An odd fix for GCC 7

Disable warning as error
Add some include<functional>
2026-07-07 14:47:40 +08:00 · 2019-10-31 15:09:55 -07:00 · 2019-10-31 15:09:49 -07:00 · 2019-10-31 15:09:36 -07:00 · 2019-10-31 15:09:36 -07:00 · 2017-07-17 15:50:03 -07:00
376 changed files with 56462 additions and 12975 deletions
@@ -6,6 +6,5 @@
    "linters"
  ],
  "lint.engine" : "FacebookFbcodeLintEngine",
-  "lint.engine.single.linter" : "FbcodeCppLinter",
-  "lint.cpplint.prefix" : "linters"
+  "lint.engine.single.linter" : "FbcodeCppLinter"
 }
@@ -1,3 +1,4 @@
+TARGETS
 build_config.mk

 *.a
@@ -12,6 +13,13 @@ build_config.mk
 *_test
 *_bench
 *_stress
+*.out
+*.class
+*.jar
+*.*jnilib*
+*.d-e
+*.o-*
+*.swp

 ldb
 manifest_dump
@@ -21,3 +29,6 @@ build_tools/VALGRIND_LOGS/
 coverage/COVERAGE_REPORT
 .gdbhistory
 .phutil_module_cache
+tags
+java/*.log
+java/include/org_rocksdb_*.h
@@ -0,0 +1,20 @@
+language: cpp
+compiler: gcc
+before_install:
+# As of this writing (10 May 2014) the Travis build environment is Ubuntu 12.04,
+# which needs the following ugly dependency incantations to build RocksDB:
+ - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
+ - sudo apt-get update -qq
+ - sudo apt-get install -y -qq gcc-4.8 g++-4.8 zlib1g-dev libbz2-dev libsnappy-dev libjemalloc-dev
+ - sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 50
+ - sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 50
+ - wget https://gflags.googlecode.com/files/libgflags0_2.0-1_amd64.deb
+ - sudo dpkg -i libgflags0_2.0-1_amd64.deb
+ - wget https://gflags.googlecode.com/files/libgflags-dev_2.0-1_amd64.deb
+ - sudo dpkg -i libgflags-dev_2.0-1_amd64.deb
+# Lousy hack to disable use and testing of fallocate, which doesn't behave quite
+# as EnvPosixTest::AllocateTest expects within the Travis OpenVZ environment.
+ - sed -i "s/fallocate(/HACK_NO_fallocate(/" build_tools/build_detect_platform
+script: make check -j8
+notifications:
+    email: false
@@ -8,7 +8,10 @@ open source project, you're good to go. If you are submitting a pull
 request for the first time, just let us know that you have completed
 the CLA and we can cross-check with your GitHub username.

-Complete your CLA here: <https://developers.facebook.com/opensource/cla>
+Complete your CLA here: <https://code.facebook.com/cla>
+
+If you prefer to sign a paper copy, we can send you a PDF.  Send us an 
+e-mail or create a new github issue to request the CLA in PDF format.

 ## License

@@ -1,5 +1,84 @@
 # Rocksdb Change Log

+## 3.3.0 (7/10/2014)
+### New Features
+* Added JSON API prototype.
+* HashLinklist reduces performance outlier caused by skewed bucket by switching data in the bucket from linked list to skip list. Add parameter threshold_use_skiplist in NewHashLinkListRepFactory().
+* RocksDB is now able to reclaim storage space more effectively during the compaction process.  This is done by compensating the size of each deletion entry by the 2X average value size, which makes compaction to be triggerred by deletion entries more easily.
+* Add TimeOut API to write.  Now WriteOptions have a variable called timeout_hint_us.  With timeout_hint_us set to non-zero, any write associated with this timeout_hint_us may be aborted when it runs longer than the specified timeout_hint_us, and it is guaranteed that any write completes earlier than the specified time-out will not be aborted due to the time-out condition.
+* Add a rate_limiter option, which controls total throughput of flush and compaction. The throughput is specified in bytes/sec. Flush always has precedence over compaction when available bandwidth is constrained.
+
+### Public API changes
+* Removed NewTotalOrderPlainTableFactory because it is not used and implemented semantically incorrect.
+
+## 3.2.0 (06/20/2014)
+
+### Public API changes
+* We removed seek compaction as a concept from RocksDB because:
+1) It makes more sense for spinning disk workloads, while RocksDB is primarily designed for flash and memory,
+2) It added some complexity to the important code-paths,
+3) None of our internal customers were really using it.
+Because of that, Options::disable_seek_compaction is now obsolete. It is still a parameter in Options, so it does not break the build, but it does not have any effect. We plan to completely remove it at some point, so we ask users to please remove this option from your code base.
+* Add two paramters to NewHashLinkListRepFactory() for logging on too many entries in a hash bucket when flushing.
+* Added new option BlockBasedTableOptions::hash_index_allow_collision. When enabled, prefix hash index for block-based table will not store prefix and allow hash collision, reducing memory consumption.
+
+### New Features
+* PlainTable now supports a new key encoding: for keys of the same prefix, the prefix is only written once. It can be enabled through encoding_type paramter of NewPlainTableFactory()
+* Add AdaptiveTableFactory, which is used to convert from a DB of PlainTable to BlockBasedTabe, or vise versa. It can be created using NewAdaptiveTableFactory()
+
+### Performance Improvements
+* Tailing Iterator re-implemeted with ForwardIterator + Cascading Search Hint , see ~20% throughput improvement.
+
+## 3.1.0 (05/21/2014)
+
+### Public API changes
+* Replaced ColumnFamilyOptions::table_properties_collectors with ColumnFamilyOptions::table_properties_collector_factories
+
+### New Features
+* Hash index for block-based table will be materialized and reconstructed more efficiently. Previously hash index is constructed by scanning the whole table during every table open.
+* FIFO compaction style
+
+## 3.0.0 (05/05/2014)
+
+### Public API changes
+* Added _LEVEL to all InfoLogLevel enums
+* Deprecated ReadOptions.prefix and ReadOptions.prefix_seek. Seek() defaults to prefix-based seek when Options.prefix_extractor is supplied. More detail is documented in https://github.com/facebook/rocksdb/wiki/Prefix-Seek-API-Changes
+* MemTableRepFactory::CreateMemTableRep() takes info logger as an extra parameter.
+
+### New Features
+* Column family support
+* Added an option to use different checksum functions in BlockBasedTableOptions
+* Added ApplyToAllCacheEntries() function to Cache
+
+## 2.8.0 (04/04/2014)
+
+* Removed arena.h from public header files.
+* By default, checksums are verified on every read from database
+* Change default value of several options, including: paranoid_checks=true, max_open_files=5000, level0_slowdown_writes_trigger=20, level0_stop_writes_trigger=24, disable_seek_compaction=true, max_background_flushes=1 and allow_mmap_writes=false
+* Added is_manual_compaction to CompactionFilter::Context
+* Added "virtual void WaitForJoin()" in class Env. Default operation is no-op.
+* Removed BackupEngine::DeleteBackupsNewerThan() function
+* Added new option -- verify_checksums_in_compaction
+* Changed Options.prefix_extractor from raw pointer to shared_ptr (take ownership)
+  Changed HashSkipListRepFactory and HashLinkListRepFactory constructor to not take SliceTransform object (use Options.prefix_extractor implicitly)
+* Added Env::GetThreadPoolQueueLen(), which returns the waiting queue length of thread pools
+* Added a command "checkconsistency" in ldb tool, which checks
+  if file system state matches DB state (file existence and file sizes)
+* Separate options related to block based table to a new struct BlockBasedTableOptions.
+* WriteBatch has a new function Count() to return total size in the batch, and Data() now returns a reference instead of a copy
+* Add more counters to perf context.
+* Supports several more DB properties: compaction-pending, background-errors and cur-size-active-mem-table.
+
+### New Features
+* If we find one truncated record at the end of the MANIFEST or WAL files,
+  we will ignore it. We assume that writers of these records were interrupted
+  and that we can safely ignore it.
+* A new SST format "PlainTable" is added, which is optimized for memory-only workloads. It can be created through NewPlainTableFactory() or NewTotalOrderPlainTableFactory().
+* A new mem table implementation hash linked list optimizing for the case that there are only few keys for each prefix, which can be created through NewHashLinkListRepFactory().
+* Merge operator supports a new function PartialMergeMulti() to allow users to do partial merges against multiple operands.
+* Now compaction filter has a V2 interface. It buffers the kv-pairs sharing the same key prefix, process them in batches, and return the batched results back to DB. The new interface uses a new structure CompactionFilterContext for the same purpose as CompactionFilter::Context in V1.
+* Geo-spatial support for locations and radial-search.
+
 ## 2.7.0 (01/28/2014)

