.
 class BlobFetcher {
 public:
-  BlobFetcher(Version* version, const ReadOptions& read_options)
+  BlobFetcher(const Version* version, const ReadOptions& read_options)
      : version_(version), read_options_(read_options) {}

-  Status FetchBlob(const Slice& user_key, const Slice& blob_index,
-                   PinnableSlice* blob_value);
+  Status FetchBlob(const Slice& user_key, const Slice& blob_index_slice,
+                   FilePrefetchBuffer* prefetch_buffer,
+                   PinnableSlice* blob_value, uint64_t* bytes_read) const;
+
+  Status FetchBlob(const Slice& user_key, const BlobIndex& blob_index,
+                   FilePrefetchBuffer* prefetch_buffer,
+                   PinnableSlice* blob_value, uint64_t* bytes_read) const;

 private:
-  Version* version_;
+  const Version* version_;
  ReadOptions read_options_;
 };
-}  // namespace ROCKSDB_NAMESPACE
+}  // namespace ROCKSDB_NAMESPACE
@@ -9,6 +9,7 @@
 #include <string>

 #include "db/blob/blob_log_format.h"
+#include "file/file_prefetch_buffer.h"
 #include "file/filename.h"
 #include "monitoring/statistics.h"
 #include "options/cf_options.h"
@@ -147,9 +148,10 @@ Status BlobFileReader::ReadHeader(const RandomAccessFileReader* file_reader,
    constexpr uint64_t read_offset = 0;
    constexpr size_t read_size = BlobLogHeader::kSize;

-    const Status s =
-        ReadFromFile(file_reader, read_offset, read_size, statistics,
-                     &header_slice, &buf, &aligned_buf);
+    // TODO: rate limit reading headers from blob files.
+    const Status s = ReadFromFile(file_reader, read_offset, read_size,
+                                  statistics, &header_slice, &buf, &aligned_buf,
+                                  Env::IO_TOTAL /* rate_limiter_priority */);
    if (!s.ok()) {
      return s;
    }
@@ -197,9 +199,10 @@ Status BlobFileReader::ReadFooter(const RandomAccessFileReader* file_reader,
    const uint64_t read_offset = file_size - BlobLogFooter::kSize;
    constexpr size_t read_size = BlobLogFooter::kSize;

-    const Status s =
-        ReadFromFile(file_reader, read_offset, read_size, statistics,
-                     &footer_slice, &buf, &aligned_buf);
+    // TODO: rate limit reading footers from blob files.
+    const Status s = ReadFromFile(file_reader, read_offset, read_size,
+                                  statistics, &footer_slice, &buf, &aligned_buf,
+                                  Env::IO_TOTAL /* rate_limiter_priority */);
    if (!s.ok()) {
      return s;
    }
@@ -229,7 +232,8 @@ Status BlobFileReader::ReadFooter(const RandomAccessFileReader* file_reader,
 Status BlobFileReader::ReadFromFile(const RandomAccessFileReader* file_reader,
                                    uint64_t read_offset, size_t read_size,
                                    Statistics* statistics, Slice* slice,
-                                    Buffer* buf, AlignedBuf* aligned_buf) {
+                                    Buffer* buf, AlignedBuf* aligned_buf,
+                                    Env::IOPriority rate_limiter_priority) {
  assert(slice);
  assert(buf);
  assert(aligned_buf);
@@ -244,13 +248,13 @@ Status BlobFileReader::ReadFromFile(const RandomAccessFileReader* file_reader,
    constexpr char* scratch = nullptr;

    s = file_reader->Read(IOOptions(), read_offset, read_size, slice, scratch,
-                          aligned_buf);
+                          aligned_buf, rate_limiter_priority);
  } else {
    buf->reset(new char[read_size]);
    constexpr AlignedBuf* aligned_scratch = nullptr;

    s = file_reader->Read(IOOptions(), read_offset, read_size, slice,
-                          buf->get(), aligned_scratch);
+                          buf->get(), aligned_scratch, rate_limiter_priority);
  }

  if (!s.ok()) {
@@ -282,6 +286,7 @@ Status BlobFileReader::GetBlob(const ReadOptions& read_options,
                               const Slice& user_key, uint64_t offset,
                               uint64_t value_size,
                               CompressionType compression_type,
+                               FilePrefetchBuffer* prefetch_buffer,
                               PinnableSlice* value,
                               uint64_t* bytes_read) const {
  assert(value);
@@ -313,20 +318,36 @@ Status BlobFileReader::GetBlob(const ReadOptions& read_options,
  Buffer buf;
  AlignedBuf aligned_buf;

-  {
+  bool prefetched = false;
+
+  if (prefetch_buffer) {
+    Status s;
+    constexpr bool for_compaction = true;
+
+    prefetched = prefetch_buffer->TryReadFromCache(
+        IOOptions(), file_reader_.get(), record_offset,
+        static_cast<size_t>(record_size), &record_slice, &s,
+        read_options.rate_limiter_priority, for_compaction);
+    if (!s.ok()) {
+      return s;
+    }
+  }
+
+  if (!prefetched) {
    TEST_SYNC_POINT("BlobFileReader::GetBlob:ReadFromFile");

    const Status s = ReadFromFile(file_reader_.get(), record_offset,
                                  static_cast<size_t>(record_size), statistics_,
-                                  &record_slice, &buf, &aligned_buf);
+                                  &record_slice, &buf, &aligned_buf,
+                                  read_options.rate_limiter_priority);
    if (!s.ok()) {
      return s;
    }
-
-    TEST_SYNC_POINT_CALLBACK("BlobFileReader::GetBlob:TamperWithResult",
-                             &record_slice);
  }

+  TEST_SYNC_POINT_CALLBACK("BlobFileReader::GetBlob:TamperWithResult",
+                           &record_slice);
+
  if (read_options.verify_checksums) {
    const Status s = VerifyBlob(record_slice, user_key, value_size);
    if (!s.ok()) {
@@ -408,7 +429,8 @@ void BlobFileReader::MultiGetBlob(
  }
  TEST_SYNC_POINT("BlobFileReader::MultiGetBlob:ReadFromFile");
  s = file_reader_->MultiRead(IOOptions(), read_reqs.data(), read_reqs.size(),
-                              direct_io ? &aligned_buf : nullptr);
+                              direct_io ? &aligned_buf : nullptr,
+                              read_options.rate_limiter_priority);
  if (!s.ok()) {
    for (auto& req : read_reqs) {
      req.status.PermitUncheckedError();
@@ -21,6 +21,7 @@ struct FileOptions;
 class HistogramImpl;
 struct ReadOptions;
 class Slice;
+class FilePrefetchBuffer;
 class PinnableSlice;
 class Statistics;

@@ -41,7 +42,8 @@ class BlobFileReader {

  Status GetBlob(const ReadOptions& read_options, const Slice& user_key,
                 uint64_t offset, uint64_t value_size,
-                 CompressionType compression_type, PinnableSlice* value,
+                 CompressionType compression_type,
+                 FilePrefetchBuffer* prefetch_buffer, PinnableSlice* value,
                 uint64_t* bytes_read) const;

  // offsets must be sorted in ascending order by caller.
@@ -81,7 +83,8 @@ class BlobFileReader {
  static Status ReadFromFile(const RandomAccessFileReader* file_reader,
                             uint64_t read_offset, size_t read_size,
                             Statistics* statistics, Slice* slice, Buffer* buf,
-                             AlignedBuf* aligned_buf);
+                             AlignedBuf* aligned_buf,
+                             Env::IOPriority rate_limiter_priority);

  static Status VerifyBlob(const Slice& record_slice, const Slice& user_key,
                           uint64_t value_size);
@@ -179,13 +179,15 @@ TEST_F(BlobFileReaderTest, CreateReaderAndGetBlob) {
  ReadOptions read_options;
  read_options.verify_checksums = false;

+  constexpr FilePrefetchBuffer* prefetch_buffer = nullptr;
+
  {
    PinnableSlice value;
    uint64_t bytes_read = 0;

    ASSERT_OK(reader->GetBlob(read_options, keys[0], blob_offsets[0],
-                              blob_sizes[0], kNoCompression, &value,
-                              &bytes_read));
+                              blob_sizes[0], kNoCompression, prefetch_buffer,
+                              &value, &bytes_read));
    ASSERT_EQ(value, blobs[0]);
    ASSERT_EQ(bytes_read, blob_sizes[0]);

@@ -222,8 +224,8 @@ TEST_F(BlobFileReaderTest, CreateReaderAndGetBlob) {
    uint64_t bytes_read = 0;

    ASSERT_OK(reader->GetBlob(read_options, keys[1], blob_offsets[1],
-                              blob_sizes[1], kNoCompression, &value,
-                              &bytes_read));
+                              blob_sizes[1], kNoCompression, prefetch_buffer,
+                              &value, &bytes_read));
    ASSERT_EQ(value, blobs[1]);

    const uint64_t key_size = keys[1].size();
@@ -239,8 +241,8 @@ TEST_F(BlobFileReaderTest, CreateReaderAndGetBlob) {

    ASSERT_TRUE(reader
                    ->GetBlob(read_options, keys[0], blob_offsets[0] - 1,
-                              blob_sizes[0], kNoCompression, &value,
-                              &bytes_read)
+                              blob_sizes[0], kNoCompression, prefetch_buffer,
+                              &value, &bytes_read)
                    .IsCorruption());
    ASSERT_EQ(bytes_read, 0);
  }
@@ -252,8 +254,8 @@ TEST_F(BlobFileReaderTest, CreateReaderAndGetBlob) {

    ASSERT_TRUE(reader
                    ->GetBlob(read_options, keys[2], blob_offsets[2] + 1,
-                              blob_sizes[2], kNoCompression, &value,
-                              &bytes_read)
+                              blob_sizes[2], kNoCompression, prefetch_buffer,
+                              &value, &bytes_read)
                    .IsCorruption());
    ASSERT_EQ(bytes_read, 0);
  }
@@ -265,7 +267,8 @@ TEST_F(BlobFileReaderTest, CreateReaderAndGetBlob) {

    ASSERT_TRUE(reader
                    ->GetBlob(read_options, keys[0], blob_offsets[0],
-                              blob_sizes[0], kZSTD, &value, &bytes_read)
+                              blob_sizes[0], kZSTD, prefetch_buffer, &value,
+                              &bytes_read)
                    .IsCorruption());
    ASSERT_EQ(bytes_read, 0);
  }
@@ -280,8 +283,8 @@ TEST_F(BlobFileReaderTest, CreateReaderAndGetBlob) {
                    ->GetBlob(read_options, shorter_key,
                              blob_offsets[0] -
                                  (keys[0].size() - sizeof(shorter_key) + 1),
-                              blob_sizes[0], kNoCompression, &value,
-                              &bytes_read)
+                              blob_sizes[0], kNoCompression, prefetch_buffer,
+                              &value, &bytes_read)
                    .IsCorruption());
    ASSERT_EQ(bytes_read, 0);

@@ -323,8 +326,8 @@ TEST_F(BlobFileReaderTest, CreateReaderAndGetBlob) {

    ASSERT_TRUE(reader
                    ->GetBlob(read_options, incorrect_key, blob_offsets[0],
-                              blob_sizes[0], kNoCompression, &value,
-                              &bytes_read)
+                              blob_sizes[0], kNoCompression, prefetch_buffer,
+                              &value, &bytes_read)
                    .IsCorruption());
    ASSERT_EQ(bytes_read, 0);

@@ -363,8 +366,8 @@ TEST_F(BlobFileReaderTest, CreateReaderAndGetBlob) {

    ASSERT_TRUE(reader
                    ->GetBlob(read_options, keys[1], blob_offsets[1],
-                              blob_sizes[1] + 1, kNoCompression, &value,
-                              &bytes_read)
+                              blob_sizes[1] + 1, kNoCompression,
+                              prefetch_buffer, &value, &bytes_read)
                    .IsCorruption());
    ASSERT_EQ(bytes_read, 0);

@@ -642,12 +645,14 @@ TEST_F(BlobFileReaderTest, BlobCRCError) {

  SyncPoint::GetInstance()->EnableProcessing();

+  constexpr FilePrefetchBuffer* prefetch_buffer = nullptr;
  PinnableSlice value;
  uint64_t bytes_read = 0;

  ASSERT_TRUE(reader
                  ->GetBlob(ReadOptions(), key, blob_offset, blob_size,
-                            kNoCompression, &value, &bytes_read)
+                            kNoCompression, prefetch_buffer, &value,
+                            &bytes_read)
                  .IsCorruption());
  ASSERT_EQ(bytes_read, 0);

@@ -695,12 +700,15 @@ TEST_F(BlobFileReaderTest, Compression) {
  ReadOptions read_options;
  read_options.verify_checksums = false;

+  constexpr FilePrefetchBuffer* prefetch_buffer = nullptr;
+
  {
    PinnableSlice value;
    uint64_t bytes_read = 0;

    ASSERT_OK(reader->GetBlob(read_options, key, blob_offset, blob_size,
-                              kSnappyCompression, &value, &bytes_read));
+                              kSnappyCompression, prefetch_buffer, &value,
+                              &bytes_read));
    ASSERT_EQ(value, blob);
    ASSERT_EQ(bytes_read, blob_size);
  }
@@ -712,7 +720,8 @@ TEST_F(BlobFileReaderTest, Compression) {
    uint64_t bytes_read = 0;

    ASSERT_OK(reader->GetBlob(read_options, key, blob_offset, blob_size,
-                              kSnappyCompression, &value, &bytes_read));
+                              kSnappyCompression, prefetch_buffer, &value,
+                              &bytes_read));
    ASSERT_EQ(value, blob);

    constexpr uint64_t key_size = sizeof(key) - 1;
@@ -770,12 +779,14 @@ TEST_F(BlobFileReaderTest, UncompressionError) {

  SyncPoint::GetInstance()->EnableProcessing();

+  constexpr FilePrefetchBuffer* prefetch_buffer = nullptr;
  PinnableSlice value;
  uint64_t bytes_read = 0;

  ASSERT_TRUE(reader
                  ->GetBlob(ReadOptions(), key, blob_offset, blob_size,
-                            kSnappyCompression, &value, &bytes_read)
+                            kSnappyCompression, prefetch_buffer, &value,
+                            &bytes_read)
                  .IsCorruption());
  ASSERT_EQ(bytes_read, 0);

@@ -854,12 +865,14 @@ TEST_P(BlobFileReaderIOErrorTest, IOError) {
  } else {
    ASSERT_OK(s);

+    constexpr FilePrefetchBuffer* prefetch_buffer = nullptr;
    PinnableSlice value;
    uint64_t bytes_read = 0;

    ASSERT_TRUE(reader
                    ->GetBlob(ReadOptions(), key, blob_offset, blob_size,
-                              kNoCompression, &value, &bytes_read)
+                              kNoCompression, prefetch_buffer, &value,
+                              &bytes_read)
                    .IsIOError());
    ASSERT_EQ(bytes_read, 0);
  }
@@ -937,12 +950,14 @@ TEST_P(BlobFileReaderDecodingErrorTest, DecodingError) {
  } else {
    ASSERT_OK(s);

+    constexpr FilePrefetchBuffer* prefetch_buffer = nullptr;
    PinnableSlice value;
    uint64_t bytes_read = 0;

    ASSERT_TRUE(reader
                    ->GetBlob(ReadOptions(), key, blob_offset, blob_size,
-                              kNoCompression, &value, &bytes_read)
+                              kNoCompression, prefetch_buffer, &value,
+                              &bytes_read)
                    .IsCorruption());
    ASSERT_EQ(bytes_read, 0);
  }
@@ -28,8 +28,10 @@ Status BlobLogSequentialReader::ReadSlice(uint64_t size, Slice* slice,
  assert(file_);

  StopWatch read_sw(clock_, statistics_, BLOB_DB_BLOB_FILE_READ_MICROS);
-  Status s = file_->Read(IOOptions(), next_byte_, static_cast<size_t>(size),
-                         slice, buf, nullptr);
+  // TODO: rate limit `BlobLogSequentialReader` reads (it appears unused?)
+  Status s =
+      file_->Read(IOOptions(), next_byte_, static_cast<size_t>(size), slice,
+                  buf, nullptr, Env::IO_TOTAL /* rate_limiter_priority */);
  next_byte_ += size;
  if (!s.ok()) {
    return s;
@@ -694,18 +694,21 @@ TEST_F(DBBlobBasicTest, Properties) {
  constexpr char key3[] = "key3";
  constexpr size_t key3_size = sizeof(key3) - 1;

-  constexpr char blob[] = "0000000000";
+  constexpr char blob[] = "00000000000000";
  constexpr size_t blob_size = sizeof(blob) - 1;

+  constexpr char longer_blob[] = "00000000000000000000";
+  constexpr size_t longer_blob_size = sizeof(longer_blob) - 1;
+
  ASSERT_OK(Put(key1, blob));
-  ASSERT_OK(Put(key2, blob));
+  ASSERT_OK(Put(key2, longer_blob));
  ASSERT_OK(Flush());

  constexpr size_t first_blob_file_expected_size =
      BlobLogHeader::kSize +
      BlobLogRecord::CalculateAdjustmentForRecordHeader(key1_size) + blob_size +
-      BlobLogRecord::CalculateAdjustmentForRecordHeader(key2_size) + blob_size +
-      BlobLogFooter::kSize;
+      BlobLogRecord::CalculateAdjustmentForRecordHeader(key2_size) +
+      longer_blob_size + BlobLogFooter::kSize;

  ASSERT_OK(Put(key3, blob));
  ASSERT_OK(Flush());
@@ -747,7 +750,12 @@ TEST_F(DBBlobBasicTest, Properties) {
  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), begin, end));

  constexpr size_t expected_garbage_size =
-      BlobLogRecord::CalculateAdjustmentForRecordHeader(key2_size) + blob_size;
+      BlobLogRecord::CalculateAdjustmentForRecordHeader(key2_size) +
+      longer_blob_size;
+
+  constexpr double expected_space_amp =
+      static_cast<double>(total_expected_size) /
+      (total_expected_size - expected_garbage_size);

  // Blob file stats
  std::string blob_stats;
@@ -757,7 +765,7 @@ TEST_F(DBBlobBasicTest, Properties) {
  oss << "Number of blob files: 2\nTotal size of blob files: "
      << total_expected_size
      << "\nTotal size of garbage in blob files: " << expected_garbage_size
-      << '\n';
+      << "\nBlob file space amplification: " << expected_space_amp << '\n';

  ASSERT_EQ(blob_stats, oss.str());
 }
@@ -1018,14 +1026,6 @@ TEST_P(DBBlobBasicIOErrorTest, CompactionFilterReadBlob_IOError) {

 }  // namespace ROCKSDB_NAMESPACE

-#ifdef ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-extern "C" {
-void RegisterCustomObjects(int argc, char** argv);
-}
-#else
-void RegisterCustomObjects(int /*argc*/, char** /*argv*/) {}
-#endif  // !ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-
 int main(int argc, char** argv) {
  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
@@ -18,7 +18,7 @@ class DBBlobCompactionTest : public DBTestBase {

 #ifndef ROCKSDB_LITE
  const std::vector<InternalStats::CompactionStats>& GetCompactionStats() {
-    VersionSet* const versions = dbfull()->TEST_GetVersionSet();
+    VersionSet* const versions = dbfull()->GetVersionSet();
    assert(versions);
    assert(versions->GetColumnFamilySet());

@@ -495,7 +495,7 @@ TEST_F(DBBlobCompactionTest, TrackGarbage) {

  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), begin, end));

-  VersionSet* const versions = dbfull()->TEST_GetVersionSet();
+  VersionSet* const versions = dbfull()->GetVersionSet();
  assert(versions);
  assert(versions->GetColumnFamilySet());

@@ -512,8 +512,7 @@ TEST_F(DBBlobCompactionTest, TrackGarbage) {
  ASSERT_EQ(blob_files.size(), 2);

  {
-    auto it = blob_files.begin();
-    const auto& meta = it->second;
+    const auto& meta = blob_files.front();
    assert(meta);

    constexpr uint64_t first_expected_bytes =
@@ -543,8 +542,7 @@ TEST_F(DBBlobCompactionTest, TrackGarbage) {
  }

  {
-    auto it = blob_files.rbegin();
-    const auto& meta = it->second;
+    const auto& meta = blob_files.back();
    assert(meta);

    constexpr uint64_t new_first_expected_bytes =
@@ -590,15 +588,125 @@ TEST_F(DBBlobCompactionTest, MergeBlobWithBase) {
  Close();
 }

-}  // namespace ROCKSDB_NAMESPACE
+TEST_F(DBBlobCompactionTest, CompactionReadaheadGarbageCollection) {
+  Options options = GetDefaultOptions();
+  options.enable_blob_files = true;
+  options.min_blob_size = 0;
+  options.enable_blob_garbage_collection = true;
+  options.blob_garbage_collection_age_cutoff = 1.0;
+  options.blob_compaction_readahead_size = 1 << 10;
+  options.disable_auto_compactions = true;

-#ifdef ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-extern "C" {
-void RegisterCustomObjects(int argc, char** argv);
+  Reopen(options);
+
+  ASSERT_OK(Put("key", "lime"));
+  ASSERT_OK(Put("foo", "bar"));
+  ASSERT_OK(Flush());
+
+  ASSERT_OK(Put("key", "pie"));
+  ASSERT_OK(Put("foo", "baz"));
+  ASSERT_OK(Flush());
+
+  size_t num_non_prefetch_reads = 0;
+  SyncPoint::GetInstance()->SetCallBack(
+      "BlobFileReader::GetBlob:ReadFromFile",
+      [&num_non_prefetch_reads](void* /* arg */) { ++num_non_prefetch_reads; });
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  constexpr Slice* begin = nullptr;
+  constexpr Slice* end = nullptr;
+
+  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), begin, end));
+
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+
+  ASSERT_EQ(Get("key"), "pie");
+  ASSERT_EQ(Get("foo"), "baz");
+  ASSERT_EQ(num_non_prefetch_reads, 0);
+
+  Close();
 }
-#else
-void RegisterCustomObjects(int /*argc*/, char** /*argv*/) {}
-#endif  // !ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
+
+TEST_F(DBBlobCompactionTest, CompactionReadaheadFilter) {
+  Options options = GetDefaultOptions();
+
+  std::unique_ptr<CompactionFilter> compaction_filter_guard(
+      new ValueMutationFilter("pie"));
+
+  options.compaction_filter = compaction_filter_guard.get();
+  options.enable_blob_files = true;
+  options.min_blob_size = 0;
+  options.blob_compaction_readahead_size = 1 << 10;
+  options.disable_auto_compactions = true;
+
+  Reopen(options);
+
+  ASSERT_OK(Put("key", "lime"));
+  ASSERT_OK(Put("foo", "bar"));
+  ASSERT_OK(Flush());
+
+  size_t num_non_prefetch_reads = 0;
+  SyncPoint::GetInstance()->SetCallBack(
+      "BlobFileReader::GetBlob:ReadFromFile",
+      [&num_non_prefetch_reads](void* /* arg */) { ++num_non_prefetch_reads; });
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  constexpr Slice* begin = nullptr;
+  constexpr Slice* end = nullptr;
+
+  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), begin, end));
+
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+
+  ASSERT_EQ(Get("key"), "limepie");
+  ASSERT_EQ(Get("foo"), "barpie");
+  ASSERT_EQ(num_non_prefetch_reads, 0);
+
+  Close();
+}
+
+TEST_F(DBBlobCompactionTest, CompactionReadaheadMerge) {
+  Options options = GetDefaultOptions();
+  options.enable_blob_files = true;
+  options.min_blob_size = 0;
+  options.blob_compaction_readahead_size = 1 << 10;
+  options.merge_operator = MergeOperators::CreateStringAppendOperator();
+  options.disable_auto_compactions = true;
+
+  Reopen(options);
+
+  ASSERT_OK(Put("key", "lime"));
+  ASSERT_OK(Put("foo", "bar"));
+  ASSERT_OK(Flush());
+
+  ASSERT_OK(Merge("key", "pie"));
+  ASSERT_OK(Merge("foo", "baz"));
+  ASSERT_OK(Flush());
+
+  size_t num_non_prefetch_reads = 0;
+  SyncPoint::GetInstance()->SetCallBack(
+      "BlobFileReader::GetBlob:ReadFromFile",
+      [&num_non_prefetch_reads](void* /* arg */) { ++num_non_prefetch_reads; });
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  constexpr Slice* begin = nullptr;
+  constexpr Slice* end = nullptr;
+
+  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), begin, end));
+
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+
+  ASSERT_EQ(Get("key"), "lime,pie");
+  ASSERT_EQ(Get("foo"), "bar,baz");
+  ASSERT_EQ(num_non_prefetch_reads, 0);
+
+  Close();
+}
+
+}  // namespace ROCKSDB_NAMESPACE

 int main(int argc, char** argv) {
  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
@@ -74,14 +74,6 @@ TEST_F(DBBlobCorruptionTest, VerifyWholeBlobFileChecksum) {
 #endif  // !ROCKSDB_LITE
 }  // namespace ROCKSDB_NAMESPACE

-#ifdef ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-extern "C" {
-void RegisterCustomObjects(int argc, char** argv);
-}
-#else
-void RegisterCustomObjects(int /*argc*/, char** /*argv*/) {}
-#endif  // !ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-
 int main(int argc, char** argv) {
  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
@@ -564,14 +564,6 @@ TEST_F(DBBlobIndexTest, IntegratedBlobIterate) {

 }  // namespace ROCKSDB_NAMESPACE

-#ifdef ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-extern "C" {
-void RegisterCustomObjects(int argc, char** argv);
-}
-#else
-void RegisterCustomObjects(int /*argc*/, char** /*argv*/) {}
-#endif  // !ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-
 int main(int argc, char** argv) {
  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
@@ -0,0 +1,21 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include "db/blob/prefetch_buffer_collection.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+FilePrefetchBuffer* PrefetchBufferCollection::GetOrCreatePrefetchBuffer(
+    uint64_t file_number) {
+  auto& prefetch_buffer = prefetch_buffers_[file_number];
+  if (!prefetch_buffer) {
+    prefetch_buffer.reset(
+        new FilePrefetchBuffer(readahead_size_, readahead_size_));
+  }
+
+  return prefetch_buffer.get();
+}
+
+}  // namespace ROCKSDB_NAMESPACE
@@ -0,0 +1,38 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#include <cassert>
+#include <cstdint>
+#include <memory>
+#include <unordered_map>
+
+#include "file/file_prefetch_buffer.h"
+#include "rocksdb/rocksdb_namespace.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// A class that owns a collection of FilePrefetchBuffers using the file number
+// as key. Used for implementing compaction readahead for blob files. Designed
+// to be accessed by a single thread only: every (sub)compaction needs its own
+// buffers since they are guaranteed to read different blobs from different
+// positions even when reading the same file.
+class PrefetchBufferCollection {
+ public:
+  explicit PrefetchBufferCollection(uint64_t readahead_size)
+      : readahead_size_(readahead_size) {
+    assert(readahead_size_ > 0);
+  }
+
+  FilePrefetchBuffer* GetOrCreatePrefetchBuffer(uint64_t file_number);
+
+ private:
+  uint64_t readahead_size_;
+  std::unordered_map<uint64_t, std::unique_ptr<FilePrefetchBuffer>>
+      prefetch_buffers_;  // maps file number to prefetch buffer
+};
+
+}  // namespace ROCKSDB_NAMESPACE
@@ -318,6 +318,7 @@ Status BuildTable(

    // TODO Also check the IO status when create the Iterator.

+    TEST_SYNC_POINT("BuildTable:BeforeOutputValidation");
    if (s.ok() && !empty) {
      // Verify that the table is usable
      // We set for_compaction to false and don't OptimizeForCompactionTableRead
@@ -328,8 +329,8 @@ Status BuildTable(
      ReadOptions read_options;
      std::unique_ptr<InternalIterator> it(table_cache->NewIterator(
          read_options, file_options, tboptions.internal_comparator, *meta,
-          nullptr /* range_del_agg */,
-          mutable_cf_options.prefix_extractor.get(), nullptr,
+          nullptr /* range_del_agg */, mutable_cf_options.prefix_extractor,
+          nullptr,
          (internal_stats == nullptr) ? nullptr
                                      : internal_stats->GetFileReadHist(0),
          TableReaderCaller::kFlush, /*arena=*/nullptr,
@@ -380,14 +381,19 @@ Status BuildTable(
    }
  }

+  Status status_for_listener = s;
  if (meta->fd.GetFileSize() == 0) {
    fname = "(nil)";
+    if (s.ok()) {
+      status_for_listener = Status::Aborted("Empty SST file not kept");
+    }
  }
  // Output to event logger and fire events.
  EventHelpers::LogAndNotifyTableFileCreationFinished(
      event_logger, ioptions.listeners, dbname, tboptions.column_family_name,
      fname, job_id, meta->fd, meta->oldest_blob_file_number, tp,
-      tboptions.reason, s, file_checksum, file_checksum_func_name);
+      tboptions.reason, status_for_listener, file_checksum,
+      file_checksum_func_name);

  return s;
 }
@@ -35,7 +35,7 @@
 #include "rocksdb/status.h"
 #include "rocksdb/table.h"
 #include "rocksdb/universal_compaction.h"
-#include "rocksdb/utilities/backupable_db.h"
+#include "rocksdb/utilities/backup_engine.h"
 #include "rocksdb/utilities/checkpoint.h"
 #include "rocksdb/utilities/db_ttl.h"
 #include "rocksdb/utilities/memory_util.h"
@@ -47,8 +47,8 @@
 #include "rocksdb/write_batch.h"
 #include "utilities/merge_operators.h"

-using ROCKSDB_NAMESPACE::BackupableDBOptions;
 using ROCKSDB_NAMESPACE::BackupEngine;
+using ROCKSDB_NAMESPACE::BackupEngineOptions;
 using ROCKSDB_NAMESPACE::BackupID;
 using ROCKSDB_NAMESPACE::BackupInfo;
 using ROCKSDB_NAMESPACE::BatchResult;
@@ -189,8 +189,8 @@ struct rocksdb_transaction_options_t {
 struct rocksdb_transaction_t {
  Transaction* rep;
 };
-struct rocksdb_backupable_db_options_t {
-  BackupableDBOptions rep;
+struct rocksdb_backup_engine_options_t {
+  BackupEngineOptions rep;
 };
 struct rocksdb_checkpoint_t {
  Checkpoint* rep;
@@ -290,45 +290,10 @@ struct rocksdb_filterpolicy_t : public FilterPolicy {
  void* state_;
  void (*destructor_)(void*);
  const char* (*name_)(void*);
-  char* (*create_)(
-      void*,
-      const char* const* key_array, const size_t* key_length_array,
-      int num_keys,
-      size_t* filter_length);
-  unsigned char (*key_match_)(
-      void*,
-      const char* key, size_t length,
-      const char* filter, size_t filter_length);
-  void (*delete_filter_)(
-      void*,
-      const char* filter, size_t filter_length);

  ~rocksdb_filterpolicy_t() override { (*destructor_)(state_); }

  const char* Name() const override { return (*name_)(state_); }
-
-  void CreateFilter(const Slice* keys, int n, std::string* dst) const override {
-    std::vector<const char*> key_pointers(n);
-    std::vector<size_t> key_sizes(n);
-    for (int i = 0; i < n; i++) {
-      key_pointers[i] = keys[i].data();
-      key_sizes[i] = keys[i].size();
-    }
-    size_t len;
-    char* filter = (*create_)(state_, &key_pointers[0], &key_sizes[0], n, &len);
-    dst->append(filter, len);
-
-    if (delete_filter_ != nullptr) {
-      (*delete_filter_)(state_, filter, len);
-    } else {
-      free(filter);
-    }
-  }
-
-  bool KeyMayMatch(const Slice& key, const Slice& filter) const override {
-    return (*key_match_)(state_, key.data(), key.size(),
-                         filter.data(), filter.size());
-  }
 };

 struct rocksdb_mergeoperator_t : public MergeOperator {
@@ -547,12 +512,11 @@ rocksdb_t* rocksdb_open_as_secondary(const rocksdb_options_t* options,
 rocksdb_backup_engine_t* rocksdb_backup_engine_open(
    const rocksdb_options_t* options, const char* path, char** errptr) {
  BackupEngine* be;
-  if (SaveError(errptr, BackupEngine::Open(options->rep.env,
-                                           BackupableDBOptions(path,
-                                                               nullptr,
-                                                               true,
-                                                               options->rep.info_log.get()),
-                                           &be))) {
+  if (SaveError(errptr, BackupEngine::Open(
+                            options->rep.env,
+                            BackupEngineOptions(path, nullptr, true,
+                                                options->rep.info_log.get()),
+                            &be))) {
    return nullptr;
  }
  rocksdb_backup_engine_t* result = new rocksdb_backup_engine_t;
@@ -561,7 +525,7 @@ rocksdb_backup_engine_t* rocksdb_backup_engine_open(
 }

 rocksdb_backup_engine_t* rocksdb_backup_engine_open_opts(
-    const rocksdb_backupable_db_options_t* options, rocksdb_env_t* env,
+    const rocksdb_backup_engine_options_t* options, rocksdb_env_t* env,
    char** errptr) {
  BackupEngine* be;
  if (SaveError(errptr, BackupEngine::Open(options->rep, env->rep, &be))) {
@@ -668,125 +632,125 @@ void rocksdb_backup_engine_close(rocksdb_backup_engine_t* be) {
  delete be;
 }

-rocksdb_backupable_db_options_t* rocksdb_backupable_db_options_create(
+rocksdb_backup_engine_options_t* rocksdb_backup_engine_options_create(
    const char* backup_dir) {
-  return new rocksdb_backupable_db_options_t{
-      BackupableDBOptions(std::string(backup_dir))};
+  return new rocksdb_backup_engine_options_t{
+      BackupEngineOptions(std::string(backup_dir))};
 }

-void rocksdb_backupable_db_options_set_backup_dir(
-    rocksdb_backupable_db_options_t* options, const char* backup_dir) {
+void rocksdb_backup_engine_options_set_backup_dir(
+    rocksdb_backup_engine_options_t* options, const char* backup_dir) {
  options->rep.backup_dir = std::string(backup_dir);
 }

-void rocksdb_backupable_db_options_set_env(
-    rocksdb_backupable_db_options_t* options, rocksdb_env_t* env) {
+void rocksdb_backup_engine_options_set_env(
+    rocksdb_backup_engine_options_t* options, rocksdb_env_t* env) {
  options->rep.backup_env = (env ? env->rep : nullptr);
 }

-void rocksdb_backupable_db_options_set_share_table_files(
-    rocksdb_backupable_db_options_t* options, unsigned char val) {
+void rocksdb_backup_engine_options_set_share_table_files(
+    rocksdb_backup_engine_options_t* options, unsigned char val) {
  options->rep.share_table_files = val;
 }

-unsigned char rocksdb_backupable_db_options_get_share_table_files(
-    rocksdb_backupable_db_options_t* options) {
+unsigned char rocksdb_backup_engine_options_get_share_table_files(
+    rocksdb_backup_engine_options_t* options) {
  return options->rep.share_table_files;
 }

-void rocksdb_backupable_db_options_set_sync(
-    rocksdb_backupable_db_options_t* options, unsigned char val) {
+void rocksdb_backup_engine_options_set_sync(
+    rocksdb_backup_engine_options_t* options, unsigned char val) {
  options->rep.sync = val;
 }

-unsigned char rocksdb_backupable_db_options_get_sync(
-    rocksdb_backupable_db_options_t* options) {
+unsigned char rocksdb_backup_engine_options_get_sync(
+    rocksdb_backup_engine_options_t* options) {
  return options->rep.sync;
 }

-void rocksdb_backupable_db_options_set_destroy_old_data(
-    rocksdb_backupable_db_options_t* options, unsigned char val) {
+void rocksdb_backup_engine_options_set_destroy_old_data(
+    rocksdb_backup_engine_options_t* options, unsigned char val) {
  options->rep.destroy_old_data = val;
 }

-unsigned char rocksdb_backupable_db_options_get_destroy_old_data(
-    rocksdb_backupable_db_options_t* options) {
+unsigned char rocksdb_backup_engine_options_get_destroy_old_data(
+    rocksdb_backup_engine_options_t* options) {
  return options->rep.destroy_old_data;
 }

-void rocksdb_backupable_db_options_set_backup_log_files(
-    rocksdb_backupable_db_options_t* options, unsigned char val) {
+void rocksdb_backup_engine_options_set_backup_log_files(
+    rocksdb_backup_engine_options_t* options, unsigned char val) {
  options->rep.backup_log_files = val;
 }

-unsigned char rocksdb_backupable_db_options_get_backup_log_files(
-    rocksdb_backupable_db_options_t* options) {
+unsigned char rocksdb_backup_engine_options_get_backup_log_files(
+    rocksdb_backup_engine_options_t* options) {
  return options->rep.backup_log_files;
 }

-void rocksdb_backupable_db_options_set_backup_rate_limit(
-    rocksdb_backupable_db_options_t* options, uint64_t limit) {
+void rocksdb_backup_engine_options_set_backup_rate_limit(
+    rocksdb_backup_engine_options_t* options, uint64_t limit) {
  options->rep.backup_rate_limit = limit;
 }

-uint64_t rocksdb_backupable_db_options_get_backup_rate_limit(
-    rocksdb_backupable_db_options_t* options) {
+uint64_t rocksdb_backup_engine_options_get_backup_rate_limit(
+    rocksdb_backup_engine_options_t* options) {
  return options->rep.backup_rate_limit;
 }

-void rocksdb_backupable_db_options_set_restore_rate_limit(
-    rocksdb_backupable_db_options_t* options, uint64_t limit) {
+void rocksdb_backup_engine_options_set_restore_rate_limit(
+    rocksdb_backup_engine_options_t* options, uint64_t limit) {
  options->rep.restore_rate_limit = limit;
 }

-uint64_t rocksdb_backupable_db_options_get_restore_rate_limit(
-    rocksdb_backupable_db_options_t* options) {
+uint64_t rocksdb_backup_engine_options_get_restore_rate_limit(
+    rocksdb_backup_engine_options_t* options) {
  return options->rep.restore_rate_limit;
 }

-void rocksdb_backupable_db_options_set_max_background_operations(
-    rocksdb_backupable_db_options_t* options, int val) {
+void rocksdb_backup_engine_options_set_max_background_operations(
+    rocksdb_backup_engine_options_t* options, int val) {
  options->rep.max_background_operations = val;
 }

-int rocksdb_backupable_db_options_get_max_background_operations(
-    rocksdb_backupable_db_options_t* options) {
+int rocksdb_backup_engine_options_get_max_background_operations(
+    rocksdb_backup_engine_options_t* options) {
  return options->rep.max_background_operations;
 }

-void rocksdb_backupable_db_options_set_callback_trigger_interval_size(
-    rocksdb_backupable_db_options_t* options, uint64_t size) {
+void rocksdb_backup_engine_options_set_callback_trigger_interval_size(
+    rocksdb_backup_engine_options_t* options, uint64_t size) {
  options->rep.callback_trigger_interval_size = size;
 }

-uint64_t rocksdb_backupable_db_options_get_callback_trigger_interval_size(
-    rocksdb_backupable_db_options_t* options) {
+uint64_t rocksdb_backup_engine_options_get_callback_trigger_interval_size(
+    rocksdb_backup_engine_options_t* options) {
  return options->rep.callback_trigger_interval_size;
 }

-void rocksdb_backupable_db_options_set_max_valid_backups_to_open(
-    rocksdb_backupable_db_options_t* options, int val) {
+void rocksdb_backup_engine_options_set_max_valid_backups_to_open(
+    rocksdb_backup_engine_options_t* options, int val) {
  options->rep.max_valid_backups_to_open = val;
 }

-int rocksdb_backupable_db_options_get_max_valid_backups_to_open(
-    rocksdb_backupable_db_options_t* options) {
+int rocksdb_backup_engine_options_get_max_valid_backups_to_open(
+    rocksdb_backup_engine_options_t* options) {
  return options->rep.max_valid_backups_to_open;
 }

-void rocksdb_backupable_db_options_set_share_files_with_checksum_naming(
-    rocksdb_backupable_db_options_t* options, int val) {
+void rocksdb_backup_engine_options_set_share_files_with_checksum_naming(
+    rocksdb_backup_engine_options_t* options, int val) {
  options->rep.share_files_with_checksum_naming =
-      static_cast<BackupableDBOptions::ShareFilesNaming>(val);
+      static_cast<BackupEngineOptions::ShareFilesNaming>(val);
 }

-int rocksdb_backupable_db_options_get_share_files_with_checksum_naming(
-    rocksdb_backupable_db_options_t* options) {
+int rocksdb_backup_engine_options_get_share_files_with_checksum_naming(
+    rocksdb_backup_engine_options_t* options) {
  return static_cast<int>(options->rep.share_files_with_checksum_naming);
 }

-void rocksdb_backupable_db_options_destroy(
-    rocksdb_backupable_db_options_t* options) {
+void rocksdb_backup_engine_options_destroy(
+    rocksdb_backup_engine_options_t* options) {
  delete options;
 }

@@ -2333,11 +2297,6 @@ void rocksdb_block_based_options_set_data_block_hash_ratio(
  options->rep.data_block_hash_table_util_ratio = v;
 }

-void rocksdb_block_based_options_set_hash_index_allow_collision(
-    rocksdb_block_based_table_options_t* options, unsigned char v) {
-  options->rep.hash_index_allow_collision = v;
-}
-
 void rocksdb_block_based_options_set_cache_index_and_filter_blocks(
    rocksdb_block_based_table_options_t* options, unsigned char v) {
  options->rep.cache_index_and_filter_blocks = v;
@@ -2760,6 +2719,16 @@ double rocksdb_options_get_blob_gc_force_threshold(rocksdb_options_t* opt) {
  return opt->rep.blob_garbage_collection_force_threshold;
 }

+void rocksdb_options_set_blob_compaction_readahead_size(rocksdb_options_t* opt,
+                                                        uint64_t val) {
+  opt->rep.blob_compaction_readahead_size = val;
+}
+
+uint64_t rocksdb_options_get_blob_compaction_readahead_size(
+    rocksdb_options_t* opt) {
+  return opt->rep.blob_compaction_readahead_size;
+}
+
 void rocksdb_options_set_num_levels(rocksdb_options_t* opt, int n) {
  opt->rep.num_levels = n;
 }
@@ -2796,9 +2765,6 @@ int rocksdb_options_get_level0_stop_writes_trigger(rocksdb_options_t* opt) {
  return opt->rep.level0_stop_writes_trigger;
 }

-void rocksdb_options_set_max_mem_compaction_level(rocksdb_options_t* /*opt*/,
-                                                  int /*n*/) {}
-
 void rocksdb_options_set_wal_recovery_mode(rocksdb_options_t* opt,int mode) {
  opt->rep.wal_recovery_mode = static_cast<WALRecoveryMode>(mode);
 }
@@ -2824,7 +2790,7 @@ int rocksdb_options_get_bottommost_compression(rocksdb_options_t* opt) {
 }

 void rocksdb_options_set_compression_per_level(rocksdb_options_t* opt,
-                                               int* level_values,
+                                               const int* level_values,
                                               size_t num_levels) {
  opt->rep.compression_per_level.resize(num_levels);
  for (size_t i = 0; i < num_levels; ++i) {
@@ -2949,10 +2915,6 @@ size_t rocksdb_options_get_manifest_preallocation_size(rocksdb_options_t* opt) {
  return opt->rep.manifest_preallocation_size;
 }

-// noop
-void rocksdb_options_set_purge_redundant_kvs_while_flush(
-    rocksdb_options_t* /*opt*/, unsigned char /*v*/) {}
-
 void rocksdb_options_set_use_direct_reads(rocksdb_options_t* opt,
                                          unsigned char v) {
  opt->rep.use_direct_reads = v;
@@ -2999,16 +2961,6 @@ unsigned char rocksdb_options_get_is_fd_close_on_exec(rocksdb_options_t* opt) {
  return opt->rep.is_fd_close_on_exec;
 }

-void rocksdb_options_set_skip_log_error_on_recovery(
-    rocksdb_options_t* opt, unsigned char v) {
-  opt->rep.skip_log_error_on_recovery = v;
-}
-
-unsigned char rocksdb_options_get_skip_log_error_on_recovery(
-    rocksdb_options_t* opt) {
-  return opt->rep.skip_log_error_on_recovery;
-}
-
 void rocksdb_options_set_stats_dump_period_sec(
    rocksdb_options_t* opt, unsigned int v) {
  opt->rep.stats_dump_period_sec = v;
@@ -3220,15 +3172,6 @@ int rocksdb_options_get_max_background_compactions(rocksdb_options_t* opt) {
  return opt->rep.max_background_compactions;
 }

-void rocksdb_options_set_base_background_compactions(rocksdb_options_t* opt,
-                                                     int n) {
-  opt->rep.base_background_compactions = n;
-}
-
-int rocksdb_options_get_base_background_compactions(rocksdb_options_t* opt) {
-  return opt->rep.base_background_compactions;
-}
-
 void rocksdb_options_set_max_background_flushes(rocksdb_options_t* opt, int n) {
  opt->rep.max_background_flushes = n;
 }
@@ -3270,22 +3213,6 @@ size_t rocksdb_options_get_recycle_log_file_num(rocksdb_options_t* opt) {
  return opt->rep.recycle_log_file_num;
 }

-void rocksdb_options_set_soft_rate_limit(rocksdb_options_t* opt, double v) {
-  opt->rep.soft_rate_limit = v;
-}
-
-double rocksdb_options_get_soft_rate_limit(rocksdb_options_t* opt) {
-  return opt->rep.soft_rate_limit;
-}
-
-void rocksdb_options_set_hard_rate_limit(rocksdb_options_t* opt, double v) {
-  opt->rep.hard_rate_limit = v;
-}
-
-double rocksdb_options_get_hard_rate_limit(rocksdb_options_t* opt) {
-  return opt->rep.hard_rate_limit;
-}
-
 void rocksdb_options_set_soft_pending_compaction_bytes_limit(rocksdb_options_t* opt, size_t v) {
  opt->rep.soft_pending_compaction_bytes_limit = v;
 }
@@ -3304,16 +3231,6 @@ size_t rocksdb_options_get_hard_pending_compaction_bytes_limit(
  return opt->rep.hard_pending_compaction_bytes_limit;
 }

-void rocksdb_options_set_rate_limit_delay_max_milliseconds(
-    rocksdb_options_t* opt, unsigned int v) {
-  opt->rep.rate_limit_delay_max_milliseconds = v;
-}
-
-unsigned int rocksdb_options_get_rate_limit_delay_max_milliseconds(
-    rocksdb_options_t* opt) {
-  return opt->rep.rate_limit_delay_max_milliseconds;
-}
-
 void rocksdb_options_set_max_manifest_file_size(
    rocksdb_options_t* opt, size_t v) {
  opt->rep.max_manifest_file_size = v;
@@ -3332,11 +3249,6 @@ int rocksdb_options_get_table_cache_numshardbits(rocksdb_options_t* opt) {
  return opt->rep.table_cache_numshardbits;
 }

-void rocksdb_options_set_table_cache_remove_scan_count_limit(
-    rocksdb_options_t* /*opt*/, int /*v*/) {
-  // this option is deprecated
-}
-
 void rocksdb_options_set_arena_block_size(
    rocksdb_options_t* opt, size_t v) {
  opt->rep.arena_block_size = v;
@@ -3527,6 +3439,14 @@ unsigned char rocksdb_options_get_manual_wal_flush(rocksdb_options_t* opt) {
  return opt->rep.manual_wal_flush;
 }

+void rocksdb_options_set_wal_compression(rocksdb_options_t* opt, int val) {
+  opt->rep.wal_compression = static_cast<CompressionType>(val);
+}
+
+int rocksdb_options_get_wal_compression(rocksdb_options_t* opt) {
+  return opt->rep.wal_compression;
+}
+
 rocksdb_ratelimiter_t* rocksdb_ratelimiter_create(
    int64_t rate_bytes_per_sec,
    int64_t refill_period_us,
@@ -3819,32 +3739,6 @@ void rocksdb_comparator_destroy(rocksdb_comparator_t* cmp) {
  delete cmp;
 }