 ### Public API changes
@@ -1,31 +1,71 @@
+## Compilation
+
+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 with C++11 support.
+
+There are few options when compiling RocksDB:
+
+* [recommended] `make static_lib` will compile librocksdb.a, RocksDB static library.
+
+* `make shared_lib` will compile librocksdb.so, RocksDB shared library.
+
+* `make check` will compile and run all the unit tests
+
+* `make all` will compile our static library, and all our tools and unit tests. Our tools
+depend on gflags. You will need to have gflags installed to run `make all`.
+
 ## Dependencies

-RocksDB is developed on Linux (CentOS release 5.2), with gcc 4.8.1.
-It depends on gcc with C++11 support.
-
-* RocksDB depends on the following libraries:
+* You can link RocksDB with following compression libraries:
  - [zlib](http://www.zlib.net/) - a library for data compression.
  - [bzip2](http://www.bzip.org/) - a library for data compression.
  - [snappy](https://code.google.com/p/snappy/) - a library for fast
      data compression.
-  - [gflags](https://code.google.com/p/gflags/) - a library that handles
-      command line flags processing.

-RocksDB will successfully compile without the compression libraries included,
-but some things may fail. We do not support releases without the compression
-libraries. You are on your own.
+* All our tools depend on:
+  - [gflags](https://code.google.com/p/gflags/) - a library that handles
+      command line flags processing. You can compile rocksdb library even
+      if you don't have gflags installed.

 ## Supported platforms

-* **Linux**
+* **Linux - Ubuntu**
    * Upgrade your gcc to version at least 4.7 to get C++11 support.
-    * Install gflags. First, try: `sudo apt-get install libgflags-dev`.
+    * 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)
    * Install snappy. This is usually as easy as:
      `sudo apt-get install libsnappy-dev`.
    * Install zlib. Try: `sudo apt-get install zlib1g-dev`.
    * Install bzip2: `sudo apt-get install libbz2-dev`.
+* **Linux - CentOS**
+    * Upgrade your gcc to version at least 4.7 to get C++11 support:
+      `yum install gcc47-c++`
+    * Install gflags:
+
+              wget https://gflags.googlecode.com/files/gflags-2.0-no-svn-files.tar.gz
+              tar -xzvf gflags-2.0-no-svn-files.tar.gz
+              cd gflags-2.0
+              ./configure && make && sudo make install
+
+    * Install snappy:
+
+              wget https://snappy.googlecode.com/files/snappy-1.1.1.tar.gz
+              tar -xzvf snappy-1.1.1.tar.gz
+              cd snappy-1.1.1
+              ./configure && make && sudo make install
+
+    * Install zlib:
+
+              sudo yum install zlib
+              sudo yum install zlib-devel
+
+    * Install bzip2:
+
+              sudo yum install bzip2
+              sudo yum install bzip2-devel
+
 * **OS X**:
    * Install latest C++ compiler that supports C++ 11:
        * Update XCode:  run `xcode-select --install` (or install it from XCode App's settting).
@@ -34,17 +74,11 @@ libraries. You are on your own.
            * run `brew tap homebrew/dupes; brew install gcc47 --use-llvm` to install gcc 4.7 (or higher).
    * Install zlib, bzip2 and snappy libraries for compression.
    * Install gflags. We have included a script
-    `build_tools/mac-install-gflags.sh`, which should automatically install it.
+    `build_tools/mac-install-gflags.sh`, which should automatically install it (execute this file instead of runing using "source" command).
    If you installed gflags by other means (for example, `brew install gflags`),
    please set `LIBRARY_PATH` and `CPATH` accordingly.
    * Please note that some of the optimizations/features are disabled in OSX.
    We did not run any production workloads on it.

-## Compilation
-`make clean; make` will compile librocksdb.a (RocskDB static library) and all
-the unit tests. You can run all unit tests with `make check`.
-
-For shared library builds, exec `make librocksdb.so` instead.
-
-If you followed the above steps and your compile or unit tests fail,
-please submit an issue: (https://github.com/facebook/rocksdb/issues)
+* **iOS**:
+  * Run: `TARGET_OS=IOS make static_lib`
@@ -2,7 +2,7 @@ BSD License

 For rocksdb software

-Copyright (c) 2013, Facebook, Inc.
+Copyright (c) 2014, Facebook, Inc.
 All rights reserved.
 ---------------------------------------------------------------------

@@ -6,18 +6,36 @@
 INSTALL_PATH ?= $(CURDIR)

 #-----------------------------------------------
-# Uncomment exactly one of the lines labelled (A), (B), and (C) below
-# to switch between compilation modes.

-# OPT ?= -DNDEBUG     # (A) Production use (optimized mode)
+ifneq ($(MAKECMDGOALS),dbg)
 OPT += -O2 -fno-omit-frame-pointer -momit-leaf-frame-pointer
+else
+# intentionally left blank
+endif
+
+ifeq ($(MAKECMDGOALS),shared_lib)
+OPT += -DNDEBUG
+endif
+
+ifeq ($(MAKECMDGOALS),static_lib)
+OPT += -DNDEBUG
+endif
+
 #-----------------------------------------------

 # detect what platform we're building on
-$(shell (export ROCKSDB_ROOT=$(CURDIR); $(CURDIR)/build_tools/build_detect_platform $(CURDIR)/build_config.mk))
+$(shell (export ROCKSDB_ROOT="$(CURDIR)"; "$(CURDIR)/build_tools/build_detect_platform" "$(CURDIR)/build_config.mk"))
 # this file is generated by the previous line to set build flags and sources
 include build_config.mk

+ifneq ($(PLATFORM), IOS)
+CFLAGS += -g
+CXXFLAGS += -g
+else
+# no debug info for IOS, that will make our library big
+OPT += -DNDEBUG
+endif
+
 # ASAN doesn't work well with jemalloc. If we're compiling with ASAN, we should use regular malloc.
 ifdef COMPILE_WITH_ASAN
 	# ASAN compile flags
@@ -31,9 +49,8 @@ else
 	PLATFORM_CCFLAGS += $(JEMALLOC_INCLUDE) -DHAVE_JEMALLOC
 endif

-WARNING_FLAGS = -Wall -Werror
-CFLAGS += -g $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CCFLAGS) $(OPT)
-CXXFLAGS += -g $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CXXFLAGS) $(OPT) -Woverloaded-virtual
+CFLAGS += $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CCFLAGS) $(OPT)
+CXXFLAGS += $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CXXFLAGS) $(OPT) -Woverloaded-virtual

 LDFLAGS += $(PLATFORM_LDFLAGS)

@@ -43,6 +60,7 @@ MEMENVOBJECTS = $(MEMENV_SOURCES:.cc=.o)

 TESTUTIL = ./util/testutil.o
 TESTHARNESS = ./util/testharness.o $(TESTUTIL)
+BENCHHARNESS = ./util/benchharness.o
 VALGRIND_ERROR = 2
 VALGRIND_DIR = build_tools/VALGRIND_LOGS
 VALGRIND_VER := $(join $(VALGRIND_VER),valgrind)
@@ -50,12 +68,16 @@ VALGRIND_OPTS = --error-exitcode=$(VALGRIND_ERROR) --leak-check=full