-rocksdb_filterpolicy_t* rocksdb_filterpolicy_create(
-    void* state,
-    void (*destructor)(void*),
-    char* (*create_filter)(
-        void*,
-        const char* const* key_array, const size_t* key_length_array,
-        int num_keys,
-        size_t* filter_length),
-    unsigned char (*key_may_match)(
-        void*,
-        const char* key, size_t length,
-        const char* filter, size_t filter_length),
-    void (*delete_filter)(
-        void*,
-        const char* filter, size_t filter_length),
-    const char* (*name)(void*)) {
-  rocksdb_filterpolicy_t* result = new rocksdb_filterpolicy_t;
-  result->state_ = state;
-  result->destructor_ = destructor;
-  result->create_ = create_filter;
-  result->key_match_ = key_may_match;
-  result->delete_filter_ = delete_filter;
-  result->name_ = name;
-  return result;
-}
-
 void rocksdb_filterpolicy_destroy(rocksdb_filterpolicy_t* filter) {
  delete filter;
 }
@@ -3858,12 +3752,8 @@ rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_bloom_format(
    const FilterPolicy* rep_;
    ~Wrapper() override { delete rep_; }
    const char* Name() const override { return rep_->Name(); }
-    void CreateFilter(const Slice* keys, int n,
-                      std::string* dst) const override {
-      return rep_->CreateFilter(keys, n, dst);
-    }
-    bool KeyMayMatch(const Slice& key, const Slice& filter) const override {
-      return rep_->KeyMayMatch(key, filter);
+    const char* CompatibilityName() const override {
+      return rep_->CompatibilityName();
    }
    // No need to override GetFilterBitsBuilder if this one is overridden
    ROCKSDB_NAMESPACE::FilterBitsBuilder* GetBuilderWithContext(
@@ -3880,7 +3770,6 @@ rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_bloom_format(
  Wrapper* wrapper = new Wrapper;
  wrapper->rep_ = NewBloomFilterPolicy(bits_per_key, original_format);
  wrapper->state_ = nullptr;
-  wrapper->delete_filter_ = nullptr;
  wrapper->destructor_ = &Wrapper::DoNothing;
  return wrapper;
 }
@@ -3903,12 +3792,8 @@ rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_ribbon_format(
    const FilterPolicy* rep_;
    ~Wrapper() override { delete rep_; }
    const char* Name() const override { return rep_->Name(); }
-    void CreateFilter(const Slice* keys, int n,
-                      std::string* dst) const override {
-      return rep_->CreateFilter(keys, n, dst);
-    }
-    bool KeyMayMatch(const Slice& key, const Slice& filter) const override {
-      return rep_->KeyMayMatch(key, filter);
+    const char* CompatibilityName() const override {
+      return rep_->CompatibilityName();
    }
    ROCKSDB_NAMESPACE::FilterBitsBuilder* GetBuilderWithContext(
        const ROCKSDB_NAMESPACE::FilterBuildingContext& context)
@@ -3925,7 +3810,6 @@ rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_ribbon_format(
  wrapper->rep_ =
      NewRibbonFilterPolicy(bloom_equivalent_bits_per_key, bloom_before_level);
  wrapper->state_ = nullptr;
-  wrapper->delete_filter_ = nullptr;
  wrapper->destructor_ = &Wrapper::DoNothing;
  return wrapper;
 }
@@ -4438,6 +4322,11 @@ rocksdb_sstfilewriter_t* rocksdb_sstfilewriter_create(
  return writer;
 }

+void rocksdb_create_dir_if_missing(rocksdb_env_t* env, const char* path,
+                                   char** errptr) {
+  SaveError(errptr, env->rep->CreateDirIfMissing(std::string(path)));
+}
+
 rocksdb_sstfilewriter_t* rocksdb_sstfilewriter_create_with_comparator(
    const rocksdb_envoptions_t* env, const rocksdb_options_t* io_options,
    const rocksdb_comparator_t* /*comparator*/) {
@@ -4585,10 +4474,11 @@ void rocksdb_slicetransform_destroy(rocksdb_slicetransform_t* st) {
  delete st;
 }

-struct Wrapper : public rocksdb_slicetransform_t {
+struct SliceTransformWrapper : public rocksdb_slicetransform_t {
  const SliceTransform* rep_;
-  ~Wrapper() override { delete rep_; }
+  ~SliceTransformWrapper() override { delete rep_; }
  const char* Name() const override { return rep_->Name(); }
+  std::string GetId() const override { return rep_->GetId(); }
  Slice Transform(const Slice& src) const override {
    return rep_->Transform(src);
  }
@@ -4600,18 +4490,18 @@ struct Wrapper : public rocksdb_slicetransform_t {
 };

 rocksdb_slicetransform_t* rocksdb_slicetransform_create_fixed_prefix(size_t prefixLen) {
-  Wrapper* wrapper = new Wrapper;
+  SliceTransformWrapper* wrapper = new SliceTransformWrapper;
  wrapper->rep_ = ROCKSDB_NAMESPACE::NewFixedPrefixTransform(prefixLen);
  wrapper->state_ = nullptr;
-  wrapper->destructor_ = &Wrapper::DoNothing;
+  wrapper->destructor_ = &SliceTransformWrapper::DoNothing;
  return wrapper;
 }

 rocksdb_slicetransform_t* rocksdb_slicetransform_create_noop() {
-  Wrapper* wrapper = new Wrapper;
+  SliceTransformWrapper* wrapper = new SliceTransformWrapper;
  wrapper->rep_ = ROCKSDB_NAMESPACE::NewNoopTransform();
  wrapper->state_ = nullptr;
-  wrapper->destructor_ = &Wrapper::DoNothing;
+  wrapper->destructor_ = &SliceTransformWrapper::DoNothing;
  return wrapper;
 }

@@ -4727,6 +4617,11 @@ int rocksdb_livefiles_count(
  return static_cast<int>(lf->rep.size());
 }

+const char* rocksdb_livefiles_column_family_name(const rocksdb_livefiles_t* lf,
+                                                 int index) {
+  return lf->rep[index].column_family_name.c_str();
+}
+
 const char* rocksdb_livefiles_name(
  const rocksdb_livefiles_t* lf,
  int index) {
@@ -7,12 +7,13 @@

 #ifndef ROCKSDB_LITE  // Lite does not support C API

-#include "rocksdb/c.h"
-
+#include <assert.h>
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
+
+#include "rocksdb/c.h"
 #ifndef OS_WIN
 #include <unistd.h>
 #endif
@@ -89,10 +90,8 @@ static void CheckEqual(const char* expected, const char* v, size_t n) {
    // ok
    return;
  } else {
-    fprintf(stderr, "%s: expected '%s', got '%s'\n",
-            phase,
-            (expected ? expected : "(null)"),
-            (v ? v : "(null"));
+    fprintf(stderr, "%s: expected '%s', got '%s'\n", phase,
+            (expected ? expected : "(null)"), (v ? v : "(null)"));
    abort();
  }
 }
@@ -226,39 +225,6 @@ static const char* CmpName(void* arg) {
  return "foo";
 }

-// Custom filter policy
-static unsigned char fake_filter_result = 1;
-static void FilterDestroy(void* arg) { (void)arg; }
-static const char* FilterName(void* arg) {
-  (void)arg;
-  return "TestFilter";
-}
-static char* FilterCreate(
-    void* arg,
-    const char* const* key_array, const size_t* key_length_array,
-    int num_keys,
-    size_t* filter_length) {
-  (void)arg;
-  (void)key_array;
-  (void)key_length_array;
-  (void)num_keys;
-  *filter_length = 4;
-  char* result = malloc(4);
-  memcpy(result, "fake", 4);
-  return result;
-}
-static unsigned char FilterKeyMatch(
-    void* arg,
-    const char* key, size_t length,
-    const char* filter, size_t filter_length) {
-  (void)arg;
-  (void)key;
-  (void)length;
-  CheckCondition(filter_length == 4);
-  CheckCondition(memcmp(filter, "fake", 4) == 0);
-  return fake_filter_result;
-}
-
 // Custom compaction filter
 static void CFilterDestroy(void* arg) { (void)arg; }
 static const char* CFilterName(void* arg) {
@@ -480,6 +446,10 @@ int main(int argc, char** argv) {
  cmp = rocksdb_comparator_create(NULL, CmpDestroy, CmpCompare, CmpName);
  dbpath = rocksdb_dbpath_create(dbpathname, 1024 * 1024);
  env = rocksdb_create_default_env();
+
+  rocksdb_create_dir_if_missing(env, GetTempDir(), &err);
+  CheckNoError(err);
+
  cache = rocksdb_cache_create_lru(100000);

  options = rocksdb_options_create();
@@ -490,7 +460,6 @@ int main(int argc, char** argv) {
  rocksdb_options_set_write_buffer_size(options, 100000);
  rocksdb_options_set_paranoid_checks(options, 1);
  rocksdb_options_set_max_open_files(options, 10);
-  rocksdb_options_set_base_background_compactions(options, 1);

  table_options = rocksdb_block_based_options_create();
  rocksdb_block_based_options_set_block_cache(table_options, cache);
@@ -1019,7 +988,36 @@ int main(int argc, char** argv) {
    CheckGet(db, roptions, "foo", NULL);
    rocksdb_release_snapshot(db, snap);
  }
-
+  StartPhase("snapshot_with_memtable_inplace_update");
+  {
+    rocksdb_close(db);
+    const rocksdb_snapshot_t* snap = NULL;
+    const char* s_key = "foo_snap";
+    const char* value1 = "hello_s1";
+    const char* value2 = "hello_s2";
+    rocksdb_options_set_allow_concurrent_memtable_write(options, 0);
+    rocksdb_options_set_inplace_update_support(options, 1);
+    rocksdb_options_set_error_if_exists(options, 0);
+    db = rocksdb_open(options, dbname, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, s_key, 8, value1, 8, &err);
+    snap = rocksdb_create_snapshot(db);
+    assert(snap != NULL);
+    rocksdb_put(db, woptions, s_key, 8, value2, 8, &err);
+    CheckNoError(err);
+    rocksdb_readoptions_set_snapshot(roptions, snap);
+    CheckGet(db, roptions, "foo", NULL);
+    // snapshot syntax is invalid, because of inplace update supported is set
+    CheckGet(db, roptions, s_key, value2);
+    // restore the data and options
+    rocksdb_delete(db, woptions, s_key, 8, &err);
+    CheckGet(db, roptions, s_key, NULL);
+    rocksdb_release_snapshot(db, snap);
+    rocksdb_readoptions_set_snapshot(roptions, NULL);
+    rocksdb_options_set_inplace_update_support(options, 0);
+    rocksdb_options_set_allow_concurrent_memtable_write(options, 1);
+    rocksdb_options_set_error_if_exists(options, 1);
+  }
  StartPhase("repair");
  {
    // If we do not compact here, then the lazy deletion of
@@ -1043,18 +1041,15 @@ int main(int argc, char** argv) {
  }

  StartPhase("filter");
-  for (run = 0; run <= 4; run++) {
-    // run=0 uses custom filter
+  for (run = 1; run <= 4; run++) {
+    // run=0 uses custom filter (not currently supported)
    // run=1 uses old block-based bloom filter
    // run=2 run uses full bloom filter
    // run=3 uses Ribbon
    // run=4 uses Ribbon-Bloom hybrid configuration
    CheckNoError(err);
    rocksdb_filterpolicy_t* policy;
-    if (run == 0) {
-      policy = rocksdb_filterpolicy_create(NULL, FilterDestroy, FilterCreate,
-                                           FilterKeyMatch, NULL, FilterName);
-    } else if (run == 1) {
+    if (run == 1) {
      policy = rocksdb_filterpolicy_create_bloom(8.0);
    } else if (run == 2) {
      policy = rocksdb_filterpolicy_create_bloom_full(8.0);
@@ -1089,19 +1084,8 @@ int main(int argc, char** argv) {
    }
    rocksdb_compact_range(db, NULL, 0, NULL, 0);

-    fake_filter_result = 1;
    CheckGet(db, roptions, "foo", "foovalue");
    CheckGet(db, roptions, "bar", "barvalue");
-    if (run == 0) {
-      // Must not find value when custom filter returns false
-      fake_filter_result = 0;
-      CheckGet(db, roptions, "foo", NULL);
-      CheckGet(db, roptions, "bar", NULL);
-      fake_filter_result = 1;
-
-      CheckGet(db, roptions, "foo", "foovalue");
-      CheckGet(db, roptions, "bar", "barvalue");
-    }

    {
      // Query some keys not added to identify Bloom filter implementation
@@ -1114,7 +1098,6 @@ int main(int argc, char** argv) {
      int i;
      char keybuf[100];
      for (i = 0; i < keys_to_query; i++) {
-        fake_filter_result = i % 2;
        snprintf(keybuf, sizeof(keybuf), "no%020d", i);
        CheckGet(db, roptions, keybuf, NULL);
      }
@@ -1124,10 +1107,10 @@ int main(int argc, char** argv) {
      if (run == 0) {
        // Due to half true, half false with fake filter result
        CheckCondition(hits == keys_to_query / 2);
-      } else if (run == 1) {
-        // Essentially a fingerprint of the block-based Bloom schema
-        CheckCondition(hits == 241);
-      } else if (run == 2 || run == 4) {
+      } else if (run == 1 || run == 2 || run == 4) {
+        // For run == 1, block-based Bloom is no longer available in public
+        // API; attempting to enable it enables full Bloom instead.
+        //
        // Essentially a fingerprint of full Bloom schema, format_version=5
        CheckCondition(hits == 188);
      } else {
@@ -1613,9 +1596,6 @@ int main(int argc, char** argv) {
    rocksdb_options_set_max_background_compactions(o, 3);
    CheckCondition(3 == rocksdb_options_get_max_background_compactions(o));

-    rocksdb_options_set_base_background_compactions(o, 4);
-    CheckCondition(4 == rocksdb_options_get_base_background_compactions(o));
-
    rocksdb_options_set_max_background_flushes(o, 5);
    CheckCondition(5 == rocksdb_options_get_max_background_flushes(o));

@@ -1631,12 +1611,6 @@ int main(int argc, char** argv) {
    rocksdb_options_set_recycle_log_file_num(o, 9);
    CheckCondition(9 == rocksdb_options_get_recycle_log_file_num(o));

-    rocksdb_options_set_soft_rate_limit(o, 2.0);
-    CheckCondition(2.0 == rocksdb_options_get_soft_rate_limit(o));
-
-    rocksdb_options_set_hard_rate_limit(o, 4.0);
-    CheckCondition(4.0 == rocksdb_options_get_hard_rate_limit(o));
-
    rocksdb_options_set_soft_pending_compaction_bytes_limit(o, 10);
    CheckCondition(10 ==
                   rocksdb_options_get_soft_pending_compaction_bytes_limit(o));
@@ -1645,10 +1619,6 @@ int main(int argc, char** argv) {
    CheckCondition(11 ==
                   rocksdb_options_get_hard_pending_compaction_bytes_limit(o));

-    rocksdb_options_set_rate_limit_delay_max_milliseconds(o, 1);
-    CheckCondition(1 ==
-                   rocksdb_options_get_rate_limit_delay_max_milliseconds(o));
-
    rocksdb_options_set_max_manifest_file_size(o, 12);
    CheckCondition(12 == rocksdb_options_get_max_manifest_file_size(o));

@@ -1686,9 +1656,6 @@ int main(int argc, char** argv) {
    rocksdb_options_set_is_fd_close_on_exec(o, 1);
    CheckCondition(1 == rocksdb_options_get_is_fd_close_on_exec(o));

-    rocksdb_options_set_skip_log_error_on_recovery(o, 1);
-    CheckCondition(1 == rocksdb_options_get_skip_log_error_on_recovery(o));
-
    rocksdb_options_set_stats_dump_period_sec(o, 18);
    CheckCondition(18 == rocksdb_options_get_stats_dump_period_sec(o));

@@ -1777,6 +1744,9 @@ int main(int argc, char** argv) {
    rocksdb_options_set_manual_wal_flush(o, 1);
    CheckCondition(1 == rocksdb_options_get_manual_wal_flush(o));

+    rocksdb_options_set_wal_compression(o, 1);
+    CheckCondition(1 == rocksdb_options_get_wal_compression(o));
+
    /* Blob Options */
    rocksdb_options_set_enable_blob_files(o, 1);
    CheckCondition(1 == rocksdb_options_get_enable_blob_files(o));
@@ -1799,6 +1769,10 @@ int main(int argc, char** argv) {
    rocksdb_options_set_blob_gc_force_threshold(o, 0.75);
    CheckCondition(0.75 == rocksdb_options_get_blob_gc_force_threshold(o));

+    rocksdb_options_set_blob_compaction_readahead_size(o, 262144);
+    CheckCondition(262144 ==
+                   rocksdb_options_get_blob_compaction_readahead_size(o));
+
    // Create a copy that should be equal to the original.
    rocksdb_options_t* copy;
    copy = rocksdb_options_create_copy(o);
@@ -1844,20 +1818,15 @@ int main(int argc, char** argv) {
    CheckCondition(123456 == rocksdb_options_get_max_subcompactions(copy));
    CheckCondition(2 == rocksdb_options_get_max_background_jobs(copy));
    CheckCondition(3 == rocksdb_options_get_max_background_compactions(copy));
-    CheckCondition(4 == rocksdb_options_get_base_background_compactions(copy));
    CheckCondition(5 == rocksdb_options_get_max_background_flushes(copy));
    CheckCondition(6 == rocksdb_options_get_max_log_file_size(copy));
    CheckCondition(7 == rocksdb_options_get_log_file_time_to_roll(copy));
    CheckCondition(8 == rocksdb_options_get_keep_log_file_num(copy));
    CheckCondition(9 == rocksdb_options_get_recycle_log_file_num(copy));
-    CheckCondition(2.0 == rocksdb_options_get_soft_rate_limit(copy));
-    CheckCondition(4.0 == rocksdb_options_get_hard_rate_limit(copy));
    CheckCondition(
        10 == rocksdb_options_get_soft_pending_compaction_bytes_limit(copy));
    CheckCondition(
        11 == rocksdb_options_get_hard_pending_compaction_bytes_limit(copy));
-    CheckCondition(1 ==
-                   rocksdb_options_get_rate_limit_delay_max_milliseconds(copy));
    CheckCondition(12 == rocksdb_options_get_max_manifest_file_size(copy));
    CheckCondition(13 == rocksdb_options_get_table_cache_numshardbits(copy));
    CheckCondition(14 == rocksdb_options_get_arena_block_size(copy));
@@ -1871,7 +1840,6 @@ int main(int argc, char** argv) {
    CheckCondition(
        1 == rocksdb_options_get_use_direct_io_for_flush_and_compaction(copy));
    CheckCondition(1 == rocksdb_options_get_is_fd_close_on_exec(copy));
-    CheckCondition(1 == rocksdb_options_get_skip_log_error_on_recovery(copy));
    CheckCondition(18 == rocksdb_options_get_stats_dump_period_sec(copy));
    CheckCondition(5 == rocksdb_options_get_stats_persist_period_sec(copy));
    CheckCondition(1 == rocksdb_options_get_advise_random_on_open(copy));
@@ -2052,10 +2020,6 @@ int main(int argc, char** argv) {
    CheckCondition(13 == rocksdb_options_get_max_background_compactions(copy));
    CheckCondition(3 == rocksdb_options_get_max_background_compactions(o));

-    rocksdb_options_set_base_background_compactions(copy, 14);
-    CheckCondition(14 == rocksdb_options_get_base_background_compactions(copy));
-    CheckCondition(4 == rocksdb_options_get_base_background_compactions(o));
-
    rocksdb_options_set_max_background_flushes(copy, 15);
    CheckCondition(15 == rocksdb_options_get_max_background_flushes(copy));
    CheckCondition(5 == rocksdb_options_get_max_background_flushes(o));
@@ -2076,14 +2040,6 @@ int main(int argc, char** argv) {
    CheckCondition(19 == rocksdb_options_get_recycle_log_file_num(copy));
    CheckCondition(9 == rocksdb_options_get_recycle_log_file_num(o));

-    rocksdb_options_set_soft_rate_limit(copy, 4.0);
-    CheckCondition(4.0 == rocksdb_options_get_soft_rate_limit(copy));
-    CheckCondition(2.0 == rocksdb_options_get_soft_rate_limit(o));
-
-    rocksdb_options_set_hard_rate_limit(copy, 2.0);
-    CheckCondition(2.0 == rocksdb_options_get_hard_rate_limit(copy));
-    CheckCondition(4.0 == rocksdb_options_get_hard_rate_limit(o));
-
    rocksdb_options_set_soft_pending_compaction_bytes_limit(copy, 110);
    CheckCondition(
        110 == rocksdb_options_get_soft_pending_compaction_bytes_limit(copy));
@@ -2096,12 +2052,6 @@ int main(int argc, char** argv) {
    CheckCondition(11 ==
                   rocksdb_options_get_hard_pending_compaction_bytes_limit(o));

-    rocksdb_options_set_rate_limit_delay_max_milliseconds(copy, 0);
-    CheckCondition(0 ==
-                   rocksdb_options_get_rate_limit_delay_max_milliseconds(copy));
-    CheckCondition(1 ==
-                   rocksdb_options_get_rate_limit_delay_max_milliseconds(o));
-
    rocksdb_options_set_max_manifest_file_size(copy, 112);
    CheckCondition(112 == rocksdb_options_get_max_manifest_file_size(copy));
    CheckCondition(12 == rocksdb_options_get_max_manifest_file_size(o));
@@ -2153,10 +2103,6 @@ int main(int argc, char** argv) {
    CheckCondition(0 == rocksdb_options_get_is_fd_close_on_exec(copy));
    CheckCondition(1 == rocksdb_options_get_is_fd_close_on_exec(o));

-    rocksdb_options_set_skip_log_error_on_recovery(copy, 0);
-    CheckCondition(0 == rocksdb_options_get_skip_log_error_on_recovery(copy));
-    CheckCondition(1 == rocksdb_options_get_skip_log_error_on_recovery(o));
-
    rocksdb_options_set_stats_dump_period_sec(copy, 218);
    CheckCondition(218 == rocksdb_options_get_stats_dump_period_sec(copy));
    CheckCondition(18 == rocksdb_options_get_stats_dump_period_sec(o));
@@ -2504,51 +2450,51 @@ int main(int argc, char** argv) {

  StartPhase("backupable_db_option");
  {
-    rocksdb_backupable_db_options_t* bdo;
-    bdo = rocksdb_backupable_db_options_create("path");
+    rocksdb_backup_engine_options_t* bdo;
+    bdo = rocksdb_backup_engine_options_create("path");

-    rocksdb_backupable_db_options_set_share_table_files(bdo, 1);
+    rocksdb_backup_engine_options_set_share_table_files(bdo, 1);
    CheckCondition(1 ==
-                   rocksdb_backupable_db_options_get_share_table_files(bdo));
+                   rocksdb_backup_engine_options_get_share_table_files(bdo));

-    rocksdb_backupable_db_options_set_sync(bdo, 1);
-    CheckCondition(1 == rocksdb_backupable_db_options_get_sync(bdo));
+    rocksdb_backup_engine_options_set_sync(bdo, 1);
+    CheckCondition(1 == rocksdb_backup_engine_options_get_sync(bdo));

-    rocksdb_backupable_db_options_set_destroy_old_data(bdo, 1);
+    rocksdb_backup_engine_options_set_destroy_old_data(bdo, 1);
    CheckCondition(1 ==
-                   rocksdb_backupable_db_options_get_destroy_old_data(bdo));
+                   rocksdb_backup_engine_options_get_destroy_old_data(bdo));

-    rocksdb_backupable_db_options_set_backup_log_files(bdo, 1);
+    rocksdb_backup_engine_options_set_backup_log_files(bdo, 1);
    CheckCondition(1 ==
-                   rocksdb_backupable_db_options_get_backup_log_files(bdo));
+                   rocksdb_backup_engine_options_get_backup_log_files(bdo));

-    rocksdb_backupable_db_options_set_backup_rate_limit(bdo, 123);
+    rocksdb_backup_engine_options_set_backup_rate_limit(bdo, 123);
    CheckCondition(123 ==
-                   rocksdb_backupable_db_options_get_backup_rate_limit(bdo));
+                   rocksdb_backup_engine_options_get_backup_rate_limit(bdo));

-    rocksdb_backupable_db_options_set_restore_rate_limit(bdo, 37);
+    rocksdb_backup_engine_options_set_restore_rate_limit(bdo, 37);
    CheckCondition(37 ==
-                   rocksdb_backupable_db_options_get_restore_rate_limit(bdo));
+                   rocksdb_backup_engine_options_get_restore_rate_limit(bdo));

-    rocksdb_backupable_db_options_set_max_background_operations(bdo, 20);
+    rocksdb_backup_engine_options_set_max_background_operations(bdo, 20);
    CheckCondition(
-        20 == rocksdb_backupable_db_options_get_max_background_operations(bdo));
+        20 == rocksdb_backup_engine_options_get_max_background_operations(bdo));

-    rocksdb_backupable_db_options_set_callback_trigger_interval_size(bdo, 9000);
+    rocksdb_backup_engine_options_set_callback_trigger_interval_size(bdo, 9000);
    CheckCondition(
        9000 ==
-        rocksdb_backupable_db_options_get_callback_trigger_interval_size(bdo));
+        rocksdb_backup_engine_options_get_callback_trigger_interval_size(bdo));

-    rocksdb_backupable_db_options_set_max_valid_backups_to_open(bdo, 40);
+    rocksdb_backup_engine_options_set_max_valid_backups_to_open(bdo, 40);
    CheckCondition(
-        40 == rocksdb_backupable_db_options_get_max_valid_backups_to_open(bdo));
+        40 == rocksdb_backup_engine_options_get_max_valid_backups_to_open(bdo));

-    rocksdb_backupable_db_options_set_share_files_with_checksum_naming(bdo, 2);
+    rocksdb_backup_engine_options_set_share_files_with_checksum_naming(bdo, 2);
    CheckCondition(
-        2 == rocksdb_backupable_db_options_get_share_files_with_checksum_naming(
+        2 == rocksdb_backup_engine_options_get_share_files_with_checksum_naming(
                 bdo));

-    rocksdb_backupable_db_options_destroy(bdo);
+    rocksdb_backup_engine_options_destroy(bdo);
  }

  StartPhase("compression_options");
@@ -2952,6 +2898,51 @@ int main(int argc, char** argv) {
    CheckNoError(err);
  }

+  StartPhase("filter_with_prefix_seek");
+  {
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    CheckNoError(err);
+
+    rocksdb_options_set_prefix_extractor(
+        options, rocksdb_slicetransform_create_fixed_prefix(1));
+    rocksdb_filterpolicy_t* filter_policy =
+        rocksdb_filterpolicy_create_bloom_full(8.0);
+    rocksdb_block_based_options_set_filter_policy(table_options, filter_policy);
+    rocksdb_options_set_block_based_table_factory(options, table_options);
+
+    db = rocksdb_open(options, dbname, &err);
+    CheckNoError(err);
+
+    int i;
+    for (i = 0; i < 10; ++i) {
+      char key = '0' + (char)i;
+      rocksdb_put(db, woptions, &key, 1, "", 1, &err);
+      CheckNoError(err);
+    }
+
+    // Flush to generate an L0 so that filter will be used later.
+    rocksdb_flushoptions_t* flush_options = rocksdb_flushoptions_create();
+    rocksdb_flushoptions_set_wait(flush_options, 1);
+    rocksdb_flush(db, flush_options, &err);
+    rocksdb_flushoptions_destroy(flush_options);
+    CheckNoError(err);
+
+    rocksdb_readoptions_t* ropts = rocksdb_readoptions_create();
+    rocksdb_iterator_t* iter = rocksdb_create_iterator(db, ropts);
+
+    rocksdb_iter_seek(iter, "0", 1);
+    int cnt = 0;
+    while (rocksdb_iter_valid(iter)) {
+      ++cnt;
+      rocksdb_iter_next(iter);
+    }
+    CheckCondition(10 == cnt);
+
+    rocksdb_iter_destroy(iter);
+    rocksdb_readoptions_destroy(ropts);
+  }
+
  StartPhase("cancel_all_background_work");
  rocksdb_cancel_all_background_work(db, 1);

@@ -75,11 +75,6 @@ ColumnFamilyHandleImpl::~ColumnFamilyHandleImpl() {
      bool defer_purge =
          db_->immutable_db_options().avoid_unnecessary_blocking_io;
      db_->PurgeObsoleteFiles(job_context, defer_purge);
-      if (defer_purge) {
-        mutex_->Lock();
-        db_->SchedulePurge();
-        mutex_->Unlock();
-      }
    }
    job_context.Clean();
  }
@@ -211,7 +206,8 @@ ColumnFamilyOptions SanitizeOptions(const ImmutableDBOptions& db_options,
  size_t clamp_max = std::conditional<
      sizeof(size_t) == 4, std::integral_constant<size_t, 0xffffffff>,
      std::integral_constant<uint64_t, 64ull << 30>>::type::value;
-  ClipToRange(&result.write_buffer_size, ((size_t)64) << 10, clamp_max);
+  ClipToRange(&result.write_buffer_size, (static_cast<size_t>(64)) << 10,
+              clamp_max);
  // if user sets arena_block_size, we trust user to use this value. Otherwise,
  // calculate a proper value from writer_buffer_size;
  if (result.arena_block_size <= 0) {
@@ -1168,12 +1164,12 @@ Compaction* ColumnFamilyData::CompactRange(
    int output_level, const CompactRangeOptions& compact_range_options,
    const InternalKey* begin, const InternalKey* end,
    InternalKey** compaction_end, bool* conflict,
-    uint64_t max_file_num_to_ignore) {
+    uint64_t max_file_num_to_ignore, const std::string& trim_ts) {
  auto* result = compaction_picker_->CompactRange(
      GetName(), mutable_cf_options, mutable_db_options,
      current_->storage_info(), input_level, output_level,
      compact_range_options, begin, end, compaction_end, conflict,
-      max_file_num_to_ignore);
+      max_file_num_to_ignore, trim_ts);
  if (result != nullptr) {
    result->SetInputVersion(current_);
  }
@@ -413,7 +413,8 @@ class ColumnFamilyData {
                           const CompactRangeOptions& compact_range_options,
                           const InternalKey* begin, const InternalKey* end,
                           InternalKey** compaction_end, bool* manual_conflict,
-                           uint64_t max_file_num_to_ignore);
+                           uint64_t max_file_num_to_ignore,
+                           const std::string& trim_ts);

  CompactionPicker* compaction_picker() { return compaction_picker_.get(); }
  // thread-safe
@@ -554,7 +554,7 @@ class ColumnFamilyTest
 INSTANTIATE_TEST_CASE_P(FormatDef, ColumnFamilyTest,
                        testing::Values(test::kDefaultFormatVersion));
 INSTANTIATE_TEST_CASE_P(FormatLatest, ColumnFamilyTest,
-                        testing::Values(test::kLatestFormatVersion));
+                        testing::Values(kLatestFormatVersion));

 TEST_P(ColumnFamilyTest, DontReuseColumnFamilyID) {
  for (int iter = 0; iter < 3; ++iter) {
@@ -746,8 +746,8 @@ INSTANTIATE_TEST_CASE_P(
                    std::make_tuple(test::kDefaultFormatVersion, false)));
 INSTANTIATE_TEST_CASE_P(
    FormatLatest, FlushEmptyCFTestWithParam,
-    testing::Values(std::make_tuple(test::kLatestFormatVersion, true),
-                    std::make_tuple(test::kLatestFormatVersion, false)));
+    testing::Values(std::make_tuple(kLatestFormatVersion, true),
+                    std::make_tuple(kLatestFormatVersion, false)));

 TEST_P(ColumnFamilyTest, AddDrop) {
  Open();
@@ -3433,14 +3433,6 @@ TEST(ColumnFamilyTest, ValidateBlobGCForceThreshold) {

 }  // namespace ROCKSDB_NAMESPACE

-#ifdef ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-extern "C" {
-void RegisterCustomObjects(int argc, char** argv);
-}
-#else
-void RegisterCustomObjects(int /*argc*/, char** /*argv*/) {}
-#endif  // !ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-
 int main(int argc, char** argv) {
  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
@@ -138,6 +138,9 @@ TEST_F(CompactFilesTest, MultipleLevel) {
    collector->ClearFlushedFiles();
    ASSERT_OK(db->Put(WriteOptions(), ToString(i), ""));
    ASSERT_OK(db->Flush(FlushOptions()));
+    // Ensure background work is fully finished including listener callbacks
+    // before accessing listener state.
+    ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForBackgroundWork());
    auto l0_files = collector->GetFlushedFiles();
    ASSERT_OK(db->CompactFiles(CompactionOptions(), l0_files, i));

@@ -296,6 +299,9 @@ TEST_F(CompactFilesTest, CapturingPendingFiles) {
    ASSERT_OK(db->Flush(FlushOptions()));
  }

+  // Ensure background work is fully finished including listener callbacks
+  // before accessing listener state.
+  ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForBackgroundWork());
  auto l0_files = collector->GetFlushedFiles();
  EXPECT_EQ(5, l0_files.size());

@@ -414,6 +420,9 @@ TEST_F(CompactFilesTest, SentinelCompressionType) {
    ASSERT_OK(db->Put(WriteOptions(), "key", "val"));
    ASSERT_OK(db->Flush(FlushOptions()));

+    // Ensure background work is fully finished including listener callbacks
+    // before accessing listener state.
+    ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForBackgroundWork());
    auto l0_files = collector->GetFlushedFiles();
    ASSERT_EQ(1, l0_files.size());

@@ -213,8 +213,8 @@ Compaction::Compaction(
    uint32_t _output_path_id, CompressionType _compression,
    CompressionOptions _compression_opts, Temperature _output_temperature,
    uint32_t _max_subcompactions, std::vector<FileMetaData*> _grandparents,
-    bool _manual_compaction, double _score, bool _deletion_compaction,
-    CompactionReason _compaction_reason)
+    bool _manual_compaction, const std::string& _trim_ts, double _score,
+    bool _deletion_compaction, CompactionReason _compaction_reason)
    : input_vstorage_(vstorage),
      start_level_(_inputs[0].level),
      output_level_(_output_level),
@@ -237,6 +237,7 @@ Compaction::Compaction(
      bottommost_level_(IsBottommostLevel(output_level_, vstorage, inputs_)),
      is_full_compaction_(IsFullCompaction(vstorage, inputs_)),
      is_manual_compaction_(_manual_compaction),
+      trim_ts_(_trim_ts),
      is_trivial_move_(false),
      compaction_reason_(_compaction_reason),
      notify_on_compaction_completion_(false) {
@@ -277,9 +278,9 @@ Compaction::~Compaction() {

 bool Compaction::InputCompressionMatchesOutput() const {
  int base_level = input_vstorage_->base_level();
-  bool matches = (GetCompressionType(immutable_options_, input_vstorage_,
-                                     mutable_cf_options_, start_level_,
-                                     base_level) == output_compression_);
+  bool matches =
+      (GetCompressionType(input_vstorage_, mutable_cf_options_, start_level_,
+                          base_level) == output_compression_);
  if (matches) {
    TEST_SYNC_POINT("Compaction::InputCompressionMatchesOutput:Matches");
    return true;
@@ -318,7 +319,8 @@ bool Compaction::IsTrivialMove() const {
  // Used in universal compaction, where trivial move can be done if the
  // input files are non overlapping
  if ((mutable_cf_options_.compaction_options_universal.allow_trivial_move) &&
-      (output_level_ != 0)) {
+      (output_level_ != 0) &&
+      (cfd_->ioptions()->compaction_style == kCompactionStyleUniversal)) {
    return is_trivial_move_;
  }

@@ -612,10 +614,19 @@ bool Compaction::DoesInputReferenceBlobFiles() const {
  return false;
 }

-uint64_t Compaction::MinInputFileOldestAncesterTime() const {
+uint64_t Compaction::MinInputFileOldestAncesterTime(
+    const InternalKey* start, const InternalKey* end) const {
  uint64_t min_oldest_ancester_time = port::kMaxUint64;
+  const InternalKeyComparator& icmp =
+      column_family_data()->internal_comparator();
  for (const auto& level_files : inputs_) {
    for (const auto& file : level_files.files) {
+      if (start != nullptr && icmp.Compare(file->largest, *start) < 0) {
+        continue;
+      }
+      if (end != nullptr && icmp.Compare(file->smallest, *end) > 0) {
+        continue;
+      }
      uint64_t oldest_ancester_time = file->TryGetOldestAncesterTime();
      if (oldest_ancester_time != 0) {
        min_oldest_ancester_time =
@@ -79,8 +79,8 @@ class Compaction {
             CompressionOptions compression_opts,
             Temperature output_temperature, uint32_t max_subcompactions,
             std::vector<FileMetaData*> grandparents,
-             bool manual_compaction = false, double score = -1,
-             bool deletion_compaction = false,
+             bool manual_compaction = false, const std::string& trim_ts = "",
+             double score = -1, bool deletion_compaction = false,
             CompactionReason compaction_reason = CompactionReason::kUnknown);

  // No copying allowed
@@ -208,6 +208,8 @@ class Compaction {
  // Was this compaction triggered manually by the client?
  bool is_manual_compaction() const { return is_manual_compaction_; }

+  std::string trim_ts() const { return trim_ts_; }
+
  // Used when allow_trivial_move option is set in
  // Universal compaction. If all the input files are
  // non overlapping, then is_trivial_move_ variable
@@ -292,7 +294,7 @@ class Compaction {

  int GetInputBaseLevel() const;

-  CompactionReason compaction_reason() { return compaction_reason_; }
+  CompactionReason compaction_reason() const { return compaction_reason_; }

  const std::vector<FileMetaData*>& grandparents() const {
    return grandparents_;
@@ -304,7 +306,10 @@ class Compaction {

  uint32_t max_subcompactions() const { return max_subcompactions_; }

-  uint64_t MinInputFileOldestAncesterTime() const;
+  // start and end are sub compact range. Null if no boundary.
+  // This is used to filter out some input files' ancester's time range.
+  uint64_t MinInputFileOldestAncesterTime(const InternalKey* start,
+                                          const InternalKey* end) const;

  // Called by DBImpl::NotifyOnCompactionCompleted to make sure number of
  // compaction begin and compaction completion callbacks match.
@@ -382,6 +387,9 @@ class Compaction {
  // Is this compaction requested by the client?
  const bool is_manual_compaction_;

+  // The data with timestamp > trim_ts_ will be removed
+  const std::string trim_ts_;
+
  // True if we can do trivial move in Universal multi level
  // compaction
  bool is_trivial_move_;
@@ -9,6 +9,8 @@

 #include "rocksdb/rocksdb_namespace.h"

+namespace ROCKSDB_NAMESPACE {
+
 struct CompactionIterationStats {
  // Compaction statistics

@@ -43,3 +45,5 @@ struct CompactionIterationStats {
  uint64_t num_blobs_relocated = 0;
  uint64_t total_blob_bytes_relocated = 0;
 };
+
+}  // namespace ROCKSDB_NAMESPACE
@@ -8,8 +8,10 @@
 #include <iterator>
 #include <limits>

+#include "db/blob/blob_fetcher.h"
 #include "db/blob/blob_file_builder.h"
 #include "db/blob/blob_index.h"
+#include "db/blob/prefetch_buffer_collection.h"
 #include "db/snapshot_checker.h"
 #include "logging/logging.h"
 #include "port/likely.h"
@@ -88,6 +90,9 @@ CompactionIterator::CompactionIterator(
      merge_out_iter_(merge_helper_),
      blob_garbage_collection_cutoff_file_number_(
          ComputeBlobGarbageCollectionCutoffFileNumber(compaction_.get())),
+      blob_fetcher_(CreateBlobFetcherIfNeeded(compaction_.get())),
+      prefetch_buffers_(
+          CreatePrefetchBufferCollectionIfNeeded(compaction_.get())),
      current_key_committed_(false),
      cmp_with_history_ts_low_(0),
      level_(compaction_ == nullptr ? 0 : compaction_->level()) {
@@ -225,6 +230,13 @@ bool CompactionIterator::InvokeFilterIfNeeded(bool* need_skip,
          compaction_filter_skip_until_.rep());
      if (CompactionFilter::Decision::kUndetermined == filter &&
          !compaction_filter_->IsStackedBlobDbInternalCompactionFilter()) {
+        if (compaction_ == nullptr) {
+          status_ =
+              Status::Corruption("Unexpected blob index outside of compaction");
+          valid_ = false;
+          return false;
+        }
+
        // For integrated BlobDB impl, CompactionIterator reads blob value.
        // For Stacked BlobDB impl, the corresponding CompactionFilter's
        // FilterV2 method should read the blob value.
@@ -235,23 +247,19 @@ bool CompactionIterator::InvokeFilterIfNeeded(bool* need_skip,
          valid_ = false;
          return false;
        }
-        if (blob_index.HasTTL() || blob_index.IsInlined()) {
-          status_ = Status::Corruption("Unexpected TTL/inlined blob index");
-          valid_ = false;
-          return false;
-        }
-        if (compaction_ == nullptr) {
-          status_ =
-              Status::Corruption("Unexpected blob index outside of compaction");
-          valid_ = false;
-          return false;
-        }
-        const Version* const version = compaction_->input_version();
-        assert(version);
+
+        FilePrefetchBuffer* prefetch_buffer =
+            prefetch_buffers_ ? prefetch_buffers_->GetOrCreatePrefetchBuffer(
+                                    blob_index.file_number())
+                              : nullptr;

        uint64_t bytes_read = 0;
-        s = version->GetBlob(ReadOptions(), ikey_.user_key, blob_index,
-                             &blob_value_, &bytes_read);
+
+        assert(blob_fetcher_);
+
+        s = blob_fetcher_->FetchBlob(ikey_.user_key, blob_index,
+                                     prefetch_buffer, &blob_value_,
+                                     &bytes_read);
        if (!s.ok()) {
          status_ = s;
          valid_ = false;
@@ -407,6 +415,12 @@ void CompactionIterator::NextFromInput() {
      // Copy key for output
      key_ = current_key_.SetInternalKey(key_, &ikey_);

+      int prev_cmp_with_ts_low =
+          !full_history_ts_low_ ? 0
+          : curr_ts_.empty()
+              ? 0
+              : cmp_->CompareTimestamp(curr_ts_, *full_history_ts_low_);
+
      // If timestamp_size_ > 0, then copy from ikey_ to curr_ts_ for the use
      // in next iteration to compare with the timestamp of next key.
      UpdateTimestampAndCompareWithFullHistoryLow();
@@ -416,14 +430,16 @@ void CompactionIterator::NextFromInput() {
      // (2) timestamp is disabled, OR
      // (3) all history will be preserved, OR
      // (4) user key (excluding timestamp) is different from previous key, OR
-      // (5) timestamp is NO older than *full_history_ts_low_
+      // (5) timestamp is NO older than *full_history_ts_low_, OR
+      // (6) timestamp is the largest one older than full_history_ts_low_,
      // then current_user_key_ must be treated as a different user key.
      // This means, if a user key (excluding ts) is the same as the previous
      // user key, and its ts is older than *full_history_ts_low_, then we
      // consider this key for GC, e.g. it may be dropped if certain conditions
      // match.
      if (!has_current_user_key_ || !timestamp_size_ || !full_history_ts_low_ ||
-          !user_key_equal_without_ts || cmp_with_history_ts_low_ >= 0) {
+          !user_key_equal_without_ts || cmp_with_history_ts_low_ >= 0 ||
+          prev_cmp_with_ts_low >= 0) {
        // Initialize for future comparison for rule (A) and etc.
        current_user_key_sequence_ = kMaxSequenceNumber;
        current_user_key_snapshot_ = 0;
@@ -433,6 +449,8 @@ void CompactionIterator::NextFromInput() {

      has_outputted_key_ = false;

+      last_key_seq_zeroed_ = false;
+
      current_key_committed_ = KeyCommitted(ikey_.sequence);

      // Apply the compaction filter to the first committed version of the user
@@ -520,6 +538,25 @@ void CompactionIterator::NextFromInput() {
      // 2) We've already returned a record in this snapshot -OR-
      //    there are no earlier earliest_write_conflict_snapshot.
      //
+      // A note about 2) above:
+      // we try to determine whether there is any earlier write conflict
+      // checking snapshot by calling DefinitelyInSnapshot() with seq and
+      // earliest_write_conflict_snapshot as arguments. For write-prepared
+      // and write-unprepared transactions, if earliest_write_conflict_snapshot
+      // is evicted from WritePreparedTxnDB::commit_cache, then
+      // DefinitelyInSnapshot(seq, earliest_write_conflict_snapshot) returns
+      // false, even if the seq is actually visible within
+      // earliest_write_conflict_snapshot. Consequently, CompactionIterator
+      // may try to zero out its sequence number, thus hitting assertion error
+      // in debug mode or cause incorrect DBIter return result.
+      // We observe that earliest_write_conflict_snapshot >= earliest_snapshot,
+      // and the seq zeroing logic depends on
+      // DefinitelyInSnapshot(seq, earliest_snapshot). Therefore, if we cannot
+      // determine whether seq is **definitely** in
+      // earliest_write_conflict_snapshot, then we can additionally check if
+      // seq is definitely in earliest_snapshot. If the latter holds, then the
+      // former holds too.
+      //
      // Rule 1 is needed for SingleDelete correctness.  Rule 2 is needed to
      // allow Transactions to do write-conflict checking (if we compacted away
      // all keys, then we wouldn't know that a write happened in this
@@ -575,17 +612,31 @@ void CompactionIterator::NextFromInput() {
        TEST_SYNC_POINT_CALLBACK(
            "CompactionIterator::NextFromInput:SingleDelete:1",
            const_cast<Compaction*>(c));
-        // Check whether the next key belongs to the same snapshot as the
-        // SingleDelete.
-        if (prev_snapshot == 0 ||
-            DefinitelyNotInSnapshot(next_ikey.sequence, prev_snapshot)) {
+        if (last_key_seq_zeroed_) {
+          ++iter_stats_.num_record_drop_hidden;
+          ++iter_stats_.num_record_drop_obsolete;
+          assert(bottommost_level_);
+          AdvanceInputIter();
+        } else if (prev_snapshot == 0 ||
+                   DefinitelyNotInSnapshot(next_ikey.sequence, prev_snapshot)) {
+          // Check whether the next key belongs to the same snapshot as the
+          // SingleDelete.
+
          TEST_SYNC_POINT_CALLBACK(
              "CompactionIterator::NextFromInput:SingleDelete:2", nullptr);
-          if (next_ikey.type == kTypeSingleDeletion) {
+          if (next_ikey.type == kTypeSingleDeletion ||
+              next_ikey.type == kTypeDeletion) {
            // We encountered two SingleDeletes for same key in a row. This
-            // could be due to unexpected user input. Skip the first
-            // SingleDelete and let the next iteration decide how to handle the
-            // second SingleDelete
+            // could be due to unexpected user input. If write-(un)prepared
+            // transaction is used, this could also be due to releasing an old
+            // snapshot between a Put and its matching SingleDelete.
+            // Furthermore, if write-(un)prepared transaction is rolled back
+            // after prepare, we will write a Delete to cancel a prior Put. If
+            // old snapshot is released between a later Put and its matching
+            // SingleDelete, we will end up with a Delete followed by
+            // SingleDelete.
+            // Skip the first SingleDelete and let the next iteration decide
+            // how to handle the second SingleDelete or Delete.