 TESTS = \
 	db_test \
+	block_hash_index_test \
 	autovector_test \
+	column_family_test \
 	table_properties_collector_test \
 	arena_test \
 	auto_roll_logger_test \
+	benchharness_test \
 	block_test \
 	bloom_test \
+	dynamic_bloom_test \
 	c_test \
 	cache_test \
 	coding_test \
@@ -74,30 +96,40 @@ TESTS = \
 	merge_test \
 	redis_test \
 	reduce_levels_test \
+	plain_table_db_test \
+	prefix_test \
 	simple_table_db_test \
 	skiplist_test \
 	stringappend_test \
 	ttl_test \
 	backupable_db_test \
+	document_db_test \
+	json_document_test \
 	version_edit_test \
 	version_set_test \
+	file_indexer_test \
 	write_batch_test\
 	deletefile_test \
-	table_test
+	table_test \
+	thread_local_test \
+        geodb_test \
+        rate_limiter_test

 TOOLS = \
        sst_dump \
+	db_sanity_test \
        db_stress \
        ldb \
 	db_repl_stress \
 	blob_store_bench

-PROGRAMS = db_bench signal_test $(TESTS) $(TOOLS)
-BENCHMARKS = db_bench_sqlite3 db_bench_tree_db table_reader_bench
+PROGRAMS = db_bench signal_test table_reader_bench log_and_apply_bench $(TOOLS)

 # The library name is configurable since we are maintaining libraries of both
 # debug/release mode.
-LIBNAME = librocksdb
+ifeq ($(LIBNAME),)
+        LIBNAME=librocksdb
+endif
 LIBRARY = ${LIBNAME}.a
 MEMENVLIBRARY = libmemenv.a

@@ -115,8 +147,8 @@ SHARED3 = $(SHARED1)
 SHARED = $(SHARED1)
 else
 # Update db.h if you change these.
-SHARED_MAJOR = 2
-SHARED_MINOR = 0
+SHARED_MAJOR = 3
+SHARED_MINOR = 3
 SHARED1 = ${LIBNAME}.$(PLATFORM_SHARED_EXT)
 SHARED2 = $(SHARED1).$(SHARED_MAJOR)
 SHARED3 = $(SHARED1).$(SHARED_MAJOR).$(SHARED_MINOR)
@@ -127,36 +159,43 @@ $(SHARED2): $(SHARED3)
 	ln -fs $(SHARED3) $(SHARED2)
 endif

-$(SHARED3): $(LIBOBJECTS)
-	$(CXX) $(PLATFORM_SHARED_LDFLAGS)$(SHARED2) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(LDFLAGS) $(SOURCES)-o $@
+$(SHARED3):
+	$(CXX) $(PLATFORM_SHARED_LDFLAGS)$(SHARED2) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(SOURCES) $(LDFLAGS) -o $@

 endif  # PLATFORM_SHARED_EXT

-all: $(LIBRARY) $(PROGRAMS)
-
 .PHONY: blackbox_crash_test check clean coverage crash_test ldb_tests \
-	release tags valgrind_check whitebox_crash_test format shared_lib
+	release tags valgrind_check whitebox_crash_test format static_lib shared_lib all \
+	dbg

-# Will also generate shared libraries. 
+all: $(LIBRARY) $(PROGRAMS) $(TESTS)
+
+static_lib: $(LIBRARY)
+
+shared_lib: $(SHARED)
+
+dbg: $(LIBRARY) $(PROGRAMS) $(TESTS)
+
+# creates static library and programs
 release:
 	$(MAKE) clean
-	OPT=-DNDEBUG $(MAKE) all -j32
+	OPT="-DNDEBUG -O2" $(MAKE) static_lib $(PROGRAMS) -j32

 coverage:
 	$(MAKE) clean
-	COVERAGEFLAGS="-fprofile-arcs -ftest-coverage" LDFLAGS+="-lgcov" $(MAKE) all check
+	COVERAGEFLAGS="-fprofile-arcs -ftest-coverage" LDFLAGS+="-lgcov" $(MAKE) all check -j32
 	(cd coverage; ./coverage_test.sh)
 	# Delete intermediate files
 	find . -type f -regex ".*\.\(\(gcda\)\|\(gcno\)\)" -exec rm {} \;

-check: all $(PROGRAMS) $(TESTS) $(TOOLS)
+check: $(TESTS) ldb
 	for t in $(TESTS); do echo "***** Running $$t"; ./$$t || exit 1; done
 	python tools/ldb_test.py

-ldb_tests: all $(PROGRAMS) $(TOOLS)
+ldb_tests: ldb
 	python tools/ldb_test.py

-crash_test: blackbox_crash_test whitebox_crash_test
+crash_test: whitebox_crash_test blackbox_crash_test

 blackbox_crash_test: db_stress
 	python -u tools/db_crashtest.py
@@ -171,7 +210,7 @@ asan_check:

 asan_crash_test:
 	$(MAKE) clean
-	COMPILE_WITH_ASAN=1 $(MAKE) crash_test -j32
+	COMPILE_WITH_ASAN=1 $(MAKE) crash_test
 	$(MAKE) clean

 valgrind_check: all $(PROGRAMS) $(TESTS)
@@ -189,7 +228,7 @@ valgrind_check: all $(PROGRAMS) $(TESTS)
 	done

 clean:
-	-rm -f $(PROGRAMS) $(BENCHMARKS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) build_config.mk
+	-rm -f $(PROGRAMS) $(TESTS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) build_config.mk
 	-rm -rf ios-x86/* ios-arm/*
 	-find . -name "*.[od]" -exec rm {} \;
 	-find . -type f -regex ".*\.\(\(gcda\)\|\(gcno\)\)" -exec rm {} \;
@@ -200,8 +239,6 @@ tags:
 format:
 	build_tools/format-diff.sh

-shared_lib: $(SHARED)
-
 # ---------------------------------------------------------------------------
 # 	Unit tests and tools
 # ---------------------------------------------------------------------------
@@ -212,21 +249,21 @@ $(LIBRARY): $(LIBOBJECTS)
 db_bench: db/db_bench.o $(LIBOBJECTS) $(TESTUTIL)
 	$(CXX) db/db_bench.o $(LIBOBJECTS) $(TESTUTIL) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)

+block_hash_index_test: table/block_hash_index_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	 $(CXX) table/block_hash_index_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 db_stress: tools/db_stress.o $(LIBOBJECTS) $(TESTUTIL)
 	$(CXX) tools/db_stress.o $(LIBOBJECTS) $(TESTUTIL) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)

+db_sanity_test: tools/db_sanity_test.o $(LIBOBJECTS) $(TESTUTIL)
+	$(CXX) tools/db_sanity_test.o $(LIBOBJECTS) $(TESTUTIL) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)
+
 db_repl_stress: tools/db_repl_stress.o $(LIBOBJECTS) $(TESTUTIL)
 	$(CXX) tools/db_repl_stress.o $(LIBOBJECTS) $(TESTUTIL) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)

 blob_store_bench: tools/blob_store_bench.o $(LIBOBJECTS) $(TESTUTIL)
 	$(CXX) tools/blob_store_bench.o $(LIBOBJECTS) $(TESTUTIL) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)

-db_bench_sqlite3: doc/bench/db_bench_sqlite3.o $(LIBOBJECTS) $(TESTUTIL)
-	$(CXX) doc/bench/db_bench_sqlite3.o $(LIBOBJECTS) $(TESTUTIL) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) -lsqlite3 $(COVERAGEFLAGS)
-
-db_bench_tree_db: doc/bench/db_bench_tree_db.o $(LIBOBJECTS) $(TESTUTIL)
-	$(CXX) doc/bench/db_bench_tree_db.o $(LIBOBJECTS) $(TESTUTIL) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) -lkyotocabinet $(COVERAGEFLAGS)
-
 signal_test: util/signal_test.o $(LIBOBJECTS)
 	$(CXX) util/signal_test.o $(LIBOBJECTS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