            // First SingleDelete has been skipped since we already called
            // input_.Next().
@@ -598,7 +649,10 @@ void CompactionIterator::NextFromInput() {
            valid_ = true;
          } else if (has_outputted_key_ ||
                     DefinitelyInSnapshot(ikey_.sequence,
-                                          earliest_write_conflict_snapshot_)) {
+                                          earliest_write_conflict_snapshot_) ||
+                     (earliest_snapshot_ < earliest_write_conflict_snapshot_ &&
+                      DefinitelyInSnapshot(ikey_.sequence,
+                                           earliest_snapshot_))) {
            // Found a matching value, we can drop the single delete and the
            // value.  It is safe to drop both records since we've already
            // outputted a key in this snapshot, or there is no earlier
@@ -639,6 +693,9 @@ void CompactionIterator::NextFromInput() {
          // We hit the next snapshot without hitting a put, so the iterator
          // returns the single delete.
          valid_ = true;
+          TEST_SYNC_POINT_CALLBACK(
+              "CompactionIterator::NextFromInput:SingleDelete:3",
+              const_cast<Compaction*>(c));
        }
      } else {
        // We are at the end of the input, could not parse the next key, or hit
@@ -661,6 +718,11 @@ void CompactionIterator::NextFromInput() {
          if (!bottommost_level_) {
            ++iter_stats_.num_optimized_del_drop_obsolete;
          }
+        } else if (last_key_seq_zeroed_) {
+          // Skip.
+          ++iter_stats_.num_record_drop_hidden;
+          ++iter_stats_.num_record_drop_obsolete;
+          assert(bottommost_level_);
        } else {
          // Output SingleDelete
          valid_ = true;
@@ -777,15 +839,15 @@ void CompactionIterator::NextFromInput() {
      }

      pinned_iters_mgr_.StartPinning();
-      Version* version = compaction_ ? compaction_->input_version() : nullptr;

      // We know the merge type entry is not hidden, otherwise we would
      // have hit (A)
      // We encapsulate the merge related state machine in a different
      // object to minimize change to the existing flow.
-      Status s = merge_helper_->MergeUntil(&input_, range_del_agg_,
-                                           prev_snapshot, bottommost_level_,
-                                           allow_data_in_errors_, version);
+      Status s = merge_helper_->MergeUntil(
+          &input_, range_del_agg_, prev_snapshot, bottommost_level_,
+          allow_data_in_errors_, blob_fetcher_.get(), prefetch_buffers_.get(),
+          &iter_stats_);
      merge_out_iter_.SeekToFirst();

      if (!s.ok() && !s.IsMergeInProgress()) {
@@ -905,26 +967,23 @@ void CompactionIterator::GarbageCollectBlobIfNeeded() {
      }
    }

-    if (blob_index.IsInlined() || blob_index.HasTTL()) {
-      status_ = Status::Corruption("Unexpected TTL/inlined blob index");
-      valid_ = false;
-
-      return;
-    }
-
    if (blob_index.file_number() >=
        blob_garbage_collection_cutoff_file_number_) {
      return;
    }

-    const Version* const version = compaction_->input_version();
-    assert(version);
+    FilePrefetchBuffer* prefetch_buffer =
+        prefetch_buffers_ ? prefetch_buffers_->GetOrCreatePrefetchBuffer(
+                                blob_index.file_number())
+                          : nullptr;

    uint64_t bytes_read = 0;

    {
-      const Status s = version->GetBlob(ReadOptions(), user_key(), blob_index,
-                                        &blob_value_, &bytes_read);
+      assert(blob_fetcher_);
+
+      const Status s = blob_fetcher_->FetchBlob(
+          user_key(), blob_index, prefetch_buffer, &blob_value_, &bytes_read);

      if (!s.ok()) {
        status_ = s;
@@ -1016,6 +1075,9 @@ void CompactionIterator::PrepareOutput() {
                        ikey_.type);
      }
      ikey_.sequence = 0;
+      last_key_seq_zeroed_ = true;
+      TEST_SYNC_POINT_CALLBACK("CompactionIterator::PrepareOutput:ZeroingSeq",
+                               &ikey_);
      if (!timestamp_size_) {
        current_key_.UpdateInternalKey(0, ikey_.type);
      } else if (full_history_ts_low_ && cmp_with_history_ts_low_ < 0) {
@@ -1084,41 +1146,6 @@ inline bool CompactionIterator::ikeyNotNeededForIncrementalSnapshot() {
         (ikey_.sequence < preserve_deletes_seqnum_);
 }

-bool CompactionIterator::IsInCurrentEarliestSnapshot(SequenceNumber sequence) {
-  assert(snapshot_checker_ != nullptr);
-  bool pre_condition = (earliest_snapshot_ == kMaxSequenceNumber ||
-                        (earliest_snapshot_iter_ != snapshots_->end() &&
-                         *earliest_snapshot_iter_ == earliest_snapshot_));
-  assert(pre_condition);
-  if (!pre_condition) {
-    ROCKS_LOG_FATAL(info_log_,
-                    "Pre-Condition is not hold in IsInEarliestSnapshot");
-  }
-  auto in_snapshot =
-      snapshot_checker_->CheckInSnapshot(sequence, earliest_snapshot_);
-  while (UNLIKELY(in_snapshot == SnapshotCheckerResult::kSnapshotReleased)) {
-    // Avoid the the current earliest_snapshot_ being return as
-    // earliest visible snapshot for the next value. So if a value's sequence
-    // is zero-ed out by PrepareOutput(), the next value will be compact out.
-    released_snapshots_.insert(earliest_snapshot_);
-    earliest_snapshot_iter_++;
-
-    if (earliest_snapshot_iter_ == snapshots_->end()) {
-      earliest_snapshot_ = kMaxSequenceNumber;
-    } else {
-      earliest_snapshot_ = *earliest_snapshot_iter_;
-    }
-    in_snapshot =
-        snapshot_checker_->CheckInSnapshot(sequence, earliest_snapshot_);
-  }
-  assert(in_snapshot != SnapshotCheckerResult::kSnapshotReleased);
-  if (in_snapshot == SnapshotCheckerResult::kSnapshotReleased) {
-    ROCKS_LOG_FATAL(info_log_,
-                    "Unexpected released snapshot in IsInEarliestSnapshot");
-  }
-  return in_snapshot == SnapshotCheckerResult::kInSnapshot;
-}
-
 uint64_t CompactionIterator::ComputeBlobGarbageCollectionCutoffFileNumber(
    const CompactionProxy* compaction) {
  if (!compaction) {
@@ -1129,7 +1156,7 @@ uint64_t CompactionIterator::ComputeBlobGarbageCollectionCutoffFileNumber(
    return 0;
  }

-  Version* const version = compaction->input_version();
+  const Version* const version = compaction->input_version();
  assert(version);

  const VersionStorageInfo* const storage_info = version->storage_info();
@@ -1137,12 +1164,55 @@ uint64_t CompactionIterator::ComputeBlobGarbageCollectionCutoffFileNumber(

  const auto& blob_files = storage_info->GetBlobFiles();

-  auto it = blob_files.begin();
-  std::advance(
-      it, compaction->blob_garbage_collection_age_cutoff() * blob_files.size());
+  const size_t cutoff_index = static_cast<size_t>(
+      compaction->blob_garbage_collection_age_cutoff() * blob_files.size());

-  return it != blob_files.end() ? it->first
-                                : std::numeric_limits<uint64_t>::max();
+  if (cutoff_index >= blob_files.size()) {
+    return std::numeric_limits<uint64_t>::max();
+  }
+
+  const auto& meta = blob_files[cutoff_index];
+  assert(meta);
+
+  return meta->GetBlobFileNumber();
+}
+
+std::unique_ptr<BlobFetcher> CompactionIterator::CreateBlobFetcherIfNeeded(
+    const CompactionProxy* compaction) {
+  if (!compaction) {
+    return nullptr;
+  }
+
+  const Version* const version = compaction->input_version();
+  if (!version) {
+    return nullptr;
+  }
+
+  return std::unique_ptr<BlobFetcher>(new BlobFetcher(version, ReadOptions()));
+}
+
+std::unique_ptr<PrefetchBufferCollection>
+CompactionIterator::CreatePrefetchBufferCollectionIfNeeded(
+    const CompactionProxy* compaction) {
+  if (!compaction) {
+    return nullptr;
+  }
+
+  if (!compaction->input_version()) {
+    return nullptr;
+  }
+
+  if (compaction->allow_mmap_reads()) {
+    return nullptr;
+  }
+
+  const uint64_t readahead_size = compaction->blob_compaction_readahead_size();
+  if (!readahead_size) {
+    return nullptr;
+  }
+
+  return std::unique_ptr<PrefetchBufferCollection>(
+      new PrefetchBufferCollection(readahead_size));
 }

 }  // namespace ROCKSDB_NAMESPACE
@@ -23,6 +23,8 @@
 namespace ROCKSDB_NAMESPACE {

 class BlobFileBuilder;
+class BlobFetcher;
+class PrefetchBufferCollection;

 // A wrapper of internal iterator whose purpose is to count how
 // many entries there are in the iterator.
@@ -92,11 +94,15 @@ class CompactionIterator {

    virtual bool preserve_deletes() const = 0;

+    virtual bool allow_mmap_reads() const = 0;
+
    virtual bool enable_blob_garbage_collection() const = 0;

    virtual double blob_garbage_collection_age_cutoff() const = 0;

-    virtual Version* input_version() const = 0;
+    virtual uint64_t blob_compaction_readahead_size() const = 0;
+
+    virtual const Version* input_version() const = 0;

    virtual bool DoesInputReferenceBlobFiles() const = 0;

@@ -133,8 +139,10 @@ class CompactionIterator {
      return compaction_->immutable_options()->allow_ingest_behind;
    }

-    bool preserve_deletes() const override {
-      return compaction_->immutable_options()->preserve_deletes;
+    bool preserve_deletes() const override { return false; }
+
+    bool allow_mmap_reads() const override {
+      return compaction_->immutable_options()->allow_mmap_reads;
    }

    bool enable_blob_garbage_collection() const override {
@@ -146,7 +154,11 @@ class CompactionIterator {
          ->blob_garbage_collection_age_cutoff;
    }

-    Version* input_version() const override {
+    uint64_t blob_compaction_readahead_size() const override {
+      return compaction_->mutable_cf_options()->blob_compaction_readahead_size;
+    }
+
+    const Version* input_version() const override {
      return compaction_->input_version();
    }

@@ -271,14 +283,10 @@ class CompactionIterator {
               SnapshotCheckerResult::kInSnapshot;
  }

-  bool IsInCurrentEarliestSnapshot(SequenceNumber sequence);
-
  bool DefinitelyInSnapshot(SequenceNumber seq, SequenceNumber snapshot);

  bool DefinitelyNotInSnapshot(SequenceNumber seq, SequenceNumber snapshot);

-  bool InCurrentEarliestSnapshot(SequenceNumber seq);
-
  // Extract user-defined timestamp from user key if possible and compare it
  // with *full_history_ts_low_ if applicable.
  inline void UpdateTimestampAndCompareWithFullHistoryLow() {
@@ -295,6 +303,10 @@ class CompactionIterator {

  static uint64_t ComputeBlobGarbageCollectionCutoffFileNumber(
      const CompactionProxy* compaction);
+  static std::unique_ptr<BlobFetcher> CreateBlobFetcherIfNeeded(
+      const CompactionProxy* compaction);
+  static std::unique_ptr<PrefetchBufferCollection>
+  CreatePrefetchBufferCollectionIfNeeded(const CompactionProxy* compaction);

  SequenceIterWrapper input_;
  const Comparator* cmp_;
@@ -383,6 +395,9 @@ class CompactionIterator {

  uint64_t blob_garbage_collection_cutoff_file_number_;

+  std::unique_ptr<BlobFetcher> blob_fetcher_;
+  std::unique_ptr<PrefetchBufferCollection> prefetch_buffers_;
+
  std::string blob_index_;
  PinnableSlice blob_value_;
  std::string compaction_filter_value_;
@@ -405,6 +420,10 @@ class CompactionIterator {

  const int level_;

+  // True if the previous internal key (same user key)'s sequence number has
+  // just been zeroed out during bottommost compaction.
+  bool last_key_seq_zeroed_{false};
+
  void AdvanceInputIter() { input_.Next(); }

  void SkipUntil(const Slice& skip_until) { input_.Seek(skip_until); }
@@ -439,10 +458,4 @@ inline bool CompactionIterator::DefinitelyNotInSnapshot(
                    SnapshotCheckerResult::kNotInSnapshot)));
 }

-inline bool CompactionIterator::InCurrentEarliestSnapshot(SequenceNumber seq) {
-  return ((seq) <= earliest_snapshot_ &&
-          (snapshot_checker_ == nullptr ||
-           LIKELY(IsInCurrentEarliestSnapshot(seq))));
-}
-
 }  // namespace ROCKSDB_NAMESPACE
@@ -168,11 +168,15 @@ class FakeCompaction : public CompactionIterator::CompactionProxy {

  bool preserve_deletes() const override { return false; }

+  bool allow_mmap_reads() const override { return false; }
+
  bool enable_blob_garbage_collection() const override { return false; }

  double blob_garbage_collection_age_cutoff() const override { return 0.0; }

-  Version* input_version() const override { return nullptr; }
+  uint64_t blob_compaction_readahead_size() const override { return 0; }
+
+  const Version* input_version() const override { return nullptr; }

  bool DoesInputReferenceBlobFiles() const override { return false; }

@@ -1075,7 +1079,7 @@ INSTANTIATE_TEST_CASE_P(CompactionIteratorWithAllowIngestBehindTestInstance,
 class CompactionIteratorTsGcTest : public CompactionIteratorTest {
 public:
  CompactionIteratorTsGcTest()
-      : CompactionIteratorTest(test::ComparatorWithU64Ts()) {}
+      : CompactionIteratorTest(test::BytewiseComparatorWithU64TsWrapper()) {}
 };

 TEST_P(CompactionIteratorTsGcTest, NoKeyEligibleForGC) {
@@ -1171,9 +1175,10 @@ TEST_P(CompactionIteratorTsGcTest, NewHidesOldSameSnapshot) {
    std::string full_history_ts_low;
    // Keys whose timestamps larger than or equal to 102 will be preserved.
    PutFixed64(&full_history_ts_low, 102);
-    const std::vector<std::string> expected_keys = {input_keys[0],
-                                                    input_keys[1]};
-    const std::vector<std::string> expected_values = {"", "a2"};
+    const std::vector<std::string> expected_keys = {
+        input_keys[0], input_keys[1], input_keys[2]};
+    const std::vector<std::string> expected_values = {"", input_values[1],
+                                                      input_values[2]};
    RunTest(input_keys, input_values, expected_keys, expected_values,
            /*last_committed_seq=*/kMaxSequenceNumber,
            /*merge_operator=*/nullptr, /*compaction_filter=*/nullptr,
@@ -31,6 +31,7 @@
 #include "db/dbformat.h"
 #include "db/error_handler.h"
 #include "db/event_helpers.h"
+#include "db/history_trimming_iterator.h"
 #include "db/log_reader.h"
 #include "db/log_writer.h"
 #include "db/memtable.h"
@@ -170,6 +171,13 @@ struct CompactionJob::SubcompactionState {
    }
  }

+  // Some identified files with old oldest ancester time and the range should be
+  // isolated out so that the output file(s) in that range can be merged down
+  // for TTL and clear the timestamps for the range.
+  std::vector<FileMetaData*> files_to_cut_for_ttl;
+  int cur_files_to_cut_for_ttl = -1;
+  int next_files_to_cut_for_ttl = 0;
+
  uint64_t current_output_file_size = 0;

  // State during the subcompaction
@@ -188,6 +196,10 @@ struct CompactionJob::SubcompactionState {
  // within the same compaction job.
  const uint32_t sub_job_id;

+  // Notify on sub-compaction completion only if listener was notified on
+  // sub-compaction begin.
+  bool notify_on_subcompaction_completion = false;
+
  SubcompactionState(Compaction* c, Slice* _start, Slice* _end, uint64_t size,
                     uint32_t _sub_job_id)
      : compaction(c),
@@ -212,6 +224,8 @@ struct CompactionJob::SubcompactionState {
    return Status::OK();
  }

+  void FillFilesToCutForTtl();
+
  // Returns true iff we should stop building the current output
  // before processing "internal_key".
  bool ShouldStopBefore(const Slice& internal_key, uint64_t curr_file_size) {
@@ -244,6 +258,40 @@ struct CompactionJob::SubcompactionState {
      return true;
    }

+    if (!files_to_cut_for_ttl.empty()) {
+      if (cur_files_to_cut_for_ttl != -1) {
+        // Previous key is inside the range of a file
+        if (icmp->Compare(internal_key,
+                          files_to_cut_for_ttl[cur_files_to_cut_for_ttl]
+                              ->largest.Encode()) > 0) {
+          next_files_to_cut_for_ttl = cur_files_to_cut_for_ttl + 1;
+          cur_files_to_cut_for_ttl = -1;
+          return true;
+        }
+      } else {
+        // Look for the key position
+        while (next_files_to_cut_for_ttl <
+               static_cast<int>(files_to_cut_for_ttl.size())) {
+          if (icmp->Compare(internal_key,
+                            files_to_cut_for_ttl[next_files_to_cut_for_ttl]
+                                ->smallest.Encode()) >= 0) {
+            if (icmp->Compare(internal_key,
+                              files_to_cut_for_ttl[next_files_to_cut_for_ttl]
+                                  ->largest.Encode()) <= 0) {
+              // With in the current file
+              cur_files_to_cut_for_ttl = next_files_to_cut_for_ttl;
+              return true;
+            }
+            // Beyond the current file
+            next_files_to_cut_for_ttl++;
+          } else {
+            // Still fall into the gap
+            break;
+          }
+        }
+      }
+    }
+
    return false;
  }

@@ -256,6 +304,46 @@ struct CompactionJob::SubcompactionState {
  }
 };

+void CompactionJob::SubcompactionState::FillFilesToCutForTtl() {
+  if (compaction->immutable_options()->compaction_style !=
+          CompactionStyle::kCompactionStyleLevel ||
+      compaction->immutable_options()->compaction_pri !=
+          CompactionPri::kMinOverlappingRatio ||
+      compaction->mutable_cf_options()->ttl == 0 ||
+      compaction->num_input_levels() < 2 || compaction->bottommost_level()) {
+    return;
+  }
+
+  // We define new file with oldest ancestor time to be younger than 1/4 TTL,
+  // and an old one to be older than 1/2 TTL time.
+  int64_t temp_current_time;
+  auto get_time_status = compaction->immutable_options()->clock->GetCurrentTime(
+      &temp_current_time);
+  if (!get_time_status.ok()) {
+    return;
+  }
+  uint64_t current_time = static_cast<uint64_t>(temp_current_time);
+  if (current_time < compaction->mutable_cf_options()->ttl) {
+    return;
+  }
+  uint64_t old_age_thres =
+      current_time - compaction->mutable_cf_options()->ttl / 2;
+
+  const std::vector<FileMetaData*>& olevel =
+      *(compaction->inputs(compaction->num_input_levels() - 1));
+  for (FileMetaData* file : olevel) {
+    // Worth filtering out by start and end?
+    uint64_t oldest_ancester_time = file->TryGetOldestAncesterTime();
+    // We put old files if they are not too small to prevent a flood
+    // of small files.
+    if (oldest_ancester_time < old_age_thres &&
+        file->fd.GetFileSize() >
+            compaction->mutable_cf_options()->target_file_size_base / 2) {
+      files_to_cut_for_ttl.push_back(file);
+    }
+  }
+}
+
 // Maintains state for the entire compaction
 struct CompactionJob::CompactionState {
  Compaction* const compaction;
@@ -342,7 +430,8 @@ CompactionJob::CompactionJob(
    const std::atomic<int>* manual_compaction_paused,
    const std::atomic<bool>* manual_compaction_canceled,
    const std::string& db_id, const std::string& db_session_id,
-    std::string full_history_ts_low, BlobFileCompletionCallback* blob_callback)
+    std::string full_history_ts_low, std::string trim_ts,
+    BlobFileCompletionCallback* blob_callback)
    : compact_(new CompactionState(compaction)),
      compaction_stats_(compaction->compaction_reason(), 1),
      db_options_(db_options),
@@ -381,6 +470,7 @@ CompactionJob::CompactionJob(
      measure_io_stats_(measure_io_stats),
      thread_pri_(thread_pri),
      full_history_ts_low_(std::move(full_history_ts_low)),
+      trim_ts_(std::move(trim_ts)),
      blob_callback_(blob_callback) {
  assert(compaction_job_stats_ != nullptr);
  assert(log_buffer_ != nullptr);
@@ -680,12 +770,16 @@ Status CompactionJob::Run() {
    constexpr IODebugContext* dbg = nullptr;

    if (output_directory_) {
-      io_s = output_directory_->Fsync(IOOptions(), dbg);
+      io_s = output_directory_->FsyncWithDirOptions(
+          IOOptions(), dbg,
+          DirFsyncOptions(DirFsyncOptions::FsyncReason::kNewFileSynced));
    }

    if (io_s.ok() && wrote_new_blob_files && blob_output_directory_ &&
        blob_output_directory_ != output_directory_) {
-      io_s = blob_output_directory_->Fsync(IOOptions(), dbg);
+      io_s = blob_output_directory_->FsyncWithDirOptions(
+          IOOptions(), dbg,
+          DirFsyncOptions(DirFsyncOptions::FsyncReason::kNewFileSynced));
    }
  }
  if (io_status_.ok()) {
@@ -703,8 +797,8 @@ Status CompactionJob::Run() {
      }
    }
    ColumnFamilyData* cfd = compact_->compaction->column_family_data();
-    auto prefix_extractor =
-        compact_->compaction->mutable_cf_options()->prefix_extractor.get();
+    auto& prefix_extractor =
+        compact_->compaction->mutable_cf_options()->prefix_extractor;
    std::atomic<size_t> next_file_idx(0);
    auto verify_table = [&](Status& output_status) {
      while (true) {
@@ -876,11 +970,14 @@ Status CompactionJob::Install(const MutableCFOptions& mutable_cf_options) {

  const auto& blob_files = vstorage->GetBlobFiles();
  if (!blob_files.empty()) {
-    ROCKS_LOG_BUFFER(log_buffer_,
-                     "[%s] Blob file summary: head=%" PRIu64 ", tail=%" PRIu64
-                     "\n",
-                     column_family_name.c_str(), blob_files.begin()->first,
-                     blob_files.rbegin()->first);
+    assert(blob_files.front());
+    assert(blob_files.back());
+
+    ROCKS_LOG_BUFFER(
+        log_buffer_,
+        "[%s] Blob file summary: head=%" PRIu64 ", tail=%" PRIu64 "\n",
+        column_family_name.c_str(), blob_files.front()->GetBlobFileNumber(),
+        blob_files.back()->GetBlobFileNumber());
  }

  UpdateCompactionJobStats(stats);
@@ -927,8 +1024,11 @@ Status CompactionJob::Install(const MutableCFOptions& mutable_cf_options) {
  stream.EndArray();

  if (!blob_files.empty()) {
-    stream << "blob_file_head" << blob_files.begin()->first;
-    stream << "blob_file_tail" << blob_files.rbegin()->first;
+    assert(blob_files.front());
+    stream << "blob_file_head" << blob_files.front()->GetBlobFileNumber();
+
+    assert(blob_files.back());
+    stream << "blob_file_tail" << blob_files.back()->GetBlobFileNumber();
  }

  CleanupCompaction();
@@ -1122,8 +1222,82 @@ CompactionJob::ProcessKeyValueCompactionWithCompactionService(
             compaction_result.bytes_written);
  return CompactionServiceJobStatus::kSuccess;
 }
+
+void CompactionJob::BuildSubcompactionJobInfo(
+    SubcompactionState* sub_compact,
+    SubcompactionJobInfo* subcompaction_job_info) const {
+  Compaction* c = compact_->compaction;
+  ColumnFamilyData* cfd = c->column_family_data();
+
+  subcompaction_job_info->cf_id = cfd->GetID();
+  subcompaction_job_info->cf_name = cfd->GetName();
+  subcompaction_job_info->status = sub_compact->status;
+  subcompaction_job_info->thread_id = env_->GetThreadID();
+  subcompaction_job_info->job_id = job_id_;
+  subcompaction_job_info->subcompaction_job_id = sub_compact->sub_job_id;
+  subcompaction_job_info->base_input_level = c->start_level();
+  subcompaction_job_info->output_level = c->output_level();
+  subcompaction_job_info->stats = sub_compact->compaction_job_stats;
+}
 #endif  // !ROCKSDB_LITE

+void CompactionJob::NotifyOnSubcompactionBegin(
+    SubcompactionState* sub_compact) {
+#ifndef ROCKSDB_LITE
+  Compaction* c = compact_->compaction;
+
+  if (db_options_.listeners.empty()) {
+    return;
+  }
+  if (shutting_down_->load(std::memory_order_acquire)) {
+    return;
+  }
+  if (c->is_manual_compaction() &&
+      manual_compaction_paused_->load(std::memory_order_acquire) > 0) {
+    return;
+  }
+
+  sub_compact->notify_on_subcompaction_completion = true;
+
+  SubcompactionJobInfo info{};
+  BuildSubcompactionJobInfo(sub_compact, &info);
+
+  for (auto listener : db_options_.listeners) {
+    listener->OnSubcompactionBegin(info);
+  }
+  info.status.PermitUncheckedError();
+
+#else
+  (void)sub_compact;
+#endif  // ROCKSDB_LITE
+}
+
+void CompactionJob::NotifyOnSubcompactionCompleted(
+    SubcompactionState* sub_compact) {
+#ifndef ROCKSDB_LITE
+
+  if (db_options_.listeners.empty()) {
+    return;
+  }
+  if (shutting_down_->load(std::memory_order_acquire)) {
+    return;
+  }
+
+  if (sub_compact->notify_on_subcompaction_completion == false) {
+    return;
+  }
+
+  SubcompactionJobInfo info{};
+  BuildSubcompactionJobInfo(sub_compact, &info);
+
+  for (auto listener : db_options_.listeners) {
+    listener->OnSubcompactionCompleted(info);
+  }
+#else
+  (void)sub_compact;
+#endif  // ROCKSDB_LITE
+}
+
 void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
  assert(sub_compact);
  assert(sub_compact->compaction);
@@ -1141,7 +1315,7 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
  }
 #endif  // !ROCKSDB_LITE

-  uint64_t prev_cpu_micros = db_options_.clock->CPUNanos() / 1000;
+  uint64_t prev_cpu_micros = db_options_.clock->CPUMicros();

  ColumnFamilyData* cfd = sub_compact->compaction->column_family_data();

@@ -1162,6 +1336,8 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
    return;
  }

+  NotifyOnSubcompactionBegin(sub_compact);
+
  CompactionRangeDelAggregator range_del_agg(&cfd->internal_comparator(),
                                             existing_snapshots_);

@@ -1171,6 +1347,7 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
  ReadOptions read_options;
  read_options.verify_checksums = true;
  read_options.fill_cache = false;
+  read_options.rate_limiter_priority = Env::IO_LOW;
  // Compaction iterators shouldn't be confined to a single prefix.
  // Compactions use Seek() for
  // (a) concurrent compactions,
@@ -1206,21 +1383,28 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {

  std::unique_ptr<InternalIterator> clip;
  if (start || end) {
-    clip.reset(new ClippingIterator(
+    clip = std::make_unique<ClippingIterator>(
        raw_input.get(), start ? &start_slice : nullptr,
-        end ? &end_slice : nullptr, &cfd->internal_comparator()));
+        end ? &end_slice : nullptr, &cfd->internal_comparator());
    input = clip.get();
  }

  std::unique_ptr<InternalIterator> blob_counter;

  if (sub_compact->compaction->DoesInputReferenceBlobFiles()) {
-    sub_compact->blob_garbage_meter.reset(new BlobGarbageMeter);
-    blob_counter.reset(
-        new BlobCountingIterator(input, sub_compact->blob_garbage_meter.get()));
+    sub_compact->blob_garbage_meter = std::make_unique<BlobGarbageMeter>();
+    blob_counter = std::make_unique<BlobCountingIterator>(
+        input, sub_compact->blob_garbage_meter.get());
    input = blob_counter.get();
  }

+  std::unique_ptr<InternalIterator> trim_history_iter;
+  if (cfd->user_comparator()->timestamp_size() > 0 && !trim_ts_.empty()) {
+    trim_history_iter = std::make_unique<HistoryTrimmingIterator>(
+        input, cfd->user_comparator(), trim_ts_);
+    input = trim_history_iter.get();
+  }
+
  input->SeekToFirst();

  AutoThreadOperationStageUpdater stage_updater(
@@ -1291,6 +1475,7 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
  auto c_iter = sub_compact->c_iter.get();
  c_iter->SeekToFirst();
  if (c_iter->Valid() && sub_compact->compaction->output_level() != 0) {
+    sub_compact->FillFilesToCutForTtl();
    // ShouldStopBefore() maintains state based on keys processed so far. The
    // compaction loop always calls it on the "next" key, thus won't tell it the
    // first key. So we do that here.
@@ -1484,7 +1669,7 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
  }

  sub_compact->compaction_job_stats.cpu_micros =
-      db_options_.clock->CPUNanos() / 1000 - prev_cpu_micros;
+      db_options_.clock->CPUMicros() - prev_cpu_micros;

  if (measure_io_stats_) {
    sub_compact->compaction_job_stats.file_write_nanos +=
@@ -1519,6 +1704,7 @@ void CompactionJob::ProcessKeyValueCompaction(SubcompactionState* sub_compact) {
  clip.reset();
  raw_input.reset();
  sub_compact->status = status;
+  NotifyOnSubcompactionCompleted(sub_compact);
 }

 uint64_t CompactionJob::GetCompactionId(SubcompactionState* sub_compact) {
@@ -1739,7 +1925,6 @@ Status CompactionJob::FinishCompactionOutputFile(
      meta->UpdateBoundariesForRange(smallest_candidate, largest_candidate,
                                     tombstone.seq_,
                                     cfd->internal_comparator());
-
      // The smallest key in a file is used for range tombstone truncation, so
      // it cannot have a seqnum of 0 (unless the smallest data key in a file
      // has a seqnum of 0). Otherwise, the truncated tombstone may expose
@@ -1763,6 +1948,23 @@ Status CompactionJob::FinishCompactionOutputFile(
  if (s.ok()) {
    meta->fd.file_size = current_bytes;
    meta->marked_for_compaction = sub_compact->builder->NeedCompact();
+    // With accurate smallest and largest key, we can get a slightly more
+    // accurate oldest ancester time.
+    // This makes oldest ancester time in manifest more accurate than in
+    // table properties. Not sure how to resolve it.
+    if (meta->smallest.size() > 0 && meta->largest.size() > 0) {
+      uint64_t refined_oldest_ancester_time;
+      Slice new_smallest = meta->smallest.user_key();
+      Slice new_largest = meta->largest.user_key();
+      if (!new_largest.empty() && !new_smallest.empty()) {
+        refined_oldest_ancester_time =
+            sub_compact->compaction->MinInputFileOldestAncesterTime(
+                &(meta->smallest), &(meta->largest));
+        if (refined_oldest_ancester_time != port::kMaxUint64) {
+          meta->oldest_ancester_time = refined_oldest_ancester_time;
+        }
+      }
+    }
  }
  sub_compact->current_output()->finished = true;
  sub_compact->total_bytes += current_bytes;
@@ -1840,17 +2042,21 @@ Status CompactionJob::FinishCompactionOutputFile(
  std::string fname;
  FileDescriptor output_fd;
  uint64_t oldest_blob_file_number = kInvalidBlobFileNumber;
+  Status status_for_listener = s;
  if (meta != nullptr) {
    fname = GetTableFileName(meta->fd.GetNumber());
    output_fd = meta->fd;
    oldest_blob_file_number = meta->oldest_blob_file_number;
  } else {
    fname = "(nil)";
+    if (s.ok()) {
+      status_for_listener = Status::Aborted("Empty SST file not kept");
+    }
  }
  EventHelpers::LogAndNotifyTableFileCreationFinished(
      event_logger_, cfd->ioptions()->listeners, dbname_, cfd->GetName(), fname,
      job_id_, output_fd, oldest_blob_file_number, tp,
-      TableFileCreationReason::kCompaction, s, file_checksum,
+      TableFileCreationReason::kCompaction, status_for_listener, file_checksum,
      file_checksum_func_name);

 #ifndef ROCKSDB_LITE
@@ -2033,8 +2239,17 @@ Status CompactionJob::OpenCompactionOutputFile(
                   get_time_status.ToString().c_str());
  }
  uint64_t current_time = static_cast<uint64_t>(temp_current_time);
+  InternalKey tmp_start, tmp_end;
+  if (sub_compact->start != nullptr) {
+    tmp_start.SetMinPossibleForUserKey(*(sub_compact->start));
+  }
+  if (sub_compact->end != nullptr) {
+    tmp_end.SetMinPossibleForUserKey(*(sub_compact->end));
+  }
  uint64_t oldest_ancester_time =
-      sub_compact->compaction->MinInputFileOldestAncesterTime();
+      sub_compact->compaction->MinInputFileOldestAncesterTime(
+          (sub_compact->start != nullptr) ? &tmp_start : nullptr,
+          (sub_compact->end != nullptr) ? &tmp_end : nullptr);
  if (oldest_ancester_time == port::kMaxUint64) {
    oldest_ancester_time = current_time;
  }
@@ -2063,9 +2278,8 @@ Status CompactionJob::OpenCompactionOutputFile(
  const auto& listeners =
      sub_compact->compaction->immutable_options()->listeners;
  sub_compact->outfile.reset(new WritableFileWriter(
-      std::move(writable_file), fname, file_options_, db_options_.clock,
-      io_tracer_, db_options_.stats, listeners,
-      db_options_.file_checksum_gen_factory.get(),
+      std::move(writable_file), fname, fo_copy, db_options_.clock, io_tracer_,
+      db_options_.stats, listeners, db_options_.file_checksum_gen_factory.get(),
      tmp_set.Contains(FileType::kTableFile), false));

  TableBuilderOptions tboptions(
@@ -2333,7 +2547,8 @@ Status CompactionServiceCompactionJob::Run() {
    constexpr IODebugContext* dbg = nullptr;

    if (output_directory_) {
-      io_s = output_directory_->Fsync(IOOptions(), dbg);
+      io_s = output_directory_->FsyncWithDirOptions(IOOptions(), dbg,
+                                                    DirFsyncOptions());
    }
  }
  if (io_status_.ok()) {
@@ -2382,34 +2597,14 @@ enum BinaryFormatVersion : uint32_t {
  kOptionsString = 1,  // Use string format similar to Option string format
 };

-// offset_of is used to get the offset of a class data member
-// ex: offset_of(&ColumnFamilyDescriptor::options)
-// This call will return the offset of options in ColumnFamilyDescriptor class
-//
-// This is the same as offsetof() but allow us to work with non standard-layout
-// classes and structures
-// refs:
-// http://en.cppreference.com/w/cpp/concept/StandardLayoutType
-// https://gist.github.com/graphitemaster/494f21190bb2c63c5516
-static ColumnFamilyDescriptor dummy_cfd("", ColumnFamilyOptions());
-template <typename T1>
-int offset_of(T1 ColumnFamilyDescriptor::*member) {
-  return int(size_t(&(dummy_cfd.*member)) - size_t(&dummy_cfd));
-}
-
-static CompactionServiceInput dummy_cs_input;
-template <typename T1>
-int offset_of(T1 CompactionServiceInput::*member) {
-  return int(size_t(&(dummy_cs_input.*member)) - size_t(&dummy_cs_input));
-}
-
 static std::unordered_map<std::string, OptionTypeInfo> cfd_type_info = {
    {"name",
-     {offset_of(&ColumnFamilyDescriptor::name), OptionType::kEncodedString,
+     {offsetof(struct ColumnFamilyDescriptor, name), OptionType::kEncodedString,
      OptionVerificationType::kNormal, OptionTypeFlags::kNone}},
    {"options",
-     {offset_of(&ColumnFamilyDescriptor::options), OptionType::kConfigurable,
-      OptionVerificationType::kNormal, OptionTypeFlags::kNone,
+     {offsetof(struct ColumnFamilyDescriptor, options),
+      OptionType::kConfigurable, OptionVerificationType::kNormal,
+      OptionTypeFlags::kNone,
      [](const ConfigOptions& opts, const std::string& /*name*/,
         const std::string& value, void* addr) {
        auto cf_options = static_cast<ColumnFamilyOptions*>(addr);
@@ -2443,13 +2638,14 @@ static std::unordered_map<std::string, OptionTypeInfo> cfd_type_info = {

 static std::unordered_map<std::string, OptionTypeInfo> cs_input_type_info = {
    {"column_family",
-     OptionTypeInfo::Struct("column_family", &cfd_type_info,
-                            offset_of(&CompactionServiceInput::column_family),
-                            OptionVerificationType::kNormal,
-                            OptionTypeFlags::kNone)},
+     OptionTypeInfo::Struct(
+         "column_family", &cfd_type_info,
+         offsetof(struct CompactionServiceInput, column_family),
+         OptionVerificationType::kNormal, OptionTypeFlags::kNone)},
    {"db_options",
-     {offset_of(&CompactionServiceInput::db_options), OptionType::kConfigurable,
-      OptionVerificationType::kNormal, OptionTypeFlags::kNone,
+     {offsetof(struct CompactionServiceInput, db_options),
+      OptionType::kConfigurable, OptionVerificationType::kNormal,
+      OptionTypeFlags::kNone,
      [](const ConfigOptions& opts, const std::string& /*name*/,
         const std::string& value, void* addr) {
        auto options = static_cast<DBOptions*>(addr);
@@ -2478,31 +2674,33 @@ static std::unordered_map<std::string, OptionTypeInfo> cs_input_type_info = {
        return result;
      }}},
    {"snapshots", OptionTypeInfo::Vector<uint64_t>(
-                      offset_of(&CompactionServiceInput::snapshots),
+                      offsetof(struct CompactionServiceInput, snapshots),
                      OptionVerificationType::kNormal, OptionTypeFlags::kNone,
                      {0, OptionType::kUInt64T})},
    {"input_files", OptionTypeInfo::Vector<std::string>(
-                        offset_of(&CompactionServiceInput::input_files),
+                        offsetof(struct CompactionServiceInput, input_files),
                        OptionVerificationType::kNormal, OptionTypeFlags::kNone,
                        {0, OptionType::kEncodedString})},
    {"output_level",
-     {offset_of(&CompactionServiceInput::output_level), OptionType::kInt,
+     {offsetof(struct CompactionServiceInput, output_level), OptionType::kInt,
      OptionVerificationType::kNormal, OptionTypeFlags::kNone}},
    {"has_begin",
-     {offset_of(&CompactionServiceInput::has_begin), OptionType::kBoolean,
+     {offsetof(struct CompactionServiceInput, has_begin), OptionType::kBoolean,
      OptionVerificationType::kNormal, OptionTypeFlags::kNone}},
    {"begin",
-     {offset_of(&CompactionServiceInput::begin), OptionType::kEncodedString,
-      OptionVerificationType::kNormal, OptionTypeFlags::kNone}},
+     {offsetof(struct CompactionServiceInput, begin),
+      OptionType::kEncodedString, OptionVerificationType::kNormal,
+      OptionTypeFlags::kNone}},
    {"has_end",
-     {offset_of(&CompactionServiceInput::has_end), OptionType::kBoolean,
+     {offsetof(struct CompactionServiceInput, has_end), OptionType::kBoolean,
      OptionVerificationType::kNormal, OptionTypeFlags::kNone}},
    {"end",
-     {offset_of(&CompactionServiceInput::end), OptionType::kEncodedString,
+     {offsetof(struct CompactionServiceInput, end), OptionType::kEncodedString,
      OptionVerificationType::kNormal, OptionTypeFlags::kNone}},
    {"approx_size",
-     {offset_of(&CompactionServiceInput::approx_size), OptionType::kUInt64T,
-      OptionVerificationType::kNormal, OptionTypeFlags::kNone}},
+     {offsetof(struct CompactionServiceInput, approx_size),
+      OptionType::kUInt64T, OptionVerificationType::kNormal,
+      OptionTypeFlags::kNone}},
 };

 static std::unordered_map<std::string, OptionTypeInfo>
@@ -82,7 +82,7 @@ class CompactionJob {
      const std::atomic<int>* manual_compaction_paused = nullptr,
      const std::atomic<bool>* manual_compaction_canceled = nullptr,
      const std::string& db_id = "", const std::string& db_session_id = "",
-      std::string full_history_ts_low = "",
+      std::string full_history_ts_low = "", std::string trim_ts = "",
      BlobFileCompletionCallback* blob_callback = nullptr);

  virtual ~CompactionJob();
@@ -167,6 +167,16 @@ class CompactionJob {
  void UpdateCompactionInputStatsHelper(
      int* num_files, uint64_t* bytes_read, int input_level);

+#ifndef ROCKSDB_LITE
+  void BuildSubcompactionJobInfo(
+      SubcompactionState* sub_compact,
+      SubcompactionJobInfo* subcompaction_job_info) const;
+#endif  // ROCKSDB_LITE
+
+  void NotifyOnSubcompactionBegin(SubcompactionState* sub_compact);
+
+  void NotifyOnSubcompactionCompleted(SubcompactionState* sub_compact);
+
  uint32_t job_id_;

  CompactionJobStats* compaction_job_stats_;
@@ -216,6 +226,7 @@ class CompactionJob {
  std::vector<uint64_t> sizes_;
  Env::Priority thread_pri_;
  std::string full_history_ts_low_;
+  std::string trim_ts_;
  BlobFileCompletionCallback* blob_callback_;

  uint64_t GetCompactionId(SubcompactionState* sub_compact);
@@ -21,6 +21,7 @@
 #include "db/version_set.h"
 #include "file/writable_file_writer.h"
 #include "rocksdb/cache.h"
+#include "rocksdb/convenience.h"
 #include "rocksdb/db.h"
 #include "rocksdb/file_system.h"
 #include "rocksdb/options.h"
@@ -73,9 +74,7 @@ class CompactionJobTestBase : public testing::Test {
 protected:
  CompactionJobTestBase(std::string dbname, const Comparator* ucmp,
                        std::function<std::string(uint64_t)> encode_u64_ts)
-      : env_(Env::Default()),
-        fs_(env_->GetFileSystem()),
-        dbname_(std::move(dbname)),
+      : dbname_(std::move(dbname)),
        ucmp_(ucmp),
        db_options_(),
        mutable_cf_options_(cf_options_),
@@ -91,7 +90,13 @@ class CompactionJobTestBase : public testing::Test {
        preserve_deletes_seqnum_(0),
        mock_table_factory_(new mock::MockTableFactory()),
        error_handler_(nullptr, db_options_, &mutex_),
-        encode_u64_ts_(std::move(encode_u64_ts)) {}
+        encode_u64_ts_(std::move(encode_u64_ts)) {
+    Env* base_env = Env::Default();
+    EXPECT_OK(
+        test::CreateEnvFromSystem(ConfigOptions(), &base_env, &env_guard_));
+    env_ = base_env;
+    fs_ = env_->GetFileSystem();
+  }

  void SetUp() override {
    EXPECT_OK(env_->CreateDirIfMissing(dbname_));
@@ -198,9 +203,11 @@ class CompactionJobTestBase : public testing::Test {

    VersionEdit edit;
    edit.AddFile(level, file_number, 0, 10, smallest_key, largest_key,
-                 smallest_seqno, largest_seqno, false, oldest_blob_file_number,
-                 kUnknownOldestAncesterTime, kUnknownFileCreationTime,
-                 kUnknownFileChecksum, kUnknownFileChecksumFuncName);
+                 smallest_seqno, largest_seqno, false, Temperature::kUnknown,
+                 oldest_blob_file_number, kUnknownOldestAncesterTime,
+                 kUnknownFileCreationTime, kUnknownFileChecksum,
+                 kUnknownFileChecksumFuncName, kDisableUserTimestamp,
+                 kDisableUserTimestamp);

    mutex_.Lock();
    EXPECT_OK(
@@ -386,6 +393,7 @@ class CompactionJobTestBase : public testing::Test {
    }
  }

+  std::shared_ptr<Env> env_guard_;
  Env* env_;
  std::shared_ptr<FileSystem> fs_;
  std::string dbname_;
@@ -1284,7 +1292,8 @@ class CompactionJobTimestampTest : public CompactionJobTestBase {
 public:
  CompactionJobTimestampTest()
      : CompactionJobTestBase(test::PerThreadDBPath("compaction_job_ts_test"),
-                              test::ComparatorWithU64Ts(), test::EncodeInt) {}
+                              test::BytewiseComparatorWithU64TsWrapper(),
+                              test::EncodeInt) {}
 };

 TEST_F(CompactionJobTimestampTest, GCDisabled) {
@@ -1392,6 +1401,7 @@ TEST_F(CompactionJobTimestampTest, SomeKeysExpired) {

  auto expected_results =
      mock::MakeMockFile({{KeyStr("a", 5, ValueType::kTypeValue, 50), "a5"},
+                          {KeyStr("a", 0, ValueType::kTypeValue, 0), "a3"},
                          {KeyStr("b", 6, ValueType::kTypeValue, 49), "b6"}});
  const auto& files = cfd_->current()->storage_info()->LevelFiles(0);

@@ -1403,6 +1413,7 @@ TEST_F(CompactionJobTimestampTest, SomeKeysExpired) {

 int main(int argc, char** argv) {
  ::testing::InitGoogleTest(&argc, argv);
+  RegisterCustomObjects(argc, argv);
  return RUN_ALL_TESTS();
 }

@@ -100,8 +100,7 @@ bool FindIntraL0Compaction(const std::vector<FileMetaData*>& level_files,
 // If enable_compression is false, then compression is always disabled no
 // matter what the values of the other two parameters are.
 // Otherwise, the compression type is determined based on options and level.
-CompressionType GetCompressionType(const ImmutableCFOptions& ioptions,
-                                   const VersionStorageInfo* vstorage,
+CompressionType GetCompressionType(const VersionStorageInfo* vstorage,
                                   const MutableCFOptions& mutable_cf_options,
                                   int level, int base_level,
                                   const bool enable_compression) {
@@ -118,17 +117,19 @@ CompressionType GetCompressionType(const ImmutableCFOptions& ioptions,
  }
  // If the user has specified a different compression level for each level,
  // then pick the compression for that level.
-  if (!ioptions.compression_per_level.empty()) {
+  if (!mutable_cf_options.compression_per_level.empty()) {
    assert(level == 0 || level >= base_level);
    int idx = (level == 0) ? 0 : level - base_level + 1;

-    const int n = static_cast<int>(ioptions.compression_per_level.size()) - 1;
+    const int n =
+        static_cast<int>(mutable_cf_options.compression_per_level.size()) - 1;
    // It is possible for level_ to be -1; in that case, we use level
    // 0's compression.  This occurs mostly in backwards compatibility
    // situations when the builder doesn't know what level the file
    // belongs to.  Likewise, if level is beyond the end of the
    // specified compression levels, use the last value.
-    return ioptions.compression_per_level[std::max(0, std::min(idx, n))];
+    return mutable_cf_options
+        .compression_per_level[std::max(0, std::min(idx, n))];
  } else {
    return mutable_cf_options.compression;
  }
@@ -347,9 +348,8 @@ Compaction* CompactionPicker::CompactFiles(
    } else {
      base_level = 1;
    }
-    compression_type =
-        GetCompressionType(ioptions_, vstorage, mutable_cf_options,
-                           output_level, base_level);
+    compression_type = GetCompressionType(vstorage, mutable_cf_options,
+                                          output_level, base_level);
  } else {
    // TODO(ajkr): `CompactionOptions` offers configurable `CompressionType`
    // without configurable `CompressionOptions`, which is inconsistent.
@@ -571,7 +571,7 @@ Compaction* CompactionPicker::CompactRange(
    int input_level, int output_level,
    const CompactRangeOptions& compact_range_options, const InternalKey* begin,
    const InternalKey* end, InternalKey** compaction_end, bool* manual_conflict,
-    uint64_t max_file_num_to_ignore) {
+    uint64_t max_file_num_to_ignore, const std::string& trim_ts) {
  // CompactionPickerFIFO has its own implementation of compact range
  assert(ioptions_.compaction_style != kCompactionStyleFIFO);