@@ -236,12 +273,18 @@ arena_test: util/arena_test.o $(LIBOBJECTS) $(TESTHARNESS)
 autovector_test: util/autovector_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) util/autovector_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+column_family_test: db/column_family_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) db/column_family_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 table_properties_collector_test: db/table_properties_collector_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/table_properties_collector_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

 bloom_test: util/bloom_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) util/bloom_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+dynamic_bloom_test: util/dynamic_bloom_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) util/dynamic_bloom_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 c_test: db/c_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/c_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

@@ -260,9 +303,15 @@ stringappend_test: utilities/merge_operators/string_append/stringappend_test.o $
 redis_test: utilities/redis/redis_lists_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) utilities/redis/redis_lists_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+benchharness_test: util/benchharness_test.o $(LIBOBJECTS) $(TESTHARNESS) $(BENCHHARNESS)
+	$(CXX) util/benchharness_test.o $(LIBOBJECTS) $(TESTHARNESS) $(BENCHHARNESS) $(EXEC_LDFLAGS) -o$@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 histogram_test: util/histogram_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) util/histogram_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o$@ $(LDFLAGS) $(COVERAGEFLAGS)

+thread_local_test: util/thread_local_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) util/thread_local_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 corruption_test: db/corruption_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/corruption_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

@@ -272,11 +321,20 @@ crc32c_test: util/crc32c_test.o $(LIBOBJECTS) $(TESTHARNESS)
 db_test: db/db_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/db_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+log_write_bench: util/log_write_bench.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) util/log_write_bench.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS) -pg
+
+plain_table_db_test: db/plain_table_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) db/plain_table_db_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 simple_table_db_test: db/simple_table_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/simple_table_db_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

 table_reader_bench: table/table_reader_bench.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) table/table_reader_bench.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+	$(CXX) table/table_reader_bench.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS) -pg
+
+log_and_apply_bench: db/log_and_apply_bench.o $(LIBOBJECTS) $(TESTHARNESS) $(BENCHHARNESS)
+	$(CXX) db/log_and_apply_bench.o $(LIBOBJECTS) $(TESTHARNESS) $(BENCHHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS) -pg

 perf_context_test: db/perf_context_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/perf_context_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS)
@@ -287,6 +345,12 @@ prefix_test: db/prefix_test.o $(LIBOBJECTS) $(TESTHARNESS)
 backupable_db_test: utilities/backupable/backupable_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) utilities/backupable/backupable_db_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)

+document_db_test: utilities/document/document_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) utilities/document/document_db_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)
+
+json_document_test: utilities/document/json_document_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) utilities/document/json_document_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)
+
 ttl_test: utilities/ttl/ttl_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) utilities/ttl/ttl_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@  $(LDFLAGS) $(COVERAGEFLAGS)

@@ -296,6 +360,9 @@ dbformat_test: db/dbformat_test.o $(LIBOBJECTS) $(TESTHARNESS)
 env_test: util/env_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) util/env_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+rate_limiter_test: util/rate_limiter_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) util/rate_limiter_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 filename_test: db/filename_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/filename_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

@@ -320,6 +387,9 @@ version_edit_test: db/version_edit_test.o $(LIBOBJECTS) $(TESTHARNESS)
 version_set_test: db/version_set_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/version_set_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+file_indexer_test : db/file_indexer_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) db/file_indexer_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 reduce_levels_test: tools/reduce_levels_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) tools/reduce_levels_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

@@ -332,12 +402,15 @@ merge_test: db/merge_test.o $(LIBOBJECTS) $(TESTHARNESS)
 deletefile_test: db/deletefile_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) db/deletefile_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS)

+geodb_test: utilities/geodb/geodb_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) utilities/geodb/geodb_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 $(MEMENVLIBRARY) : $(MEMENVOBJECTS)
 	rm -f $@
 	$(AR) -rs $@ $(MEMENVOBJECTS)

-memenv_test : helpers/memenv/memenv_test.o $(MEMENVLIBRARY) $(LIBRARY) $(TESTHARNESS)
-	$(CXX) helpers/memenv/memenv_test.o $(MEMENVLIBRARY) $(LIBRARY) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+memenv_test : helpers/memenv/memenv_test.o $(MEMENVOBJECTS) $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) helpers/memenv/memenv_test.o $(MEMENVOBJECTS) $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

 manual_compaction_test: util/manual_compaction_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) util/manual_compaction_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
@@ -360,6 +433,35 @@ sst_dump: tools/sst_dump.o $(LIBOBJECTS)
 ldb: tools/ldb.o $(LIBOBJECTS)
 	$(CXX) tools/ldb.o $(LIBOBJECTS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+# ---------------------------------------------------------------------------
+# Jni stuff
+# ---------------------------------------------------------------------------
+
+JNI_NATIVE_SOURCES = ./java/rocksjni/*.cc
+JAVA_INCLUDE = -I$(JAVA_HOME)/include/ -I$(JAVA_HOME)/include/linux
+ROCKSDBJNILIB = ./java/librocksdbjni.so
+
+ifeq ($(PLATFORM), OS_MACOSX)
+ROCKSDBJNILIB = ./java/librocksdbjni.jnilib
+JAVA_INCLUDE = -I/System/Library/Frameworks/JavaVM.framework/Headers/
+endif
+
+rocksdbjava:
+	OPT="-fPIC -DNDEBUG -O2" $(MAKE) $(LIBRARY) -j32
+	cd java;$(MAKE) java;
+	rm -f $(ROCKSDBJNILIB)
+	$(CXX) $(CXXFLAGS) -I./java/. $(JAVA_INCLUDE) -shared -fPIC -o $(ROCKSDBJNILIB) $(JNI_NATIVE_SOURCES) $(LIBOBJECTS) $(LDFLAGS) $(COVERAGEFLAGS)
+
+jclean:
+	cd java;$(MAKE) clean;
+	rm -f $(ROCKSDBJNILIB)
+
+jtest:
+	cd java;$(MAKE) sample;$(MAKE) test;
+
+jdb_bench:
+	cd java;$(MAKE) db_bench;
+
 # ---------------------------------------------------------------------------
 #  	Platform-specific compilation
 # ---------------------------------------------------------------------------
@@ -370,20 +472,20 @@ ifeq ($(PLATFORM), IOS)
 PLATFORMSROOT=/Applications/Xcode.app/Contents/Developer/Platforms
 SIMULATORROOT=$(PLATFORMSROOT)/iPhoneSimulator.platform/Developer
 DEVICEROOT=$(PLATFORMSROOT)/iPhoneOS.platform/Developer
-IOSVERSION=$(shell defaults read $(PLATFORMSROOT)/iPhoneOS.platform/versionCFBundleShortVersionString)
+IOSVERSION=$(shell defaults read $(PLATFORMSROOT)/iPhoneOS.platform/version CFBundleShortVersionString)

 .cc.o:
 	mkdir -p ios-x86/$(dir $@)
-	$(SIMULATORROOT)/usr/bin/$(CXX) $(CXXFLAGS) -isysroot $(SIMULATORROOT)/SDKs/iPhoneSimulator$(IOSVERSION).sdk -arch i686 -c $< -o ios-x86/$@ $(COVERAGEFLAGS)
+	$(CXX) $(CXXFLAGS) -isysroot $(SIMULATORROOT)/SDKs/iPhoneSimulator$(IOSVERSION).sdk -arch i686 -arch x86_64 -c $< -o ios-x86/$@
 	mkdir -p ios-arm/$(dir $@)
-	$(DEVICEROOT)/usr/bin/$(CXX) $(CXXFLAGS) -isysroot $(DEVICEROOT)/SDKs/iPhoneOS$(IOSVERSION).sdk -arch armv6 -arch armv7 -c $< -o ios-arm/$@ $(COVERAGEFLAGS)
+	xcrun -sdk iphoneos $(CXX) $(CXXFLAGS) -isysroot $(DEVICEROOT)/SDKs/iPhoneOS$(IOSVERSION).sdk -arch armv6 -arch armv7 -arch armv7s -arch arm64 -c $< -o ios-arm/$@
 	lipo ios-x86/$@ ios-arm/$@ -create -output $@

 .c.o:
 	mkdir -p ios-x86/$(dir $@)
-	$(SIMULATORROOT)/usr/bin/$(CC) $(CFLAGS) -isysroot $(SIMULATORROOT)/SDKs/iPhoneSimulator$(IOSVERSION).sdk -arch i686 -c $< -o ios-x86/$@
+	$(CC) $(CFLAGS) -isysroot $(SIMULATORROOT)/SDKs/iPhoneSimulator$(IOSVERSION).sdk -arch i686 -arch x86_64 -c $< -o ios-x86/$@
 	mkdir -p ios-arm/$(dir $@)
-	$(DEVICEROOT)/usr/bin/$(CC) $(CFLAGS) -isysroot $(DEVICEROOT)/SDKs/iPhoneOS$(IOSVERSION).sdk -arch armv6 -arch armv7 -c $< -o ios-arm/$@
+	xcrun -sdk iphoneos $(CC) $(CFLAGS) -isysroot $(DEVICEROOT)/SDKs/iPhoneOS$(IOSVERSION).sdk -arch armv6 -arch armv7 -arch armv7s -arch arm64 -c $< -o ios-arm/$@
 	lipo ios-x86/$@ ios-arm/$@ -create -output $@

 else
@@ -423,6 +525,10 @@ depend: $(DEPFILES)
 # working solution.
 ifneq ($(MAKECMDGOALS),clean)
 ifneq ($(MAKECMDGOALS),format)
+ifneq ($(MAKECMDGOALS),jclean)
+ifneq ($(MAKECMDGOALS),jtest)
 -include $(DEPFILES)
 endif
 endif
+endif
+endif
@@ -1,82 +0,0 @@
-rocksdb: A persistent key-value store for flash storage
-Authors: * The Facebook Database Engineering Team
-         * Build on earlier work on leveldb by Sanjay Ghemawat
-           (sanjay@google.com) and Jeff Dean (jeff@google.com)
-
-This code is a library that forms the core building block for a fast
-key value server, especially suited for storing data on flash drives.
-It has an Log-Structured-Merge-Database (LSM) design with flexible tradeoffs
-between Write-Amplification-Factor(WAF), Read-Amplification-Factor (RAF)
-and Space-Amplification-Factor(SAF). It has multi-threaded compactions,
-making it specially suitable for storing multiple terabytes of data in a
-single database.
-
-The core of this code has been derived from open-source leveldb.
-
-The code under this directory implements a system for maintaining a
-persistent key/value store.
-
-See doc/index.html and github wiki (https://github.com/facebook/rocksdb/wiki)
-for more explanation.
-
-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.
-
-Guide to header files:
-
-include/rocksdb/db.h
-    Main interface to the DB: Start here
-
-include/rocksdb/options.h
-    Control over the behavior of an entire database, and also
-    control over the behavior of individual reads and writes.
-
-include/rocksdb/comparator.h
-    Abstraction for user-specified comparison function.  If you want
-    just bytewise comparison of keys, you can use the default comparator,
-    but clients can write their own comparator implementations if they
-    want custom ordering (e.g. to handle different character
-    encodings, etc.)
-
-include/rocksdb/iterator.h
-    Interface for iterating over data. You can get an iterator
-    from a DB object.
-
-include/rocksdb/write_batch.h
-    Interface for atomically applying multiple updates to a database.
-
-include/rocksdb/slice.h
-    A simple module for maintaining a pointer and a length into some
-    other byte array.
-
-include/rocksdb/status.h
-    Status is returned from many of the public interfaces and is used
-    to report success and various kinds of errors.
-
-include/rocksdb/env.h
-    Abstraction of the OS environment.  A posix implementation of
-    this interface is in util/env_posix.cc
-
-include/rocksdb/table_builder.h
-    Lower-level modules that most clients probably won't use directly
-
-include/rocksdb/cache.h
-    An API for the block cache.
-
-include/rocksdb/compaction_filter.h
-    An API for a application filter invoked on every compaction.
-
-include/rocksdb/filter_policy.h
-    An API for configuring a bloom filter.
-
-include/rocksdb/memtablerep.h
-    An API for implementing a memtable.
-
-include/rocksdb/statistics.h
-    An API to retrieve various database statistics.
-
-include/rocksdb/transaction_log.h
-    An API to retrieve transaction logs from a database.
-
-Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/
@@ -1,3 +0,0 @@
-* Detailed instructions on how to compile using fbcode and jemalloc
-
-* Latest release is 2.7.fb
@@ -0,0 +1,25 @@
+## RocksDB: A Persistent Key-Value Store for Flash and RAM Storage
+
+[![Build Status](https://travis-ci.org/facebook/rocksdb.svg?branch=master)](https://travis-ci.org/facebook/rocksdb)
+
+RocksDB is developed and maintained by Facebook Database Engineering Team.
+It is built on on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com)
+and Jeff Dean (jeff@google.com)
+
+This code is a library that forms the core building block for a fast
+key value server, especially suited for storing data on flash drives.
+It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs
+between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF)
+and Space-Amplification-Factor (SAF). It has multi-threaded compactions,
+making it specially suitable for storing multiple terabytes of data in a
+single database.
+
+Start with example usage here: https://github.com/facebook/rocksdb/tree/master/examples
+
+See the [github wiki](https://github.com/facebook/rocksdb/wiki) for more explanation.
+
+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/
@@ -0,0 +1,20 @@
+# RocksDBLite
+
+RocksDBLite is a project focused on mobile use cases, which don't need a lot of fancy things we've built for server workloads and they are very sensitive to binary size. For that reason, we added a compile flag ROCKSDB_LITE that comments out a lot of the nonessential code and keeps the binary lean.
+
+Some examples of the features disabled by ROCKSDB_LITE:
+* compiled-in support for LDB tool
+* No backupable DB
+* No support for replication (which we provide in form of TrasactionalIterator)
+* No advanced monitoring tools
+* No special-purpose memtables that are highly optimized for specific use cases
+
+When adding a new big feature to RocksDB, please add ROCKSDB_LITE compile guard if:
+* Nobody from mobile really needs your feature,
+* Your feature is adding a lot of weight to the binary.
+
+Don't add ROCKSDB_LITE compile guard if:
+* It would introduce a lot of code complexity. Compile guards make code harder to read. It's a trade-off.
+* Your feature is not adding a lot of weight.
+
+If unsure, ask. :)
@@ -19,7 +19,9 @@
 #
 #       -DLEVELDB_PLATFORM_POSIX if cstdatomic is present
 #       -DLEVELDB_PLATFORM_NOATOMIC if it is not
-#       -DSNAPPY                     if the Snappy library is present
+#       -DSNAPPY                    if the Snappy library is present
+#       -DLZ4                       if the LZ4 library is present
+#       -DNUMA                      if the NUMA library is present
 #
 # Using gflags in rocksdb:
 # Our project depends on gflags, which requires users to take some extra steps
@@ -38,7 +40,7 @@ if test -z "$OUTPUT"; then
 fi

 # we depend on C++11
-PLATFORM_CXXFLAGS="-std=gnu++11"
+PLATFORM_CXXFLAGS="-std=c++11"
 # we currently depend on POSIX platform
 COMMON_FLAGS="-DROCKSDB_PLATFORM_POSIX"