@@ -637,12 +637,10 @@ Compaction* CompactionPicker::CompactRange(
                            ioptions_.compaction_style),
        /* max_compaction_bytes */ LLONG_MAX,
        compact_range_options.target_path_id,
-        GetCompressionType(ioptions_, vstorage, mutable_cf_options,
-                           output_level, 1),
+        GetCompressionType(vstorage, mutable_cf_options, output_level, 1),
        GetCompressionOptions(mutable_cf_options, vstorage, output_level),
        Temperature::kUnknown, compact_range_options.max_subcompactions,
-        /* grandparents */ {},
-        /* is manual */ true);
+        /* grandparents */ {}, /* is manual */ true, trim_ts);
    RegisterCompaction(c);
    vstorage->ComputeCompactionScore(ioptions_, mutable_cf_options);
    return c;
@@ -816,12 +814,12 @@ Compaction* CompactionPicker::CompactRange(
                          ioptions_.level_compaction_dynamic_level_bytes),
      mutable_cf_options.max_compaction_bytes,
      compact_range_options.target_path_id,
-      GetCompressionType(ioptions_, vstorage, mutable_cf_options, output_level,
+      GetCompressionType(vstorage, mutable_cf_options, output_level,
                         vstorage->base_level()),
      GetCompressionOptions(mutable_cf_options, vstorage, output_level),
      Temperature::kUnknown, compact_range_options.max_subcompactions,
      std::move(grandparents),
-      /* is manual compaction */ true);
+      /* is manual compaction */ true, trim_ts);

  TEST_SYNC_POINT_CALLBACK("CompactionPicker::CompactRange:Return", compaction);
  RegisterCompaction(compaction);
@@ -78,7 +78,7 @@ class CompactionPicker {
      const CompactRangeOptions& compact_range_options,
      const InternalKey* begin, const InternalKey* end,
      InternalKey** compaction_end, bool* manual_conflict,
-      uint64_t max_file_num_to_ignore);
+      uint64_t max_file_num_to_ignore, const std::string& trim_ts);

  // The maximum allowed output level.  Default value is NumberLevels() - 1.
  virtual int MaxOutputLevel() const { return NumberLevels() - 1; }
@@ -270,7 +270,8 @@ class NullCompactionPicker : public CompactionPicker {
                           const InternalKey* /*end*/,
                           InternalKey** /*compaction_end*/,
                           bool* /*manual_conflict*/,
-                           uint64_t /*max_file_num_to_ignore*/) override {
+                           uint64_t /*max_file_num_to_ignore*/,
+                           const std::string& /*trim_ts*/) override {
    return nullptr;
  }

@@ -304,8 +305,7 @@ bool FindIntraL0Compaction(
    CompactionInputFiles* comp_inputs,
    SequenceNumber earliest_mem_seqno = kMaxSequenceNumber);

-CompressionType GetCompressionType(const ImmutableCFOptions& ioptions,
-                                   const VersionStorageInfo* vstorage,
+CompressionType GetCompressionType(const VersionStorageInfo* vstorage,
                                   const MutableCFOptions& mutable_cf_options,
                                   int level, int base_level,
                                   const bool enable_compression = true);
@@ -115,7 +115,7 @@ Compaction* FIFOCompactionPicker::PickTTLCompaction(
      std::move(inputs), 0, 0, 0, 0, kNoCompression,
      mutable_cf_options.compression_opts, Temperature::kUnknown,
      /* max_subcompactions */ 0, {}, /* is manual */ false,
-      vstorage->CompactionScore(0),
+      /* trim_ts */ "", vstorage->CompactionScore(0),
      /* is deletion compaction */ true, CompactionReason::kFIFOTtl);
  return c;
 }
@@ -157,8 +157,8 @@ Compaction* FIFOCompactionPicker::PickSizeCompaction(
            0 /* max compaction bytes, not applicable */,
            0 /* output path ID */, mutable_cf_options.compression,
            mutable_cf_options.compression_opts, Temperature::kUnknown,
-            0 /* max_subcompactions */, {},
-            /* is manual */ false, vstorage->CompactionScore(0),
+            0 /* max_subcompactions */, {}, /* is manual */ false,
+            /* trim_ts */ "", vstorage->CompactionScore(0),
            /* is deletion compaction */ false,
            CompactionReason::kFIFOReduceNumFiles);
        return c;
@@ -208,7 +208,7 @@ Compaction* FIFOCompactionPicker::PickSizeCompaction(
      std::move(inputs), 0, 0, 0, 0, kNoCompression,
      mutable_cf_options.compression_opts, Temperature::kUnknown,
      /* max_subcompactions */ 0, {}, /* is manual */ false,
-      vstorage->CompactionScore(0),
+      /* trim_ts */ "", vstorage->CompactionScore(0),
      /* is deletion compaction */ true, CompactionReason::kFIFOMaxSize);
  return c;
 }
@@ -313,7 +313,7 @@ Compaction* FIFOCompactionPicker::PickCompactionToWarm(
      0 /* max compaction bytes, not applicable */, 0 /* output path ID */,
      mutable_cf_options.compression, mutable_cf_options.compression_opts,
      Temperature::kWarm,
-      /* max_subcompactions */ 0, {}, /* is manual */ false,
+      /* max_subcompactions */ 0, {}, /* is manual */ false, /* trim_ts */ "",
      vstorage->CompactionScore(0),
      /* is deletion compaction */ false, CompactionReason::kChangeTemperature);
  return c;
@@ -349,7 +349,7 @@ Compaction* FIFOCompactionPicker::CompactRange(
    const CompactRangeOptions& /*compact_range_options*/,
    const InternalKey* /*begin*/, const InternalKey* /*end*/,
    InternalKey** compaction_end, bool* /*manual_conflict*/,
-    uint64_t /*max_file_num_to_ignore*/) {
+    uint64_t /*max_file_num_to_ignore*/, const std::string& /*trim_ts*/) {
 #ifdef NDEBUG
  (void)input_level;
  (void)output_level;
@@ -32,7 +32,7 @@ class FIFOCompactionPicker : public CompactionPicker {
      const CompactRangeOptions& compact_range_options,
      const InternalKey* begin, const InternalKey* end,
      InternalKey** compaction_end, bool* manual_conflict,
-      uint64_t max_file_num_to_ignore) override;
+      uint64_t max_file_num_to_ignore, const std::string& trim_ts) override;

  // The maximum allowed output level.  Always returns 0.
  virtual int MaxOutputLevel() const override { return 0; }
@@ -343,12 +343,13 @@ Compaction* LevelCompactionBuilder::GetCompaction() {
                          ioptions_.level_compaction_dynamic_level_bytes),
      mutable_cf_options_.max_compaction_bytes,
      GetPathId(ioptions_, mutable_cf_options_, output_level_),
-      GetCompressionType(ioptions_, vstorage_, mutable_cf_options_,
-                         output_level_, vstorage_->base_level()),
+      GetCompressionType(vstorage_, mutable_cf_options_, output_level_,
+                         vstorage_->base_level()),
      GetCompressionOptions(mutable_cf_options_, vstorage_, output_level_),
      Temperature::kUnknown,
      /* max_subcompactions */ 0, std::move(grandparents_), is_manual_,
-      start_level_score_, false /* deletion_compaction */, compaction_reason_);
+      /* trim_ts */ "", start_level_score_, false /* deletion_compaction */,
+      compaction_reason_);

  // If it's level 0 compaction, make sure we don't execute any other level 0
  // compactions in parallel
@@ -3,15 +3,15 @@
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).

-
 #include <limits>
 #include <string>
 #include <utility>
+
 #include "db/compaction/compaction.h"
 #include "db/compaction/compaction_picker_fifo.h"
 #include "db/compaction/compaction_picker_level.h"
 #include "db/compaction/compaction_picker_universal.h"
-
+#include "db/compaction/file_pri.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
 #include "util/string_util.h"
@@ -76,7 +76,7 @@ class CompactionPickerTest : public testing::Test {
    options_.num_levels = num_levels;
    vstorage_.reset(new VersionStorageInfo(&icmp_, ucmp_, options_.num_levels,
                                           style, nullptr, false));
-    vstorage_->CalculateBaseBytes(ioptions_, mutable_cf_options_);
+    vstorage_->PrepareForVersionAppend(ioptions_, mutable_cf_options_);
  }

  // Create a new VersionStorageInfo object so we can add mode files and then
@@ -112,12 +112,12 @@ class CompactionPickerTest : public testing::Test {
        file_number, path_id, file_size,
        InternalKey(smallest, smallest_seq, kTypeValue),
        InternalKey(largest, largest_seq, kTypeValue), smallest_seq,
-        largest_seq, marked_for_compact, kInvalidBlobFileNumber,
+        largest_seq, marked_for_compact, temperature, kInvalidBlobFileNumber,
        kUnknownOldestAncesterTime, kUnknownFileCreationTime,
-        kUnknownFileChecksum, kUnknownFileChecksumFuncName);
+        kUnknownFileChecksum, kUnknownFileChecksumFuncName,
+        kDisableUserTimestamp, kDisableUserTimestamp);
    f->compensated_file_size =
        (compensated_file_size != 0) ? compensated_file_size : file_size;
-    f->temperature = temperature;
    f->oldest_ancester_time = oldest_ancestor_time;
    vstorage->AddFile(level, f);
    files_.emplace_back(f);
@@ -148,35 +148,10 @@ class CompactionPickerTest : public testing::Test {
      ASSERT_OK(builder.SaveTo(temp_vstorage_.get()));
      vstorage_ = std::move(temp_vstorage_);
    }
-    vstorage_->CalculateBaseBytes(ioptions_, mutable_cf_options_);
-    vstorage_->UpdateFilesByCompactionPri(ioptions_.compaction_pri);
-    vstorage_->UpdateNumNonEmptyLevels();
-    vstorage_->GenerateFileIndexer();
-    vstorage_->GenerateLevelFilesBrief();
+    vstorage_->PrepareForVersionAppend(ioptions_, mutable_cf_options_);
    vstorage_->ComputeCompactionScore(ioptions_, mutable_cf_options_);
-    vstorage_->GenerateLevel0NonOverlapping();
-    vstorage_->ComputeFilesMarkedForCompaction();
    vstorage_->SetFinalized();
  }
-  void AddFileToVersionStorage(int level, uint32_t file_number,
-                               const char* smallest, const char* largest,
-                               uint64_t file_size = 1, uint32_t path_id = 0,
-                               SequenceNumber smallest_seq = 100,
-                               SequenceNumber largest_seq = 100,
-                               size_t compensated_file_size = 0,
-                               bool marked_for_compact = false) {
-    VersionStorageInfo* base_vstorage = vstorage_.release();
-    vstorage_.reset(new VersionStorageInfo(&icmp_, ucmp_, options_.num_levels,
-                                           kCompactionStyleUniversal,
-                                           base_vstorage, false));
-    Add(level, file_number, smallest, largest, file_size, path_id, smallest_seq,
-        largest_seq, compensated_file_size, marked_for_compact);
-
-    VersionBuilder builder(FileOptions(), &ioptions_, nullptr, base_vstorage,
-                           nullptr);
-    builder.SaveTo(vstorage_.get());
-    UpdateVersionStorageInfo();
-  }

 private:
  std::unique_ptr<VersionStorageInfo> temp_vstorage_;
@@ -964,13 +939,11 @@ TEST_F(CompactionPickerTest, NeedsCompactionFIFO) {

  // verify whether compaction is needed based on the current
  // size of L0 files.
-  uint64_t current_size = 0;
  for (int i = 1; i <= kFileCount; ++i) {
    NewVersionStorage(1, kCompactionStyleFIFO);
    Add(0, i, ToString((i + 100) * 1000).c_str(),
-        ToString((i + 100) * 1000 + 999).c_str(),
-        kFileSize, 0, i * 100, i * 100 + 99);
-    current_size += kFileSize;
+        ToString((i + 100) * 1000 + 999).c_str(), kFileSize, 0, i * 100,
+        i * 100 + 99);
    UpdateVersionStorageInfo();
    ASSERT_EQ(fifo_compaction_picker.NeedsCompaction(vstorage_.get()),
              vstorage_->CompactionScore(0) >= 1);
@@ -1673,6 +1646,66 @@ TEST_F(CompactionPickerTest, OverlappingUserKeys11) {
  ASSERT_EQ(7U, compaction->input(1, 0)->fd.GetNumber());
 }

+TEST_F(CompactionPickerTest, FileTtlBooster) {
+  // Set TTL to 2048
+  // TTL boosting for all levels starts at 1024,
+  // Whole TTL range is 2048 * 31 / 32 - 1024 = 1984 - 1024 = 960.
+  // From second last level (L5), range starts at
+  // 1024 + 480, 1024 + 240, 1024 + 120 (which is L3).
+  // Boosting step 124 / 16 = 7.75 -> 7
+  //
+  const uint64_t kCurrentTime = 1000000;
+  FileMetaData meta;
+
+  {
+    FileTtlBooster booster(kCurrentTime, 2048, 7, 3);
+
+    // Not triggering if the file is younger than ttl/2
+    meta.oldest_ancester_time = kCurrentTime - 1023;
+    ASSERT_EQ(1, booster.GetBoostScore(&meta));
+    meta.oldest_ancester_time = kCurrentTime - 1024;
+    ASSERT_EQ(1, booster.GetBoostScore(&meta));
+    meta.oldest_ancester_time = kCurrentTime + 10;
+    ASSERT_EQ(1, booster.GetBoostScore(&meta));
+
+    // Within one boosting step
+    meta.oldest_ancester_time = kCurrentTime - (1024 + 120 + 6);
+    ASSERT_EQ(1, booster.GetBoostScore(&meta));
+
+    // One boosting step
+    meta.oldest_ancester_time = kCurrentTime - (1024 + 120 + 7);
+    ASSERT_EQ(2, booster.GetBoostScore(&meta));
+    meta.oldest_ancester_time = kCurrentTime - (1024 + 120 + 8);
+    ASSERT_EQ(2, booster.GetBoostScore(&meta));
+
+    // Multiple boosting steps
+    meta.oldest_ancester_time = kCurrentTime - (1024 + 120 + 30);
+    ASSERT_EQ(5, booster.GetBoostScore(&meta));
+
+    // Very high boosting steps
+    meta.oldest_ancester_time = kCurrentTime - (1024 + 120 + 700);
+    ASSERT_EQ(101, booster.GetBoostScore(&meta));
+  }
+  {
+    // Test second last level
+    FileTtlBooster booster(kCurrentTime, 2048, 7, 5);
+    meta.oldest_ancester_time = kCurrentTime - (1024 + 480);
+    ASSERT_EQ(1, booster.GetBoostScore(&meta));
+    meta.oldest_ancester_time = kCurrentTime - (1024 + 480 + 60);
+    ASSERT_EQ(3, booster.GetBoostScore(&meta));
+  }
+  {
+    // Test last level
+    FileTtlBooster booster(kCurrentTime, 2048, 7, 6);
+    meta.oldest_ancester_time = kCurrentTime - (1024 + 480);
+    ASSERT_EQ(1, booster.GetBoostScore(&meta));
+    meta.oldest_ancester_time = kCurrentTime - (1024 + 480 + 60);
+    ASSERT_EQ(1, booster.GetBoostScore(&meta));
+    meta.oldest_ancester_time = kCurrentTime - 3000;
+    ASSERT_EQ(1, booster.GetBoostScore(&meta));
+  }
+}
+
 TEST_F(CompactionPickerTest, NotScheduleL1IfL0WithHigherPri1) {
  NewVersionStorage(6, kCompactionStyleLevel);
  mutable_cf_options_.level0_file_num_compaction_trigger = 2;
@@ -2615,12 +2648,13 @@ TEST_F(CompactionPickerTest, UniversalMarkedManualCompaction) {
  ASSERT_EQ(3U, vstorage_->FilesMarkedForCompaction().size());

  bool manual_conflict = false;
-  InternalKey* manual_end = NULL;
+  InternalKey* manual_end = nullptr;
  std::unique_ptr<Compaction> compaction(
      universal_compaction_picker.CompactRange(
          cf_name_, mutable_cf_options_, mutable_db_options_, vstorage_.get(),
-          ColumnFamilyData::kCompactAllLevels, 6, CompactRangeOptions(), NULL,
-          NULL, &manual_end, &manual_conflict, port::kMaxUint64));
+          ColumnFamilyData::kCompactAllLevels, 6, CompactRangeOptions(),
+          nullptr, nullptr, &manual_end, &manual_conflict, port::kMaxUint64,
+          ""));

  ASSERT_TRUE(compaction);

@@ -498,8 +498,11 @@ Compaction* UniversalCompactionBuilder::PickCompaction() {
  }
 #endif
  // update statistics
-  RecordInHistogram(ioptions_.stats, NUM_FILES_IN_SINGLE_COMPACTION,
-                    c->inputs(0)->size());
+  size_t num_files = 0;
+  for (auto& each_level : *c->inputs()) {
+    num_files += each_level.files.size();
+  }
+  RecordInHistogram(ioptions_.stats, NUM_FILES_IN_SINGLE_COMPACTION, num_files);

  picker_->RegisterCompaction(c);
  vstorage_->ComputeCompactionScore(ioptions_, mutable_cf_options_);
@@ -743,19 +746,19 @@ Compaction* UniversalCompactionBuilder::PickCompactionToReduceSortedRuns(
  } else {
    compaction_reason = CompactionReason::kUniversalSortedRunNum;
  }
-  return new Compaction(
-      vstorage_, ioptions_, mutable_cf_options_, mutable_db_options_,
-      std::move(inputs), output_level,
-      MaxFileSizeForLevel(mutable_cf_options_, output_level,
-                          kCompactionStyleUniversal),
-      GetMaxOverlappingBytes(), path_id,
-      GetCompressionType(ioptions_, vstorage_, mutable_cf_options_, start_level,
-                         1, enable_compression),
-      GetCompressionOptions(mutable_cf_options_, vstorage_, start_level,
-                            enable_compression),
-      Temperature::kUnknown,
-      /* max_subcompactions */ 0, grandparents, /* is manual */ false, score_,
-      false /* deletion_compaction */, compaction_reason);
+  return new Compaction(vstorage_, ioptions_, mutable_cf_options_,
+                        mutable_db_options_, std::move(inputs), output_level,
+                        MaxFileSizeForLevel(mutable_cf_options_, output_level,
+                                            kCompactionStyleUniversal),
+                        GetMaxOverlappingBytes(), path_id,
+                        GetCompressionType(vstorage_, mutable_cf_options_,
+                                           start_level, 1, enable_compression),
+                        GetCompressionOptions(mutable_cf_options_, vstorage_,
+                                              start_level, enable_compression),
+                        Temperature::kUnknown,
+                        /* max_subcompactions */ 0, grandparents,
+                        /* is manual */ false, /* trim_ts */ "", score_,
+                        false /* deletion_compaction */, compaction_reason);
 }

 // Look at overall size amplification. If size amplification
@@ -1073,13 +1076,13 @@ Compaction* UniversalCompactionBuilder::PickIncrementalForReduceSizeAmp(
      MaxFileSizeForLevel(mutable_cf_options_, output_level,
                          kCompactionStyleUniversal),
      GetMaxOverlappingBytes(), path_id,
-      GetCompressionType(ioptions_, vstorage_, mutable_cf_options_,
-                         output_level, 1, true /* enable_compression */),
+      GetCompressionType(vstorage_, mutable_cf_options_, output_level, 1,
+                         true /* enable_compression */),
      GetCompressionOptions(mutable_cf_options_, vstorage_, output_level,
                            true /* enable_compression */),
      Temperature::kUnknown,
      /* max_subcompactions */ 0, /* grandparents */ {}, /* is manual */ false,
-      score_, false /* deletion_compaction */,
+      /* trim_ts */ "", score_, false /* deletion_compaction */,
      CompactionReason::kUniversalSizeAmplification);
 }

@@ -1217,12 +1220,11 @@ Compaction* UniversalCompactionBuilder::PickDeleteTriggeredCompaction() {
      MaxFileSizeForLevel(mutable_cf_options_, output_level,
                          kCompactionStyleUniversal),
      /* max_grandparent_overlap_bytes */ GetMaxOverlappingBytes(), path_id,
-      GetCompressionType(ioptions_, vstorage_, mutable_cf_options_,
-                         output_level, 1),
+      GetCompressionType(vstorage_, mutable_cf_options_, output_level, 1),
      GetCompressionOptions(mutable_cf_options_, vstorage_, output_level),
      Temperature::kUnknown,
-      /* max_subcompactions */ 0, grandparents, /* is manual */ false, score_,
-      false /* deletion_compaction */,
+      /* max_subcompactions */ 0, grandparents, /* is manual */ false,
+      /* trim_ts */ "", score_, false /* deletion_compaction */,
      CompactionReason::kFilesMarkedForCompaction);
 }

@@ -1291,13 +1293,14 @@ Compaction* UniversalCompactionBuilder::PickCompactionToOldest(
      MaxFileSizeForLevel(mutable_cf_options_, output_level,
                          kCompactionStyleUniversal),
      GetMaxOverlappingBytes(), path_id,
-      GetCompressionType(ioptions_, vstorage_, mutable_cf_options_,
-                         output_level, 1, true /* enable_compression */),
+      GetCompressionType(vstorage_, mutable_cf_options_, output_level, 1,
+                         true /* enable_compression */),
      GetCompressionOptions(mutable_cf_options_, vstorage_, output_level,
                            true /* enable_compression */),
      Temperature::kUnknown,
      /* max_subcompactions */ 0, /* grandparents */ {}, /* is manual */ false,
-      score_, false /* deletion_compaction */, compaction_reason);
+      /* trim_ts */ "", score_, false /* deletion_compaction */,
+      compaction_reason);
 }

 Compaction* UniversalCompactionBuilder::PickPeriodicCompaction() {
@@ -10,126 +10,7 @@

 namespace ROCKSDB_NAMESPACE {

-class TestCompactionServiceBase {
- public:
-  virtual int GetCompactionNum() = 0;
-
-  void OverrideStartStatus(CompactionServiceJobStatus s) {
-    is_override_start_status = true;
-    override_start_status = s;
-  }
-
-  void OverrideWaitStatus(CompactionServiceJobStatus s) {
-    is_override_wait_status = true;
-    override_wait_status = s;
-  }
-
-  void OverrideWaitResult(std::string str) {
-    is_override_wait_result = true;
-    override_wait_result = std::move(str);
-  }
-
-  void ResetOverride() {
-    is_override_wait_result = false;
-    is_override_start_status = false;
-    is_override_wait_status = false;
-  }
-
-  virtual ~TestCompactionServiceBase() = default;
-
- protected:
-  bool is_override_start_status = false;
-  CompactionServiceJobStatus override_start_status =
-      CompactionServiceJobStatus::kFailure;
-  bool is_override_wait_status = false;
-  CompactionServiceJobStatus override_wait_status =
-      CompactionServiceJobStatus::kFailure;
-  bool is_override_wait_result = false;
-  std::string override_wait_result;
-};
-
-class MyTestCompactionServiceLegacy : public CompactionService,
-                                      public TestCompactionServiceBase {
- public:
-  MyTestCompactionServiceLegacy(std::string db_path, Options& options,
-                                std::shared_ptr<Statistics>& statistics)
-      : db_path_(std::move(db_path)),
-        options_(options),
-        statistics_(statistics) {}
-
-  static const char* kClassName() { return "MyTestCompactionServiceLegacy"; }
-
-  const char* Name() const override { return kClassName(); }
-
-  CompactionServiceJobStatus Start(const std::string& compaction_service_input,
-                                   uint64_t job_id) override {
-    InstrumentedMutexLock l(&mutex_);
-    jobs_.emplace(job_id, compaction_service_input);
-    CompactionServiceJobStatus s = CompactionServiceJobStatus::kSuccess;
-    if (is_override_start_status) {
-      return override_start_status;
-    }
-    return s;
-  }
-
-  CompactionServiceJobStatus WaitForComplete(
-      uint64_t job_id, std::string* compaction_service_result) override {
-    std::string compaction_input;
-    {
-      InstrumentedMutexLock l(&mutex_);
-      auto i = jobs_.find(job_id);
-      if (i == jobs_.end()) {
-        return CompactionServiceJobStatus::kFailure;
-      }
-      compaction_input = std::move(i->second);
-      jobs_.erase(i);
-    }
-
-    if (is_override_wait_status) {
-      return override_wait_status;
-    }
-
-    CompactionServiceOptionsOverride options_override;
-    options_override.env = options_.env;
-    options_override.file_checksum_gen_factory =
-        options_.file_checksum_gen_factory;
-    options_override.comparator = options_.comparator;
-    options_override.merge_operator = options_.merge_operator;
-    options_override.compaction_filter = options_.compaction_filter;
-    options_override.compaction_filter_factory =
-        options_.compaction_filter_factory;
-    options_override.prefix_extractor = options_.prefix_extractor;
-    options_override.table_factory = options_.table_factory;
-    options_override.sst_partitioner_factory = options_.sst_partitioner_factory;
-    options_override.statistics = statistics_;
-
-    Status s = DB::OpenAndCompact(
-        db_path_, db_path_ + "/" + ROCKSDB_NAMESPACE::ToString(job_id),
-        compaction_input, compaction_service_result, options_override);
-    if (is_override_wait_result) {
-      *compaction_service_result = override_wait_result;
-    }
-    compaction_num_.fetch_add(1);
-    if (s.ok()) {
-      return CompactionServiceJobStatus::kSuccess;
-    } else {
-      return CompactionServiceJobStatus::kFailure;
-    }
-  }
-
-  int GetCompactionNum() override { return compaction_num_.load(); }
-
- private:
-  InstrumentedMutex mutex_;
-  std::atomic_int compaction_num_{0};
-  std::map<uint64_t, std::string> jobs_;
-  const std::string db_path_;
-  Options options_;
-  std::shared_ptr<Statistics> statistics_;
-};
-
-class MyTestCompactionService : public CompactionService,
-                                public TestCompactionServiceBase {
+class MyTestCompactionService : public CompactionService {
 public:
  MyTestCompactionService(std::string db_path, Options& options,
                          std::shared_ptr<Statistics>& statistics)
@@ -151,8 +32,8 @@ class MyTestCompactionService : public CompactionService,
    assert(info.db_name == db_path_);
    jobs_.emplace(info.job_id, compaction_service_input);
    CompactionServiceJobStatus s = CompactionServiceJobStatus::kSuccess;
-    if (is_override_start_status) {
-      return override_start_status;
+    if (is_override_start_status_) {
+      return override_start_status_;
    }
    return s;
  }
@@ -173,8 +54,8 @@ class MyTestCompactionService : public CompactionService,
      jobs_.erase(i);
    }

-    if (is_override_wait_status) {
-      return override_wait_status;
+    if (is_override_wait_status_) {
+      return override_wait_status_;
    }

    CompactionServiceOptionsOverride options_override;
@@ -194,8 +75,8 @@ class MyTestCompactionService : public CompactionService,
    Status s = DB::OpenAndCompact(
        db_path_, db_path_ + "/" + ROCKSDB_NAMESPACE::ToString(info.job_id),
        compaction_input, compaction_service_result, options_override);
-    if (is_override_wait_result) {
-      *compaction_service_result = override_wait_result;
+    if (is_override_wait_result_) {
+      *compaction_service_result = override_wait_result_;
    }
    compaction_num_.fetch_add(1);
    if (s.ok()) {
@@ -205,11 +86,32 @@ class MyTestCompactionService : public CompactionService,
    }
  }

-  int GetCompactionNum() override { return compaction_num_.load(); }
+  int GetCompactionNum() { return compaction_num_.load(); }

  CompactionServiceJobInfo GetCompactionInfoForStart() { return start_info_; }
  CompactionServiceJobInfo GetCompactionInfoForWait() { return wait_info_; }

+  void OverrideStartStatus(CompactionServiceJobStatus s) {
+    is_override_start_status_ = true;
+    override_start_status_ = s;
+  }
+
+  void OverrideWaitStatus(CompactionServiceJobStatus s) {
+    is_override_wait_status_ = true;
+    override_wait_status_ = s;
+  }
+
+  void OverrideWaitResult(std::string str) {
+    is_override_wait_result_ = true;
+    override_wait_result_ = std::move(str);
+  }
+
+  void ResetOverride() {
+    is_override_wait_result_ = false;
+    is_override_start_status_ = false;
+    is_override_wait_status_ = false;
+  }
+
 private:
  InstrumentedMutex mutex_;
  std::atomic_int compaction_num_{0};
@@ -219,17 +121,17 @@ class MyTestCompactionService : public CompactionService,
  std::shared_ptr<Statistics> statistics_;
  CompactionServiceJobInfo start_info_;
  CompactionServiceJobInfo wait_info_;
+  bool is_override_start_status_ = false;
+  CompactionServiceJobStatus override_start_status_ =
+      CompactionServiceJobStatus::kFailure;
+  bool is_override_wait_status_ = false;
+  CompactionServiceJobStatus override_wait_status_ =
+      CompactionServiceJobStatus::kFailure;
+  bool is_override_wait_result_ = false;
+  std::string override_wait_result_;
 };

-// This is only for listing test classes
-enum TestCompactionServiceType {
-  MyTestCompactionServiceType,
-  MyTestCompactionServiceLegacyType,
-};
-
-class CompactionServiceTest
-    : public DBTestBase,
-      public testing::WithParamInterface<TestCompactionServiceType> {
+class CompactionServiceTest : public DBTestBase {
 public:
  explicit CompactionServiceTest()
      : DBTestBase("compaction_service_test", true) {}
@@ -240,19 +142,9 @@ class CompactionServiceTest
    primary_statistics_ = CreateDBStatistics();
    options->statistics = primary_statistics_;
    compactor_statistics_ = CreateDBStatistics();
-    TestCompactionServiceType cs_type = GetParam();
-    switch (cs_type) {
-      case MyTestCompactionServiceType:
-        compaction_service_ = std::make_shared<MyTestCompactionService>(
-            dbname_, *options, compactor_statistics_);
-        break;
-      case MyTestCompactionServiceLegacyType:
-        compaction_service_ = std::make_shared<MyTestCompactionServiceLegacy>(
-            dbname_, *options, compactor_statistics_);
-        break;
-      default:
-        assert(false);
-    }
+
+    compaction_service_ = std::make_shared<MyTestCompactionService>(
+        dbname_, *options, compactor_statistics_);
    options->compaction_service = compaction_service_;
    DestroyAndReopen(*options);
  }
@@ -261,9 +153,9 @@ class CompactionServiceTest

  Statistics* GetPrimaryStatistics() { return primary_statistics_.get(); }

-  TestCompactionServiceBase* GetCompactionService() {
+  MyTestCompactionService* GetCompactionService() {
    CompactionService* cs = compaction_service_.get();
-    return dynamic_cast<TestCompactionServiceBase*>(cs);
+    return static_cast_with_check<MyTestCompactionService>(cs);
  }

  void GenerateTestData() {
@@ -306,7 +198,7 @@ class CompactionServiceTest
  std::shared_ptr<CompactionService> compaction_service_;
 };

-TEST_P(CompactionServiceTest, BasicCompactions) {
+TEST_F(CompactionServiceTest, BasicCompactions) {
  Options options = CurrentOptions();
  ReopenWithCompactionService(&options);

@@ -393,7 +285,7 @@ TEST_P(CompactionServiceTest, BasicCompactions) {
  ASSERT_TRUE(s.IsAborted());
 }

-TEST_P(CompactionServiceTest, ManualCompaction) {
+TEST_F(CompactionServiceTest, ManualCompaction) {
  Options options = CurrentOptions();
  options.disable_auto_compactions = true;
  ReopenWithCompactionService(&options);
@@ -430,7 +322,7 @@ TEST_P(CompactionServiceTest, ManualCompaction) {
  VerifyTestData();
 }

-TEST_P(CompactionServiceTest, FailedToStart) {
+TEST_F(CompactionServiceTest, FailedToStart) {
  Options options = CurrentOptions();
  options.disable_auto_compactions = true;
  ReopenWithCompactionService(&options);
@@ -448,7 +340,7 @@ TEST_P(CompactionServiceTest, FailedToStart) {
  ASSERT_TRUE(s.IsIncomplete());
 }

-TEST_P(CompactionServiceTest, InvalidResult) {
+TEST_F(CompactionServiceTest, InvalidResult) {
  Options options = CurrentOptions();
  options.disable_auto_compactions = true;
  ReopenWithCompactionService(&options);
@@ -466,7 +358,7 @@ TEST_P(CompactionServiceTest, InvalidResult) {
  ASSERT_FALSE(s.ok());
 }

-TEST_P(CompactionServiceTest, SubCompaction) {
+TEST_F(CompactionServiceTest, SubCompaction) {
  Options options = CurrentOptions();
  options.max_subcompactions = 10;
  options.target_file_size_base = 1 << 10;  // 1KB
@@ -505,7 +397,7 @@ class PartialDeleteCompactionFilter : public CompactionFilter {
  const char* Name() const override { return "PartialDeleteCompactionFilter"; }
 };

-TEST_P(CompactionServiceTest, CompactionFilter) {
+TEST_F(CompactionServiceTest, CompactionFilter) {
  Options options = CurrentOptions();
  std::unique_ptr<CompactionFilter> delete_comp_filter(
      new PartialDeleteCompactionFilter());
@@ -546,7 +438,7 @@ TEST_P(CompactionServiceTest, CompactionFilter) {
  ASSERT_GE(my_cs->GetCompactionNum(), 1);
 }

-TEST_P(CompactionServiceTest, Snapshot) {
+TEST_F(CompactionServiceTest, Snapshot) {
  Options options = CurrentOptions();
  ReopenWithCompactionService(&options);

@@ -567,7 +459,7 @@ TEST_P(CompactionServiceTest, Snapshot) {
  db_->ReleaseSnapshot(s1);
 }

-TEST_P(CompactionServiceTest, ConcurrentCompaction) {
+TEST_F(CompactionServiceTest, ConcurrentCompaction) {
  Options options = CurrentOptions();
  options.level0_file_num_compaction_trigger = 100;
  options.max_background_jobs = 20;
@@ -579,7 +471,7 @@ TEST_P(CompactionServiceTest, ConcurrentCompaction) {

  std::vector<std::thread> threads;
  for (const auto& file : meta.levels[1].files) {
-    threads.push_back(std::thread([&]() {
+    threads.emplace_back(std::thread([&]() {
      std::string fname = file.db_path + "/" + file.name;
      ASSERT_OK(db_->CompactFiles(CompactionOptions(), {fname}, 2));
    }));
@@ -604,12 +496,7 @@ TEST_P(CompactionServiceTest, ConcurrentCompaction) {
  ASSERT_EQ(FilesPerLevel(), "0,0,10");
 }

-TEST_P(CompactionServiceTest, CompactionInfo) {
-  // only test compaction info for new compaction service interface
-  if (GetParam() != MyTestCompactionServiceType) {
-    return;
-  }
-
+TEST_F(CompactionServiceTest, CompactionInfo) {
  Options options = CurrentOptions();
  ReopenWithCompactionService(&options);

@@ -688,7 +575,7 @@ TEST_P(CompactionServiceTest, CompactionInfo) {
  ASSERT_EQ(Env::BOTTOM, info.priority);
 }

-TEST_P(CompactionServiceTest, FallbackLocalAuto) {
+TEST_F(CompactionServiceTest, FallbackLocalAuto) {
  Options options = CurrentOptions();
  ReopenWithCompactionService(&options);

@@ -740,7 +627,7 @@ TEST_P(CompactionServiceTest, FallbackLocalAuto) {
  ASSERT_EQ(primary_statistics->getTickerCount(REMOTE_COMPACT_WRITE_BYTES), 0);
 }

-TEST_P(CompactionServiceTest, FallbackLocalManual) {
+TEST_F(CompactionServiceTest, FallbackLocalManual) {
  Options options = CurrentOptions();
  options.disable_auto_compactions = true;
  ReopenWithCompactionService(&options);
@@ -798,22 +685,8 @@ TEST_P(CompactionServiceTest, FallbackLocalManual) {
  VerifyTestData();
 }

-INSTANTIATE_TEST_CASE_P(
-    CompactionServiceTest, CompactionServiceTest,
-    ::testing::Values(
-        TestCompactionServiceType::MyTestCompactionServiceType,
-        TestCompactionServiceType::MyTestCompactionServiceLegacyType));
-
 }  // namespace ROCKSDB_NAMESPACE

-#ifdef ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-extern "C" {
-void RegisterCustomObjects(int argc, char** argv);
-}
-#else
-void RegisterCustomObjects(int /*argc*/, char** /*argv*/) {}
-#endif  // !ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-
 int main(int argc, char** argv) {
  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
@@ -0,0 +1,92 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+
+#pragma once
+#include <algorithm>
+
+#include "db/version_edit.h"
+
+namespace ROCKSDB_NAMESPACE {
+// We boost files that are closer to TTL limit. This boosting could be
+// through FileMetaData.compensated_file_size but this compensated size
+// is widely used as something similar to file size so dramatically boost
+// the value might cause unintended consequences.
+//
+// This boosting algorithm can go very fancy, but here we use a simple
+// formula which can satisify:
+// (1) Different levels are triggered slightly differently to avoid
+//     too many cascading cases
+// (2) Files in the same level get boosting more when TTL gets closer.
+//
+// Don't do any boosting before TTL has past by half. This is to make
+// sure lower write amp for most of the case. And all levels should be
+// fully boosted when total TTL compaction threshold triggers.
+// Differientiate boosting ranges of each level by 1/2. This will make
+// range for each level exponentially increasing. We could do it by
+// having them to be equal, or go even fancier. We can adjust it after
+// we observe the behavior in production.
+// The threshold starting boosting:
+// +------------------------------------------------------------------ +
+// ^                            ^   ^     ^       ^                 ^
+// Age 0                        ... |     |    second last level    thresold
+//                                  |     |
+//                                  |  third last level
+//                                  |
+//                            forth last level
+//
+// We arbitrarily set with 0 when a file is aged boost_age_start and
+// grow linearly. The ratio is arbitrarily set so that when the next level
+// starts to boost, the previous level's boosting amount is 16.
+class FileTtlBooster {
+ public:
+  FileTtlBooster(uint64_t current_time, uint64_t ttl, int num_non_empty_levels,
+                 int level)
+      : current_time_(current_time) {
+    if (ttl == 0 || level == 0 || level >= num_non_empty_levels - 1) {
+      enabled_ = false;
+      boost_age_start_ = 0;
+      boost_step_ = 1;
+    } else {
+      enabled_ = true;
+      uint64_t all_boost_start_age = ttl / 2;
+      uint64_t all_boost_age_range = (ttl / 32) * 31 - all_boost_start_age;
+      uint64_t boost_age_range =
+          all_boost_age_range >> (num_non_empty_levels - level - 1);
+      boost_age_start_ = all_boost_start_age + boost_age_range;
+      const uint64_t kBoostRatio = 16;
+      // prevent 0 value to avoid divide 0 error.
+      boost_step_ = std::max(boost_age_range / kBoostRatio, uint64_t{1});
+    }
+  }
+
+  uint64_t GetBoostScore(FileMetaData* f) {
+    if (!enabled_) {
+      return 1;
+    }
+    uint64_t oldest_ancester_time = f->TryGetOldestAncesterTime();
+    if (oldest_ancester_time >= current_time_) {
+      return 1;
+    }
+    uint64_t age = current_time_ - oldest_ancester_time;
+    if (age > boost_age_start_) {
+      // Use integer just for convenience.
+      // We could make all file_to_order double if we want.
+      // Technically this can overflow if users override timing and
+      // give a very high current time. Ignore the case for simplicity.
+      // Boosting is addition to current value, so +1. This will effectively
+      // make boosting to kick in after the first boost_step_ is reached.
+      return (age - boost_age_start_) / boost_step_ + 1;
+    }
+    return 1;
+  }
+
+ private:
+  bool enabled_;
+  uint64_t current_time_;
+  uint64_t boost_age_start_;
+  uint64_t boost_step_;
+};
+}  // namespace ROCKSDB_NAMESPACE
@@ -62,7 +62,7 @@ std::shared_ptr<SstPartitionerFactory> NewSstPartitionerFixedPrefixFactory(
 namespace {
 static int RegisterSstPartitionerFactories(ObjectLibrary& library,
                                           const std::string& /*arg*/) {
-  library.Register<SstPartitionerFactory>(
+  library.AddFactory<SstPartitionerFactory>(
      SstPartitionerFixedPrefixFactory::kClassName(),
      [](const std::string& /*uri*/,
         std::unique_ptr<SstPartitionerFactory>* guard,
@@ -317,7 +317,7 @@ class ComparatorDBTest
 INSTANTIATE_TEST_CASE_P(FormatDef, ComparatorDBTest,
                        testing::Values(test::kDefaultFormatVersion));
 INSTANTIATE_TEST_CASE_P(FormatLatest, ComparatorDBTest,
-                        testing::Values(test::kLatestFormatVersion));
+                        testing::Values(kLatestFormatVersion));

 TEST_P(ComparatorDBTest, Bytewise) {
  for (int rand_seed = 301; rand_seed < 306; rand_seed++) {
@@ -56,10 +56,13 @@ Status VerifySstFileChecksum(const Options& options,
  }
  std::unique_ptr<TableReader> table_reader;
  std::unique_ptr<RandomAccessFileReader> file_reader(
-      new RandomAccessFileReader(std::move(file), file_path));
+      new RandomAccessFileReader(
+          std::move(file), file_path, ioptions.clock, nullptr /* io_tracer */,
+          nullptr /* stats */, 0 /* hist_type */, nullptr /* file_read_hist */,
+          ioptions.rate_limiter.get()));
  const bool kImmortal = true;
  s = ioptions.table_factory->NewTableReader(
-      TableReaderOptions(ioptions, options.prefix_extractor.get(), env_options,
+      TableReaderOptions(ioptions, options.prefix_extractor, env_options,
                         internal_comparator, false /* skip_filters */,
                         !kImmortal, false /* force_direct_prefetch */,
                         -1 /* level */),
@@ -39,11 +39,35 @@
 namespace ROCKSDB_NAMESPACE {

 static constexpr int kValueSize = 1000;
+namespace {
+// A wrapper that allows injection of errors.
+class ErrorEnv : public EnvWrapper {
+ public:
+  bool writable_file_error_;
+  int num_writable_file_errors_;

+  explicit ErrorEnv(Env* _target)
+      : EnvWrapper(_target),
+        writable_file_error_(false),
+        num_writable_file_errors_(0) {}
+  const char* Name() const override { return "ErrorEnv"; }
+
+  virtual Status NewWritableFile(const std::string& fname,
+                                 std::unique_ptr<WritableFile>* result,
+                                 const EnvOptions& soptions) override {
+    result->reset();
+    if (writable_file_error_) {
+      ++num_writable_file_errors_;
+      return Status::IOError(fname, "fake error");
+    }
+    return target()->NewWritableFile(fname, result, soptions);
+  }
+};
+}  // namespace
 class CorruptionTest : public testing::Test {
 public:
  std::shared_ptr<Env> env_guard_;
-  test::ErrorEnv* env_;
+  ErrorEnv* env_;
  std::string dbname_;
  std::shared_ptr<Cache> tiny_cache_;
  Options options_;
@@ -58,7 +82,7 @@ class CorruptionTest : public testing::Test {
    EXPECT_OK(
        test::CreateEnvFromSystem(ConfigOptions(), &base_env, &env_guard_));
    EXPECT_NE(base_env, nullptr);
-    env_ = new test::ErrorEnv(base_env);
+    env_ = new ErrorEnv(base_env);
    options_.wal_recovery_mode = WALRecoveryMode::kTolerateCorruptedTailRecords;
    options_.env = env_;
    dbname_ = test::PerThreadDBPath(env_, "corruption_test");
@@ -544,9 +568,9 @@ TEST_F(CorruptionTest, RangeDeletionCorrupted) {
      fs->GetFileSize(filename, file_opts.io_options, &file_size, nullptr));

  BlockHandle range_del_handle;
-  ASSERT_OK(FindMetaBlock(
+  ASSERT_OK(FindMetaBlockInFile(
      file_reader.get(), file_size, kBlockBasedTableMagicNumber,
-      ImmutableOptions(options_), kRangeDelBlock, &range_del_handle));
+      ImmutableOptions(options_), kRangeDelBlockName, &range_del_handle));

  ASSERT_OK(TryReopen());
  ASSERT_OK(test::CorruptFile(env_, filename,
@@ -890,14 +914,6 @@ TEST_F(CorruptionTest, VerifyWholeTableChecksum) {

 }  // namespace ROCKSDB_NAMESPACE

-#ifdef ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-extern "C" {
-void RegisterCustomObjects(int argc, char** argv);
-}
-#else
-void RegisterCustomObjects(int /*argc*/, char** /*argv*/) {}
-#endif  // !ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-
 int main(int argc, char** argv) {
  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
@@ -10,10 +10,12 @@
 #include <cstring>

 #include "db/db_test_util.h"
+#include "options/options_helper.h"
 #include "port/stack_trace.h"
 #include "rocksdb/flush_block_policy.h"
 #include "rocksdb/merge_operator.h"
 #include "rocksdb/perf_context.h"
+#include "rocksdb/table.h"
 #include "rocksdb/utilities/debug.h"
 #include "table/block_based/block_based_table_reader.h"
 #include "table/block_based/block_builder.h"
@@ -49,6 +51,24 @@ TEST_F(DBBasicTest, OpenWhenOpen) {
  delete db2;
 }

+TEST_F(DBBasicTest, EnableDirectIOWithZeroBuf) {
+  if (!IsDirectIOSupported()) {
+    ROCKSDB_GTEST_BYPASS("Direct IO not supported");
+    return;
+  }
+  Options options = GetDefaultOptions();
+  options.create_if_missing = true;
+  options.use_direct_io_for_flush_and_compaction = true;
+  options.writable_file_max_buffer_size = 0;
+  ASSERT_TRUE(TryReopen(options).IsInvalidArgument());
+
+  options.writable_file_max_buffer_size = 1024;
+  Reopen(options);
+  const std::unordered_map<std::string, std::string> new_db_opts = {
+      {"writable_file_max_buffer_size", "0"}};
+  ASSERT_TRUE(db_->SetDBOptions(new_db_opts).IsInvalidArgument());
+}
+
 TEST_F(DBBasicTest, UniqueSession) {
  Options options = CurrentOptions();
  std::string sid1, sid2, sid3, sid4;
@@ -971,16 +991,24 @@ TEST_F(DBBasicTest, MultiGetEmpty) {
  } while (ChangeCompactOptions());
 }

-TEST_F(DBBasicTest, ChecksumTest) {
+class DBBlockChecksumTest : public DBBasicTest,
+                            public testing::WithParamInterface<uint32_t> {};
+
+INSTANTIATE_TEST_CASE_P(FormatVersions, DBBlockChecksumTest,
+                        testing::ValuesIn(test::kFooterFormatVersionsToTest));
+
+TEST_P(DBBlockChecksumTest, BlockChecksumTest) {
  BlockBasedTableOptions table_options;
+  table_options.format_version = GetParam();
  Options options = CurrentOptions();
-  // change when new checksum type added
-  int max_checksum = static_cast<int>(kxxHash64);
  const int kNumPerFile = 2;

+  const auto algs = GetSupportedChecksums();
+  const int algs_size = static_cast<int>(algs.size());
+
  // generate one table with each type of checksum
-  for (int i = 0; i <= max_checksum; ++i) {
-    table_options.checksum = static_cast<ChecksumType>(i);
+  for (int i = 0; i < algs_size; ++i) {
+    table_options.checksum = algs[i];
    options.table_factory.reset(NewBlockBasedTableFactory(table_options));
    Reopen(options);
    for (int j = 0; j < kNumPerFile; ++j) {
@@ -990,15 +1018,20 @@ TEST_F(DBBasicTest, ChecksumTest) {
  }