@@ -46,21 +48,15 @@ COMMON_FLAGS="-DROCKSDB_PLATFORM_POSIX"
 if [ -d /mnt/gvfs/third-party -a -z "$CXX" ]; then
    FBCODE_BUILD="true"
    if [ -z "$USE_CLANG" ]; then
-        CENTOS_VERSION=`rpm -q --qf "%{VERSION}" \
-          $(rpm -q --whatprovides redhat-release)`
-        if [ "$CENTOS_VERSION" = "6" ]; then
-          source $PWD/build_tools/fbcode.gcc481.sh
-        else
-          source $PWD/build_tools/fbcode.gcc471.sh
-        fi
+        source $PWD/build_tools/fbcode_config.sh
    else
-        source $PWD/build_tools/fbcode.clang31.sh
+        source "$PWD/build_tools/fbcode.clang31.sh"
    fi
 fi

 # Delete existing output, if it exists
-rm -f $OUTPUT
-touch $OUTPUT
+rm -f "$OUTPUT"
+touch "$OUTPUT"

 if test -z "$CC"; then
   CC=cc
@@ -86,7 +82,7 @@ PLATFORM_SHARED_CFLAGS="-fPIC"
 PLATFORM_SHARED_VERSIONED=false

 # generic port files (working on all platform by #ifdef) go directly in /port
-GENERIC_PORT_FILES=`find $ROCKSDB_ROOT/port -name '*.cc' | tr "\n" " "`
+GENERIC_PORT_FILES=`cd "$ROCKSDB_ROOT"; find port -name '*.cc' | tr "\n" " "`

 # On GCC, we pick libc's memcmp over GCC's memcmp via -fno-builtin-memcmp
 case "$TARGET_OS" in
@@ -97,6 +93,13 @@ case "$TARGET_OS" in
        PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name "
        # PORT_FILES=port/darwin/darwin_specific.cc
        ;;
+    IOS)
+        PLATFORM=IOS
+        COMMON_FLAGS="$COMMON_FLAGS -DOS_MACOSX -DIOS_CROSS_COMPILE -DROCKSDB_LITE"
+        PLATFORM_SHARED_EXT=dylib
+        PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name "
+        CROSS_COMPILE=true
+        ;;
    Linux)
        PLATFORM=OS_LINUX
        COMMON_FLAGS="$COMMON_FLAGS -DOS_LINUX"
@@ -148,7 +151,9 @@ case "$TARGET_OS" in
        exit 1
 esac

-$PWD/build_tools/build_detect_version
+if test -z "$DO_NOT_RUN_BUILD_DETECT_VERSION"; then
+  "$PWD/build_tools/build_detect_version"
+fi

 # We want to make a list of all cc files within util, db, table, and helpers
 # except for the test and benchmark files. By default, find will output a list
@@ -158,28 +163,22 @@ DIRS="util db table utilities"

 set -f # temporarily disable globbing so that our patterns arent expanded
 PRUNE_TEST="-name *test*.cc -prune"
-PRUNE_BENCH="-name *_bench.cc -prune"
-PORTABLE_FILES=`cd $ROCKSDB_ROOT; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cc' -print | sort | tr "\n" " "`
-PORTABLE_CPP=`cd $ROCKSDB_ROOT; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cpp' -print | sort | tr "\n" " "`
+PRUNE_BENCH="-name *bench*.cc -prune"
+PORTABLE_FILES=`cd "$ROCKSDB_ROOT"; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cc' -print | sort | tr "\n" " "`
+PORTABLE_CPP=`cd "$ROCKSDB_ROOT"; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cpp' -print | sort | tr "\n" " "`
 set +f # re-enable globbing

 # The sources consist of the portable files, plus the platform-specific port
 # file.
-echo "SOURCES=$PORTABLE_FILES $GENERIC_PORT_FILES $PORT_FILES" >> $OUTPUT
-echo "SOURCESCPP=$PORTABLE_CPP" >> $OUTPUT
-echo "MEMENV_SOURCES=helpers/memenv/memenv.cc" >> $OUTPUT
+echo "SOURCES=$PORTABLE_FILES $GENERIC_PORT_FILES $PORT_FILES" >> "$OUTPUT"
+echo "SOURCESCPP=$PORTABLE_CPP" >> "$OUTPUT"
+echo "MEMENV_SOURCES=helpers/memenv/memenv.cc" >> "$OUTPUT"

 if [ "$CROSS_COMPILE" = "true" -o "$FBCODE_BUILD" = "true" ]; then
    # Cross-compiling; do not try any compilation tests.
    # Also don't need any compilation tests if compiling on fbcode
    true
 else
-    # do fPIC on 64 bit in non-fbcode environment
-    case "$TARGET_OS" in
-        x86_64)
-            PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS -fPIC"
-    esac
-
    # If -std=c++0x works, use <atomic>.  Otherwise use port_posix.h.
    $CXX $CFLAGS -std=c++0x -x c++ - -o /dev/null 2>/dev/null  <<EOF
      #include <atomic>
@@ -215,12 +214,25 @@ EOF

    # Test whether gflags library is installed
    # http://code.google.com/p/gflags/
+    # check if the namespace is gflags
    $CXX $CFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
      #include <gflags/gflags.h>
+      using namespace gflags;
      int main() {}
 EOF
    if [ "$?" = 0 ]; then
-        COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS"
+        COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS=gflags"
+        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lgflags"
+    fi
+
+    # check if namespace is google
+    $CXX $CFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+      #include <gflags/gflags.h>
+      using namespace google;
+      int main() {}
+EOF
+    if [ "$?" = 0 ]; then
+        COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS=gflags"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lgflags"
    fi

@@ -244,6 +256,28 @@ EOF
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lbz2"
    fi

+    # Test whether lz4 library is installed
+    $CXX $CFLAGS $COMMON_FLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+      #include <lz4.h>
+      #include <lz4hc.h>
+      int main() {}
+EOF
+    if [ "$?" = 0 ]; then
+        COMMON_FLAGS="$COMMON_FLAGS -DLZ4"
+        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -llz4"
+    fi
+
+    # Test whether numa is available
+    $CXX $CFLAGS -x c++ - -o /dev/null -lnuma 2>/dev/null  <<EOF
+      #include <numa.h>
+      #inlcude <numaif.h>
+      int main() {}
+EOF
+    if [ "$?" = 0 ]; then
+        COMMON_FLAGS="$COMMON_FLAGS -DNUMA"
+        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lnuma"
+    fi
+
    # Test whether tcmalloc is available
    $CXX $CFLAGS -x c++ - -o /dev/null -ltcmalloc 2>/dev/null  <<EOF
      int main() {}
@@ -261,7 +295,7 @@ if test "$USE_HDFS"; then
    exit 1
  fi
  HDFS_CCFLAGS="$HDFS_CCFLAGS -I$JAVA_HOME/include -I$JAVA_HOME/include/linux -DUSE_HDFS"
-  HDFS_LDFLAGS="$HDFS_LDFLAGS -Wl,--no-whole-archive hdfs/libhdfs.a -L$JAVA_HOME/jre/lib/amd64"
+  HDFS_LDFLAGS="$HDFS_LDFLAGS -Wl,--no-whole-archive -lhdfs -L$JAVA_HOME/jre/lib/amd64"
  HDFS_LDFLAGS="$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 $HDFS_CCFLAGS"
@@ -276,17 +310,17 @@ PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS $COMMON_FLAGS"

 VALGRIND_VER="$VALGRIND_VER"