  // with each valid checksum type setting...
-  for (int i = 0; i <= max_checksum; ++i) {
-    table_options.checksum = static_cast<ChecksumType>(i);
+  for (int i = 0; i < algs_size; ++i) {
+    table_options.checksum = algs[i];
    options.table_factory.reset(NewBlockBasedTableFactory(table_options));
    Reopen(options);
    // verify every type of checksum (should be regardless of that setting)
-    for (int j = 0; j < (max_checksum + 1) * kNumPerFile; ++j) {
+    for (int j = 0; j < algs_size * kNumPerFile; ++j) {
      ASSERT_EQ(Key(j), Get(Key(j)));
    }
  }
+
+  // Now test invalid checksum type
+  table_options.checksum = static_cast<ChecksumType>(123);
+  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  ASSERT_TRUE(TryReopen(options).IsInvalidArgument());
 }

 // On Windows you can have either memory mapped file or a file
@@ -1033,6 +1066,8 @@ TEST_F(DBBasicTest, MmapAndBufferOptions) {
 class TestEnv : public EnvWrapper {
 public:
  explicit TestEnv(Env* base_env) : EnvWrapper(base_env), close_count(0) {}
+  static const char* kClassName() { return "TestEnv"; }
+  const char* Name() const override { return kClassName(); }

  class TestLogger : public Logger {
   public:
@@ -1875,7 +1910,6 @@ TEST_F(DBBasicTest, MultiGetBatchedValueSizeMultiLevelMerge) {

  ASSERT_EQ(values.size(), keys.size());

-  uint64_t curr_value_size = 0;
  for (unsigned int j = 0; j < 26; ++j) {
    int key = j + 10;
    std::string value;
@@ -1892,11 +1926,9 @@ TEST_F(DBBasicTest, MultiGetBatchedValueSizeMultiLevelMerge) {
      value.append(",");
      value.append("val_mem_" + std::to_string(key));
    }
-    curr_value_size += value.size();
    ASSERT_EQ(values[j], value);
    ASSERT_OK(statuses[j]);
  }
-  // ASSERT_TRUE(curr_value_size <= read_options.value_size_hard_limit);

  // All remaning keys status is set Status::Abort
  for (unsigned int j = 26; j < 40; j++) {
@@ -1924,8 +1956,9 @@ TEST_F(DBBasicTest, MultiGetStats) {
  int total_keys = 2000;
  std::vector<std::string> keys_str(total_keys);
  std::vector<Slice> keys(total_keys);
-  std::vector<PinnableSlice> values(total_keys);
-  std::vector<Status> s(total_keys);
+  static size_t kMultiGetBatchSize = 100;
+  std::vector<PinnableSlice> values(kMultiGetBatchSize);
+  std::vector<Status> s(kMultiGetBatchSize);
  ReadOptions read_opts;

  Random rnd(309);
@@ -1962,15 +1995,16 @@ TEST_F(DBBasicTest, MultiGetStats) {
    }
  }
  ASSERT_OK(Flush(1));
+  MoveFilesToLevel(1, 1);
  Close();

  ReopenWithColumnFamilies({"default", "pikachu"}, options);
  ASSERT_OK(options.statistics->Reset());

-  db_->MultiGet(read_opts, handles_[1], total_keys, keys.data(), values.data(),
-                s.data(), false);
+  db_->MultiGet(read_opts, handles_[1], kMultiGetBatchSize, &keys[1250],
+                values.data(), s.data(), false);

-  ASSERT_EQ(values.size(), total_keys);
+  ASSERT_EQ(values.size(), kMultiGetBatchSize);
  HistogramData hist_data_blocks;
  HistogramData hist_index_and_filter_blocks;
  HistogramData hist_sst;
@@ -1982,16 +2016,16 @@ TEST_F(DBBasicTest, MultiGetStats) {
  options.statistics->histogramData(NUM_SST_READ_PER_LEVEL, &hist_sst);

  // Maximum number of blocks read from a file system in a level.
-  ASSERT_GT(hist_data_blocks.max, 0);
+  ASSERT_EQ(hist_data_blocks.max, 32);
  ASSERT_GT(hist_index_and_filter_blocks.max, 0);
  // Maximum number of sst files read from file system in a level.
-  ASSERT_GT(hist_sst.max, 0);
+  ASSERT_EQ(hist_sst.max, 2);

  // Minimun number of blocks read in a level.
-  ASSERT_EQ(hist_data_blocks.min, 3);
+  ASSERT_EQ(hist_data_blocks.min, 4);
  ASSERT_GT(hist_index_and_filter_blocks.min, 0);
  // Minimun number of sst files read in a level.
-  ASSERT_GT(hist_sst.max, 0);
+  ASSERT_EQ(hist_sst.min, 1);
 }

 // Test class for batched MultiGet with prefix extractor
@@ -2550,7 +2584,7 @@ TEST_F(DBBasicTest, DisableTrackWal) {
  ASSERT_OK(dbfull()->TEST_SwitchMemtable());
  ASSERT_OK(db_->SyncWAL());
  // Some WALs are tracked.
-  ASSERT_FALSE(dbfull()->TEST_GetVersionSet()->GetWalSet().GetWals().empty());
+  ASSERT_FALSE(dbfull()->GetVersionSet()->GetWalSet().GetWals().empty());
  Close();

  // Disable WAL tracking.
@@ -2558,14 +2592,14 @@ TEST_F(DBBasicTest, DisableTrackWal) {
  options.create_if_missing = false;
  ASSERT_OK(TryReopen(options));
  // Previously tracked WALs are cleared.
-  ASSERT_TRUE(dbfull()->TEST_GetVersionSet()->GetWalSet().GetWals().empty());
+  ASSERT_TRUE(dbfull()->GetVersionSet()->GetWalSet().GetWals().empty());
  Close();

  // Re-enable WAL tracking again.
  options.track_and_verify_wals_in_manifest = true;
  options.create_if_missing = false;
  ASSERT_OK(TryReopen(options));
-  ASSERT_TRUE(dbfull()->TEST_GetVersionSet()->GetWalSet().GetWals().empty());
+  ASSERT_TRUE(dbfull()->GetVersionSet()->GetWalSet().GetWals().empty());
  Close();
 }
 #endif  // !ROCKSDB_LITE
@@ -3049,6 +3083,8 @@ TEST_P(DBBasicTestWithParallelIO, MultiGetDirectIO) {

   public:
    FakeDirectIOEnv(Env* env) : EnvWrapper(env) {}
+    static const char* kClassName() { return "FakeDirectIOEnv"; }
+    const char* Name() const override { return kClassName(); }

    Status NewRandomAccessFile(const std::string& fname,
                               std::unique_ptr<RandomAccessFile>* result,
@@ -3289,6 +3325,9 @@ class DeadlineFS : public FileSystemWrapper {
        ignore_deadline_(false),
        error_on_delay_(error_on_delay) {}

+  static const char* kClassName() { return "DeadlineFileSystem"; }
+  const char* Name() const override { return kClassName(); }
+
  IOStatus NewRandomAccessFile(const std::string& fname,
                               const FileOptions& opts,
                               std::unique_ptr<FSRandomAccessFile>* result,
@@ -3610,6 +3649,35 @@ TEST_F(DBBasicTest, ManifestWriteFailure) {
  Reopen(options);
 }

+TEST_F(DBBasicTest, DestroyDefaultCfHandle) {
+  Options options = GetDefaultOptions();
+  options.create_if_missing = true;
+  DestroyAndReopen(options);
+  CreateAndReopenWithCF({"pikachu"}, options);
+  for (const auto* h : handles_) {
+    ASSERT_NE(db_->DefaultColumnFamily(), h);
+  }
+
+  // We have two handles to the default column family. The two handles point to
+  // different ColumnFamilyHandle objects.
+  assert(db_->DefaultColumnFamily());
+  ASSERT_EQ(0U, db_->DefaultColumnFamily()->GetID());
+  assert(handles_[0]);
+  ASSERT_EQ(0U, handles_[0]->GetID());
+
+  // You can destroy handles_[...].
+  for (auto* h : handles_) {
+    ASSERT_OK(db_->DestroyColumnFamilyHandle(h));
+  }
+  handles_.clear();
+
+  // But you should not destroy db_->DefaultColumnFamily(), since it's going to
+  // be deleted in `DBImpl::CloseHelper()`. Before that, it may be used
+  // elsewhere internally too.
+  ColumnFamilyHandle* default_cf = db_->DefaultColumnFamily();
+  ASSERT_TRUE(db_->DestroyColumnFamilyHandle(default_cf).IsInvalidArgument());
+}
+
 #ifndef ROCKSDB_LITE
 TEST_F(DBBasicTest, VerifyFileChecksums) {
  Options options = GetDefaultOptions();
@@ -3850,14 +3918,6 @@ INSTANTIATE_TEST_CASE_P(DBBasicTestDeadline, DBBasicTestDeadline,
                                          std::make_tuple(true, true)));
 }  // namespace ROCKSDB_NAMESPACE

-#ifdef ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-extern "C" {
-void RegisterCustomObjects(int argc, char** argv);
-}
-#else
-void RegisterCustomObjects(int /*argc*/, char** /*argv*/) {}
-#endif  // !ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS
-
 int main(int argc, char** argv) {
  ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
  ::testing::InitGoogleTest(&argc, argv);
@@ -9,16 +9,26 @@
 #include <cstdlib>
 #include <functional>
 #include <memory>
+#include <unordered_set>

 #include "cache/cache_entry_roles.h"
+#include "cache/cache_key.h"
 #include "cache/lru_cache.h"
 #include "db/column_family.h"
+#include "db/db_impl/db_impl.h"
 #include "db/db_test_util.h"
+#include "env/unique_id_gen.h"
 #include "port/stack_trace.h"
+#include "rocksdb/persistent_cache.h"
 #include "rocksdb/statistics.h"
 #include "rocksdb/table.h"
+#include "rocksdb/table_properties.h"
+#include "table/block_based/block_based_table_reader.h"
+#include "table/unique_id_impl.h"
 #include "util/compression.h"
 #include "util/defer.h"
+#include "util/hash.h"
+#include "util/math.h"
 #include "util/random.h"
 #include "utilities/fault_injection_fs.h"

@@ -336,6 +346,143 @@ TEST_F(DBBlockCacheTest, TestWithCompressedBlockCache) {
  CheckCacheCounters(options, 1, 0, 1, 0);
  CheckCompressedCacheCounters(options, 0, 1, 0, 0);
 }
+
+namespace {
+class PersistentCacheFromCache : public PersistentCache {
+ public:
+  PersistentCacheFromCache(std::shared_ptr<Cache> cache, bool read_only)
+      : cache_(cache), read_only_(read_only) {}
+
+  Status Insert(const Slice& key, const char* data,
+                const size_t size) override {
+    if (read_only_) {
+      return Status::NotSupported();
+    }
+    std::unique_ptr<char[]> copy{new char[size]};
+    std::copy_n(data, size, copy.get());
+    Status s = cache_->Insert(
+        key, copy.get(), size,
+        GetCacheEntryDeleterForRole<char[], CacheEntryRole::kMisc>());
+    if (s.ok()) {
+      copy.release();
+    }
+    return s;
+  }
+
+  Status Lookup(const Slice& key, std::unique_ptr<char[]>* data,
+                size_t* size) override {
+    auto handle = cache_->Lookup(key);
+    if (handle) {
+      char* ptr = static_cast<char*>(cache_->Value(handle));
+      *size = cache_->GetCharge(handle);
+      data->reset(new char[*size]);
+      std::copy_n(ptr, *size, data->get());
+      cache_->Release(handle);
+      return Status::OK();
+    } else {
+      return Status::NotFound();
+    }
+  }
+
+  bool IsCompressed() override { return false; }
+
+  StatsType Stats() override { return StatsType(); }
+
+  std::string GetPrintableOptions() const override { return ""; }
+
+  uint64_t NewId() override { return cache_->NewId(); }
+
+ private:
+  std::shared_ptr<Cache> cache_;
+  bool read_only_;
+};
+
+class ReadOnlyCacheWrapper : public CacheWrapper {
+  using CacheWrapper::CacheWrapper;
+
+  using Cache::Insert;
+  Status Insert(const Slice& /*key*/, void* /*value*/, size_t /*charge*/,
+                void (*)(const Slice& key, void* value) /*deleter*/,
+                Handle** /*handle*/, Priority /*priority*/) override {
+    return Status::NotSupported();
+  }
+};
+
+}  // namespace
+
+TEST_F(DBBlockCacheTest, TestWithSameCompressed) {
+  auto table_options = GetTableOptions();
+  auto options = GetOptions(table_options);
+  InitTable(options);
+
+  std::shared_ptr<Cache> rw_cache{NewLRUCache(1000000)};
+  std::shared_ptr<PersistentCacheFromCache> rw_pcache{
+      new PersistentCacheFromCache(rw_cache, /*read_only*/ false)};
+  // Exercise some obscure behavior with read-only wrappers
+  std::shared_ptr<Cache> ro_cache{new ReadOnlyCacheWrapper(rw_cache)};
+  std::shared_ptr<PersistentCacheFromCache> ro_pcache{
+      new PersistentCacheFromCache(rw_cache, /*read_only*/ true)};
+
+  // Simple same pointer
+  table_options.block_cache = rw_cache;
+  table_options.block_cache_compressed = rw_cache;
+  table_options.persistent_cache.reset();
+  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  ASSERT_EQ(TryReopen(options).ToString(),
+            "Invalid argument: block_cache same as block_cache_compressed not "
+            "currently supported, and would be bad for performance anyway");
+
+  // Other cases
+  table_options.block_cache = ro_cache;
+  table_options.block_cache_compressed = rw_cache;
+  table_options.persistent_cache.reset();
+  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  ASSERT_EQ(TryReopen(options).ToString(),
+            "Invalid argument: block_cache and block_cache_compressed share "
+            "the same key space, which is not supported");
+
+  table_options.block_cache = rw_cache;
+  table_options.block_cache_compressed = ro_cache;
+  table_options.persistent_cache.reset();
+  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  ASSERT_EQ(TryReopen(options).ToString(),
+            "Invalid argument: block_cache_compressed and block_cache share "
+            "the same key space, which is not supported");
+
+  table_options.block_cache = ro_cache;
+  table_options.block_cache_compressed.reset();
+  table_options.persistent_cache = rw_pcache;
+  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  ASSERT_EQ(TryReopen(options).ToString(),
+            "Invalid argument: block_cache and persistent_cache share the same "
+            "key space, which is not supported");
+
+  table_options.block_cache = rw_cache;
+  table_options.block_cache_compressed.reset();
+  table_options.persistent_cache = ro_pcache;
+  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  ASSERT_EQ(TryReopen(options).ToString(),
+            "Invalid argument: persistent_cache and block_cache share the same "
+            "key space, which is not supported");
+
+  table_options.block_cache.reset();
+  table_options.no_block_cache = true;
+  table_options.block_cache_compressed = ro_cache;
+  table_options.persistent_cache = rw_pcache;
+  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  ASSERT_EQ(TryReopen(options).ToString(),
+            "Invalid argument: block_cache_compressed and persistent_cache "
+            "share the same key space, which is not supported");
+
+  table_options.block_cache.reset();
+  table_options.no_block_cache = true;
+  table_options.block_cache_compressed = rw_cache;
+  table_options.persistent_cache = ro_pcache;
+  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  ASSERT_EQ(TryReopen(options).ToString(),
+            "Invalid argument: persistent_cache and block_cache_compressed "
+            "share the same key space, which is not supported");
+}
 #endif  // SNAPPY

 #ifndef ROCKSDB_LITE
@@ -513,17 +660,46 @@ TEST_F(DBBlockCacheTest, WarmCacheWithDataBlocksDuringFlush) {
 }

 // This test cache data, index and filter blocks during flush.
-TEST_F(DBBlockCacheTest, WarmCacheWithBlocksDuringFlush) {
+class DBBlockCacheTest1 : public DBTestBase,
+                          public ::testing::WithParamInterface<uint32_t> {
+ public:
+  const size_t kNumBlocks = 10;
+  const size_t kValueSize = 100;
+  DBBlockCacheTest1() : DBTestBase("db_block_cache_test1", true) {}
+};
+
+INSTANTIATE_TEST_CASE_P(DBBlockCacheTest1, DBBlockCacheTest1,
+                        ::testing::Values(1, 2, 3));
+
+TEST_P(DBBlockCacheTest1, WarmCacheWithBlocksDuringFlush) {
  Options options = CurrentOptions();
  options.create_if_missing = true;
  options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();

  BlockBasedTableOptions table_options;
  table_options.block_cache = NewLRUCache(1 << 25, 0, false);
+
+  uint32_t filter_type = GetParam();
+  switch (filter_type) {
+    case 1:  // partition_filter
+      table_options.partition_filters = true;
+      table_options.index_type =
+          BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
+      table_options.filter_policy.reset(NewBloomFilterPolicy(10, false));
+      break;
+    case 2:  // block-based filter
+      table_options.filter_policy.reset(NewBloomFilterPolicy(10, true));
+      break;
+    case 3:  // full filter
+      table_options.filter_policy.reset(NewBloomFilterPolicy(10, false));
+      break;
+    default:
+      assert(false);
+  }
+
  table_options.cache_index_and_filter_blocks = true;
  table_options.prepopulate_block_cache =
      BlockBasedTableOptions::PrepopulateBlockCache::kFlushOnly;
-  table_options.filter_policy.reset(NewBloomFilterPolicy(10, false));
  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
  DestroyAndReopen(options);

@@ -532,9 +708,15 @@ TEST_F(DBBlockCacheTest, WarmCacheWithBlocksDuringFlush) {
    ASSERT_OK(Put(ToString(i), value));
    ASSERT_OK(Flush());
    ASSERT_EQ(i, options.statistics->getTickerCount(BLOCK_CACHE_DATA_ADD));
-    ASSERT_EQ(i, options.statistics->getTickerCount(BLOCK_CACHE_INDEX_ADD));
-    ASSERT_EQ(i, options.statistics->getTickerCount(BLOCK_CACHE_FILTER_ADD));
-
+    if (filter_type == 1) {
+      ASSERT_EQ(2 * i,
+                options.statistics->getTickerCount(BLOCK_CACHE_INDEX_ADD));
+      ASSERT_EQ(2 * i,
+                options.statistics->getTickerCount(BLOCK_CACHE_FILTER_ADD));
+    } else {
+      ASSERT_EQ(i, options.statistics->getTickerCount(BLOCK_CACHE_INDEX_ADD));
+      ASSERT_EQ(i, options.statistics->getTickerCount(BLOCK_CACHE_FILTER_ADD));
+    }
    ASSERT_EQ(value, Get(ToString(i)));

    ASSERT_EQ(0, options.statistics->getTickerCount(BLOCK_CACHE_DATA_MISS));
@@ -542,11 +724,16 @@ TEST_F(DBBlockCacheTest, WarmCacheWithBlocksDuringFlush) {

    ASSERT_EQ(0, options.statistics->getTickerCount(BLOCK_CACHE_INDEX_MISS));
    ASSERT_EQ(i * 3, options.statistics->getTickerCount(BLOCK_CACHE_INDEX_HIT));
-
+    if (filter_type == 1) {
+      ASSERT_EQ(i * 3,
+                options.statistics->getTickerCount(BLOCK_CACHE_FILTER_HIT));
+    } else {
+      ASSERT_EQ(i * 2,
+                options.statistics->getTickerCount(BLOCK_CACHE_FILTER_HIT));
+    }
    ASSERT_EQ(0, options.statistics->getTickerCount(BLOCK_CACHE_FILTER_MISS));
-    ASSERT_EQ(i * 2,
-              options.statistics->getTickerCount(BLOCK_CACHE_FILTER_HIT));
  }
+
  // Verify compaction not counted
  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), /*begin=*/nullptr,
                              /*end=*/nullptr));
@@ -555,10 +742,17 @@ TEST_F(DBBlockCacheTest, WarmCacheWithBlocksDuringFlush) {
  // Index and filter blocks are automatically warmed when the new table file
  // is automatically opened at the end of compaction. This is not easily
  // disabled so results in the new index and filter blocks being warmed.
-  EXPECT_EQ(1 + kNumBlocks,
-            options.statistics->getTickerCount(BLOCK_CACHE_INDEX_ADD));
-  EXPECT_EQ(1 + kNumBlocks,
-            options.statistics->getTickerCount(BLOCK_CACHE_FILTER_ADD));
+  if (filter_type == 1) {
+    EXPECT_EQ(2 * (1 + kNumBlocks),
+              options.statistics->getTickerCount(BLOCK_CACHE_INDEX_ADD));
+    EXPECT_EQ(2 * (1 + kNumBlocks),
+              options.statistics->getTickerCount(BLOCK_CACHE_FILTER_ADD));
+  } else {
+    EXPECT_EQ(1 + kNumBlocks,
+              options.statistics->getTickerCount(BLOCK_CACHE_INDEX_ADD));
+    EXPECT_EQ(1 + kNumBlocks,
+              options.statistics->getTickerCount(BLOCK_CACHE_FILTER_ADD));
+  }
 }

 TEST_F(DBBlockCacheTest, DynamicallyWarmCacheDuringFlush) {
@@ -1404,7 +1598,8 @@ TEST_P(DBBlockCacheKeyTest, StableCacheKeys) {
    // This is a "control" side of the test that also ensures safely degraded
    // behavior on old files.
    ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
-        "PropertyBlockBuilder::AddTableProperty:Start", [&](void* arg) {
+        "BlockBasedTableBuilder::BlockBasedTableBuilder:PreSetupBaseCacheKey",
+        [&](void* arg) {
          TableProperties* props = reinterpret_cast<TableProperties*>(arg);
          props->orig_file_number = 0;
        });
@@ -1464,11 +1659,7 @@ TEST_P(DBBlockCacheKeyTest, StableCacheKeys) {
  }

  if (exclude_file_numbers_) {
-    // FIXME(peterd): figure out where these extra two ADDs are coming from
-    options.statistics->recordTick(BLOCK_CACHE_INDEX_ADD,
-                                   uint64_t{0} - uint64_t{2});
-    options.statistics->recordTick(BLOCK_CACHE_FILTER_ADD,
-                                   uint64_t{0} - uint64_t{2});
+    // FIXME(peterd): figure out where these extra ADDs are coming from
    options.statistics->recordTick(BLOCK_CACHE_COMPRESSED_ADD,
                                   uint64_t{0} - uint64_t{2});
  }
@@ -1523,14 +1714,6 @@ TEST_P(DBBlockCacheKeyTest, StableCacheKeys) {
  IngestExternalFileOptions ingest_opts;
  ASSERT_OK(db_->IngestExternalFile(handles_[1], {external}, ingest_opts));

-  if (exclude_file_numbers_) {
-    // FIXME(peterd): figure out where these extra two ADDs are coming from
-    options.statistics->recordTick(BLOCK_CACHE_INDEX_ADD,
-                                   uint64_t{0} - uint64_t{2});
-    options.statistics->recordTick(BLOCK_CACHE_FILTER_ADD,
-                                   uint64_t{0} - uint64_t{2});
-  }
-
  perform_gets();
  verify_stats();
 #endif  // !ROCKSDB_LITE
@@ -1540,6 +1723,238 @@ TEST_P(DBBlockCacheKeyTest, StableCacheKeys) {
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->DisableProcessing();
 }

+class CacheKeyTest : public testing::Test {
+ public:
+  void SetupStableBase() {
+    // Like SemiStructuredUniqueIdGen::GenerateNext
+    tp_.db_session_id = EncodeSessionId(base_session_upper_,
+                                        base_session_lower_ ^ session_counter_);
+    tp_.db_id = ToString(db_id_);
+    tp_.orig_file_number = file_number_;
+    bool is_stable;
+    std::string cur_session_id = "";  // ignored
+    uint64_t cur_file_number = 42;    // ignored
+    BlockBasedTable::SetupBaseCacheKey(&tp_, cur_session_id, cur_file_number,
+                                       file_size_, &base_cache_key_,
+                                       &is_stable);
+    ASSERT_TRUE(is_stable);
+  }
+  CacheKey WithOffset(uint64_t offset) {
+    return BlockBasedTable::GetCacheKey(base_cache_key_,
+                                        BlockHandle(offset, /*size*/ 5));
+  }
+
+ protected:
+  OffsetableCacheKey base_cache_key_;
+  TableProperties tp_;
+  uint64_t file_size_ = 0;
+  uint64_t base_session_upper_ = 0;
+  uint64_t base_session_lower_ = 0;
+  uint64_t session_counter_ = 0;
+  uint64_t file_number_ = 0;
+  uint64_t db_id_ = 0;
+};
+
+namespace {
+template <typename T>
+int CountBitsDifferent(const T& t1, const T& t2) {
+  int diff = 0;
+  const uint8_t* p1 = reinterpret_cast<const uint8_t*>(&t1);
+  const uint8_t* p2 = reinterpret_cast<const uint8_t*>(&t2);
+  static_assert(sizeof(*p1) == 1, "Expecting uint8_t byte");
+  for (size_t i = 0; i < sizeof(T); ++i) {
+    diff += BitsSetToOne(p1[i] ^ p2[i]);
+  }
+  return diff;
+}
+
+}  // namespace
+
+TEST_F(CacheKeyTest, DBImplSessionIdStructure) {
+  // We have to generate our own session IDs for simulation purposes in other
+  // tests. Here we verify that the DBImpl implementation seems to match
+  // our construction here, by using lowest XORed-in bits for "session
+  // counter."
+  std::string session_id1 = DBImpl::GenerateDbSessionId(/*env*/ nullptr);
+  std::string session_id2 = DBImpl::GenerateDbSessionId(/*env*/ nullptr);
+  uint64_t upper1, upper2, lower1, lower2;
+  ASSERT_OK(DecodeSessionId(session_id1, &upper1, &lower1));
+  ASSERT_OK(DecodeSessionId(session_id2, &upper2, &lower2));
+  // Because generated in same process
+  ASSERT_EQ(upper1, upper2);
+  // Unless we generate > 4 billion session IDs in this process...
+  ASSERT_EQ(Upper32of64(lower1), Upper32of64(lower2));
+  // But they must be different somewhere
+  ASSERT_NE(Lower32of64(lower1), Lower32of64(lower2));
+}
+
+TEST_F(CacheKeyTest, StandardEncodingLimit) {
+  base_session_upper_ = 1234;
+  base_session_lower_ = 5678;
+  session_counter_ = 42;
+  file_number_ = 42;
+  db_id_ = 1234;
+
+  file_size_ = 42;
+  SetupStableBase();
+  CacheKey ck1;
+  ASSERT_TRUE(ck1.IsEmpty());
+  ck1 = WithOffset(0);
+  ASSERT_FALSE(ck1.IsEmpty());
+
+  // Should use same encoding
+  file_size_ = BlockBasedTable::kMaxFileSizeStandardEncoding;
+  SetupStableBase();
+  CacheKey ck2 = WithOffset(0);
+  ASSERT_EQ(CountBitsDifferent(ck1, ck2), 0);
+
+  // Should use different encoding
+  ++file_size_;
+  SetupStableBase();
+  CacheKey ck3 = WithOffset(0);
+  ASSERT_GT(CountBitsDifferent(ck2, ck3), 0);
+}
+
+TEST_F(CacheKeyTest, Encodings) {
+  // Claim from cache_key.cc:
+  // In fact, if our SST files are all < 4TB (see
+  // BlockBasedTable::kMaxFileSizeStandardEncoding), then SST files generated
+  // in a single process are guaranteed to have unique cache keys, unless/until
+  // number session ids * max file number = 2**86, e.g. 1 trillion DB::Open in
+  // a single process and 64 trillion files generated.
+
+  // We can generalize that. For
+  // * z bits in maximum file size
+  // * n bits in maximum file number
+  // * s bits in maximum session counter
+  // uniqueness is guaranteed at least when all of these hold:
+  // *  z + n + s <= 121  (128 - 2 meta + 2 offset trim - (8-1) byte granularity
+  //                       in encoding)
+  // *  n + s <= 86       (encoding limitation)
+  // *  s <= 62           (because of 2-bit metadata)
+
+  // We can verify this indirectly by how input bits get into the cache key,
+  // but we have to be mindful that for sufficiently large file sizes,
+  // different encodings might be used. But for cases mixing large and small
+  // files, we have to verify uniqueness between encodings.
+
+  // Going through all combinations would be a little expensive, so we test
+  // only one random "stripe" of the configuration space per run.
+  constexpr uint32_t kStripeBits = 8;
+  constexpr uint32_t kStripeMask = (uint32_t{1} << kStripeBits) - 1;
+
+  // Also cycle through stripes on repeated runs (not thread safe)
+  static uint32_t stripe =
+      static_cast<uint32_t>(std::random_device{}()) & kStripeMask;
+  stripe = (stripe + 1) & kStripeMask;
+
+  fprintf(stderr, "%u\n", stripe);
+
+  // We are going to randomly initialize some values which *should* not affect
+  // result
+  Random64 r{std::random_device{}()};
+
+  int max_num_encodings = 0;
+  uint32_t config_num = 0;
+  uint32_t session_counter_bits, file_number_bits, max_file_size_bits;
+
+  // Inner loop body, used later in a loop over configurations
+  auto TestConfig = [&]() {
+    base_session_upper_ = r.Next();
+    base_session_lower_ = r.Next();
+    session_counter_ = r.Next();
+    if (session_counter_bits < 64) {
+      // Avoid shifting UB
+      session_counter_ = session_counter_ >> 1 >> (63 - session_counter_bits);
+    }
+    file_number_ = r.Next() >> (64 - file_number_bits);
+    // Need two bits set to avoid temporary zero below
+    if (BitsSetToOne(file_number_) < 2) {
+      file_number_ = 3;
+    }
+    db_id_ = r.Next();
+
+    // Work-around clang-analyzer which thinks empty last_base is garbage
+    CacheKey last_base = CacheKey::CreateUniqueForProcessLifetime();
+
+    std::unordered_set<std::string> seen;
+    int num_encodings = 0;
+
+    // Loop over encodings by increasing file size bits
+    for (uint32_t file_size_bits = 1; file_size_bits <= max_file_size_bits;
+         ++file_size_bits) {
+      file_size_ = uint64_t{1} << (file_size_bits - 1);
+      SetupStableBase();
+      CacheKey new_base = WithOffset(0);
+      if (CountBitsDifferent(last_base, new_base) == 0) {
+        // Same as previous encoding
+        continue;
+      }
+
+      // New encoding
+      ++num_encodings;
+      ASSERT_TRUE(seen.insert(new_base.AsSlice().ToString()).second);
+      last_base = new_base;
+      for (uint32_t i = 0; i < file_size_bits; ++i) {
+        CacheKey ck = WithOffset(uint64_t{1} << i);
+        if (i < 2) {
+          // These cases are not relevant and optimized by dropping two
+          // lowest bits because there's always at least 5 bytes between
+          // blocks.
+          ASSERT_EQ(CountBitsDifferent(ck, new_base), 0);
+        } else {
+          // Normal case
+          // 1 bit different from base and never been seen implies the bit
+          // is encoded into cache key without overlapping other structured
+          // data.
+          ASSERT_EQ(CountBitsDifferent(ck, new_base), 1);
+          ASSERT_TRUE(seen.insert(ck.AsSlice().ToString()).second);
+        }
+      }
+      for (uint32_t i = 0; i < session_counter_bits; ++i) {
+        SaveAndRestore<uint64_t> tmp(&session_counter_,
+                                     session_counter_ ^ (uint64_t{1} << i));
+        SetupStableBase();
+        CacheKey ck = WithOffset(0);
+        ASSERT_EQ(CountBitsDifferent(ck, new_base), 1);
+        ASSERT_TRUE(seen.insert(ck.AsSlice().ToString()).second);
+      }
+      for (uint32_t i = 0; i < file_number_bits; ++i) {
+        SaveAndRestore<uint64_t> tmp(&file_number_,
+                                     file_number_ ^ (uint64_t{1} << i));
+        SetupStableBase();
+        CacheKey ck = WithOffset(0);
+        ASSERT_EQ(CountBitsDifferent(ck, new_base), 1);
+        ASSERT_TRUE(seen.insert(ck.AsSlice().ToString()).second);
+      }
+      max_num_encodings = std::max(max_num_encodings, num_encodings);
+    }
+  };
+
+  // Loop over configurations and test those in stripe
+  for (session_counter_bits = 0; session_counter_bits <= 62;
+       ++session_counter_bits) {
+    uint32_t max_file_number_bits =
+        std::min(uint32_t{64}, uint32_t{86} - session_counter_bits);
+    // Start with 2 to avoid file_number_ == 0 in testing
+    for (file_number_bits = 2; file_number_bits <= max_file_number_bits;
+         ++file_number_bits) {
+      uint32_t max_max_file_size_bits =
+          std::min(uint32_t{64},
+                   uint32_t{121} - file_number_bits - session_counter_bits);
+      for (max_file_size_bits = 1; max_file_size_bits <= max_max_file_size_bits;
+           ++max_file_size_bits) {
+        if ((config_num++ & kStripeMask) == stripe) {
+          TestConfig();
+        }
+      }
+    }
+  }
+
+  // Make sure the current implementation is exercised
+  ASSERT_EQ(max_num_encodings, 4);
+}
+
 INSTANTIATE_TEST_CASE_P(DBBlockCacheKeyTest, DBBlockCacheKeyTest,
                        ::testing::Combine(::testing::Bool(),
                                           ::testing::Bool()));
@@ -369,89 +369,6 @@ TEST_P(DBCompactionTestWithParam, CompactionDeletionTrigger) {
 }
 #endif  // !defined(ROCKSDB_VALGRIND_RUN) || defined(ROCKSDB_FULL_VALGRIND_RUN)

-TEST_P(DBCompactionTestWithParam, CompactionsPreserveDeletes) {
-  //  For each options type we test following
-  //  - Enable preserve_deletes
-  //  - write bunch of keys and deletes
-  //  - Set start_seqnum to the beginning; compact; check that keys are present
-  //  - rewind start_seqnum way forward; compact; check that keys are gone
-
-  for (int tid = 0; tid < 3; ++tid) {
-    Options options = DeletionTriggerOptions(CurrentOptions());
-    options.max_subcompactions = max_subcompactions_;
-    options.preserve_deletes=true;
-    options.num_levels = 2;
-
-    if (tid == 1) {
-      options.skip_stats_update_on_db_open = true;
-    } else if (tid == 2) {
-      // third pass with universal compaction
-      options.compaction_style = kCompactionStyleUniversal;
-    }
-
-    DestroyAndReopen(options);
-    Random rnd(301);
-    // highlight the default; all deletes should be preserved
-    SetPreserveDeletesSequenceNumber(0);
-
-    const int kTestSize = kCDTKeysPerBuffer;
-    std::vector<std::string> values;
-    for (int k = 0; k < kTestSize; ++k) {
-      values.push_back(rnd.RandomString(kCDTValueSize));
-      ASSERT_OK(Put(Key(k), values[k]));
-    }
-
-    for (int k = 0; k < kTestSize; ++k) {
-      ASSERT_OK(Delete(Key(k)));
-    }
-    // to ensure we tackle all tombstones
-    CompactRangeOptions cro;
-    cro.change_level = true;
-    cro.target_level = 2;
-    cro.bottommost_level_compaction =
-        BottommostLevelCompaction::kForceOptimized;
-
-    ASSERT_OK(dbfull()->TEST_WaitForFlushMemTable());
-    ASSERT_TRUE(
-        dbfull()->CompactRange(cro, nullptr, nullptr).IsInvalidArgument());
-
-    // check that normal user iterator doesn't see anything
-    Iterator* db_iter = dbfull()->NewIterator(ReadOptions());
-    int i = 0;
-    for (db_iter->SeekToFirst(); db_iter->Valid(); db_iter->Next()) {
-      i++;
-    }
-    ASSERT_OK(db_iter->status());
-    ASSERT_EQ(i, 0);
-    delete db_iter;
-
-    // check that iterator that sees internal keys sees tombstones
-    ReadOptions ro;
-    ro.iter_start_seqnum=1;
-    db_iter = dbfull()->NewIterator(ro);
-    ASSERT_OK(db_iter->status());
-    i = 0;
-    for (db_iter->SeekToFirst(); db_iter->Valid(); db_iter->Next()) {
-      i++;
-    }
-    ASSERT_EQ(i, 4);
-    delete db_iter;
-
-    // now all deletes should be gone
-    SetPreserveDeletesSequenceNumber(100000000);
-    ASSERT_NOK(dbfull()->CompactRange(cro, nullptr, nullptr));
-
-    db_iter = dbfull()->NewIterator(ro);
-    ASSERT_TRUE(db_iter->status().IsInvalidArgument());
-    i = 0;
-    for (db_iter->SeekToFirst(); db_iter->Valid(); db_iter->Next()) {
-      i++;
-    }
-    ASSERT_EQ(i, 0);
-    delete db_iter;
-  }
-}
-
 TEST_F(DBCompactionTest, SkipStatsUpdateTest) {
  // This test verify UpdateAccumulatedStats is not on
  // if options.skip_stats_update_on_db_open = true
@@ -501,7 +418,6 @@ TEST_F(DBCompactionTest, SkipStatsUpdateTest) {
 TEST_F(DBCompactionTest, TestTableReaderForCompaction) {
  Options options = CurrentOptions();
  options.env = env_;
-  options.new_table_reader_for_compaction_inputs = true;
  options.max_open_files = 20;
  options.level0_file_num_compaction_trigger = 3;
  // Avoid many shards with small max_open_files, where as little as
@@ -4302,6 +4218,67 @@ TEST_F(DBCompactionTest, LevelPeriodicAndTtlCompaction) {
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->DisableProcessing();
 }

+TEST_F(DBCompactionTest, LevelTtlBooster) {
+  const int kNumKeysPerFile = 32;
+  const int kNumLevelFiles = 3;
+  const int kValueSize = 1000;
+
+  Options options = CurrentOptions();
+  options.ttl = 10 * 60 * 60;                           // 10 hours
+  options.periodic_compaction_seconds = 480 * 60 * 60;  // very long
+  options.level0_file_num_compaction_trigger = 2;
+  options.max_bytes_for_level_base = 5 * uint64_t{kNumKeysPerFile * kValueSize};
+  options.max_open_files = -1;  // needed for both periodic and ttl compactions
+  options.compaction_pri = CompactionPri::kMinOverlappingRatio;
+  env_->SetMockSleep();
+  options.env = env_;
+
+  // NOTE: Presumed unnecessary and removed: resetting mock time in env
+
+  DestroyAndReopen(options);
+
+  Random rnd(301);
+  for (int i = 0; i < kNumLevelFiles; ++i) {
+    for (int j = 0; j < kNumKeysPerFile; ++j) {
+      ASSERT_OK(
+          Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
+    }
+    ASSERT_OK(Flush());
+  }
+  ASSERT_OK(dbfull()->TEST_WaitForCompact());
+
+  MoveFilesToLevel(2);
+
+  ASSERT_EQ("0,0,3", FilesPerLevel());
+
+  // Create some files for L1
+  for (int i = 0; i < 2; i++) {
+    for (int j = 0; j < kNumKeysPerFile; ++j) {
+      ASSERT_OK(Put(Key(2 * j + i), rnd.RandomString(kValueSize)));
+    }
+    ASSERT_OK(Flush());
+    ASSERT_OK(dbfull()->TEST_WaitForCompact());
+  }
+
+  ASSERT_EQ("0,1,3", FilesPerLevel());
+
+  // Make the new L0 files qualify TTL boosting and generate one more to trigger
+  // L1 -> L2 compaction. Old files will be picked even if their priority is
+  // lower without boosting.
+  env_->MockSleepForSeconds(8 * 60 * 60);
+  for (int i = 0; i < 2; i++) {
+    for (int j = 0; j < kNumKeysPerFile; ++j) {
+      ASSERT_OK(Put(Key(kNumKeysPerFile * 2 + 2 * j + i),
+                    rnd.RandomString(kValueSize * 2)));
+    }
+    ASSERT_OK(Flush());
+    ASSERT_OK(dbfull()->TEST_WaitForCompact());
+  }
+  ASSERT_EQ("0,1,2", FilesPerLevel());
+
+  ASSERT_GT(SizeAtLevel(1), kNumKeysPerFile * 4 * kValueSize);
+}
+
 TEST_F(DBCompactionTest, LevelPeriodicCompactionWithCompactionFilters) {
  class TestCompactionFilter : public CompactionFilter {
    const char* Name() const override { return "TestCompactionFilter"; }
@@ -4694,6 +4671,98 @@ TEST_F(DBCompactionTest, CompactionStatsTest) {
  VerifyCompactionStats(*cfd, *collector);
 }

+TEST_F(DBCompactionTest, SubcompactionEvent) {
+  class SubCompactionEventListener : public EventListener {
+   public:
+    void OnCompactionBegin(DB* /*db*/, const CompactionJobInfo& ci) override {
+      InstrumentedMutexLock l(&mutex_);
+      ASSERT_EQ(running_compactions_.find(ci.job_id),
+                running_compactions_.end());
+      running_compactions_.emplace(ci.job_id, std::unordered_set<int>());
+    }
+
+    void OnCompactionCompleted(DB* /*db*/,
+                               const CompactionJobInfo& ci) override {
+      InstrumentedMutexLock l(&mutex_);
+      auto it = running_compactions_.find(ci.job_id);
+      ASSERT_NE(it, running_compactions_.end());
+      ASSERT_EQ(it->second.size(), 0);
+      running_compactions_.erase(it);
+    }
+
+    void OnSubcompactionBegin(const SubcompactionJobInfo& si) override {
+      InstrumentedMutexLock l(&mutex_);
+      auto it = running_compactions_.find(si.job_id);
+      ASSERT_NE(it, running_compactions_.end());
+      auto r = it->second.insert(si.subcompaction_job_id);
+      ASSERT_TRUE(r.second);  // each subcompaction_job_id should be different
+      total_subcompaction_cnt_++;
+    }
+
+    void OnSubcompactionCompleted(const SubcompactionJobInfo& si) override {
+      InstrumentedMutexLock l(&mutex_);
+      auto it = running_compactions_.find(si.job_id);
+      ASSERT_NE(it, running_compactions_.end());
+      auto r = it->second.erase(si.subcompaction_job_id);
+      ASSERT_EQ(r, 1);
+    }
+
+    size_t GetRunningCompactionCount() {
+      InstrumentedMutexLock l(&mutex_);
+      return running_compactions_.size();
+    }
+
+    size_t GetTotalSubcompactionCount() {
+      InstrumentedMutexLock l(&mutex_);
+      return total_subcompaction_cnt_;
+    }
+
+   private:
+    InstrumentedMutex mutex_;
+    std::unordered_map<int, std::unordered_set<int>> running_compactions_;
+    size_t total_subcompaction_cnt_ = 0;
+  };
+
+  Options options = CurrentOptions();
+  options.target_file_size_base = 1024;
+  options.level0_file_num_compaction_trigger = 10;
+  auto* listener = new SubCompactionEventListener();
+  options.listeners.emplace_back(listener);
+
+  DestroyAndReopen(options);
+
+  // generate 4 files @ L2
+  for (int i = 0; i < 4; i++) {
+    for (int j = 0; j < 10; j++) {
+      int key_id = i * 10 + j;
+      ASSERT_OK(Put(Key(key_id), "value" + ToString(key_id)));
+    }
+    ASSERT_OK(Flush());
+  }
+  MoveFilesToLevel(2);
+
+  // generate 2 files @ L1 which overlaps with L2 files
+  for (int i = 0; i < 2; i++) {
+    for (int j = 0; j < 10; j++) {
+      int key_id = i * 20 + j * 2;
+      ASSERT_OK(Put(Key(key_id), "value" + ToString(key_id)));
+    }
+    ASSERT_OK(Flush());
+  }
+  MoveFilesToLevel(1);
+  ASSERT_EQ(FilesPerLevel(), "0,2,4");
+
+  CompactRangeOptions comp_opts;
+  comp_opts.max_subcompactions = 4;
+  Status s = dbfull()->CompactRange(comp_opts, nullptr, nullptr);
+  ASSERT_OK(s);
+  ASSERT_OK(dbfull()->TEST_WaitForCompact());
+  // make sure there's no running compaction
+  ASSERT_EQ(listener->GetRunningCompactionCount(), 0);
+  // and sub compaction is triggered
+  ASSERT_GT(listener->GetTotalSubcompactionCount(), 0);
+}
+
 TEST_F(DBCompactionTest, CompactFilesOutputRangeConflict) {
  // LSM setup:
  // L1:      [ba bz]
@@ -6066,7 +6135,7 @@ TEST_F(DBCompactionTest, CompactionWithBlob) {
  ASSERT_EQ(Get(first_key), third_value);
  ASSERT_EQ(Get(second_key), third_value);

-  VersionSet* const versions = dbfull()->TEST_GetVersionSet();
+  VersionSet* const versions = dbfull()->GetVersionSet();
  assert(versions);

  ColumnFamilyData* const cfd = versions->GetColumnFamilySet()->GetDefault();
@@ -6087,7 +6156,7 @@ TEST_F(DBCompactionTest, CompactionWithBlob) {
  const auto& blob_files = storage_info->GetBlobFiles();
  ASSERT_EQ(blob_files.size(), 1);

-  const auto& blob_file = blob_files.begin()->second;
+  const auto& blob_file = blob_files.front();
  ASSERT_NE(blob_file, nullptr);

  ASSERT_EQ(table_file->smallest.user_key(), first_key);
@@ -6169,7 +6238,7 @@ TEST_P(DBCompactionTestBlobError, CompactionError) {
  SyncPoint::GetInstance()->DisableProcessing();
  SyncPoint::GetInstance()->ClearAllCallBacks();

-  VersionSet* const versions = dbfull()->TEST_GetVersionSet();
+  VersionSet* const versions = dbfull()->GetVersionSet();
  assert(versions);

  ColumnFamilyData* const cfd = versions->GetColumnFamilySet()->GetDefault();
@@ -6291,7 +6360,7 @@ TEST_P(DBCompactionTestBlobGC, CompactionWithBlobGC) {
    ASSERT_EQ(new_blob_files[i - cutoff_index], original_blob_files[i]);
  }

-  VersionSet* const versions = dbfull()->TEST_GetVersionSet();
+  VersionSet* const versions = dbfull()->GetVersionSet();
  assert(versions);
  assert(versions->GetColumnFamilySet());

@@ -6820,6 +6889,319 @@ TEST_F(DBCompactionTest, FIFOWarm) {
  Destroy(options);
 }

+TEST_F(DBCompactionTest, DisableMultiManualCompaction) {
+  const int kNumL0Files = 10;
+
+  Options options = CurrentOptions();
+  options.level0_file_num_compaction_trigger = kNumL0Files;
+  Reopen(options);
+
+  // Generate 2 levels of file to make sure the manual compaction is not skipped
+  for (int i = 0; i < 10; i++) {
+    ASSERT_OK(Put(Key(i), "value"));
+    if (i % 2) {
+      ASSERT_OK(Flush());
+    }
+  }
+  MoveFilesToLevel(2);
+
+  for (int i = 0; i < 10; i++) {
+    ASSERT_OK(Put(Key(i), "value"));
+    if (i % 2) {
+      ASSERT_OK(Flush());
+    }
+  }
+  MoveFilesToLevel(1);
+
+  // Block compaction queue
+  test::SleepingBackgroundTask sleeping_task_low;
+  env_->Schedule(&test::SleepingBackgroundTask::DoSleepTask, &sleeping_task_low,
+                 Env::Priority::LOW);
+
+  port::Thread compact_thread1([&]() {
+    CompactRangeOptions cro;
+    cro.exclusive_manual_compaction = false;
+    std::string begin_str = Key(0);
+    std::string end_str = Key(3);
+    Slice b = begin_str;
+    Slice e = end_str;
+    auto s = db_->CompactRange(cro, &b, &e);
+    ASSERT_TRUE(s.IsIncomplete());
+  });
+
+  port::Thread compact_thread2([&]() {
+    CompactRangeOptions cro;
+    cro.exclusive_manual_compaction = false;
+    std::string begin_str = Key(4);
+    std::string end_str = Key(7);
+    Slice b = begin_str;
+    Slice e = end_str;
+    auto s = db_->CompactRange(cro, &b, &e);
+    ASSERT_TRUE(s.IsIncomplete());
+  });
+
+  // Disable manual compaction should cancel both manual compactions and both
+  // compaction should return incomplete.
+  db_->DisableManualCompaction();
+
+  compact_thread1.join();
+  compact_thread2.join();
+
+  sleeping_task_low.WakeUp();
+  sleeping_task_low.WaitUntilDone();
+  ASSERT_OK(dbfull()->TEST_WaitForCompact(true));
+}
+
+TEST_F(DBCompactionTest, DisableJustStartedManualCompaction) {
+  const int kNumL0Files = 4;
+
+  Options options = CurrentOptions();
+  options.level0_file_num_compaction_trigger = kNumL0Files;
+  Reopen(options);
+
+  // generate files, but avoid trigger auto compaction
+  for (int i = 0; i < kNumL0Files / 2; i++) {
+    ASSERT_OK(Put(Key(1), "value1"));
+    ASSERT_OK(Put(Key(2), "value2"));
+    ASSERT_OK(Flush());
+  }
+
+  // make sure the manual compaction background is started but not yet set the
+  // status to in_progress, then cancel the manual compaction, which should not
+  // result in segfault
+  SyncPoint::GetInstance()->LoadDependency(
+      {{"DBImpl::BGWorkCompaction",
+        "DBCompactionTest::DisableJustStartedManualCompaction:"
+        "PreDisableManualCompaction"},
+       {"DBImpl::RunManualCompaction:Unscheduled",
+        "BackgroundCallCompaction:0"}});
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  port::Thread compact_thread([&]() {
+    CompactRangeOptions cro;
+    cro.exclusive_manual_compaction = true;
+    auto s = db_->CompactRange(cro, nullptr, nullptr);
+    ASSERT_TRUE(s.IsIncomplete());
+  });
+  TEST_SYNC_POINT(
+      "DBCompactionTest::DisableJustStartedManualCompaction:"
+      "PreDisableManualCompaction");
+  db_->DisableManualCompaction();
+
+  compact_thread.join();
+}
+
+TEST_F(DBCompactionTest, DisableInProgressManualCompaction) {
+  const int kNumL0Files = 4;
+
+  Options options = CurrentOptions();
+  options.level0_file_num_compaction_trigger = kNumL0Files;
+  Reopen(options);
+
+  SyncPoint::GetInstance()->LoadDependency(
+      {{"DBImpl::BackgroundCompaction:InProgress",
+        "DBCompactionTest::DisableInProgressManualCompaction:"
+        "PreDisableManualCompaction"},
+       {"DBImpl::RunManualCompaction:Unscheduled",
+        "CompactionJob::Run():Start"}});
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  // generate files, but avoid trigger auto compaction
+  for (int i = 0; i < kNumL0Files / 2; i++) {
+    ASSERT_OK(Put(Key(1), "value1"));
+    ASSERT_OK(Put(Key(2), "value2"));
+    ASSERT_OK(Flush());
+  }
+
+  port::Thread compact_thread([&]() {
+    CompactRangeOptions cro;
+    cro.exclusive_manual_compaction = true;
+    auto s = db_->CompactRange(cro, nullptr, nullptr);
+    ASSERT_TRUE(s.IsIncomplete());
+  });
+
+  TEST_SYNC_POINT(
+      "DBCompactionTest::DisableInProgressManualCompaction:"
+      "PreDisableManualCompaction");
+  db_->DisableManualCompaction();
+
+  compact_thread.join();
+}
+
+TEST_F(DBCompactionTest, DisableManualCompactionThreadQueueFull) {
+  const int kNumL0Files = 4;
+
+  SyncPoint::GetInstance()->LoadDependency(
+      {{"DBImpl::RunManualCompaction:Scheduled",
+        "DBCompactionTest::DisableManualCompactionThreadQueueFull:"
+        "PreDisableManualCompaction"}});
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  Options options = CurrentOptions();
+  options.level0_file_num_compaction_trigger = kNumL0Files;
+  Reopen(options);
+
+  // Block compaction queue
+  test::SleepingBackgroundTask sleeping_task_low;
+  env_->Schedule(&test::SleepingBackgroundTask::DoSleepTask, &sleeping_task_low,
+                 Env::Priority::LOW);
+
+  // generate files, but avoid trigger auto compaction
+  for (int i = 0; i < kNumL0Files / 2; i++) {
+    ASSERT_OK(Put(Key(1), "value1"));
+    ASSERT_OK(Put(Key(2), "value2"));
+    ASSERT_OK(Flush());
+  }
+
+  port::Thread compact_thread([&]() {
+    CompactRangeOptions cro;
+    cro.exclusive_manual_compaction = true;
+    auto s = db_->CompactRange(cro, nullptr, nullptr);
+    ASSERT_TRUE(s.IsIncomplete());
+  });
+
+  TEST_SYNC_POINT(
+      "DBCompactionTest::DisableManualCompactionThreadQueueFull:"
+      "PreDisableManualCompaction");
+
+  // Generate more files to trigger auto compaction which is scheduled after
+  // manual compaction. Has to generate 4 more files because existing files are
+  // pending compaction
+  for (int i = 0; i < kNumL0Files; i++) {
+    ASSERT_OK(Put(Key(1), "value1"));
+    ASSERT_OK(Put(Key(2), "value2"));
+    ASSERT_OK(Flush());
+  }
+  ASSERT_EQ(ToString(kNumL0Files + (kNumL0Files / 2)), FilesPerLevel(0));
+
+  db_->DisableManualCompaction();
+
+  // CompactRange should return before the compaction has the chance to run
+  compact_thread.join();
+
+  sleeping_task_low.WakeUp();
+  sleeping_task_low.WaitUntilDone();
+  ASSERT_OK(dbfull()->TEST_WaitForCompact(true));
+  ASSERT_EQ("0,1", FilesPerLevel(0));
+}
+
+TEST_F(DBCompactionTest, DisableManualCompactionThreadQueueFullDBClose) {
+  const int kNumL0Files = 4;
+
+  SyncPoint::GetInstance()->LoadDependency(
+      {{"DBImpl::RunManualCompaction:Scheduled",
+        "DBCompactionTest::DisableManualCompactionThreadQueueFullDBClose:"
+        "PreDisableManualCompaction"}});
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  Options options = CurrentOptions();
+  options.level0_file_num_compaction_trigger = kNumL0Files;
+  Reopen(options);
+
+  // Block compaction queue
+  test::SleepingBackgroundTask sleeping_task_low;
+  env_->Schedule(&test::SleepingBackgroundTask::DoSleepTask, &sleeping_task_low,
+                 Env::Priority::LOW);
+
+  // generate files, but avoid trigger auto compaction
+  for (int i = 0; i < kNumL0Files / 2; i++) {
+    ASSERT_OK(Put(Key(1), "value1"));
+    ASSERT_OK(Put(Key(2), "value2"));
+    ASSERT_OK(Flush());
+  }
+
+  port::Thread compact_thread([&]() {
+    CompactRangeOptions cro;
+    cro.exclusive_manual_compaction = true;
+    auto s = db_->CompactRange(cro, nullptr, nullptr);
+    ASSERT_TRUE(s.IsIncomplete());
+  });
+
+  TEST_SYNC_POINT(
+      "DBCompactionTest::DisableManualCompactionThreadQueueFullDBClose:"
+      "PreDisableManualCompaction");
+
+  // Generate more files to trigger auto compaction which is scheduled after
+  // manual compaction. Has to generate 4 more files because existing files are
+  // pending compaction
+  for (int i = 0; i < kNumL0Files; i++) {
+    ASSERT_OK(Put(Key(1), "value1"));
+    ASSERT_OK(Put(Key(2), "value2"));
+    ASSERT_OK(Flush());
+  }
+  ASSERT_EQ(ToString(kNumL0Files + (kNumL0Files / 2)), FilesPerLevel(0));
+
+  db_->DisableManualCompaction();
+
+  // CompactRange should return before the compaction has the chance to run
+  compact_thread.join();
+
+  // Try close DB while manual compaction is canceled but still in the queue.
+  // And an auto-triggered compaction is also in the queue.
+  auto s = db_->Close();
+  ASSERT_OK(s);
+
+  sleeping_task_low.WakeUp();
+  sleeping_task_low.WaitUntilDone();
+}
+
+TEST_F(DBCompactionTest, DBCloseWithManualCompaction) {
+  const int kNumL0Files = 4;
+
+  SyncPoint::GetInstance()->LoadDependency(
+      {{"DBImpl::RunManualCompaction:Scheduled",
+        "DBCompactionTest::DisableManualCompactionThreadQueueFullDBClose:"
+        "PreDisableManualCompaction"}});
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  Options options = CurrentOptions();
+  options.level0_file_num_compaction_trigger = kNumL0Files;
+  Reopen(options);
+
+  // Block compaction queue
+  test::SleepingBackgroundTask sleeping_task_low;
+  env_->Schedule(&test::SleepingBackgroundTask::DoSleepTask, &sleeping_task_low,
+                 Env::Priority::LOW);
+
+  // generate files, but avoid trigger auto compaction
+  for (int i = 0; i < kNumL0Files / 2; i++) {
+    ASSERT_OK(Put(Key(1), "value1"));
+    ASSERT_OK(Put(Key(2), "value2"));
+    ASSERT_OK(Flush());
+  }
+
+  port::Thread compact_thread([&]() {
+    CompactRangeOptions cro;
+    cro.exclusive_manual_compaction = true;
+    auto s = db_->CompactRange(cro, nullptr, nullptr);
+    ASSERT_TRUE(s.IsIncomplete());
+  });
+
+  TEST_SYNC_POINT(
+      "DBCompactionTest::DisableManualCompactionThreadQueueFullDBClose:"
+      "PreDisableManualCompaction");
+
+  // Generate more files to trigger auto compaction which is scheduled after
+  // manual compaction. Has to generate 4 more files because existing files are
+  // pending compaction
+  for (int i = 0; i < kNumL0Files; i++) {
+    ASSERT_OK(Put(Key(1), "value1"));
+    ASSERT_OK(Put(Key(2), "value2"));
+    ASSERT_OK(Flush());
+  }
+  ASSERT_EQ(ToString(kNumL0Files + (kNumL0Files / 2)), FilesPerLevel(0));
+
+  // Close DB with manual compaction and auto triggered compaction in the queue.
+  auto s = db_->Close();
+  ASSERT_OK(s);
+
+  // manual compaction thread should return with Incomplete().
+  compact_thread.join();
+
+  sleeping_task_low.WakeUp();
+  sleeping_task_low.WaitUntilDone();
+}
+
 TEST_F(DBCompactionTest,
       DisableManualCompactionDoesNotWaitForDrainingAutomaticCompaction) {
  // When `CompactRangeOptions::exclusive_manual_compaction == true`, we wait
@@ -6863,6 +7245,141 @@ TEST_F(DBCompactionTest,
  ASSERT_TRUE(callback_completed);
 }

+TEST_F(DBCompactionTest, ChangeLevelConflictsWithManual) {
+  Options options = CurrentOptions();
+  options.num_levels = 3;
+  Reopen(options);
+
+  // Setup an LSM with L2 populated.
+  Random rnd(301);
+  ASSERT_OK(Put(Key(0), rnd.RandomString(990)));
+  ASSERT_OK(Put(Key(1), rnd.RandomString(990)));
+  {
+    CompactRangeOptions cro;
+    cro.change_level = true;
+    cro.target_level = 2;
+    ASSERT_OK(dbfull()->CompactRange(cro, nullptr, nullptr));
+  }
+  ASSERT_EQ("0,0,1", FilesPerLevel(0));
+
+  // The background thread will refit L2->L1 while the foreground thread will
+  // attempt to run a compaction on new data. The following dependencies
+  // ensure the background manual compaction's refitting phase disables manual
+  // compaction immediately before the foreground manual compaction can register
+  // itself. Manual compaction is kept disabled until the foreground manual
+  // checks for the failure once.
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency({
+      // Only do Put()s for foreground CompactRange() once the background
+      // CompactRange() has reached the refitting phase.
+      {
+          "DBImpl::CompactRange:BeforeRefit:1",
+          "DBCompactionTest::ChangeLevelConflictsWithManual:"
+          "PreForegroundCompactRange",
+      },
+      // Right before we register the manual compaction, proceed with
+      // the refitting phase so manual compactions are disabled. Stay in
+      // the refitting phase with manual compactions disabled until it is
+      // noticed.
+      {
+          "DBImpl::RunManualCompaction:0",
+          "DBImpl::CompactRange:BeforeRefit:2",
+      },
+      {
+          "DBImpl::CompactRange:PreRefitLevel",
+          "DBImpl::RunManualCompaction:1",
+      },
+      {
+          "DBImpl::RunManualCompaction:PausedAtStart",
+          "DBImpl::CompactRange:PostRefitLevel",
+      },
+      // If compaction somehow were scheduled, let's let it run after reenabling
+      // manual compactions. This dependency is not expected to be hit but is
+      // here for speculatively coercing future bugs.
+      {
+          "DBImpl::CompactRange:PostRefitLevel:ManualCompactionEnabled",
+          "BackgroundCallCompaction:0",
+      },
+  });
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
+
+  ROCKSDB_NAMESPACE::port::Thread refit_level_thread([&] {
+    CompactRangeOptions cro;
+    cro.change_level = true;
+    cro.target_level = 1;
+    ASSERT_OK(dbfull()->CompactRange(cro, nullptr, nullptr));
+  });
+
+  TEST_SYNC_POINT(
+      "DBCompactionTest::ChangeLevelConflictsWithManual:"
+      "PreForegroundCompactRange");
+  ASSERT_OK(Put(Key(0), rnd.RandomString(990)));
+  ASSERT_OK(Put(Key(1), rnd.RandomString(990)));
+  ASSERT_TRUE(dbfull()
+                  ->CompactRange(CompactRangeOptions(), nullptr, nullptr)
+                  .IsIncomplete());
+
+  refit_level_thread.join();
+}
+
+TEST_F(DBCompactionTest, BottomPriCompactionCountsTowardConcurrencyLimit) {
+  // Flushes several files to trigger compaction while lock is released during
+  // a bottom-pri compaction. Verifies it does not get scheduled to thread pool
+  // because per-DB limit for compaction parallelism is one (default).
+  const int kNumL0Files = 4;
+  const int kNumLevels = 3;
+
+  env_->SetBackgroundThreads(1, Env::Priority::BOTTOM);
+
+  Options options = CurrentOptions();
+  options.level0_file_num_compaction_trigger = kNumL0Files;
+  options.num_levels = kNumLevels;
+  DestroyAndReopen(options);
+
+  // Setup last level to be non-empty since it's a bit unclear whether
+  // compaction to an empty level would be considered "bottommost".
+  ASSERT_OK(Put(Key(0), "val"));
+  ASSERT_OK(Flush());
+  MoveFilesToLevel(kNumLevels - 1);
+
+  SyncPoint::GetInstance()->LoadDependency(
+      {{"DBImpl::BGWorkBottomCompaction",
+        "DBCompactionTest::BottomPriCompactionCountsTowardConcurrencyLimit:"
+        "PreTriggerCompaction"},
+       {"DBCompactionTest::BottomPriCompactionCountsTowardConcurrencyLimit:"
+        "PostTriggerCompaction",
+        "BackgroundCallCompaction:0"}});
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  port::Thread compact_range_thread([&] {
+    CompactRangeOptions cro;
+    cro.bottommost_level_compaction = BottommostLevelCompaction::kForce;
+    cro.exclusive_manual_compaction = false;
+    ASSERT_OK(dbfull()->CompactRange(cro, nullptr, nullptr));
+  });
+
+  // Sleep in the low-pri thread so any newly scheduled compaction will be
+  // queued. Otherwise it might finish before we check its existence.
+  test::SleepingBackgroundTask sleeping_task_low;
+  env_->Schedule(&test::SleepingBackgroundTask::DoSleepTask, &sleeping_task_low,
+                 Env::Priority::LOW);
+
+  TEST_SYNC_POINT(
+      "DBCompactionTest::BottomPriCompactionCountsTowardConcurrencyLimit:"
+      "PreTriggerCompaction");
+  for (int i = 0; i < kNumL0Files; ++i) {
+    ASSERT_OK(Put(Key(0), "val"));
+    ASSERT_OK(Flush());
+  }
+  ASSERT_EQ(0u, env_->GetThreadPoolQueueLen(Env::Priority::LOW));
+  TEST_SYNC_POINT(
+      "DBCompactionTest::BottomPriCompactionCountsTowardConcurrencyLimit:"
+      "PostTriggerCompaction");
+
+  sleeping_task_low.WakeUp();
+  sleeping_task_low.WaitUntilDone();
+  compact_range_thread.join();
+}
+
 #endif  // !defined(ROCKSDB_LITE)

 }  // namespace ROCKSDB_NAMESPACE
@@ -69,7 +69,6 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBase) {
      options.level_compaction_dynamic_level_bytes = true;
      options.max_bytes_for_level_base = 10240;
      options.max_bytes_for_level_multiplier = 4;
-      options.soft_rate_limit = 1.1;
      options.max_background_compactions = max_background_compactions;
      options.num_levels = 5;

@@ -370,7 +369,6 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBaseInc) {
  options.level_compaction_dynamic_level_bytes = true;
  options.max_bytes_for_level_base = 10240;
  options.max_bytes_for_level_multiplier = 4;
-  options.soft_rate_limit = 1.1;
  options.max_background_compactions = 2;
  options.num_levels = 5;
  options.max_compaction_bytes = 100000000;
@@ -422,7 +420,6 @@ TEST_F(DBTestDynamicLevel, DISABLED_MigrateToDynamicLevelMaxBytesBase) {
  options.level_compaction_dynamic_level_bytes = false;
  options.max_bytes_for_level_base = 10240;
  options.max_bytes_for_level_multiplier = 4;
-  options.soft_rate_limit = 1.1;
  options.num_levels = 8;

  DestroyAndReopen(options);
@@ -127,31 +127,30 @@ Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
 }

 Status DBImpl::GetSortedWalFiles(VectorLogPtr& files) {
+  // If caller disabled deletions, this function should return files that are
+  // guaranteed not to be deleted until deletions are re-enabled. We need to
+  // wait for pending purges to finish since WalManager doesn't know which
+  // files are going to be purged. Additional purges won't be scheduled as
+  // long as deletions are disabled (so the below loop must terminate).
+  // Also note that we disable deletions anyway to avoid the case where a
+  // file is deleted in the middle of the scan, causing IO error.
+  Status deletions_disabled = DisableFileDeletions();
  {
-    // If caller disabled deletions, this function should return files that are
-    // guaranteed not to be deleted until deletions are re-enabled. We need to
-    // wait for pending purges to finish since WalManager doesn't know which
-    // files are going to be purged. Additional purges won't be scheduled as
-    // long as deletions are disabled (so the below loop must terminate).
    InstrumentedMutexLock l(&mutex_);
-    while (disable_delete_obsolete_files_ > 0 &&
-           (pending_purge_obsolete_files_ > 0 || bg_purge_scheduled_ > 0)) {
+    while (pending_purge_obsolete_files_ > 0 || bg_purge_scheduled_ > 0) {
      bg_cv_.Wait();
    }
  }

-  // Disable deletion in order to avoid the case where a file is deleted in
-  // the middle of the process so IO error is returned.
-  Status s = DisableFileDeletions();
-  bool file_deletion_supported = !s.IsNotSupported();
-  if (s.ok() || !file_deletion_supported) {
-    s = wal_manager_.GetSortedWalFiles(files);
-    if (file_deletion_supported) {
-      Status s2 = EnableFileDeletions(false);
-      if (!s2.ok() && s.ok()) {
-        s = s2;
-      }
-    }
+  Status s = wal_manager_.GetSortedWalFiles(files);
+
+  // DisableFileDeletions / EnableFileDeletions not supported in read-only DB
+  if (deletions_disabled.ok()) {
+    Status s2 = EnableFileDeletions(/*force*/ false);
+    assert(s2.ok());
+    s2.PermitUncheckedError();
+  } else {
+    assert(deletions_disabled.IsNotSupported());
  }

  return s;
@@ -261,15 +260,14 @@ Status DBImpl::GetLiveFilesStorageInfo(
      }
    }
    const auto& blob_files = vsi.GetBlobFiles();
-    for (const auto& pair : blob_files) {
-      const auto& meta = pair.second;
+    for (const auto& meta : blob_files) {
      assert(meta);

      results.emplace_back();
      LiveFileStorageInfo& info = results.back();

      info.relative_filename = BlobFileName(meta->GetBlobFileNumber());
-      info.directory = GetName();  // TODO?: support db_paths/cf_paths
+      info.directory = GetDir(/* path_id */ 0);
      info.file_number = meta->GetBlobFileNumber();
      info.file_type = kBlobFile;
      info.size = meta->GetBlobFileSize();
@@ -676,6 +676,7 @@ class TestFlushListener : public EventListener {
  ~TestFlushListener() override {
    prev_fc_info_.status.PermitUncheckedError();  // Ignore the status
  }
+
  void OnTableFileCreated(const TableFileCreationInfo& info) override {
    // remember the info for later checking the FlushJobInfo.
    prev_fc_info_ = info;
@@ -783,8 +784,8 @@ TEST_F(DBFlushTest, MemPurgeBasic) {
  options.listeners.emplace_back(listener);
 #endif  // !ROCKSDB_LITE
  ASSERT_OK(TryReopen(options));
-  uint32_t mempurge_count = 0;
-  uint32_t sst_count = 0;
+  std::atomic<uint32_t> mempurge_count{0};
+  std::atomic<uint32_t> sst_count{0};
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
      "DBImpl::FlushJob:MemPurgeSuccessful",
      [&](void* /*arg*/) { mempurge_count++; });
@@ -859,10 +860,8 @@ TEST_F(DBFlushTest, MemPurgeBasic) {
  // Check that there was no SST files created during flush.
  const uint32_t EXPECTED_SST_COUNT = 0;

-  EXPECT_GE(mempurge_count, EXPECTED_MIN_MEMPURGE_COUNT);
-  EXPECT_EQ(sst_count, EXPECTED_SST_COUNT);
-
-  const uint32_t mempurge_count_record = mempurge_count;
+  EXPECT_GE(mempurge_count.exchange(0), EXPECTED_MIN_MEMPURGE_COUNT);
+  EXPECT_EQ(sst_count.exchange(0), EXPECTED_SST_COUNT);

  // Insertion of of K-V pairs, no overwrites.
  for (size_t i = 0; i < NUM_REPEAT; i++) {
@@ -893,9 +892,9 @@ TEST_F(DBFlushTest, MemPurgeBasic) {
  }

  // Assert that at least one flush to storage has been performed
-  ASSERT_GT(sst_count, EXPECTED_SST_COUNT);
+  EXPECT_GT(sst_count.exchange(0), EXPECTED_SST_COUNT);
  // (which will consequently increase the number of mempurges recorded too).
-  ASSERT_GE(mempurge_count, mempurge_count_record);
+  EXPECT_GE(mempurge_count.exchange(0), EXPECTED_MIN_MEMPURGE_COUNT);

  // Assert that there is no data corruption, even with
  // a flush to storage.
@@ -935,8 +934,8 @@ TEST_F(DBFlushTest, MemPurgeDeleteAndDeleteRange) {

  ASSERT_OK(TryReopen(options));

-  uint32_t mempurge_count = 0;
-  uint32_t sst_count = 0;
+  std::atomic<uint32_t> mempurge_count{0};
+  std::atomic<uint32_t> sst_count{0};
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
      "DBImpl::FlushJob:MemPurgeSuccessful",
      [&](void* /*arg*/) { mempurge_count++; });
@@ -1024,8 +1023,8 @@ TEST_F(DBFlushTest, MemPurgeDeleteAndDeleteRange) {
  // Check that there was no SST files created during flush.
  const uint32_t EXPECTED_SST_COUNT = 0;

-  EXPECT_GE(mempurge_count, EXPECTED_MIN_MEMPURGE_COUNT);
-  EXPECT_EQ(sst_count, EXPECTED_SST_COUNT);
+  EXPECT_GE(mempurge_count.exchange(0), EXPECTED_MIN_MEMPURGE_COUNT);
+  EXPECT_EQ(sst_count.exchange(0), EXPECTED_SST_COUNT);

  // Additional test for the iterator+memPurge.
  ASSERT_OK(Put(KEY2, p_v2));
@@ -1142,8 +1141,8 @@ TEST_F(DBFlushTest, MemPurgeAndCompactionFilter) {

  ASSERT_OK(TryReopen(options));

-  uint32_t mempurge_count = 0;
-  uint32_t sst_count = 0;
+  std::atomic<uint32_t> mempurge_count{0};
+  std::atomic<uint32_t> sst_count{0};
  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
      "DBImpl::FlushJob:MemPurgeSuccessful",
      [&](void* /*arg*/) { mempurge_count++; });
@@ -1189,8 +1188,8 @@ TEST_F(DBFlushTest, MemPurgeAndCompactionFilter) {
  // Check that there was no SST files created during flush.
  const uint32_t EXPECTED_SST_COUNT = 0;

-  EXPECT_GE(mempurge_count, EXPECTED_MIN_MEMPURGE_COUNT);
-  EXPECT_EQ(sst_count, EXPECTED_SST_COUNT);
+  EXPECT_GE(mempurge_count.exchange(0), EXPECTED_MIN_MEMPURGE_COUNT);
+  EXPECT_EQ(sst_count.exchange(0), EXPECTED_SST_COUNT);

  // Verify that the ConditionalUpdateCompactionFilter
  // updated the values of KEY2 and KEY3, and not KEY4 and KEY5.
@@ -1201,7 +1200,7 @@ TEST_F(DBFlushTest, MemPurgeAndCompactionFilter) {
  ASSERT_EQ(Get(KEY5), p_v5);
 }

-TEST_F(DBFlushTest, MemPurgeWALSupport) {
+TEST_F(DBFlushTest, DISABLED_MemPurgeWALSupport) {
  Options options = CurrentOptions();

  options.statistics = CreateDBStatistics();
@@ -1233,8 +1232,8 @@ TEST_F(DBFlushTest, MemPurgeWALSupport) {
    ASSERT_OK(Put(0, "bar", "v2"));
    ASSERT_OK(Put(1, "bar", "v2"));
    ASSERT_OK(Put(1, "foo", "v3"));
-    uint32_t mempurge_count = 0;
-    uint32_t sst_count = 0;
+    std::atomic<uint32_t> mempurge_count{0};
+    std::atomic<uint32_t> sst_count{0};
    ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
        "DBImpl::FlushJob:MemPurgeSuccessful",
        [&](void* /*arg*/) { mempurge_count++; });
@@ -1330,10 +1329,10 @@ TEST_F(DBFlushTest, MemPurgeWALSupport) {
    // Check that there was no SST files created during flush.
    const uint32_t EXPECTED_SST_COUNT = 0;

-    EXPECT_GE(mempurge_count, EXPECTED_MIN_MEMPURGE_COUNT);
+    EXPECT_GE(mempurge_count.exchange(0), EXPECTED_MIN_MEMPURGE_COUNT);
    if (options.experimental_mempurge_threshold ==
        std::numeric_limits<double>::max()) {
-      EXPECT_EQ(sst_count, EXPECTED_SST_COUNT);
+      EXPECT_EQ(sst_count.exchange(0), EXPECTED_SST_COUNT);
    }

    ReopenWithColumnFamilies({"default", "pikachu"}, options);
@@ -1359,7 +1358,7 @@ TEST_F(DBFlushTest, MemPurgeWALSupport) {
      ASSERT_OK(Put(1, RNDKEY, RNDVALUE));
    }
    // ASsert than there was at least one flush to storage.
-    EXPECT_GT(sst_count, EXPECTED_SST_COUNT);
+    EXPECT_GT(sst_count.exchange(0), EXPECTED_SST_COUNT);
    ReopenWithColumnFamilies({"default", "pikachu"}, options);
    ASSERT_EQ("v4", Get(1, "foo"));
    ASSERT_EQ("v2", Get(1, "bar"));
@@ -1375,6 +1374,140 @@ TEST_F(DBFlushTest, MemPurgeWALSupport) {
  } while (ChangeWalOptions());
 }

+TEST_F(DBFlushTest, MemPurgeCorrectLogNumberAndSSTFileCreation) {
+  // Before our bug fix, we noticed that when 2 memtables were
+  // being flushed (with one memtable being the output of a
+  // previous MemPurge and one memtable being a newly-sealed memtable),
+  // the SST file created was not properly added to the DB version
+  // (via the VersionEdit obj), leading to data loss (the SST file
+  // was later being purged as an obsolete file).
+  // Therefore, we reproduce this scenario to test our fix.
+  Options options = CurrentOptions();
+
+  options.create_if_missing = true;
+  options.compression = kNoCompression;
+  options.inplace_update_support = false;
+  options.allow_concurrent_memtable_write = true;
+
+  // Enforce size of a single MemTable to 1MB (64MB = 1048576 bytes).
+  options.write_buffer_size = 1 << 20;
+  // Activate the MemPurge prototype.
+  options.experimental_mempurge_threshold = 1.0;
+
+  // Force to have more than one memtable to trigger a flush.
+  // For some reason this option does not seem to be enforced,
+  // so the following test is designed to make sure that we
+  // are testing the correct test case.
+  options.min_write_buffer_number_to_merge = 3;
+  options.max_write_buffer_number = 5;
+  options.max_write_buffer_size_to_maintain = 2 * (options.write_buffer_size);
+  options.disable_auto_compactions = true;
+  ASSERT_OK(TryReopen(options));
+
+  std::atomic<uint32_t> mempurge_count{0};
+  std::atomic<uint32_t> sst_count{0};
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::FlushJob:MemPurgeSuccessful",
+      [&](void* /*arg*/) { mempurge_count++; });
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::FlushJob:SSTFileCreated", [&](void* /*arg*/) { sst_count++; });
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
+
+  // Dummy variable used for the following callback function.
+  uint64_t ZERO = 0;
+  // We will first execute mempurge operations exclusively.
+  // Therefore, when the first flush is triggered, we want to make
+  // sure there is at least 2 memtables being flushed: one output
+  // from a previous mempurge, and one newly sealed memtable.
+  // This is when we observed in the past that some SST files created
+  // were not properly added to the DB version (via the VersionEdit obj).
+  std::atomic<uint64_t> num_memtable_at_first_flush(0);
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
+      "FlushJob::WriteLevel0Table:num_memtables", [&](void* arg) {
+        uint64_t* mems_size = reinterpret_cast<uint64_t*>(arg);
+        // atomic_compare_exchange_strong sometimes updates the value
+        // of ZERO (the "expected" object), so we make sure ZERO is indeed...
+        // zero.
+        ZERO = 0;
+        std::atomic_compare_exchange_strong(&num_memtable_at_first_flush, &ZERO,
+                                            *mems_size);
+      });
+
+  const std::vector<std::string> KEYS = {
+      "ThisIsKey1", "ThisIsKey2", "ThisIsKey3", "ThisIsKey4", "ThisIsKey5",
+      "ThisIsKey6", "ThisIsKey7", "ThisIsKey8", "ThisIsKey9"};
+  const std::string NOT_FOUND = "NOT_FOUND";
+
+  Random rnd(117);
+  const uint64_t NUM_REPEAT_OVERWRITES = 100;
+  const uint64_t NUM_RAND_INSERTS = 500;
+  const uint64_t RAND_VALUES_LENGTH = 10240;
+
+  std::string key, value;
+  std::vector<std::string> values(9, "");
+
+  // Keys used to check that no SST file disappeared.
+  for (uint64_t k = 0; k < 5; k++) {
+    values[k] = rnd.RandomString(RAND_VALUES_LENGTH);
+    ASSERT_OK(Put(KEYS[k], values[k]));
+  }
+
+  // Insertion of of K-V pairs, multiple times.
+  // Trigger at least one mempurge and no SST file creation.
+  for (size_t i = 0; i < NUM_REPEAT_OVERWRITES; i++) {
+    // Create value strings of arbitrary length RAND_VALUES_LENGTH bytes.
+    for (uint64_t k = 5; k < values.size(); k++) {
+      values[k] = rnd.RandomString(RAND_VALUES_LENGTH);
+      ASSERT_OK(Put(KEYS[k], values[k]));
+    }
+    // Check database consistency.
+    for (uint64_t k = 0; k < values.size(); k++) {
+      ASSERT_EQ(Get(KEYS[k]), values[k]);
+    }
+  }
+
+  // Check that there was at least one mempurge
+  uint32_t expected_min_mempurge_count = 1;
+  // Check that there was no SST files created during flush.
+  uint32_t expected_sst_count = 0;
+  EXPECT_GE(mempurge_count.load(), expected_min_mempurge_count);
+  EXPECT_EQ(sst_count.load(), expected_sst_count);
+
+  // Trigger an SST file creation and no mempurge.
+  for (size_t i = 0; i < NUM_RAND_INSERTS; i++) {
+    key = rnd.RandomString(RAND_VALUES_LENGTH);
+    // Create value strings of arbitrary length RAND_VALUES_LENGTH bytes.
+    value = rnd.RandomString(RAND_VALUES_LENGTH);
+    ASSERT_OK(Put(key, value));
+    // Check database consistency.
+    for (uint64_t k = 0; k < values.size(); k++) {
+      ASSERT_EQ(Get(KEYS[k]), values[k]);
+    }
+    ASSERT_EQ(Get(key), value);
+  }
+
+  // Check that there was at least one SST files created during flush.
+  expected_sst_count = 1;
+  EXPECT_GE(sst_count.load(), expected_sst_count);
+
+  // Oddly enough, num_memtable_at_first_flush is not enforced to be
+  // equal to min_write_buffer_number_to_merge. So by asserting that
+  // the first SST file creation comes from one output memtable
+  // from a previous mempurge, and one newly sealed memtable. This
+  // is the scenario where we observed that some SST files created
+  // were not properly added to the DB version before our bug fix.
+  ASSERT_GE(num_memtable_at_first_flush.load(), 2);
+
+  // Check that no data was lost after SST file creation.
+  for (uint64_t k = 0; k < values.size(); k++) {
+    ASSERT_EQ(Get(KEYS[k]), values[k]);
+  }
+  // Extra check of database consistency.
+  ASSERT_EQ(Get(key), value);
+
+  Close();
+}
+
 TEST_P(DBFlushDirectIOTest, DirectIO) {
  Options options;
  options.create_if_missing = true;
@@ -1534,7 +1667,7 @@ TEST_F(DBFlushTest, FireOnFlushCompletedAfterCommittedResult) {
  std::shared_ptr<TestListener> listener = std::make_shared<TestListener>();

  SyncPoint::GetInstance()->LoadDependency(
-      {{"DBImpl::BackgroundCallFlush:start",
+      {{"DBImpl::FlushMemTableToOutputFile:AfterPickMemtables",
        "DBFlushTest::FireOnFlushCompletedAfterCommittedResult:WaitFirst"},
       {"DBImpl::FlushMemTableToOutputFile:Finish",
        "DBFlushTest::FireOnFlushCompletedAfterCommittedResult:WaitSecond"}});
@@ -1576,6 +1709,9 @@ TEST_F(DBFlushTest, FireOnFlushCompletedAfterCommittedResult) {
  flush_opts.wait = false;
  ASSERT_OK(db_->Flush(flush_opts));
  t1.join();
+  // Ensure background work is fully finished including listener callbacks
+  // before accessing listener state.
+  ASSERT_OK(dbfull()->TEST_WaitForBackgroundWork());
  ASSERT_TRUE(listener->completed1);
  ASSERT_TRUE(listener->completed2);
  SyncPoint::GetInstance()->DisableProcessing();
@@ -1610,7 +1746,7 @@ TEST_F(DBFlushTest, FlushWithBlob) {
  ASSERT_EQ(Get("key1"), short_value);
  ASSERT_EQ(Get("key2"), long_value);

-  VersionSet* const versions = dbfull()->TEST_GetVersionSet();
+  VersionSet* const versions = dbfull()->GetVersionSet();
  assert(versions);

  ColumnFamilyData* const cfd = versions->GetColumnFamilySet()->GetDefault();
@@ -1631,7 +1767,7 @@ TEST_F(DBFlushTest, FlushWithBlob) {
  const auto& blob_files = storage_info->GetBlobFiles();
  ASSERT_EQ(blob_files.size(), 1);

-  const auto& blob_file = blob_files.begin()->second;
+  const auto& blob_file = blob_files.front();
  assert(blob_file);

  ASSERT_EQ(table_file->smallest.user_key(), "key1");
@@ -1860,6 +1996,50 @@ TEST_F(DBFlushTest, FlushWithChecksumHandoffManifest2) {
  Destroy(options);
 }

+TEST_F(DBFlushTest, PickRightMemtables) {
+  Options options = CurrentOptions();
+  DestroyAndReopen(options);
+  options.create_if_missing = true;
+
+  const std::string test_cf_name = "test_cf";
+  options.max_write_buffer_number = 128;
+  CreateColumnFamilies({test_cf_name}, options);
+
+  Close();
+
+  ReopenWithColumnFamilies({kDefaultColumnFamilyName, test_cf_name}, options);
+
+  ASSERT_OK(db_->Put(WriteOptions(), "key", "value"));
+
+  ASSERT_OK(db_->Put(WriteOptions(), handles_[1], "key", "value"));
+
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+  SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::SyncClosedLogs:BeforeReLock", [&](void* /*arg*/) {
+        ASSERT_OK(db_->Put(WriteOptions(), handles_[1], "what", "v"));
+        auto* cfhi =
+            static_cast_with_check<ColumnFamilyHandleImpl>(handles_[1]);
+        assert(cfhi);
+        ASSERT_OK(dbfull()->TEST_SwitchMemtable(cfhi->cfd()));
+      });
+  SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::FlushMemTableToOutputFile:AfterPickMemtables", [&](void* arg) {
+        auto* job = reinterpret_cast<FlushJob*>(arg);
+        assert(job);
+        const auto& mems = job->GetMemTables();
+        assert(mems.size() == 1);
+        assert(mems[0]);
+        ASSERT_EQ(1, mems[0]->GetID());
+      });
+  SyncPoint::GetInstance()->EnableProcessing();
+
+  ASSERT_OK(db_->Flush(FlushOptions(), handles_[1]));
+
+  SyncPoint::GetInstance()->DisableProcessing();
+  SyncPoint::GetInstance()->ClearAllCallBacks();
+}
+
 class DBFlushTestBlobError : public DBFlushTest,
                             public testing::WithParamInterface<std::string> {
 public:
@@ -1896,7 +2076,7 @@ TEST_P(DBFlushTestBlobError, FlushError) {
  SyncPoint::GetInstance()->DisableProcessing();
  SyncPoint::GetInstance()->ClearAllCallBacks();

-  VersionSet* const versions = dbfull()->TEST_GetVersionSet();
+  VersionSet* const versions = dbfull()->GetVersionSet();
  assert(versions);

  ColumnFamilyData* const cfd = versions->GetColumnFamilySet()->GetDefault();
@@ -1957,6 +2137,61 @@ TEST_P(DBFlushTestBlobError, FlushError) {
 }

 #ifndef ROCKSDB_LITE
+TEST_F(DBFlushTest, TombstoneVisibleInSnapshot) {
+  class SimpleTestFlushListener : public EventListener {
+   public:
+    explicit SimpleTestFlushListener(DBFlushTest* _test) : test_(_test) {}
+    ~SimpleTestFlushListener() override {}
+
+    void OnFlushBegin(DB* db, const FlushJobInfo& info) override {
+      ASSERT_EQ(static_cast<uint32_t>(0), info.cf_id);
+
+      ASSERT_OK(db->Delete(WriteOptions(), "foo"));
+      snapshot_ = db->GetSnapshot();
+      ASSERT_OK(db->Put(WriteOptions(), "foo", "value"));
+
+      auto* dbimpl = static_cast_with_check<DBImpl>(db);
+      assert(dbimpl);
+
+      ColumnFamilyHandle* cfh = db->DefaultColumnFamily();
+      auto* cfhi = static_cast_with_check<ColumnFamilyHandleImpl>(cfh);
+      assert(cfhi);
+      ASSERT_OK(dbimpl->TEST_SwitchMemtable(cfhi->cfd()));
+    }
+
+    DBFlushTest* test_ = nullptr;
+    const Snapshot* snapshot_ = nullptr;
+  };
+
+  Options options = CurrentOptions();
+  options.create_if_missing = true;
+  auto* listener = new SimpleTestFlushListener(this);
+  options.listeners.emplace_back(listener);
+  DestroyAndReopen(options);
+
+  ASSERT_OK(db_->Put(WriteOptions(), "foo", "value0"));
+
+  ManagedSnapshot snapshot_guard(db_);
+
+  ColumnFamilyHandle* default_cf = db_->DefaultColumnFamily();
+  ASSERT_OK(db_->Flush(FlushOptions(), default_cf));
+
+  const Snapshot* snapshot = listener->snapshot_;
+  assert(snapshot);
+
+  ReadOptions read_opts;
+  read_opts.snapshot = snapshot;
+
+  // Using snapshot should not see "foo".
+  {
+    std::string value;
+    Status s = db_->Get(read_opts, "foo", &value);
+    ASSERT_TRUE(s.IsNotFound());
+  }
+
+  db_->ReleaseSnapshot(snapshot);
+}
+
 TEST_P(DBAtomicFlushTest, ManualFlushUnder2PC) {
  Options options = CurrentOptions();
  options.create_if_missing = true;
@@ -2107,7 +2342,7 @@ TEST_P(DBAtomicFlushTest, PrecomputeMinLogNumberToKeepNon2PC) {
    flush_edits.push_back({});
    auto unflushed_cfh = static_cast<ColumnFamilyHandleImpl*>(handles_[1]);

-    ASSERT_EQ(PrecomputeMinLogNumberToKeepNon2PC(dbfull()->TEST_GetVersionSet(),
+    ASSERT_EQ(PrecomputeMinLogNumberToKeepNon2PC(dbfull()->GetVersionSet(),
                                                 flushed_cfds, flush_edits),
              unflushed_cfh->cfd()->GetLogNumber());
  }
@@ -2132,7 +2367,7 @@ TEST_P(DBAtomicFlushTest, PrecomputeMinLogNumberToKeepNon2PC) {
          std::min(min_log_number_to_keep, cfh->cfd()->GetLogNumber());
    }
    ASSERT_EQ(min_log_number_to_keep, log_num_after_flush);
-    ASSERT_EQ(PrecomputeMinLogNumberToKeepNon2PC(dbfull()->TEST_GetVersionSet(),
+    ASSERT_EQ(PrecomputeMinLogNumberToKeepNon2PC(dbfull()->GetVersionSet(),
                                                 flushed_cfds, flush_edits),
              min_log_number_to_keep);
  }
@@ -40,6 +40,11 @@ size_t CompactedDBImpl::FindFile(const Slice& key) {

 Status CompactedDBImpl::Get(const ReadOptions& options, ColumnFamilyHandle*,
                            const Slice& key, PinnableSlice* value) {
+  assert(user_comparator_);
+  if (options.timestamp || user_comparator_->timestamp_size()) {
+    // TODO: support timestamp
+    return Status::NotSupported();
+  }
  GetContext get_context(user_comparator_, nullptr, nullptr, nullptr,
                         GetContext::kNotFound, key, value, nullptr, nullptr,
                         nullptr, true, nullptr, nullptr);
@@ -58,6 +63,11 @@ Status CompactedDBImpl::Get(const ReadOptions& options, ColumnFamilyHandle*,
 std::vector<Status> CompactedDBImpl::MultiGet(const ReadOptions& options,
    const std::vector<ColumnFamilyHandle*>&,
    const std::vector<Slice>& keys, std::vector<std::string>* values) {
+  assert(user_comparator_);
+  if (user_comparator_->timestamp_size() || options.timestamp) {
+    // TODO: support timestamp
+    return std::vector<Status>(keys.size(), Status::NotSupported());
+  }
  autovector<TableReader*, 16> reader_list;
  for (const auto& key : keys) {
    const FdWithKeyRange& f = files_.files[FindFile(key)];
@@ -69,6 +79,7 @@ std::vector<Status> CompactedDBImpl::MultiGet(const ReadOptions& options,
      reader_list.push_back(f.fd.table_reader);
    }
  }
+
  std::vector<Status> statuses(keys.size(), Status::NotFound());
  values->resize(keys.size());
  int idx = 0;
@@ -160,7 +171,9 @@ Status CompactedDBImpl::Open(const Options& options,
  std::unique_ptr<CompactedDBImpl> db(new CompactedDBImpl(db_options, dbname));
  Status s = db->Init(options);
  if (s.ok()) {
-    db->StartPeriodicWorkScheduler();
+    s = db->StartPeriodicWorkScheduler();
+  }
+  if (s.ok()) {
    ROCKS_LOG_INFO(db->immutable_db_options_.info_log,
                   "Opened the db as fully compacted mode");
    LogFlush(db->immutable_db_options_.info_log);
@@ -119,18 +119,16 @@ CompressionType GetCompressionFlush(
  // Compressing memtable flushes might not help unless the sequential load
  // optimization is used for leveled compaction. Otherwise the CPU and
  // latency overhead is not offset by saving much space.
-  if (ioptions.compaction_style == kCompactionStyleUniversal) {
-    if (mutable_cf_options.compaction_options_universal
-            .compression_size_percent < 0) {
-      return mutable_cf_options.compression;
-    } else {
-      return kNoCompression;
-    }
-  } else if (!ioptions.compression_per_level.empty()) {
-    // For leveled compress when min_level_to_compress != 0.
-    return ioptions.compression_per_level[0];
-  } else {
+  if (ioptions.compaction_style == kCompactionStyleUniversal &&
+      mutable_cf_options.compaction_options_universal
+              .compression_size_percent >= 0) {
+    return kNoCompression;
+  }
+  if (mutable_cf_options.compression_per_level.empty()) {
    return mutable_cf_options.compression;
+  } else {
+    // For leveled compress when min_level_to_compress != 0.
+    return mutable_cf_options.compression_per_level[0];
  }
 }

@@ -234,7 +232,6 @@ DBImpl::DBImpl(const DBOptions& options, const std::string& dbname,
      use_custom_gc_(seq_per_batch),
      shutdown_initiated_(false),
      own_sfm_(options.sst_file_manager == nullptr),
-      preserve_deletes_(options.preserve_deletes),
      closed_(false),
      atomic_flush_install_cv_(&mutex_),
      blob_callback_(immutable_db_options_.sst_file_manager.get(), &mutex_,
@@ -272,11 +269,6 @@ DBImpl::DBImpl(const DBOptions& options, const std::string& dbname,
  mutable_db_options_.Dump(immutable_db_options_.info_log.get());
  DumpSupportInfo(immutable_db_options_.info_log.get());

-  // always open the DB with 0 here, which means if preserve_deletes_==true
-  // we won't drop any deletion markers until SetPreserveDeletesSequenceNumber()
-  // is called by client and this seqnum is advanced.
-  preserve_deletes_seqnum_.store(0);
-
  if (write_buffer_manager_) {
    wbm_stall_.reset(new WBMStallInterface());
  }
@@ -406,14 +398,6 @@ Status DBImpl::ResumeImpl(DBRecoverContext context) {