-echo "CC=$CC" >> $OUTPUT
-echo "CXX=$CXX" >> $OUTPUT
-echo "PLATFORM=$PLATFORM" >> $OUTPUT
-echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> $OUTPUT
-echo "VALGRIND_VER=$VALGRIND_VER" >> $OUTPUT
-echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> $OUTPUT
-echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> $OUTPUT
-echo "PLATFORM_SHARED_CFLAGS=$PLATFORM_SHARED_CFLAGS" >> $OUTPUT
-echo "PLATFORM_SHARED_EXT=$PLATFORM_SHARED_EXT" >> $OUTPUT
-echo "PLATFORM_SHARED_LDFLAGS=$PLATFORM_SHARED_LDFLAGS" >> $OUTPUT
-echo "PLATFORM_SHARED_VERSIONED=$PLATFORM_SHARED_VERSIONED" >> $OUTPUT
-echo "EXEC_LDFLAGS=$EXEC_LDFLAGS" >> $OUTPUT
-echo "JEMALLOC_INCLUDE=$JEMALLOC_INCLUDE" >> $OUTPUT
-echo "JEMALLOC_LIB=$JEMALLOC_LIB" >> $OUTPUT
+echo "CC=$CC" >> "$OUTPUT"
+echo "CXX=$CXX" >> "$OUTPUT"
+echo "PLATFORM=$PLATFORM" >> "$OUTPUT"
+echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> "$OUTPUT"
+echo "VALGRIND_VER=$VALGRIND_VER" >> "$OUTPUT"
+echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> "$OUTPUT"
+echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> "$OUTPUT"
+echo "PLATFORM_SHARED_CFLAGS=$PLATFORM_SHARED_CFLAGS" >> "$OUTPUT"
+echo "PLATFORM_SHARED_EXT=$PLATFORM_SHARED_EXT" >> "$OUTPUT"
+echo "PLATFORM_SHARED_LDFLAGS=$PLATFORM_SHARED_LDFLAGS" >> "$OUTPUT"
+echo "PLATFORM_SHARED_VERSIONED=$PLATFORM_SHARED_VERSIONED" >> "$OUTPUT"
+echo "EXEC_LDFLAGS=$EXEC_LDFLAGS" >> "$OUTPUT"
+echo "JEMALLOC_INCLUDE=$JEMALLOC_INCLUDE" >> "$OUTPUT"
+echo "JEMALLOC_LIB=$JEMALLOC_LIB" >> "$OUTPUT"
@@ -0,0 +1,19 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+GCC_BASE=/mnt/gvfs/third-party2/gcc/7331085db891a2ef4a88a48a751d834e8d68f4cb/7.x/centos7-native/b2ef2b6
+CLANG_BASE=/mnt/gvfs/third-party2/llvm-fb/963d9aeda70cc4779885b1277484fe7544a04e3e/9.0.0/platform007/9e92d53/
+LIBGCC_BASE=/mnt/gvfs/third-party2/libgcc/6ace84e956873d53638c738b6f65f3f469cca74c/7.x/platform007/5620abc
+GLIBC_BASE=/mnt/gvfs/third-party2/glibc/192b0f42d63dcf6210d6ceae387b49af049e6e0c/2.26/platform007/f259413
+SNAPPY_BASE=/mnt/gvfs/third-party2/snappy/7f9bdaada18f59bc27ec2b0871eb8a6144343aef/1.1.3/platform007/ca4da3d
+ZLIB_BASE=/mnt/gvfs/third-party2/zlib/2d9f0b9a4274cc21f61272a9e89bdb859bce8f1f/1.2.8/platform007/ca4da3d
+BZIP2_BASE=/mnt/gvfs/third-party2/bzip2/dc49a21c5fceec6456a7a28a94dcd16690af1337/1.0.6/platform007/ca4da3d
+LZ4_BASE=/mnt/gvfs/third-party2/lz4/0f607f8fc442ea7d6b876931b1898bb573d5e5da/1.9.1/platform007/ca4da3d
+ZSTD_BASE=/mnt/gvfs/third-party2/zstd/ca22bc441a4eb709e9e0b1f9fec9750fed7b31c5/1.4.x/platform007/15a3614
+GFLAGS_BASE=/mnt/gvfs/third-party2/gflags/0b9929d2588991c65a57168bf88aff2db87c5d48/2.2.0/platform007/ca4da3d
+JEMALLOC_BASE=/mnt/gvfs/third-party2/jemalloc/c26f08f47ac35fc31da2633b7da92d6b863246eb/master/platform007/c26c002
+NUMA_BASE=/mnt/gvfs/third-party2/numa/3f3fb57a5ccc5fd21c66416c0b83e0aa76a05376/2.0.11/platform007/ca4da3d
+LIBUNWIND_BASE=/mnt/gvfs/third-party2/libunwind/40c73d874898b386a71847f1b99115d93822d11f/1.4/platform007/6f3e0a9
+TBB_BASE=/mnt/gvfs/third-party2/tbb/4ce8e8dba77cdbd81b75d6f0c32fd7a1b76a11ec/2018_U5/platform007/ca4da3d
+KERNEL_HEADERS_BASE=/mnt/gvfs/third-party2/kernel-headers/fb251ecd2f5ae16f8671f7014c246e52a748fe0b/fb/platform007/da39a3e
+BINUTILS_BASE=/mnt/gvfs/third-party2/binutils/ab9f09bba370e7066cafd4eb59752db93f2e8312/2.29.1/platform007/15a3614
+VALGRIND_BASE=/mnt/gvfs/third-party2/valgrind/d42d152a15636529b0861ec493927200ebebca8e/3.15.0/platform007/ca4da3d
+LUA_BASE=/mnt/gvfs/third-party2/lua/f0cd714433206d5139df61659eb7b28b1dea6683/5.3.4/platform007/5007832
@@ -55,7 +55,7 @@ CFLAGS="-B$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/gold -m64
 CFLAGS+=" -I $TOOLCHAIN_LIB_BASE/jemalloc/$TOOL_JEMALLOC/include -DHAVE_JEMALLOC"
 CFLAGS+=" $LIBGCC_INCLUDE $GLIBC_INCLUDE"
 CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_ATOMIC_PRESENT -DROCKSDB_FALLOCATE_PRESENT"
-CFLAGS+=" -DSNAPPY -DGFLAGS -DZLIB -DBZIP2"
+CFLAGS+=" -DSNAPPY -DGFLAGS=google -DZLIB -DBZIP2"

 EXEC_LDFLAGS=" -Wl,--whole-archive $TOOLCHAIN_LIB_BASE/jemalloc/$TOOL_JEMALLOC/lib/libjemalloc.a"
 EXEC_LDFLAGS+=" -Wl,--no-whole-archive $TOOLCHAIN_LIB_BASE/libunwind/libunwind-1.0.1/350336c/lib/libunwind.a"
@@ -43,6 +43,10 @@ ZLIB_LIBS=" $TOOLCHAIN_LIB_BASE/zlib/zlib-1.2.5/c3f970a/lib/libz.a"
 BZIP_INCLUDE=" -I $TOOLCHAIN_LIB_BASE/bzip2/bzip2-1.0.6/c3f970a/include"
 BZIP_LIBS=" $TOOLCHAIN_LIB_BASE/bzip2/bzip2-1.0.6/c3f970a/lib/libbz2.a"

+LZ4_REV=065ec7e38fe83329031f6668c43bef83eff5808b
+LZ4_INCLUDE=" -I /mnt/gvfs/third-party2/lz4/$LZ4_REV/r108/gcc-4.8.1-glibc-2.17/c3f970a/include"
+LZ4_LIBS=" /mnt/gvfs/third-party2/lz4/$LZ4_REV/r108/gcc-4.8.1-glibc-2.17/c3f970a/lib/liblz4.a"
+
 # location of gflags headers and libraries
 GFLAGS_INCLUDE=" -I $TOOLCHAIN_LIB_BASE/gflags/gflags-1.6/c3f970a/include"
 GFLAGS_LIBS=" $TOOLCHAIN_LIB_BASE/gflags/gflags-1.6/c3f970a/lib/libgflags.a"
@@ -51,26 +55,31 @@ GFLAGS_LIBS=" $TOOLCHAIN_LIB_BASE/gflags/gflags-1.6/c3f970a/lib/libgflags.a"
 JEMALLOC_INCLUDE=" -I $TOOLCHAIN_LIB_BASE/jemalloc/jemalloc-3.4.1/4d53c6f/include/"
 JEMALLOC_LIB=" -Wl,--whole-archive $TOOLCHAIN_LIB_BASE/jemalloc/jemalloc-3.4.1/4d53c6f/lib/libjemalloc.a"