  JobContext job_context(0);
  FindObsoleteFiles(&job_context, true);
-  if (s.ok()) {
-    s = error_handler_.ClearBGError();
-  } else {
-    // NOTE: this is needed to pass ASSERT_STATUS_CHECKED
-    // in the DBSSTTest.DBWithMaxSpaceAllowedRandomized test.
-    // See https://github.com/facebook/rocksdb/pull/7715#issuecomment-754947952
-    error_handler_.GetRecoveryError().PermitUncheckedError();
-  }
  mutex_.Unlock();

  job_context.manifest_file_number = 1;
@@ -434,11 +418,31 @@ Status DBImpl::ResumeImpl(DBRecoverContext context) {
            immutable_db_options_.info_log,
            "DB resume requested but could not enable file deletions [%s]",
            s.ToString().c_str());
+        assert(false);
      }
    }
-    ROCKS_LOG_INFO(immutable_db_options_.info_log, "Successfully resumed DB");
  }
+
  mutex_.Lock();
+  if (s.ok()) {
+    // This will notify and unblock threads waiting for error recovery to
+    // finish. Those previouly waiting threads can now proceed, which may
+    // include closing the db.
+    s = error_handler_.ClearBGError();
+  } else {
+    // NOTE: this is needed to pass ASSERT_STATUS_CHECKED
+    // in the DBSSTTest.DBWithMaxSpaceAllowedRandomized test.
+    // See https://github.com/facebook/rocksdb/pull/7715#issuecomment-754947952
+    error_handler_.GetRecoveryError().PermitUncheckedError();
+  }
+
+  if (s.ok()) {
+    ROCKS_LOG_INFO(immutable_db_options_.info_log, "Successfully resumed DB");
+  } else {
+    ROCKS_LOG_INFO(immutable_db_options_.info_log, "Failed to resume DB [%s]",
+                   s.ToString().c_str());
+  }
+
  // Check for shutdown again before scheduling further compactions,
  // since we released and re-acquired the lock above
  if (shutdown_initiated_) {
@@ -533,10 +537,19 @@ Status DBImpl::CloseHelper() {
  // marker. After this we do a variant of the waiting and unschedule work
  // (to consider: moving all the waiting into CancelAllBackgroundWork(true))
  CancelAllBackgroundWork(false);
+
+  // Cancel manual compaction if there's any
+  if (HasPendingManualCompaction()) {
+    DisableManualCompaction();
+  }
  mutex_.Lock();
-  env_->UnSchedule(this, Env::Priority::BOTTOM);
-  env_->UnSchedule(this, Env::Priority::LOW);
-  env_->UnSchedule(this, Env::Priority::HIGH);
+  // Unschedule all tasks for this DB
+  for (uint8_t i = 0; i < static_cast<uint8_t>(TaskType::kCount); i++) {
+    env_->UnSchedule(GetTaskTag(i), Env::Priority::BOTTOM);
+    env_->UnSchedule(GetTaskTag(i), Env::Priority::LOW);
+    env_->UnSchedule(GetTaskTag(i), Env::Priority::HIGH);
+  }
+
  Status ret = Status::OK();

  // Wait for background work to finish
@@ -755,7 +768,7 @@ void DBImpl::PrintStatistics() {
  }
 }

-void DBImpl::StartPeriodicWorkScheduler() {
+Status DBImpl::StartPeriodicWorkScheduler() {
 #ifndef ROCKSDB_LITE

 #ifndef NDEBUG
@@ -765,7 +778,7 @@ void DBImpl::StartPeriodicWorkScheduler() {
      "DBImpl::StartPeriodicWorkScheduler:DisableScheduler",
      &disable_scheduler);
  if (disable_scheduler) {
-    return;
+    return Status::OK();
  }
 #endif  // !NDEBUG

@@ -776,10 +789,11 @@ void DBImpl::StartPeriodicWorkScheduler() {
                             &periodic_work_scheduler_);
  }

-  periodic_work_scheduler_->Register(
+  return periodic_work_scheduler_->Register(
      this, mutable_db_options_.stats_dump_period_sec,
      mutable_db_options_.stats_persist_period_sec);
 #endif  // !ROCKSDB_LITE
+  return Status::OK();
 }

 // esitmate the total size of stats_history_
@@ -790,8 +804,7 @@ size_t DBImpl::EstimateInMemoryStatsHistorySize() const {
  size_t size_per_slice =
      sizeof(uint64_t) + sizeof(std::map<std::string, uint64_t>);
  // non-empty map, stats_history_.begin() guaranteed to exist
-  std::map<std::string, uint64_t> sample_slice(stats_history_.begin()->second);
-  for (const auto& pairs : sample_slice) {
+  for (const auto& pairs : stats_history_.begin()->second) {
    size_per_slice +=
        pairs.first.capacity() + sizeof(pairs.first) + sizeof(pairs.second);
  }
@@ -1214,7 +1227,7 @@ Status DBImpl::SetDBOptions(
              mutable_db_options_.stats_persist_period_sec) {
        mutex_.Unlock();
        periodic_work_scheduler_->Unregister(this);
-        periodic_work_scheduler_->Register(
+        s = periodic_work_scheduler_->Register(
            this, new_options.stats_dump_period_sec,
            new_options.stats_persist_period_sec);
        mutex_.Lock();
@@ -1389,7 +1402,9 @@ Status DBImpl::SyncWAL() {
    IOStatusCheck(io_s);
  }
  if (status.ok() && need_log_dir_sync) {
-    status = directories_.GetWalDir()->Fsync(IOOptions(), nullptr);
+    status = directories_.GetWalDir()->FsyncWithDirOptions(
+        IOOptions(), nullptr,
+        DirFsyncOptions(DirFsyncOptions::FsyncReason::kNewFileSynced));
  }
  TEST_SYNC_POINT("DBWALTest::SyncWALNotWaitWrite:2");

@@ -1485,13 +1500,28 @@ void DBImpl::SetLastPublishedSequence(SequenceNumber seq) {
  versions_->SetLastPublishedSequence(seq);
 }

-bool DBImpl::SetPreserveDeletesSequenceNumber(SequenceNumber seqnum) {
-  if (seqnum > preserve_deletes_seqnum_.load()) {
-    preserve_deletes_seqnum_.store(seqnum);
-    return true;
-  } else {
-    return false;
+Status DBImpl::GetFullHistoryTsLow(ColumnFamilyHandle* column_family,
+                                   std::string* ts_low) {
+  if (ts_low == nullptr) {
+    return Status::InvalidArgument("ts_low is nullptr");
  }
+  ColumnFamilyData* cfd = nullptr;
+  if (column_family == nullptr) {
+    cfd = default_cf_handle_->cfd();
+  } else {
+    auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
+    assert(cfh != nullptr);
+    cfd = cfh->cfd();
+  }
+  assert(cfd != nullptr && cfd->user_comparator() != nullptr);
+  if (cfd->user_comparator()->timestamp_size() == 0) {
+    return Status::InvalidArgument(
+        "Timestamp is not enabled in this column family");
+  }
+  InstrumentedMutexLock l(&mutex_);
+  *ts_low = cfd->GetFullHistoryTsLow();
+  assert(cfd->user_comparator()->timestamp_size() == ts_low->size());
+  return Status::OK();
 }

 InternalIterator* DBImpl::NewInternalIterator(const ReadOptions& read_options,
@@ -1544,6 +1574,8 @@ void DBImpl::BackgroundCallPurge() {
    mutex_.Lock();
  }

+  assert(bg_purge_scheduled_ > 0);
+
  // Can't use iterator to go over purge_files_ because inside the loop we're
  // unlocking the mutex that protects purge_files_.
  while (!purge_files_.empty()) {
@@ -1611,17 +1643,7 @@ static void CleanupIteratorState(void* arg1, void* /*arg2*/) {
      delete state->super_version;
    }
    if (job_context.HaveSomethingToDelete()) {
-      if (state->background_purge) {
-        // PurgeObsoleteFiles here does not delete files. Instead, it adds the
-        // files to be deleted to a job queue, and deletes it in a separate
-        // background thread.
-        state->db->PurgeObsoleteFiles(job_context, true /* schedule only */);
-        state->mu->Lock();
-        state->db->SchedulePurge();
-        state->mu->Unlock();
-      } else {
-        state->db->PurgeObsoleteFiles(job_context);
-      }
+      state->db->PurgeObsoleteFiles(job_context, state->background_purge);
    }
    job_context.Clean();
  }
@@ -1727,19 +1749,21 @@ Status DBImpl::GetImpl(const ReadOptions& read_options, const Slice& key,
         get_impl_options.merge_operands != nullptr);

  assert(get_impl_options.column_family);
-  const Comparator* ucmp = get_impl_options.column_family->GetComparator();
-  assert(ucmp);
-  size_t ts_sz = ucmp->timestamp_size();
-  GetWithTimestampReadCallback read_cb(0);  // Will call Refresh

-#ifndef NDEBUG
-  if (ts_sz > 0) {
-    assert(read_options.timestamp);
-    assert(read_options.timestamp->size() == ts_sz);
+  if (read_options.timestamp) {
+    const Status s = FailIfTsSizesMismatch(get_impl_options.column_family,
+                                           *(read_options.timestamp));
+    if (!s.ok()) {
+      return s;
+    }
  } else {
-    assert(!read_options.timestamp);
+    const Status s = FailIfCfHasTs(get_impl_options.column_family);
+    if (!s.ok()) {
+      return s;
+    }
  }
-#endif  // NDEBUG
+
+  GetWithTimestampReadCallback read_cb(0);  // Will call Refresh

  PERF_CPU_TIMER_GUARD(get_cpu_nanos, immutable_db_options_.clock);
  StopWatch sw(immutable_db_options_.clock, stats_, DB_GET);
@@ -1808,7 +1832,9 @@ Status DBImpl::GetImpl(const ReadOptions& read_options, const Slice& key,
  // only if t <= read_opts.timestamp and s <= snapshot.
  // HACK: temporarily overwrite input struct field but restore
  SaveAndRestore<ReadCallback*> restore_callback(&get_impl_options.callback);
-  if (ts_sz > 0) {
+  const Comparator* ucmp = get_impl_options.column_family->GetComparator();
+  assert(ucmp);
+  if (ucmp->timestamp_size() > 0) {
    assert(!get_impl_options
                .callback);  // timestamp with callback is not supported
    read_cb.Refresh(snapshot);
@@ -1831,7 +1857,8 @@ Status DBImpl::GetImpl(const ReadOptions& read_options, const Slice& key,
  bool skip_memtable = (read_options.read_tier == kPersistedTier &&
                        has_unpersisted_data_.load(std::memory_order_relaxed));
  bool done = false;
-  std::string* timestamp = ts_sz > 0 ? get_impl_options.timestamp : nullptr;
+  std::string* timestamp =
+      ucmp->timestamp_size() > 0 ? get_impl_options.timestamp : nullptr;
  if (!skip_memtable) {
    // Get value associated with key
    if (get_impl_options.get_value) {
@@ -1873,11 +1900,12 @@ Status DBImpl::GetImpl(const ReadOptions& read_options, const Slice& key,
      return s;
    }
  }
+  PinnedIteratorsManager pinned_iters_mgr;
  if (!done) {
    PERF_TIMER_GUARD(get_from_output_files_time);
    sv->current->Get(
        read_options, lkey, get_impl_options.value, timestamp, &s,
-        &merge_context, &max_covering_tombstone_seq,
+        &merge_context, &max_covering_tombstone_seq, &pinned_iters_mgr,
        get_impl_options.get_value ? get_impl_options.value_found : nullptr,
        nullptr, nullptr,
        get_impl_options.get_value ? get_impl_options.callback : nullptr,
@@ -1938,19 +1966,36 @@ std::vector<Status> DBImpl::MultiGet(
  StopWatch sw(immutable_db_options_.clock, stats_, DB_MULTIGET);
  PERF_TIMER_GUARD(get_snapshot_time);

-#ifndef NDEBUG
-  for (const auto* cfh : column_family) {
-    assert(cfh);
-    const Comparator* const ucmp = cfh->GetComparator();
-    assert(ucmp);
-    if (ucmp->timestamp_size() > 0) {
-      assert(read_options.timestamp);
-      assert(ucmp->timestamp_size() == read_options.timestamp->size());
+  size_t num_keys = keys.size();
+  assert(column_family.size() == num_keys);
+  std::vector<Status> stat_list(num_keys);
+
+  bool should_fail = false;
+  for (size_t i = 0; i < num_keys; ++i) {
+    assert(column_family[i]);
+    if (read_options.timestamp) {
+      stat_list[i] =
+          FailIfTsSizesMismatch(column_family[i], *(read_options.timestamp));
+      if (!stat_list[i].ok()) {
+        should_fail = true;
+      }
    } else {
-      assert(!read_options.timestamp);
+      stat_list[i] = FailIfCfHasTs(column_family[i]);
+      if (!stat_list[i].ok()) {
+        should_fail = true;
+      }
    }
  }
-#endif  // NDEBUG
+
+  if (should_fail) {
+    for (auto& s : stat_list) {
+      if (s.ok()) {
+        s = Status::Incomplete(
+            "DB not queried due to invalid argument(s) in the same MultiGet");
+      }
+    }
+    return stat_list;
+  }

  if (tracer_) {
    // TODO: This mutex should be removed later, to improve performance when
@@ -1993,8 +2038,6 @@ std::vector<Status> DBImpl::MultiGet(
  MergeContext merge_context;

  // Note: this always resizes the values array
-  size_t num_keys = keys.size();
-  std::vector<Status> stat_list(num_keys);
  values->resize(num_keys);
  if (timestamps) {
    timestamps->resize(num_keys);
@@ -2054,11 +2097,13 @@ std::vector<Status> DBImpl::MultiGet(
    if (!done) {
      PinnableSlice pinnable_val;
      PERF_TIMER_GUARD(get_from_output_files_time);
-      super_version->current->Get(
-          read_options, lkey, &pinnable_val, timestamp, &s, &merge_context,
-          &max_covering_tombstone_seq, /*value_found=*/nullptr,
-          /*key_exists=*/nullptr,
-          /*seq=*/nullptr, read_callback);
+      PinnedIteratorsManager pinned_iters_mgr;
+      super_version->current->Get(read_options, lkey, &pinnable_val, timestamp,
+                                  &s, &merge_context,
+                                  &max_covering_tombstone_seq,
+                                  &pinned_iters_mgr, /*value_found=*/nullptr,
+                                  /*key_exists=*/nullptr,
+                                  /*seq=*/nullptr, read_callback);
      value->assign(pinnable_val.data(), pinnable_val.size());
      RecordTick(stats_, MEMTABLE_MISS);
    }
@@ -2259,20 +2304,31 @@ void DBImpl::MultiGet(const ReadOptions& read_options, const size_t num_keys,
    return;
  }

-#ifndef NDEBUG
+  bool should_fail = false;
  for (size_t i = 0; i < num_keys; ++i) {
    ColumnFamilyHandle* cfh = column_families[i];
    assert(cfh);
-    const Comparator* const ucmp = cfh->GetComparator();
-    assert(ucmp);
-    if (ucmp->timestamp_size() > 0) {
-      assert(read_options.timestamp);
-      assert(read_options.timestamp->size() == ucmp->timestamp_size());
+    if (read_options.timestamp) {
+      statuses[i] = FailIfTsSizesMismatch(cfh, *(read_options.timestamp));
+      if (!statuses[i].ok()) {
+        should_fail = true;
+      }
    } else {
-      assert(!read_options.timestamp);
+      statuses[i] = FailIfCfHasTs(cfh);
+      if (!statuses[i].ok()) {
+        should_fail = true;
+      }
    }
  }
-#endif  // NDEBUG
+  if (should_fail) {
+    for (size_t i = 0; i < num_keys; ++i) {
+      if (statuses[i].ok()) {
+        statuses[i] = Status::Incomplete(
+            "DB not queried due to invalid argument(s) in the same MultiGet");
+      }
+    }
+    return;
+  }

  if (tracer_) {
    // TODO: This mutex should be removed later, to improve performance when
@@ -2899,15 +2955,22 @@ Iterator* DBImpl::NewIterator(const ReadOptions& read_options,
    return NewErrorIterator(Status::NotSupported(
        "ReadTier::kPersistedData is not yet supported in iterators."));
  }
-  // if iterator wants internal keys, we can only proceed if
-  // we can guarantee the deletes haven't been processed yet
-  if (immutable_db_options_.preserve_deletes &&
-      read_options.iter_start_seqnum > 0 &&
-      read_options.iter_start_seqnum < preserve_deletes_seqnum_.load()) {
-    return NewErrorIterator(Status::InvalidArgument(
-        "Iterator requested internal keys which are too old and are not"
-        " guaranteed to be preserved, try larger iter_start_seqnum opt."));
+
+  assert(column_family);
+
+  if (read_options.timestamp) {
+    const Status s =
+        FailIfTsSizesMismatch(column_family, *(read_options.timestamp));
+    if (!s.ok()) {
+      return NewErrorIterator(s);
+    }
+  } else {
+    const Status s = FailIfCfHasTs(column_family);
+    if (!s.ok()) {
+      return NewErrorIterator(s);
+    }
  }
+
  auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
  ColumnFamilyData* cfd = cfh->cfd();
  assert(cfd != nullptr);
@@ -3034,6 +3097,25 @@ Status DBImpl::NewIterators(
    return Status::NotSupported(
        "ReadTier::kPersistedData is not yet supported in iterators.");
  }
+
+  if (read_options.timestamp) {
+    for (auto* cf : column_families) {
+      assert(cf);
+      const Status s = FailIfTsSizesMismatch(cf, *(read_options.timestamp));
+      if (!s.ok()) {
+        return s;
+      }
+    }
+  } else {
+    for (auto* cf : column_families) {
+      assert(cf);
+      const Status s = FailIfCfHasTs(cf);
+      if (!s.ok()) {
+        return s;
+      }
+    }
+  }
+
  ReadCallback* read_callback = nullptr;  // No read callback provided.
  iterators->clear();
  iterators->reserve(column_families.size());
@@ -3123,6 +3205,12 @@ bool CfdListContains(const CfdList& list, ColumnFamilyData* cfd) {
 }  //  namespace

 void DBImpl::ReleaseSnapshot(const Snapshot* s) {
+  if (s == nullptr) {
+    // DBImpl::GetSnapshot() can return nullptr when snapshot
+    // not supported by specifying the condition:
+    // inplace_update_support enabled.
+    return;
+  }
  const SnapshotImpl* casted_s = reinterpret_cast<const SnapshotImpl*>(s);
  {
    InstrumentedMutexLock l(&mutex_);
@@ -3532,7 +3620,7 @@ void DBImpl::GetApproximateMemTableStats(ColumnFamilyHandle* column_family,
 Status DBImpl::GetApproximateSizes(const SizeApproximationOptions& options,
                                   ColumnFamilyHandle* column_family,
                                   const Range* range, int n, uint64_t* sizes) {
-  if (!options.include_memtabtles && !options.include_files) {
+  if (!options.include_memtables && !options.include_files) {
    return Status::InvalidArgument("Invalid options");
  }

@@ -3570,7 +3658,7 @@ Status DBImpl::GetApproximateSizes(const SizeApproximationOptions& options,
          options, v, k1.Encode(), k2.Encode(), /*start_level=*/0,
          /*end_level=*/-1, TableReaderCaller::kUserApproximateSize);
    }
-    if (options.include_memtabtles) {
+    if (options.include_memtables) {
      sizes[i] += sv->mem->ApproximateStats(k1.Encode(), k2.Encode()).size;
      sizes[i] += sv->imm->ApproximateStats(k1.Encode(), k2.Encode()).size;
    }
@@ -3947,16 +4035,25 @@ Status DBImpl::GetDbSessionId(std::string& session_id) const {
  return Status::OK();
 }

+namespace {
+SemiStructuredUniqueIdGen* DbSessionIdGen() {
+  static SemiStructuredUniqueIdGen gen;
+  return &gen;
+}
+}  // namespace
+
+void DBImpl::TEST_ResetDbSessionIdGen() { DbSessionIdGen()->Reset(); }
+
 std::string DBImpl::GenerateDbSessionId(Env*) {
  // See SemiStructuredUniqueIdGen for its desirable properties.
-  static SemiStructuredUniqueIdGen gen;
+  auto gen = DbSessionIdGen();

  uint64_t lo, hi;
-  gen.GenerateNext(&hi, &lo);
+  gen->GenerateNext(&hi, &lo);
  if (lo == 0) {
    // Avoid emitting session ID with lo==0, so that SST unique
    // IDs can be more easily ensured non-zero
-    gen.GenerateNext(&hi, &lo);
+    gen->GenerateNext(&hi, &lo);
    assert(lo != 0);
  }
  return EncodeSessionId(hi, lo);
@@ -3997,6 +4094,10 @@ Status DB::DropColumnFamilies(
 }

 Status DB::DestroyColumnFamilyHandle(ColumnFamilyHandle* column_family) {
+  if (DefaultColumnFamily() == column_family) {
+    return Status::InvalidArgument(
+        "Cannot destroy the handle returned by DefaultColumnFamily()");
+  }
  delete column_family;
  return Status::OK();
 }
@@ -4288,6 +4389,14 @@ Status DBImpl::RenameTempFileToOptionsFile(const std::string& file_name) {
  if (s.ok()) {
    // Retry if the file name happen to conflict with an existing one.
    s = GetEnv()->RenameFile(file_name, options_file_name);
+    std::unique_ptr<FSDirectory> dir_obj;
+    if (s.ok()) {
+      s = fs_->NewDirectory(GetName(), IOOptions(), &dir_obj, nullptr);
+    }
+    if (s.ok()) {
+      s = dir_obj->FsyncWithDirOptions(IOOptions(), nullptr,
+                                       DirFsyncOptions(options_file_name));
+    }
  }
  if (s.ok()) {
    InstrumentedMutexLock l(&mutex_);
@@ -4366,25 +4475,38 @@ SequenceNumber DBImpl::GetEarliestMemTableSequenceNumber(SuperVersion* sv,
  return earliest_seq;
 }

-Status DBImpl::GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,
-                                       bool cache_only,
-                                       SequenceNumber lower_bound_seq,
-                                       SequenceNumber* seq,
-                                       bool* found_record_for_key,
-                                       bool* is_blob_index) {
+Status DBImpl::GetLatestSequenceForKey(
+    SuperVersion* sv, const Slice& key, bool cache_only,
+    SequenceNumber lower_bound_seq, SequenceNumber* seq, std::string* timestamp,
+    bool* found_record_for_key, bool* is_blob_index) {
  Status s;
  MergeContext merge_context;
  SequenceNumber max_covering_tombstone_seq = 0;

  ReadOptions read_options;
  SequenceNumber current_seq = versions_->LastSequence();
-  LookupKey lkey(key, current_seq);
+
+  ColumnFamilyData* cfd = sv->cfd;
+  assert(cfd);
+  const Comparator* const ucmp = cfd->user_comparator();
+  assert(ucmp);
+  size_t ts_sz = ucmp->timestamp_size();
+  std::string ts_buf;
+  if (ts_sz > 0) {
+    assert(timestamp);
+    ts_buf.assign(ts_sz, '\xff');
+  } else {
+    assert(!timestamp);
+  }
+  Slice ts(ts_buf);
+
+  LookupKey lkey(key, current_seq, ts_sz == 0 ? nullptr : &ts);

  *seq = kMaxSequenceNumber;
  *found_record_for_key = false;

  // Check if there is a record for this key in the latest memtable
-  sv->mem->Get(lkey, nullptr, nullptr, &s, &merge_context,
+  sv->mem->Get(lkey, /*value=*/nullptr, timestamp, &s, &merge_context,
               &max_covering_tombstone_seq, seq, read_options,
               nullptr /*read_callback*/, is_blob_index);

@@ -4396,6 +4518,10 @@ Status DBImpl::GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,

    return s;
  }
+  assert(!ts_sz ||
+         (*seq != kMaxSequenceNumber &&
+          *timestamp != std::string(ts_sz, '\xff')) ||
+         (*seq == kMaxSequenceNumber && timestamp->empty()));

  if (*seq != kMaxSequenceNumber) {
    // Found a sequence number, no need to check immutable memtables
@@ -4411,7 +4537,7 @@ Status DBImpl::GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,
  }

  // Check if there is a record for this key in the immutable memtables
-  sv->imm->Get(lkey, nullptr, nullptr, &s, &merge_context,
+  sv->imm->Get(lkey, /*value=*/nullptr, timestamp, &s, &merge_context,
               &max_covering_tombstone_seq, seq, read_options,
               nullptr /*read_callback*/, is_blob_index);

@@ -4424,6 +4550,11 @@ Status DBImpl::GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,
    return s;
  }

+  assert(!ts_sz ||
+         (*seq != kMaxSequenceNumber &&
+          *timestamp != std::string(ts_sz, '\xff')) ||
+         (*seq == kMaxSequenceNumber && timestamp->empty()));
+
  if (*seq != kMaxSequenceNumber) {
    // Found a sequence number, no need to check memtable history
    *found_record_for_key = true;
@@ -4438,9 +4569,9 @@ Status DBImpl::GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,
  }

  // Check if there is a record for this key in the immutable memtables
-  sv->imm->GetFromHistory(lkey, nullptr, nullptr, &s, &merge_context,
-                          &max_covering_tombstone_seq, seq, read_options,
-                          is_blob_index);
+  sv->imm->GetFromHistory(lkey, /*value=*/nullptr, timestamp, &s,
+                          &merge_context, &max_covering_tombstone_seq, seq,
+                          read_options, is_blob_index);

  if (!(s.ok() || s.IsNotFound() || s.IsMergeInProgress())) {
    // unexpected error reading memtable.
@@ -4452,8 +4583,13 @@ Status DBImpl::GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,
    return s;
  }

+  assert(!ts_sz ||
+         (*seq != kMaxSequenceNumber &&
+          *timestamp != std::string(ts_sz, '\xff')) ||
+         (*seq == kMaxSequenceNumber && timestamp->empty()));
  if (*seq != kMaxSequenceNumber) {
    // Found a sequence number, no need to check SST files
+    assert(0 == ts_sz || *timestamp != std::string(ts_sz, '\xff'));
    *found_record_for_key = true;
    return Status::OK();
  }
@@ -4466,8 +4602,10 @@ Status DBImpl::GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,
  // SST files if cache_only=true?
  if (!cache_only) {
    // Check tables
-    sv->current->Get(read_options, lkey, nullptr, nullptr, &s, &merge_context,
-                     &max_covering_tombstone_seq, nullptr /* value_found */,
+    PinnedIteratorsManager pinned_iters_mgr;
+    sv->current->Get(read_options, lkey, /*value=*/nullptr, timestamp, &s,
+                     &merge_context, &max_covering_tombstone_seq,
+                     &pinned_iters_mgr, nullptr /* value_found */,
                     found_record_for_key, seq, nullptr /*read_callback*/,
                     is_blob_index);

@@ -5000,10 +5138,11 @@ Status DBImpl::VerifyChecksumInternal(const ReadOptions& read_options,

    if (s.ok() && use_file_checksum) {
      const auto& blob_files = vstorage->GetBlobFiles();
-      for (const auto& pair : blob_files) {
-        const uint64_t blob_file_number = pair.first;
-        const auto& meta = pair.second;
+      for (const auto& meta : blob_files) {
        assert(meta);
+
+        const uint64_t blob_file_number = meta->GetBlobFileNumber();
+
        const std::string blob_file_name = BlobFileName(
            cfd->ioptions()->cf_paths.front().path, blob_file_number);
        s = VerifyFullFileChecksum(meta->GetChecksumValue(),
@@ -5062,7 +5201,8 @@ Status DBImpl::VerifyFullFileChecksum(const std::string& file_checksum_expected,
      fs_.get(), fname, immutable_db_options_.file_checksum_gen_factory.get(),
      func_name_expected, &file_checksum, &func_name,
      read_options.readahead_size, immutable_db_options_.allow_mmap_reads,
-      io_tracer_, immutable_db_options_.rate_limiter.get());
+      io_tracer_, immutable_db_options_.rate_limiter.get(),
+      read_options.rate_limiter_priority);
  if (s.ok()) {
    assert(func_name_expected == func_name);
    if (file_checksum != file_checksum_expected) {
@@ -146,24 +146,36 @@ class DBImpl : public DB {
  // ---- Implementations of the DB interface ----

  using DB::Resume;
-  virtual Status Resume() override;
+  Status Resume() override;

  using DB::Put;
-  virtual Status Put(const WriteOptions& options,
-                     ColumnFamilyHandle* column_family, const Slice& key,
-                     const Slice& value) override;
+  Status Put(const WriteOptions& options, ColumnFamilyHandle* column_family,
+             const Slice& key, const Slice& value) override;
+  Status Put(const WriteOptions& options, ColumnFamilyHandle* column_family,
+             const Slice& key, const Slice& ts, const Slice& value) override;
+
  using DB::Merge;
-  virtual Status Merge(const WriteOptions& options,
-                       ColumnFamilyHandle* column_family, const Slice& key,
-                       const Slice& value) override;
+  Status Merge(const WriteOptions& options, ColumnFamilyHandle* column_family,
+               const Slice& key, const Slice& value) override;
  using DB::Delete;
-  virtual Status Delete(const WriteOptions& options,
-                        ColumnFamilyHandle* column_family,
-                        const Slice& key) override;
+  Status Delete(const WriteOptions& options, ColumnFamilyHandle* column_family,
+                const Slice& key) override;
+  Status Delete(const WriteOptions& options, ColumnFamilyHandle* column_family,
+                const Slice& key, const Slice& ts) override;
+
  using DB::SingleDelete;
-  virtual Status SingleDelete(const WriteOptions& options,
-                              ColumnFamilyHandle* column_family,
-                              const Slice& key) override;
+  Status SingleDelete(const WriteOptions& options,
+                      ColumnFamilyHandle* column_family,
+                      const Slice& key) override;
+  Status SingleDelete(const WriteOptions& options,
+                      ColumnFamilyHandle* column_family, const Slice& key,
+                      const Slice& ts) override;
+
+  using DB::DeleteRange;
+  Status DeleteRange(const WriteOptions& options,
+                     ColumnFamilyHandle* column_family, const Slice& begin_key,
+                     const Slice& end_key) override;
+
  using DB::Write;
  virtual Status Write(const WriteOptions& options,
                       WriteBatch* updates) override;
@@ -353,7 +365,15 @@ class DBImpl : public DB {

  virtual SequenceNumber GetLatestSequenceNumber() const override;

-  virtual bool SetPreserveDeletesSequenceNumber(SequenceNumber seqnum) override;
+  // IncreaseFullHistoryTsLow(ColumnFamilyHandle*, std::string) will acquire
+  // and release db_mutex
+  Status IncreaseFullHistoryTsLow(ColumnFamilyHandle* column_family,
+                                  std::string ts_low) override;
+
+  // GetFullHistoryTsLow(ColumnFamilyHandle*, std::string*) will acquire and
+  // release db_mutex
+  Status GetFullHistoryTsLow(ColumnFamilyHandle* column_family,
+                             std::string* ts_low) override;

  virtual Status GetDbIdentity(std::string& identity) const override;

@@ -582,9 +602,15 @@ class DBImpl : public DB {
  // in the memtables, including memtable history.  If cache_only is false,
  // SST files will also be checked.
  //
+  // `key` should NOT have user-defined timestamp appended to user key even if
+  // timestamp is enabled.
+  //
  // If a key is found, *found_record_for_key will be set to true and
  // *seq will be set to the stored sequence number for the latest
-  // operation on this key or kMaxSequenceNumber if unknown.
+  // operation on this key or kMaxSequenceNumber if unknown. If user-defined
+  // timestamp is enabled for this column family and timestamp is not nullptr,
+  // then *timestamp will be set to the stored timestamp for the latest
+  // operation on this key.
  // If no key is found, *found_record_for_key will be set to false.
  //
  // Note: If cache_only=false, it is possible for *seq to be set to 0 if
@@ -608,9 +634,9 @@ class DBImpl : public DB {
  Status GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,
                                 bool cache_only,
                                 SequenceNumber lower_bound_seq,
-                                 SequenceNumber* seq,
+                                 SequenceNumber* seq, std::string* timestamp,
                                 bool* found_record_for_key,
-                                 bool* is_blob_index = nullptr);
+                                 bool* is_blob_index);

  Status TraceIteratorSeek(const uint32_t& cf_id, const Slice& key,
                           const Slice& lower_bound, const Slice upper_bound);
@@ -637,7 +663,8 @@ class DBImpl : public DB {
                             const CompactRangeOptions& compact_range_options,
                             const Slice* begin, const Slice* end,
                             bool exclusive, bool disallow_trivial_move,
-                             uint64_t max_file_num_to_ignore);
+                             uint64_t max_file_num_to_ignore,
+                             const std::string& trim_ts);

  // Return an internal iterator over the current state of the database.
  // The keys of this iterator are internal keys (see format.h).
@@ -936,6 +963,13 @@ class DBImpl : public DB {
                                     int max_entries_to_print,
                                     std::string* out_str);

+  VersionSet* GetVersionSet() const { return versions_.get(); }
+
+  // Wait for any compaction
+  // We add a bool parameter to wait for unscheduledCompactions_ == 0, but this
+  // is only for the special test of CancelledCompactions
+  Status WaitForCompact(bool waitUnscheduled = false);
+
 #ifndef NDEBUG
  // Compact any files in the named level that overlap [*begin, *end]
  Status TEST_CompactRange(int level, const Slice* begin, const Slice* end,
@@ -966,6 +1000,9 @@ class DBImpl : public DB {
  Status TEST_AtomicFlushMemTables(const autovector<ColumnFamilyData*>& cfds,
                                   const FlushOptions& flush_opts);

+  // Wait for background threads to complete scheduled work.
+  Status TEST_WaitForBackgroundWork();
+
  // Wait for memtable compaction
  Status TEST_WaitForFlushMemTable(ColumnFamilyHandle* column_family = nullptr);

@@ -974,6 +1011,9 @@ class DBImpl : public DB {
  // is only for the special test of CancelledCompactions
  Status TEST_WaitForCompact(bool waitUnscheduled = false);

+  // Wait for any background purge
+  Status TEST_WaitForPurge();
+
  // Get the background error status
  Status TEST_GetBGError();

@@ -1040,8 +1080,6 @@ class DBImpl : public DB {
  void TEST_WaitForStatsDumpRun(std::function<void()> callback) const;
  size_t TEST_EstimateInMemoryStatsHistorySize() const;

-  VersionSet* TEST_GetVersionSet() const { return versions_.get(); }
-
  uint64_t TEST_GetCurrentLogNumber() const {
    InstrumentedMutexLock l(mutex());
    assert(!logs_.empty());
@@ -1119,10 +1157,12 @@ class DBImpl : public DB {
    State state_;
  };

+  static void TEST_ResetDbSessionIdGen();
  static std::string GenerateDbSessionId(Env* env);

 protected:
  const std::string dbname_;
+  // TODO(peterd): unify with VersionSet::db_id_
  std::string db_id_;
  // db_session_id_ is an identifier that gets reset
  // every time the DB is opened
@@ -1148,7 +1188,10 @@ class DBImpl : public DB {
  // WriteToWAL need different synchronization: log_empty_, alive_log_files_,
  // logs_, logfile_number_. Refer to the definition of each variable below for
  // more description.
-  mutable InstrumentedMutex mutex_;
+  //
+  // `mutex_` can be a hot lock in some workloads, so it deserves dedicated
+  // cachelines.
+  mutable CacheAlignedInstrumentedMutex mutex_;

  ColumnFamilyHandleImpl* default_cf_handle_;
  InternalStats* default_cf_internal_stats_;
@@ -1205,7 +1248,8 @@ class DBImpl : public DB {

  Status CompactRangeInternal(const CompactRangeOptions& options,
                              ColumnFamilyHandle* column_family,
-                              const Slice* begin, const Slice* end);
+                              const Slice* begin, const Slice* end,
+                              const std::string& trim_ts);

  // The following two functions can only be called when:
  // 1. WriteThread::Writer::EnterUnbatched() is used.
@@ -1341,6 +1385,10 @@ class DBImpl : public DB {
  // to ensure that db_session_id_ gets updated every time the DB is opened
  void SetDbSessionId();

+  Status FailIfCfHasTs(const ColumnFamilyHandle* column_family) const;
+  Status FailIfTsSizesMismatch(const ColumnFamilyHandle* column_family,
+                               const Slice& ts) const;
+
 private:
  friend class DB;
  friend class ErrorHandler;
@@ -1468,19 +1516,31 @@ class DBImpl : public DB {

  // Information for a manual compaction
  struct ManualCompactionState {
+    ManualCompactionState(ColumnFamilyData* _cfd, int _input_level,
+                          int _output_level, uint32_t _output_path_id,
+                          bool _exclusive, bool _disallow_trivial_move,
+                          std::atomic<bool>* _canceled)
+        : cfd(_cfd),
+          input_level(_input_level),
+          output_level(_output_level),
+          output_path_id(_output_path_id),
+          exclusive(_exclusive),
+          disallow_trivial_move(_disallow_trivial_move),
+          canceled(_canceled) {}
+
    ColumnFamilyData* cfd;
    int input_level;
    int output_level;
    uint32_t output_path_id;
    Status status;
-    bool done;
-    bool in_progress;             // compaction request being processed?
-    bool incomplete;              // only part of requested range compacted
-    bool exclusive;               // current behavior of only one manual
-    bool disallow_trivial_move;   // Force actual compaction to run
-    const InternalKey* begin;     // nullptr means beginning of key range
-    const InternalKey* end;       // nullptr means end of key range
-    InternalKey* manual_end;      // how far we are compacting
+    bool done = false;
+    bool in_progress = false;    // compaction request being processed?
+    bool incomplete = false;     // only part of requested range compacted
+    bool exclusive;              // current behavior of only one manual
+    bool disallow_trivial_move;  // Force actual compaction to run
+    const InternalKey* begin = nullptr;  // nullptr means beginning of key range
+    const InternalKey* end = nullptr;    // nullptr means end of key range
+    InternalKey* manual_end = nullptr;   // how far we are compacting
    InternalKey tmp_storage;      // Used to keep track of compaction progress
    InternalKey tmp_storage1;     // Used to keep track of compaction progress
    std::atomic<bool>* canceled;  // Compaction canceled by the user?
@@ -1687,6 +1747,25 @@ class DBImpl : public DB {
    }
  }

+  // TaskType is used to identify tasks in thread-pool, currently only
+  // differentiate manual compaction, which could be unscheduled from the
+  // thread-pool.
+  enum class TaskType : uint8_t {
+    kDefault = 0,
+    kManualCompaction = 1,
+    kCount = 2,
+  };
+
+  // Task tag is used to identity tasks in thread-pool, which is
+  // dbImpl obj address + type
+  inline void* GetTaskTag(TaskType type) {
+    return GetTaskTag(static_cast<uint8_t>(type));
+  }
+
+  inline void* GetTaskTag(uint8_t type) {
+    return static_cast<uint8_t*>(static_cast<void*>(this)) + type;
+  }
+
  // REQUIRES: mutex locked and in write thread.
  void AssignAtomicFlushSeq(const autovector<ColumnFamilyData*>& cfds);

@@ -1704,8 +1783,13 @@ class DBImpl : public DB {
                         WriteBatch* tmp_batch, size_t* write_with_wal,
                         WriteBatch** to_be_cached_state);

+  // rate_limiter_priority is used to charge `DBOptions::rate_limiter`
+  // for automatic WAL flush (`Options::manual_wal_flush` == false)
+  // associated with this WriteToWAL
  IOStatus WriteToWAL(const WriteBatch& merged_batch, log::Writer* log_writer,
-                      uint64_t* log_used, uint64_t* log_size);
+                      uint64_t* log_used, uint64_t* log_size,
+                      Env::IOPriority rate_limiter_priority,
+                      bool with_db_mutex = false, bool with_log_mutex = false);

  IOStatus WriteToWAL(const WriteThread::WriteGroup& write_group,
                      log::Writer* log_writer, uint64_t* log_used,
@@ -1801,7 +1885,7 @@ class DBImpl : public DB {
                              LogBuffer* log_buffer);

  // Schedule background tasks
-  void StartPeriodicWorkScheduler();
+  Status StartPeriodicWorkScheduler();

  void PrintStatistics();

@@ -1973,7 +2057,8 @@ class DBImpl : public DB {

  Status DisableFileDeletionsWithLock();

-  Status IncreaseFullHistoryTsLow(ColumnFamilyData* cfd, std::string ts_low);
+  Status IncreaseFullHistoryTsLowImpl(ColumnFamilyData* cfd,
+                                      std::string ts_low);

  // Lock over the persistent DB state.  Non-nullptr iff successfully acquired.
  FileLock* db_lock_;
@@ -2030,12 +2115,15 @@ class DBImpl : public DB {
  bool persistent_stats_cfd_exists_ = true;

  // Without two_write_queues, read and writes to alive_log_files_ are
-  // protected by mutex_. However since back() is never popped, and push_back()
-  // is done only from write_thread_, the same thread can access the item
-  // reffered by back() without mutex_. With two_write_queues_, writes
+  // protected by mutex_. With two_write_queues_, writes
  // are protected by locking both mutex_ and log_write_mutex_, and reads must
  // be under either mutex_ or log_write_mutex_.
  std::deque<LogFileNumberSize> alive_log_files_;
+  // Caching the result of `alive_log_files_.back()` so that we do not have to
+  // call `alive_log_files_.back()` in the write thread (WriteToWAL()) which
+  // requires locking db mutex if log_mutex_ is not already held in
+  // two-write-queues mode.
+  std::deque<LogFileNumberSize>::reverse_iterator alive_log_files_tail_;
  // Log files that aren't fully synced, and the current log file.
  // Synchronization:
  //  - push_back() is done from write_thread_ with locked mutex_ and
@@ -2281,12 +2369,10 @@ class DBImpl : public DB {
  // DB::Open() or passed to us
  bool own_sfm_;

-  // Clients must periodically call SetPreserveDeletesSequenceNumber()
-  // to advance this seqnum. Default value is 0 which means ALL deletes are
-  // preserved. Note that this has no effect if DBOptions.preserve_deletes
-  // is set to false.
-  std::atomic<SequenceNumber> preserve_deletes_seqnum_;
-  const bool preserve_deletes_;
+  // Default value is 0 which means ALL deletes are
+  // preserved. Note that this has no effect if preserve_deletes is false.
+  const std::atomic<SequenceNumber> preserve_deletes_seqnum_{0};
+  const bool preserve_deletes_ = false;

  // Flag to check whether Close() has been called on this DB
  bool closed_;
@@ -2356,11 +2442,10 @@ extern uint64_t PrecomputeMinLogNumberToKeepNon2PC(
 // will not depend on any WAL file. nullptr means no memtable is being flushed.
 // The function is only applicable to 2pc mode.
 extern uint64_t FindMinPrepLogReferencedByMemTable(
-    VersionSet* vset, const ColumnFamilyData* cfd_to_flush,
-    const autovector<MemTable*>& memtables_to_flush);
+    VersionSet* vset, const autovector<MemTable*>& memtables_to_flush);
 // For atomic flush.
 extern uint64_t FindMinPrepLogReferencedByMemTable(
-    VersionSet* vset, const autovector<ColumnFamilyData*>& cfds_to_flush,
+    VersionSet* vset,
    const autovector<const autovector<MemTable*>*>& memtables_to_flush);

 // Fix user-supplied options to be reasonable
@@ -2370,4 +2455,43 @@ static void ClipToRange(T* ptr, V minvalue, V maxvalue) {
  if (static_cast<V>(*ptr) < minvalue) *ptr = minvalue;
 }

+inline Status DBImpl::FailIfCfHasTs(
+    const ColumnFamilyHandle* column_family) const {
+  column_family = column_family ? column_family : DefaultColumnFamily();
+  assert(column_family);
+  const Comparator* const ucmp = column_family->GetComparator();
+  assert(ucmp);
+  if (ucmp->timestamp_size() > 0) {
+    std::ostringstream oss;
+    oss << "cannot call this method on column family "
+        << column_family->GetName() << " that enables timestamp";
+    return Status::InvalidArgument(oss.str());
+  }
+  return Status::OK();
+}
+
+inline Status DBImpl::FailIfTsSizesMismatch(
+    const ColumnFamilyHandle* column_family, const Slice& ts) const {
+  if (!column_family) {
+    return Status::InvalidArgument("column family handle cannot be null");
+  }
+  assert(column_family);
+  const Comparator* const ucmp = column_family->GetComparator();
+  assert(ucmp);
+  if (0 == ucmp->timestamp_size()) {
+    std::stringstream oss;
+    oss << "cannot call this method on column family "
+        << column_family->GetName() << " that does not enable timestamp";
+    return Status::InvalidArgument(oss.str());
+  }
+  const size_t ts_sz = ts.size();
+  if (ts_sz != ucmp->timestamp_size()) {
+    std::stringstream oss;
+    oss << "Timestamp sizes mismatch: expect " << ucmp->timestamp_size() << ", "
+        << ts_sz << " given";
+    return Status::InvalidArgument(oss.str());
+  }
+  return Status::OK();
+}
+
 }  // namespace ROCKSDB_NAMESPACE
@@ -103,6 +103,8 @@ IOStatus DBImpl::SyncClosedLogs(JobContext* job_context) {
  if (!logs_to_sync.empty()) {
    mutex_.Unlock();

+    assert(job_context);
+
    for (log::Writer* log : logs_to_sync) {
      ROCKS_LOG_INFO(immutable_db_options_.info_log,
                     "[JOB %d] Syncing log #%" PRIu64, job_context->job_id,
@@ -120,9 +122,13 @@ IOStatus DBImpl::SyncClosedLogs(JobContext* job_context) {
      }
    }
    if (io_s.ok()) {
-      io_s = directories_.GetWalDir()->Fsync(IOOptions(), nullptr);
+      io_s = directories_.GetWalDir()->FsyncWithDirOptions(
+          IOOptions(), nullptr,
+          DirFsyncOptions(DirFsyncOptions::FsyncReason::kNewFileSynced));
    }

+    TEST_SYNC_POINT_CALLBACK("DBImpl::SyncClosedLogs:BeforeReLock",
+                             /*arg=*/nullptr);
    mutex_.Lock();

    // "number <= current_log_number - 1" is equivalent to
@@ -151,14 +157,59 @@ Status DBImpl::FlushMemTableToOutputFile(
    Env::Priority thread_pri) {
  mutex_.AssertHeld();
  assert(cfd);
+  assert(cfd->imm());
  assert(cfd->imm()->NumNotFlushed() != 0);
  assert(cfd->imm()->IsFlushPending());
+  assert(versions_);
+  assert(versions_->GetColumnFamilySet());
+  // If there are more than one column families, we need to make sure that
+  // all the log files except the most recent one are synced. Otherwise if
+  // the host crashes after flushing and before WAL is persistent, the
+  // flushed SST may contain data from write batches whose updates to
+  // other (unflushed) column families are missing.
+  const bool needs_to_sync_closed_wals =
+      logfile_number_ > 0 &&
+      versions_->GetColumnFamilySet()->NumberOfColumnFamilies() > 1;
+
+  // If needs_to_sync_closed_wals is true, we need to record the current
+  // maximum memtable ID of this column family so that a later PickMemtables()
+  // call will not pick memtables whose IDs are higher. This is due to the fact
+  // that SyncClosedLogs() may release the db mutex, and memtable switch can
+  // happen for this column family in the meantime. The newly created memtables
+  // have their data backed by unsynced WALs, thus they cannot be included in
+  // this flush job.
+  // Another reason why we must record the current maximum memtable ID of this
+  // column family: SyncClosedLogs() may release db mutex, thus it's possible
+  // for application to continue to insert into memtables increasing db's
+  // sequence number. The application may take a snapshot, but this snapshot is
+  // not included in `snapshot_seqs` which will be passed to flush job because
+  // `snapshot_seqs` has already been computed before this function starts.
+  // Recording the max memtable ID ensures that the flush job does not flush
+  // a memtable without knowing such snapshot(s).
+  uint64_t max_memtable_id = needs_to_sync_closed_wals
+                                 ? cfd->imm()->GetLatestMemTableID()
+                                 : port::kMaxUint64;
+
+  // If needs_to_sync_closed_wals is false, then the flush job will pick ALL
+  // existing memtables of the column family when PickMemTable() is called
+  // later. Although we won't call SyncClosedLogs() in this case, we may still
+  // call the callbacks of the listeners, i.e. NotifyOnFlushBegin() which also
+  // releases and re-acquires the db mutex. In the meantime, the application
+  // can still insert into the memtables and increase the db's sequence number.
+  // The application can take a snapshot, hoping that the latest visible state
+  // to this snapshto is preserved. This is hard to guarantee since db mutex
+  // not held. This newly-created snapshot is not included in `snapshot_seqs`
+  // and the flush job is unaware of its presence. Consequently, the flush job
+  // may drop certain keys when generating the L0, causing incorrect data to be
+  // returned for snapshot read using this snapshot.
+  // To address this, we make sure NotifyOnFlushBegin() executes after memtable
+  // picking so that no new snapshot can be taken between the two functions.
+
  FlushJob flush_job(
-      dbname_, cfd, immutable_db_options_, mutable_cf_options,
-      port::kMaxUint64 /* memtable_id */, file_options_for_compaction_,
-      versions_.get(), &mutex_, &shutting_down_, snapshot_seqs,
-      earliest_write_conflict_snapshot, snapshot_checker, job_context,
-      log_buffer, directories_.GetDbDir(), GetDataDir(cfd, 0U),
+      dbname_, cfd, immutable_db_options_, mutable_cf_options, max_memtable_id,
+      file_options_for_compaction_, versions_.get(), &mutex_, &shutting_down_,
+      snapshot_seqs, earliest_write_conflict_snapshot, snapshot_checker,
+      job_context, log_buffer, directories_.GetDbDir(), GetDataDir(cfd, 0U),
      GetCompressionFlush(*cfd->ioptions(), mutable_cf_options), stats_,
      &event_logger_, mutable_cf_options.report_bg_io_stats,
      true /* sync_output_directory */, true /* write_manifest */, thread_pri,
@@ -166,21 +217,10 @@ Status DBImpl::FlushMemTableToOutputFile(
      &blob_callback_);
  FileMetaData file_meta;

-#ifndef ROCKSDB_LITE
-  // may temporarily unlock and lock the mutex.
-  NotifyOnFlushBegin(cfd, &file_meta, mutable_cf_options, job_context->job_id);
-#endif  // ROCKSDB_LITE
-
  Status s;
  bool need_cancel = false;
  IOStatus log_io_s = IOStatus::OK();
-  if (logfile_number_ > 0 &&
-      versions_->GetColumnFamilySet()->NumberOfColumnFamilies() > 1) {
-    // If there are more than one column families, we need to make sure that
-    // all the log files except the most recent one are synced. Otherwise if
-    // the host crashes after flushing and before WAL is persistent, the
-    // flushed SST may contain data from write batches whose updates to
-    // other column families are missing.
+  if (needs_to_sync_closed_wals) {
    // SyncClosedLogs() may unlock and re-lock the db_mutex.
    log_io_s = SyncClosedLogs(job_context);
    if (!log_io_s.ok() && !log_io_s.IsShutdownInProgress() &&
@@ -199,7 +239,14 @@ Status DBImpl::FlushMemTableToOutputFile(
    flush_job.PickMemTable();
    need_cancel = true;
  }
-  TEST_SYNC_POINT("DBImpl::FlushMemTableToOutputFile:AfterPickMemtables");
+  TEST_SYNC_POINT_CALLBACK(
+      "DBImpl::FlushMemTableToOutputFile:AfterPickMemtables", &flush_job);
+
+#ifndef ROCKSDB_LITE
+  // may temporarily unlock and lock the mutex.
+  NotifyOnFlushBegin(cfd, &file_meta, mutable_cf_options, job_context->job_id);
+#endif  // ROCKSDB_LITE
+
  bool switched_to_mempurge = false;
  // Within flush_job.Run, rocksdb may call event listener to notify
  // file creation and deletion.
@@ -216,11 +263,6 @@ Status DBImpl::FlushMemTableToOutputFile(
  if (!s.ok() && need_cancel) {
    flush_job.Cancel();
  }
-  IOStatus io_s = IOStatus::OK();
-  io_s = flush_job.io_status();
-  if (s.ok()) {
-    s = io_s;
-  }

  if (s.ok()) {
    InstallSuperVersionAndScheduleWork(cfd, superversion_context,
@@ -244,18 +286,19 @@ Status DBImpl::FlushMemTableToOutputFile(

    const auto& blob_files = storage_info->GetBlobFiles();
    if (!blob_files.empty()) {
-      ROCKS_LOG_BUFFER(log_buffer,
-                       "[%s] Blob file summary: head=%" PRIu64 ", tail=%" PRIu64
-                       "\n",
-                       column_family_name.c_str(), blob_files.begin()->first,
-                       blob_files.rbegin()->first);
+      assert(blob_files.front());
+      assert(blob_files.back());
+
+      ROCKS_LOG_BUFFER(
+          log_buffer,
+          "[%s] Blob file summary: head=%" PRIu64 ", tail=%" PRIu64 "\n",
+          column_family_name.c_str(), blob_files.front()->GetBlobFileNumber(),
+          blob_files.back()->GetBlobFileNumber());
    }
  }

  if (!s.ok() && !s.IsShutdownInProgress() && !s.IsColumnFamilyDropped()) {
-    if (!io_s.ok() && !io_s.IsShutdownInProgress() &&
-        !io_s.IsColumnFamilyDropped()) {
-      assert(log_io_s.ok());
+    if (log_io_s.ok()) {
      // Error while writing to MANIFEST.
      // In fact, versions_->io_status() can also be the result of renaming
      // CURRENT file. With current code, it's just difficult to tell. So just
@@ -266,24 +309,19 @@ Status DBImpl::FlushMemTableToOutputFile(
        // error), all the Manifest write will be map to soft error.
        // TODO: kManifestWriteNoWAL and kFlushNoWAL are misleading. Refactor is
        // needed.
-        error_handler_.SetBGError(io_s,
+        error_handler_.SetBGError(s,
                                  BackgroundErrorReason::kManifestWriteNoWAL);
      } else {
        // If WAL sync is successful (either WAL size is 0 or there is no IO
        // error), all the other SST file write errors will be set as
        // kFlushNoWAL.
-        error_handler_.SetBGError(io_s, BackgroundErrorReason::kFlushNoWAL);
+        error_handler_.SetBGError(s, BackgroundErrorReason::kFlushNoWAL);
      }
    } else {
-      if (log_io_s.ok()) {
-        Status new_bg_error = s;
-        error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush);
-      }
+      assert(s == log_io_s);
+      Status new_bg_error = s;
+      error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush);
    }
-  } else {
-    // If we got here, then we decided not to care about the i_os status (either
-    // from never needing it or ignoring the flush job status
-    io_s.PermitUncheckedError();
  }
  // If flush ran smoothly and no mempurge happened
  // install new SST file path.
@@ -332,13 +370,14 @@ Status DBImpl::FlushMemTablesToOutputFiles(
                     &earliest_write_conflict_snapshot, &snapshot_checker);
  const auto& bg_flush_arg = bg_flush_args[0];
  ColumnFamilyData* cfd = bg_flush_arg.cfd_;
-  MutableCFOptions mutable_cf_options = *cfd->GetLatestMutableCFOptions();
+  // intentional infrequent copy for each flush
+  MutableCFOptions mutable_cf_options_copy = *cfd->GetLatestMutableCFOptions();
  SuperVersionContext* superversion_context =
      bg_flush_arg.superversion_context_;
  Status s = FlushMemTableToOutputFile(
-      cfd, mutable_cf_options, made_progress, job_context, superversion_context,
-      snapshot_seqs, earliest_write_conflict_snapshot, snapshot_checker,
-      log_buffer, thread_pri);
+      cfd, mutable_cf_options_copy, made_progress, job_context,
+      superversion_context, snapshot_seqs, earliest_write_conflict_snapshot,
+      snapshot_checker, log_buffer, thread_pri);
  return s;
 }

@@ -365,6 +404,7 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
  for (const auto cfd : cfds) {
    assert(cfd->imm()->NumNotFlushed() != 0);
    assert(cfd->imm()->IsFlushPending());
+    assert(cfd->GetFlushReason() == cfds[0]->GetFlushReason());
  }
 #endif /* !NDEBUG */

@@ -451,12 +491,10 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
  // exec_status stores the execution status of flush_jobs as
  // <bool /* executed */, Status /* status code */>
  autovector<std::pair<bool, Status>> exec_status;
-  autovector<IOStatus> io_status;
  std::vector<bool> pick_status;
  for (int i = 0; i != num_cfs; ++i) {
    // Initially all jobs are not executed, with status OK.
    exec_status.emplace_back(false, Status::OK());
-    io_status.emplace_back(IOStatus::OK());
    pick_status.push_back(false);
  }

@@ -476,7 +514,6 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
          jobs[i]->Run(&logs_with_prep_tracker_, &file_meta[i],
                       &(switched_to_mempurge.at(i)));
      exec_status[i].first = true;
-      io_status[i] = jobs[i]->io_status();
    }
    if (num_cfs > 1) {
      TEST_SYNC_POINT(
@@ -490,7 +527,6 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
        &logs_with_prep_tracker_, file_meta.data() /* &file_meta[0] */,
        switched_to_mempurge.empty() ? nullptr : &(switched_to_mempurge.at(0)));
    exec_status[0].first = true;
-    io_status[0] = jobs[0]->io_status();

    Status error_status;
    for (const auto& e : exec_status) {
@@ -509,21 +545,6 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
    s = error_status.ok() ? s : error_status;
  }

-  IOStatus io_s = IOStatus::OK();
-  if (io_s.ok()) {
-    IOStatus io_error = IOStatus::OK();
-    for (int i = 0; i != static_cast<int>(io_status.size()); i++) {
-      if (!io_status[i].ok() && !io_status[i].IsShutdownInProgress() &&
-          !io_status[i].IsColumnFamilyDropped()) {
-        io_error = io_status[i];
-      }
-    }
-    io_s = io_error;
-    if (s.ok() && !io_s.ok()) {
-      s = io_s;
-    }
-  }
-
  if (s.IsColumnFamilyDropped()) {
    s = Status::OK();
  }
@@ -532,7 +553,9 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
    // Sync on all distinct output directories.
    for (auto dir : distinct_output_dirs) {
      if (dir != nullptr) {
-        Status error_status = dir->Fsync(IOOptions(), nullptr);
+        Status error_status = dir->FsyncWithDirOptions(
+            IOOptions(), nullptr,
+            DirFsyncOptions(DirFsyncOptions::FsyncReason::kNewFileSynced));
        if (!error_status.ok()) {
          s = error_status;
          break;
@@ -594,7 +617,10 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
      return std::make_pair(Status::OK(), !ready);
    };

-    bool resuming_from_bg_err = error_handler_.IsDBStopped();
+    bool resuming_from_bg_err =
+        error_handler_.IsDBStopped() ||
+        (cfds[0]->GetFlushReason() == FlushReason::kErrorRecovery ||
+         cfds[0]->GetFlushReason() == FlushReason::kErrorRecoveryRetryFlush);
    while ((!resuming_from_bg_err || error_handler_.GetRecoveryError().ok())) {
      std::pair<Status, bool> res = wait_to_install_func();

@@ -609,7 +635,10 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
      }
      atomic_flush_install_cv_.Wait();

-      resuming_from_bg_err = error_handler_.IsDBStopped();
+      resuming_from_bg_err =
+          error_handler_.IsDBStopped() ||
+          (cfds[0]->GetFlushReason() == FlushReason::kErrorRecovery ||
+           cfds[0]->GetFlushReason() == FlushReason::kErrorRecoveryRetryFlush);
    }

    if (!resuming_from_bg_err) {
@@ -683,11 +712,14 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(

      const auto& blob_files = storage_info->GetBlobFiles();
      if (!blob_files.empty()) {
-        ROCKS_LOG_BUFFER(log_buffer,
-                         "[%s] Blob file summary: head=%" PRIu64
-                         ", tail=%" PRIu64 "\n",
-                         column_family_name.c_str(), blob_files.begin()->first,
-                         blob_files.rbegin()->first);
+        assert(blob_files.front());
+        assert(blob_files.back());
+
+        ROCKS_LOG_BUFFER(
+            log_buffer,
+            "[%s] Blob file summary: head=%" PRIu64 ", tail=%" PRIu64 "\n",
+            column_family_name.c_str(), blob_files.front()->GetBlobFileNumber(),
+            blob_files.back()->GetBlobFileNumber());
      }
    }
    if (made_progress) {
@@ -730,8 +762,7 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
  // Need to undo atomic flush if something went wrong, i.e. s is not OK and
  // it is not because of CF drop.
  if (!s.ok() && !s.IsColumnFamilyDropped()) {
-    if (!io_s.ok() && !io_s.IsColumnFamilyDropped()) {
-      assert(log_io_s.ok());
+    if (log_io_s.ok()) {
      // Error while writing to MANIFEST.
      // In fact, versions_->io_status() can also be the result of renaming
      // CURRENT file. With current code, it's just difficult to tell. So just
@@ -742,19 +773,18 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
        // error), all the Manifest write will be map to soft error.
        // TODO: kManifestWriteNoWAL and kFlushNoWAL are misleading. Refactor
        // is needed.
-        error_handler_.SetBGError(io_s,
+        error_handler_.SetBGError(s,
                                  BackgroundErrorReason::kManifestWriteNoWAL);
      } else {
        // If WAL sync is successful (either WAL size is 0 or there is no IO
        // error), all the other SST file write errors will be set as
        // kFlushNoWAL.
-        error_handler_.SetBGError(io_s, BackgroundErrorReason::kFlushNoWAL);
+        error_handler_.SetBGError(s, BackgroundErrorReason::kFlushNoWAL);
      }
    } else {
-      if (log_io_s.ok()) {
-        Status new_bg_error = s;
-        error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush);
-      }
+      assert(s == log_io_s);
+      Status new_bg_error = s;
+      error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush);
    }
  }

@@ -839,6 +869,8 @@ void DBImpl::NotifyOnFlushCompleted(
      for (auto listener : immutable_db_options_.listeners) {
        listener->OnFlushCompleted(this, *info);
      }
+      TEST_SYNC_POINT(
+          "DBImpl::NotifyOnFlushCompleted::PostAllOnFlushCompleted");
    }
    flush_jobs_info->clear();
  }
@@ -869,7 +901,7 @@ Status DBImpl::CompactRange(const CompactRangeOptions& options,
  size_t ts_sz = ucmp->timestamp_size();
  if (ts_sz == 0) {
    return CompactRangeInternal(options, column_family, begin_without_ts,
-                                end_without_ts);
+                                end_without_ts, "" /*trim_ts*/);
  }

  std::string begin_str;
@@ -891,11 +923,32 @@ Status DBImpl::CompactRange(const CompactRangeOptions& options,
  Slice* end_with_ts = end_without_ts ? &end : nullptr;

  return CompactRangeInternal(options, column_family, begin_with_ts,
-                              end_with_ts);
+                              end_with_ts, "" /*trim_ts*/);
 }

-Status DBImpl::IncreaseFullHistoryTsLow(ColumnFamilyData* cfd,
+Status DBImpl::IncreaseFullHistoryTsLow(ColumnFamilyHandle* column_family,
                                        std::string ts_low) {
+  ColumnFamilyData* cfd = nullptr;
+  if (column_family == nullptr) {
+    cfd = default_cf_handle_->cfd();
+  } else {
+    auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
+    assert(cfh != nullptr);
+    cfd = cfh->cfd();
+  }
+  assert(cfd != nullptr && cfd->user_comparator() != nullptr);
+  if (cfd->user_comparator()->timestamp_size() == 0) {
+    return Status::InvalidArgument(
+        "Timestamp is not enabled in this column family");
+  }
+  if (cfd->user_comparator()->timestamp_size() != ts_low.size()) {
+    return Status::InvalidArgument("ts_low size mismatch");
+  }
+  return IncreaseFullHistoryTsLowImpl(cfd, ts_low);
+}
+
+Status DBImpl::IncreaseFullHistoryTsLowImpl(ColumnFamilyData* cfd,
+                                            std::string ts_low) {
  VersionEdit edit;
  edit.SetColumnFamily(cfd->GetID());
  edit.SetFullHistoryTsLow(ts_low);
@@ -903,6 +956,7 @@ Status DBImpl::IncreaseFullHistoryTsLow(ColumnFamilyData* cfd,
  InstrumentedMutexLock l(&mutex_);
  std::string current_ts_low = cfd->GetFullHistoryTsLow();
  const Comparator* ucmp = cfd->user_comparator();
+  assert(ucmp->timestamp_size() == ts_low.size() && !ts_low.empty());
  if (!current_ts_low.empty() &&
      ucmp->CompareTimestamp(ts_low, current_ts_low) < 0) {
    return Status::InvalidArgument(
@@ -915,7 +969,8 @@ Status DBImpl::IncreaseFullHistoryTsLow(ColumnFamilyData* cfd,

 Status DBImpl::CompactRangeInternal(const CompactRangeOptions& options,
                                    ColumnFamilyHandle* column_family,
-                                    const Slice* begin, const Slice* end) {
+                                    const Slice* begin, const Slice* end,
+                                    const std::string& trim_ts) {
  auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
  auto cfd = cfh->cfd();

@@ -933,7 +988,7 @@ Status DBImpl::CompactRangeInternal(const CompactRangeOptions& options,
      return Status::InvalidArgument(
          "Cannot specify compaction range with full_history_ts_low");
    }
-    Status s = IncreaseFullHistoryTsLow(cfd, ts_low);
+    Status s = IncreaseFullHistoryTsLowImpl(cfd, ts_low);
    if (!s.ok()) {
      LogFlush(immutable_db_options_.info_log);
      return s;
@@ -986,7 +1041,7 @@ Status DBImpl::CompactRangeInternal(const CompactRangeOptions& options,
    }
    s = RunManualCompaction(cfd, ColumnFamilyData::kCompactAllLevels,
                            final_output_level, options, begin, end, exclusive,
-                            false, port::kMaxUint64);
+                            false, port::kMaxUint64, trim_ts);
  } else {
    int first_overlapped_level = kInvalidLevel;
    int max_overlapped_level = kInvalidLevel;
@@ -1072,9 +1127,13 @@ Status DBImpl::CompactRangeInternal(const CompactRangeOptions& options,
            disallow_trivial_move = true;
          }
        }
+        // trim_ts need real compaction to remove latest record
+        if (!trim_ts.empty()) {
+          disallow_trivial_move = true;
+        }
        s = RunManualCompaction(cfd, level, output_level, options, begin, end,
                                exclusive, disallow_trivial_move,
-                                max_file_num_to_ignore);
+                                max_file_num_to_ignore, trim_ts);
        if (!s.ok()) {
          break;
        }
@@ -1110,6 +1169,8 @@ Status DBImpl::CompactRangeInternal(const CompactRangeOptions& options,
      assert(temp_s.ok());
    }
    EnableManualCompaction();
+    TEST_SYNC_POINT(
+        "DBImpl::CompactRange:PostRefitLevel:ManualCompactionEnabled");
  }
  LogFlush(immutable_db_options_.info_log);

@@ -1311,7 +1372,8 @@ Status DBImpl::CompactFilesImpl(
      c->mutable_cf_options()->report_bg_io_stats, dbname_,
      &compaction_job_stats, Env::Priority::USER, io_tracer_,
      &manual_compaction_paused_, nullptr, db_id_, db_session_id_,
-      c->column_family_data()->GetFullHistoryTsLow(), &blob_callback_);
+      c->column_family_data()->GetFullHistoryTsLow(), c->trim_ts(),
+      &blob_callback_);

  // Creating a compaction influences the compaction score because the score
  // takes running compactions into account (by skipping files that are already
@@ -1583,12 +1645,12 @@ Status DBImpl::ReFitLevel(ColumnFamilyData* cfd, int level, int target_level) {
    edit.SetColumnFamily(cfd->GetID());
    for (const auto& f : vstorage->LevelFiles(level)) {
      edit.DeleteFile(level, f->fd.GetNumber());
-      edit.AddFile(to_level, f->fd.GetNumber(), f->fd.GetPathId(),
-                   f->fd.GetFileSize(), f->smallest, f->largest,
-                   f->fd.smallest_seqno, f->fd.largest_seqno,
-                   f->marked_for_compaction, f->oldest_blob_file_number,
-                   f->oldest_ancester_time, f->file_creation_time,
-                   f->file_checksum, f->file_checksum_func_name);
+      edit.AddFile(
+          to_level, f->fd.GetNumber(), f->fd.GetPathId(), f->fd.GetFileSize(),
+          f->smallest, f->largest, f->fd.smallest_seqno, f->fd.largest_seqno,
+          f->marked_for_compaction, f->temperature, f->oldest_blob_file_number,
+          f->oldest_ancester_time, f->file_creation_time, f->file_checksum,
+          f->file_checksum_func_name, f->min_timestamp, f->max_timestamp);
    }
    ROCKS_LOG_DEBUG(immutable_db_options_.info_log,
                    "[%s] Apply version edit:\n%s", cfd->GetName().c_str(),
@@ -1700,26 +1762,21 @@ Status DBImpl::RunManualCompaction(
    ColumnFamilyData* cfd, int input_level, int output_level,
    const CompactRangeOptions& compact_range_options, const Slice* begin,
    const Slice* end, bool exclusive, bool disallow_trivial_move,
-    uint64_t max_file_num_to_ignore) {
+    uint64_t max_file_num_to_ignore, const std::string& trim_ts) {
  assert(input_level == ColumnFamilyData::kCompactAllLevels ||
         input_level >= 0);

  InternalKey begin_storage, end_storage;
-  CompactionArg* ca;
+  CompactionArg* ca = nullptr;

  bool scheduled = false;
+  bool unscheduled = false;
+  Env::Priority thread_pool_priority = Env::Priority::TOTAL;
  bool manual_conflict = false;
-  ManualCompactionState manual;
-  manual.cfd = cfd;
-  manual.input_level = input_level;
-  manual.output_level = output_level;
-  manual.output_path_id = compact_range_options.target_path_id;
-  manual.done = false;
-  manual.in_progress = false;
-  manual.incomplete = false;
-  manual.exclusive = exclusive;
-  manual.disallow_trivial_move = disallow_trivial_move;
-  manual.canceled = compact_range_options.canceled;
+
+  ManualCompactionState manual(
+      cfd, input_level, output_level, compact_range_options.target_path_id,
+      exclusive, disallow_trivial_move, compact_range_options.canceled);
  // For universal compaction, we enforce every manual compaction to compact
  // all files.
  if (begin == nullptr ||
@@ -1743,6 +1800,17 @@ Status DBImpl::RunManualCompaction(
  TEST_SYNC_POINT("DBImpl::RunManualCompaction:1");
  InstrumentedMutexLock l(&mutex_);

+  if (manual_compaction_paused_ > 0) {
+    // Does not make sense to `AddManualCompaction()` in this scenario since
+    // `DisableManualCompaction()` just waited for the manual compaction queue
+    // to drain. So return immediately.
+    TEST_SYNC_POINT("DBImpl::RunManualCompaction:PausedAtStart");
+    manual.status =
+        Status::Incomplete(Status::SubCode::kManualCompactionPaused);
+    manual.done = true;
+    return manual.status;
+  }
+
  // When a manual compaction arrives, temporarily disable scheduling of
  // non-manual compactions and wait until the number of scheduled compaction
  // jobs drops to zero. This used to be needed to ensure that this manual
@@ -1806,13 +1874,30 @@ Status DBImpl::RunManualCompaction(
               *manual.cfd->GetLatestMutableCFOptions(), mutable_db_options_,
               manual.input_level, manual.output_level, compact_range_options,
               manual.begin, manual.end, &manual.manual_end, &manual_conflict,
-               max_file_num_to_ignore)) == nullptr &&
+               max_file_num_to_ignore, trim_ts)) == nullptr &&
          manual_conflict))) {
      // exclusive manual compactions should not see a conflict during
      // CompactRange
      assert(!exclusive || !manual_conflict);
      // Running either this or some other manual compaction
      bg_cv_.Wait();
+      if (manual_compaction_paused_ > 0 && scheduled && !unscheduled) {
+        assert(thread_pool_priority != Env::Priority::TOTAL);
+        // unschedule all manual compactions
+        auto unscheduled_task_num = env_->UnSchedule(
+            GetTaskTag(TaskType::kManualCompaction), thread_pool_priority);
+        if (unscheduled_task_num > 0) {
+          ROCKS_LOG_INFO(
+              immutable_db_options_.info_log,
+              "[%s] Unscheduled %d number of manual compactions from the "
+              "thread-pool",
+              cfd->GetName().c_str(), unscheduled_task_num);
+          // it may unschedule other manual compactions, notify others.
+          bg_cv_.SignalAll();
+        }
+        unscheduled = true;
+        TEST_SYNC_POINT("DBImpl::RunManualCompaction:Unscheduled");
+      }
      if (scheduled && manual.incomplete == true) {
        assert(!manual.in_progress);
        scheduled = false;
@@ -1826,7 +1911,6 @@ Status DBImpl::RunManualCompaction(
      }
      ca = new CompactionArg;
      ca->db = this;
-      ca->compaction_pri_ = Env::Priority::LOW;
      ca->prepicked_compaction = new PrepickedCompaction;
      ca->prepicked_compaction->manual_compaction_state = &manual;
      ca->prepicked_compaction->compaction = compaction;
@@ -1836,15 +1920,25 @@ Status DBImpl::RunManualCompaction(
        assert(false);
      }
      manual.incomplete = false;
-      bg_compaction_scheduled_++;
-      Env::Priority thread_pool_pri = Env::Priority::LOW;
      if (compaction->bottommost_level() &&
          env_->GetBackgroundThreads(Env::Priority::BOTTOM) > 0) {
-        thread_pool_pri = Env::Priority::BOTTOM;
+        bg_bottom_compaction_scheduled_++;
+        ca->compaction_pri_ = Env::Priority::BOTTOM;
+        env_->Schedule(&DBImpl::BGWorkBottomCompaction, ca,
+                       Env::Priority::BOTTOM,
+                       GetTaskTag(TaskType::kManualCompaction),
+                       &DBImpl::UnscheduleCompactionCallback);
+        thread_pool_priority = Env::Priority::BOTTOM;
+      } else {
+        bg_compaction_scheduled_++;
+        ca->compaction_pri_ = Env::Priority::LOW;
+        env_->Schedule(&DBImpl::BGWorkCompaction, ca, Env::Priority::LOW,
+                       GetTaskTag(TaskType::kManualCompaction),
+                       &DBImpl::UnscheduleCompactionCallback);
+        thread_pool_priority = Env::Priority::LOW;
      }
-      env_->Schedule(&DBImpl::BGWorkCompaction, ca, thread_pool_pri, this,
-                     &DBImpl::UnscheduleCompactionCallback);
      scheduled = true;
+      TEST_SYNC_POINT("DBImpl::RunManualCompaction:Scheduled");
    }
  }

@@ -1852,6 +1946,13 @@ Status DBImpl::RunManualCompaction(
  assert(!manual.in_progress);
  assert(HasPendingManualCompaction());
  RemoveManualCompaction(&manual);
+  // if the manual job is unscheduled, try schedule other jobs in case there's
+  // any unscheduled compaction job which was blocked by exclusive manual
+  // compaction.
+  if (manual.status.IsIncomplete() &&
+      manual.status.subcode() == Status::SubCode::kManualCompactionPaused) {
+    MaybeScheduleFlushOrCompaction();
+  }
  bg_cv_.SignalAll();
  return manual.status;
 }
@@ -2202,21 +2303,27 @@ Status DBImpl::WaitForFlushMemTables(
  int num = static_cast<int>(cfds.size());
  // Wait until the compaction completes
  InstrumentedMutexLock l(&mutex_);
+  Status s;
  // If the caller is trying to resume from bg error, then
  // error_handler_.IsDBStopped() is true.
  while (resuming_from_bg_err || !error_handler_.IsDBStopped()) {
    if (shutting_down_.load(std::memory_order_acquire)) {
-      return Status::ShutdownInProgress();
+      s = Status::ShutdownInProgress();
+      return s;
    }
    // If an error has occurred during resumption, then no need to wait.
+    // But flush operation may fail because of this error, so need to
+    // return the status.
    if (!error_handler_.GetRecoveryError().ok()) {
+      s = error_handler_.GetRecoveryError();
      break;
    }
    // If BGWorkStopped, which indicate that there is a BG error and
    // 1) soft error but requires no BG work, 2) no in auto_recovery_
    if (!resuming_from_bg_err && error_handler_.IsBGWorkStopped() &&
        error_handler_.GetBGError().severity() < Status::Severity::kHardError) {
-      return error_handler_.GetBGError();
+      s = error_handler_.GetBGError();
+      return s;
    }

    // Number of column families that have been dropped.
@@ -2234,7 +2341,8 @@ Status DBImpl::WaitForFlushMemTables(
      }
    }
    if (1 == num_dropped && 1 == num) {
-      return Status::ColumnFamilyDropped();
+      s = Status::ColumnFamilyDropped();
+      return s;
    }
    // Column families involved in this flush request have either been dropped
    // or finished flush. Then it's time to finish waiting.
@@ -2243,7 +2351,6 @@ Status DBImpl::WaitForFlushMemTables(
    }
    bg_cv_.Wait();
  }
-  Status s;
  // If not resuming from bg error, and an error has caused the DB to stop,
  // then report the bg error to caller.
  if (!resuming_from_bg_err && error_handler_.IsDBStopped()) {
@@ -2358,7 +2465,8 @@ void DBImpl::MaybeScheduleFlushOrCompaction() {
    return;
  }

-  while (bg_compaction_scheduled_ < bg_job_limits.max_compactions &&
+  while (bg_compaction_scheduled_ + bg_bottom_compaction_scheduled_ <
+             bg_job_limits.max_compactions &&
         unscheduled_compactions_ > 0) {
    CompactionArg* ca = new CompactionArg;
    ca->db = this;
@@ -2547,8 +2655,7 @@ void DBImpl::BGWorkBottomCompaction(void* arg) {
  IOSTATS_SET_THREAD_POOL_ID(Env::Priority::BOTTOM);
  TEST_SYNC_POINT("DBImpl::BGWorkBottomCompaction");
  auto* prepicked_compaction = ca.prepicked_compaction;
-  assert(prepicked_compaction && prepicked_compaction->compaction &&
-         !prepicked_compaction->manual_compaction_state);
+  assert(prepicked_compaction && prepicked_compaction->compaction);
  ca.db->BackgroundCallCompaction(prepicked_compaction, Env::Priority::BOTTOM);
  delete prepicked_compaction;
 }
@@ -2573,7 +2680,15 @@ void DBImpl::UnscheduleCompactionCallback(void* arg) {
  CompactionArg ca = *(ca_ptr);
  delete reinterpret_cast<CompactionArg*>(arg);
  if (ca.prepicked_compaction != nullptr) {
+    // if it's a manual compaction, set status to ManualCompactionPaused
+    if (ca.prepicked_compaction->manual_compaction_state) {
+      ca.prepicked_compaction->manual_compaction_state->done = true;
+      ca.prepicked_compaction->manual_compaction_state->status =
+          Status::Incomplete(Status::SubCode::kManualCompactionPaused);
+    }
    if (ca.prepicked_compaction->compaction != nullptr) {
+      ca.prepicked_compaction->compaction->ReleaseCompactionFiles(
+          Status::Incomplete(Status::SubCode::kManualCompactionPaused));
      delete ca.prepicked_compaction->compaction;
    }
    delete ca.prepicked_compaction;
@@ -2812,6 +2927,7 @@ void DBImpl::BackgroundCallCompaction(PrepickedCompaction* prepicked_compaction,
      immutable_db_options_.clock->SleepForMicroseconds(1000000);
      mutex_.Lock();
    } else if (s.IsManualCompactionPaused()) {
+      assert(prepicked_compaction);
      ManualCompactionState* m = prepicked_compaction->manual_compaction_state;
      assert(m);
      ROCKS_LOG_BUFFER(&log_buffer, "[%s] [JOB %d] Manual compaction paused",
@@ -2820,9 +2936,9 @@ void DBImpl::BackgroundCallCompaction(PrepickedCompaction* prepicked_compaction,

    ReleaseFileNumberFromPendingOutputs(pending_outputs_inserted_elem);

-    // If compaction failed, we want to delete all temporary files that we might
-    // have created (they might not be all recorded in job_context in case of a
-    // failure). Thus, we force full scan in FindObsoleteFiles()
+    // If compaction failed, we want to delete all temporary files that we
+    // might have created (they might not be all recorded in job_context in
+    // case of a failure). Thus, we force full scan in FindObsoleteFiles()
    FindObsoleteFiles(&job_context, !s.ok() && !s.IsShutdownInProgress() &&
                                        !s.IsManualCompactionPaused() &&
                                        !s.IsColumnFamilyDropped() &&
@@ -2849,6 +2965,7 @@ void DBImpl::BackgroundCallCompaction(PrepickedCompaction* prepicked_compaction,

    assert(num_running_compactions_ > 0);
    num_running_compactions_--;
+
    if (bg_thread_pri == Env::Priority::LOW) {
      bg_compaction_scheduled_--;
    } else {
@@ -2867,7 +2984,6 @@ void DBImpl::BackgroundCallCompaction(PrepickedCompaction* prepicked_compaction,
      // must be done before we potentially signal the DB close process to
      // proceed below.
      prepicked_compaction->task_token.reset();
-      ;
    }

    if (made_progress ||
@@ -2954,6 +3070,8 @@ Status DBImpl::BackgroundCompaction(bool* made_progress,
    manual_compaction->in_progress = true;
  }

+  TEST_SYNC_POINT("DBImpl::BackgroundCompaction:InProgress");
+
  std::unique_ptr<TaskLimiterToken> task_token;

  // InternalKey manual_end_storage;
@@ -3063,8 +3181,12 @@ Status DBImpl::BackgroundCompaction(bool* made_progress,
          status = Status::CompactionTooLarge();
        } else {
          // update statistics
-          RecordInHistogram(stats_, NUM_FILES_IN_SINGLE_COMPACTION,
-                            c->inputs(0)->size());
+          size_t num_files = 0;
+          for (auto& each_level : *c->inputs()) {
+            num_files += each_level.files.size();
+          }
+          RecordInHistogram(stats_, NUM_FILES_IN_SINGLE_COMPACTION, num_files);
+
          // There are three things that can change compaction score:
          // 1) When flush or compaction finish. This case is covered by
          // InstallSuperVersionAndScheduleWork
@@ -3149,13 +3271,13 @@ Status DBImpl::BackgroundCompaction(bool* made_progress,
      for (size_t i = 0; i < c->num_input_files(l); i++) {
        FileMetaData* f = c->input(l, i);
        c->edit()->DeleteFile(c->level(l), f->fd.GetNumber());
-        c->edit()->AddFile(c->output_level(), f->fd.GetNumber(),
-                           f->fd.GetPathId(), f->fd.GetFileSize(), f->smallest,
-                           f->largest, f->fd.smallest_seqno,
-                           f->fd.largest_seqno, f->marked_for_compaction,
-                           f->oldest_blob_file_number, f->oldest_ancester_time,
-                           f->file_creation_time, f->file_checksum,
-                           f->file_checksum_func_name);
+        c->edit()->AddFile(
+            c->output_level(), f->fd.GetNumber(), f->fd.GetPathId(),
+            f->fd.GetFileSize(), f->smallest, f->largest, f->fd.smallest_seqno,
+            f->fd.largest_seqno, f->marked_for_compaction, f->temperature,
+            f->oldest_blob_file_number, f->oldest_ancester_time,
+            f->file_creation_time, f->file_checksum, f->file_checksum_func_name,
+            f->min_timestamp, f->max_timestamp);

        ROCKS_LOG_BUFFER(
            log_buffer,
@@ -3249,7 +3371,7 @@ Status DBImpl::BackgroundCompaction(bool* made_progress,
        is_manual ? &manual_compaction_paused_ : nullptr,
        is_manual ? manual_compaction->canceled : nullptr, db_id_,
        db_session_id_, c->column_family_data()->GetFullHistoryTsLow(),
-        &blob_callback_);
+        c->trim_ts(), &blob_callback_);
    compaction_job.Prepare();

    NotifyOnCompactionBegin(c->column_family_data(), c.get(), status,
@@ -3384,6 +3506,7 @@ bool DBImpl::HasPendingManualCompaction() {
 }

 void DBImpl::AddManualCompaction(DBImpl::ManualCompactionState* m) {
+  assert(manual_compaction_paused_ == 0);
  manual_compaction_dequeue_.push_back(m);
 }

@@ -3648,4 +3771,22 @@ void DBImpl::GetSnapshotContext(
  }
  *snapshot_seqs = snapshots_.GetAll(earliest_write_conflict_snapshot);
 }
+
+Status DBImpl::WaitForCompact(bool wait_unscheduled) {
+  // Wait until the compaction completes
+
+  // TODO: a bug here. This function actually does not necessarily
+  // wait for compact. It actually waits for scheduled compaction
+  // OR flush to finish.
+
+  InstrumentedMutexLock l(&mutex_);
+  while ((bg_bottom_compaction_scheduled_ || bg_compaction_scheduled_ ||
+          bg_flush_scheduled_ ||
+          (wait_unscheduled && unscheduled_compactions_)) &&
+         (error_handler_.GetBGError().ok())) {
+    bg_cv_.Wait();
+  }
+  return error_handler_.GetBGError();
+}
+
 }  // namespace ROCKSDB_NAMESPACE
@@ -60,24 +60,37 @@ void DBImpl::TEST_GetFilesMetaData(
    ColumnFamilyHandle* column_family,
    std::vector<std::vector<FileMetaData>>* metadata,
    std::vector<std::shared_ptr<BlobFileMetaData>>* blob_metadata) {
+  assert(metadata);
+
  auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
+  assert(cfh);
+
  auto cfd = cfh->cfd();
+  assert(cfd);
+
  InstrumentedMutexLock l(&mutex_);
+
+  const auto* current = cfd->current();
+  assert(current);
+
+  const auto* vstorage = current->storage_info();
+  assert(vstorage);
+
  metadata->resize(NumberLevels());
-  for (int level = 0; level < NumberLevels(); level++) {
-    const std::vector<FileMetaData*>& files =
-        cfd->current()->storage_info()->LevelFiles(level);
+
+  for (int level = 0; level < NumberLevels(); ++level) {
+    const std::vector<FileMetaData*>& files = vstorage->LevelFiles(level);

    (*metadata)[level].clear();
+    (*metadata)[level].reserve(files.size());
+
    for (const auto& f : files) {
      (*metadata)[level].push_back(*f);
    }
  }
-  if (blob_metadata != nullptr) {
-    blob_metadata->clear();
-    for (const auto& blob : cfd->current()->storage_info()->GetBlobFiles()) {
-      blob_metadata->push_back(blob.second);
-    }
+
+  if (blob_metadata) {
+    *blob_metadata = vstorage->GetBlobFiles();
  }
 }

@@ -107,7 +120,8 @@ Status DBImpl::TEST_CompactRange(int level, const Slice* begin,
          : level + 1;
  return RunManualCompaction(cfd, level, output_level, CompactRangeOptions(),
                             begin, end, true, disallow_trivial_move,
-                             port::kMaxUint64 /*max_file_num_to_ignore*/);
+                             port::kMaxUint64 /*max_file_num_to_ignore*/,
+                             "" /*trim_ts*/);
 }

 Status DBImpl::TEST_SwitchMemtable(ColumnFamilyData* cfd) {
@@ -156,6 +170,12 @@ Status DBImpl::TEST_AtomicFlushMemTables(
  return AtomicFlushMemTables(cfds, flush_opts, FlushReason::kTest);
 }

+Status DBImpl::TEST_WaitForBackgroundWork() {
+  InstrumentedMutexLock l(&mutex_);
+  WaitForBackgroundWork();
+  return error_handler_.GetBGError();
+}
+
 Status DBImpl::TEST_WaitForFlushMemTable(ColumnFamilyHandle* column_family) {
  ColumnFamilyData* cfd;
  if (column_family == nullptr) {
@@ -169,16 +189,12 @@ Status DBImpl::TEST_WaitForFlushMemTable(ColumnFamilyHandle* column_family) {

 Status DBImpl::TEST_WaitForCompact(bool wait_unscheduled) {
  // Wait until the compaction completes
+  return WaitForCompact(wait_unscheduled);
+}

-  // TODO: a bug here. This function actually does not necessarily
-  // wait for compact. It actually waits for scheduled compaction
-  // OR flush to finish.
-
+Status DBImpl::TEST_WaitForPurge() {
  InstrumentedMutexLock l(&mutex_);
-  while ((bg_bottom_compaction_scheduled_ || bg_compaction_scheduled_ ||
-          bg_flush_scheduled_ ||
-          (wait_unscheduled && unscheduled_compactions_)) &&
-         (error_handler_.GetBGError().ok())) {
+  while (bg_purge_scheduled_ && error_handler_.GetBGError().ok()) {
    bg_cv_.Wait();
  }
  return error_handler_.GetBGError();
@@ -248,8 +264,7 @@ size_t DBImpl::TEST_LogsWithPrepSize() {

 uint64_t DBImpl::TEST_FindMinPrepLogReferencedByMemTable() {
  autovector<MemTable*> empty_list;
-  return FindMinPrepLogReferencedByMemTable(versions_.get(), nullptr,
-                                            empty_list);
+  return FindMinPrepLogReferencedByMemTable(versions_.get(), empty_list);
 }

 Status DBImpl::TEST_GetLatestMutableCFOptions(
@@ -76,7 +76,8 @@ Status DBImpl::PromoteL0(ColumnFamilyHandle* column_family, int target_level) {
                     "PromoteL0 FAILED. Target level %d does not exist\n",
                     target_level);
      job_context.Clean();
-      return Status::InvalidArgument("Target level does not exist");
+      status = Status::InvalidArgument("Target level does not exist");
+      return status;
    }

    // Sort L0 files by range.
@@ -96,7 +97,9 @@ Status DBImpl::PromoteL0(ColumnFamilyHandle* column_family, int target_level) {
                       "PromoteL0 FAILED. File %" PRIu64 " being compacted\n",
                       f->fd.GetNumber());
        job_context.Clean();
-        return Status::InvalidArgument("PromoteL0 called during L0 compaction");
+        status =
+            Status::InvalidArgument("PromoteL0 called during L0 compaction");
+        return status;
      }

      if (i == 0) continue;
@@ -107,7 +110,8 @@ Status DBImpl::PromoteL0(ColumnFamilyHandle* column_family, int target_level) {
                       " have overlapping ranges\n",
                       prev_f->fd.GetNumber(), f->fd.GetNumber());
        job_context.Clean();
-        return Status::InvalidArgument("L0 has overlapping files");
+        status = Status::InvalidArgument("L0 has overlapping files");
+        return status;
      }
    }

@@ -117,21 +121,23 @@ Status DBImpl::PromoteL0(ColumnFamilyHandle* column_family, int target_level) {
        ROCKS_LOG_INFO(immutable_db_options_.info_log,
                       "PromoteL0 FAILED. Level %d not empty\n", level);
        job_context.Clean();
-        return Status::InvalidArgument(
+        status = Status::InvalidArgument(
            "All levels up to target_level "
            "must be empty");
+        return status;
      }
    }

    edit.SetColumnFamily(cfd->GetID());
    for (const auto& f : l0_files) {
      edit.DeleteFile(0, f->fd.GetNumber());
-      edit.AddFile(target_level, f->fd.GetNumber(), f->fd.GetPathId(),
-                   f->fd.GetFileSize(), f->smallest, f->largest,
-                   f->fd.smallest_seqno, f->fd.largest_seqno,
-                   f->marked_for_compaction, f->oldest_blob_file_number,
-                   f->oldest_ancester_time, f->file_creation_time,
-                   f->file_checksum, f->file_checksum_func_name);
+      edit.AddFile(
+          target_level, f->fd.GetNumber(), f->fd.GetPathId(),
+          f->fd.GetFileSize(), f->smallest, f->largest, f->fd.smallest_seqno,
+          f->fd.largest_seqno, f->marked_for_compaction, f->temperature,
+          f->oldest_blob_file_number, f->oldest_ancester_time,
+          f->file_creation_time, f->file_checksum, f->file_checksum_func_name,
+          f->min_timestamp, f->max_timestamp);
    }

    status = versions_->LogAndApply(cfd, *cfd->GetLatestMutableCFOptions(),
@@ -56,6 +56,8 @@ Status DBImpl::DisableFileDeletions() {
  return s;
 }

+// FIXME: can be inconsistent with DisableFileDeletions in cases like
+// DBImplReadOnly
 Status DBImpl::DisableFileDeletionsWithLock() {
  mutex_.AssertHeld();
  ++disable_delete_obsolete_files_;
@@ -642,6 +644,11 @@ void DBImpl::PurgeObsoleteFiles(JobContext& state, bool schedule_only) {
  InstrumentedMutexLock l(&mutex_);
  --pending_purge_obsolete_files_;
  assert(pending_purge_obsolete_files_ >= 0);
+  if (schedule_only) {
+    // Must change from pending_purge_obsolete_files_ to bg_purge_scheduled_
+    // while holding mutex (for GetSortedWalFiles() etc.)
+    SchedulePurge();
+  }
  if (pending_purge_obsolete_files_ == 0) {
    bg_cv_.SignalAll();
  }
@@ -655,15 +662,15 @@ void DBImpl::DeleteObsoleteFiles() {

  mutex_.Unlock();
  if (job_context.HaveSomethingToDelete()) {
-    PurgeObsoleteFiles(job_context);
+    bool defer_purge = immutable_db_options_.avoid_unnecessary_blocking_io;
+    PurgeObsoleteFiles(job_context, defer_purge);
  }
  job_context.Clean();
  mutex_.Lock();
 }

 uint64_t FindMinPrepLogReferencedByMemTable(
-    VersionSet* vset, const ColumnFamilyData* cfd_to_flush,
-    const autovector<MemTable*>& memtables_to_flush) {
+    VersionSet* vset, const autovector<MemTable*>& memtables_to_flush) {
  uint64_t min_log = 0;

  // we must look through the memtables for two phase transactions
@@ -671,7 +678,7 @@ uint64_t FindMinPrepLogReferencedByMemTable(
  std::unordered_set<MemTable*> memtables_to_flush_set(
      memtables_to_flush.begin(), memtables_to_flush.end());
  for (auto loop_cfd : *vset->GetColumnFamilySet()) {
-    if (loop_cfd->IsDropped() || loop_cfd == cfd_to_flush) {
+    if (loop_cfd->IsDropped()) {
      continue;
    }

@@ -693,18 +700,16 @@ uint64_t FindMinPrepLogReferencedByMemTable(
 }

 uint64_t FindMinPrepLogReferencedByMemTable(
-    VersionSet* vset, const autovector<ColumnFamilyData*>& cfds_to_flush,
+    VersionSet* vset,
    const autovector<const autovector<MemTable*>*>& memtables_to_flush) {
  uint64_t min_log = 0;

-  std::unordered_set<ColumnFamilyData*> cfds_to_flush_set(cfds_to_flush.begin(),
-                                                          cfds_to_flush.end());
  std::unordered_set<MemTable*> memtables_to_flush_set;
  for (const autovector<MemTable*>* memtables : memtables_to_flush) {
    memtables_to_flush_set.insert(memtables->begin(), memtables->end());
  }
  for (auto loop_cfd : *vset->GetColumnFamilySet()) {
-    if (loop_cfd->IsDropped() || cfds_to_flush_set.count(loop_cfd)) {
+    if (loop_cfd->IsDropped()) {
      continue;
    }

@@ -820,8 +825,8 @@ uint64_t PrecomputeMinLogNumberToKeep2PC(
    min_log_number_to_keep = min_log_in_prep_heap;
  }

-  uint64_t min_log_refed_by_mem = FindMinPrepLogReferencedByMemTable(
-      vset, &cfd_to_flush, memtables_to_flush);
+  uint64_t min_log_refed_by_mem =
+      FindMinPrepLogReferencedByMemTable(vset, memtables_to_flush);

  if (min_log_refed_by_mem != 0 &&
      min_log_refed_by_mem < min_log_number_to_keep) {
@@ -851,8 +856,8 @@ uint64_t PrecomputeMinLogNumberToKeep2PC(
    min_log_number_to_keep = min_log_in_prep_heap;
  }

-  uint64_t min_log_refed_by_mem = FindMinPrepLogReferencedByMemTable(
-      vset, cfds_to_flush, memtables_to_flush);
+  uint64_t min_log_refed_by_mem =
+      FindMinPrepLogReferencedByMemTable(vset, memtables_to_flush);

  if (min_log_refed_by_mem != 0 &&
      min_log_refed_by_mem < min_log_number_to_keep) {
--- a/Show More
+++ b/Show More