+# location of numa
+NUMA_REV=829d10dac0230f99cd7e1778869d2adf3da24b65
+NUMA_INCLUDE=" -I /mnt/gvfs/third-party2/numa/$NUMA_REV/2.0.8/gcc-4.8.1-glibc-2.17/c3f970a/include/"
+NUMA_LIB=" /mnt/gvfs/third-party2/numa/$NUMA_REV/2.0.8/gcc-4.8.1-glibc-2.17/c3f970a/lib/libnuma.a"
+
 # use Intel SSE support for checksum calculations
 export USE_SSE=" -msse -msse4.2 "

 CC="$TOOLCHAIN_EXECUTABLES/gcc/gcc-4.8.1/cc6c9dc/bin/gcc"
-CXX="$TOOLCHAIN_EXECUTABLES/gcc/gcc-4.8.1/cc6c9dc/bin/g++ $JINCLUDE $SNAPPY_INCLUDE $ZLIB_INCLUDE $BZIP_INCLUDE $GFLAGS_INCLUDE"
+CXX="$TOOLCHAIN_EXECUTABLES/gcc/gcc-4.8.1/cc6c9dc/bin/g++ $JINCLUDE $SNAPPY_INCLUDE $ZLIB_INCLUDE $BZIP_INCLUDE $LZ4_INCLUDE $GFLAGS_INCLUDE $NUMA_INCLUDE"
 AR=$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/ar
 RANLIB=$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/ranlib

 CFLAGS="-B$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/gold -m64 -mtune=generic"
 CFLAGS+=" $LIBGCC_INCLUDE $GLIBC_INCLUDE"
 CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_ATOMIC_PRESENT -DROCKSDB_FALLOCATE_PRESENT"
-CFLAGS+=" -DSNAPPY -DGFLAGS -DZLIB -DBZIP2"
+CFLAGS+=" -DSNAPPY -DGFLAGS=google -DZLIB -DBZIP2 -DLZ4 -DNUMA"

 EXEC_LDFLAGS="-Wl,--dynamic-linker,/usr/local/fbcode/gcc-4.8.1-glibc-2.17/lib/ld.so"
 EXEC_LDFLAGS+=" -Wl,--no-whole-archive $TOOLCHAIN_LIB_BASE/libunwind/libunwind-1.0.1/675d945/lib/libunwind.a"
-EXEC_LDFLAGS+=" $HDFSLIB $SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $GFLAGS_LIBS"
+EXEC_LDFLAGS+=" $HDFSLIB $SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $LZ4_LIBS $GFLAGS_LIBS $NUMA_LIB"

 PLATFORM_LDFLAGS="$LIBGCC_LIBS $GLIBC_LIBS "

-EXEC_LDFLAGS_SHARED="$SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $GFLAGS_LIBS"
+EXEC_LDFLAGS_SHARED="$SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $LZ4_LIBS $GFLAGS_LIBS"

 VALGRIND_VER="$TOOLCHAIN_LIB_BASE/valgrind/valgrind-3.8.1/c3f970a/bin/"

@@ -0,0 +1,134 @@
+#!/bin/sh
+#
+# Set environment variables so that we can compile rocksdb using
+# fbcode settings.  It uses the latest g++ and clang compilers and also
+# uses jemalloc
+# Environment variables that change the behavior of this script:
+# PIC_BUILD -- if true, it will only take pic versions of libraries from fbcode. libraries that don't have pic variant will not be included
+
+
+BASEDIR=`dirname $BASH_SOURCE`
+source "$BASEDIR/dependencies.sh"
+
+CFLAGS=""
+
+# libgcc
+LIBGCC_INCLUDE="$LIBGCC_BASE/include/c++/7.3.0"
+LIBGCC_LIBS=" -L $LIBGCC_BASE/lib"
+
+# glibc
+GLIBC_INCLUDE="$GLIBC_BASE/include"
+GLIBC_LIBS=" -L $GLIBC_BASE/lib"
+
+# 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
+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"
+
+  LZ4_INCLUDE=" -I $LZ4_BASE/include/"
+  LZ4_LIBS=" $LZ4_BASE/lib/liblz4.a"
+  CFLAGS+=" -DLZ4"
+fi
+
+# 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
+CFLAGS+=" -DGFLAGS=gflags"
+
+# location of jemalloc
+JEMALLOC_INCLUDE=" -I $JEMALLOC_BASE/include/"
+JEMALLOC_LIB=" $JEMALLOC_BASE/lib/libjemalloc.a"
+
+if test -z $PIC_BUILD; then
+  # location of libunwind
+  LIBUNWIND="$LIBUNWIND_BASE/lib/libunwind.a"
+fi
+
+# 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="$TBB_BASE/lib/libtbb_pic.a"
+fi
+CFLAGS+=" -DTBB"
+
+# use Intel SSE support for checksum calculations
+export USE_SSE=" -msse -msse4.2 "
+
+BINUTILS="$BINUTILS_BASE/bin"
+AR="$BINUTILS/ar"
+
+DEPS_INCLUDE="$SNAPPY_INCLUDE $ZLIB_INCLUDE $LZ4_INCLUDE $GFLAGS_INCLUDE"
+
+STDLIBS="-L $GCC_BASE/lib64"
+
+CLANG_BIN="$CLANG_BASE/bin"
+CLANG_LIB="$CLANG_BASE/lib"
+CLANG_SRC="$CLANG_BASE/../../src"
+
+CLANG_ANALYZER="$CLANG_BIN/clang++"
+CLANG_SCAN_BUILD="$CLANG_SRC/llvm/tools/clang/tools/scan-build/bin/scan-build"
+
+if [ -z "$USE_CLANG" ]; then
+  # gcc
+  CC="$GCC_BASE/bin/gcc"
+  CXX="$GCC_BASE/bin/g++"
+
+  CFLAGS+=" -B$BINUTILS/gold"
+  CFLAGS+=" -isystem $LIBGCC_INCLUDE"
+  CFLAGS+=" -isystem $GLIBC_INCLUDE"
+  JEMALLOC=1
+else
+  # clang
+  CLANG_INCLUDE="$CLANG_LIB/clang/stable/include"
+  CC="$CLANG_BIN/clang"
+  CXX="$CLANG_BIN/clang++"
+
+  KERNEL_HEADERS_INCLUDE="$KERNEL_HEADERS_BASE/include"
+
+  CFLAGS+=" -B$BINUTILS/gold -nostdinc -nostdlib"
+  CFLAGS+=" -isystem $LIBGCC_BASE/include/c++/7.x "
+  CFLAGS+=" -isystem $LIBGCC_BASE/include/c++/7.x/x86_64-facebook-linux "
+  CFLAGS+=" -isystem $GLIBC_INCLUDE"
+  CFLAGS+=" -isystem $LIBGCC_INCLUDE"
+  CFLAGS+=" -isystem $CLANG_INCLUDE"
+  CFLAGS+=" -isystem $KERNEL_HEADERS_INCLUDE/linux "
+  CFLAGS+=" -isystem $KERNEL_HEADERS_INCLUDE "
+  CFLAGS+=" -Wno-expansion-to-defined "
+  CXXFLAGS="-nostdinc++"
+fi
+
+CFLAGS+=" $DEPS_INCLUDE"
+CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_LIB_IO_POSIX -DROCKSDB_FALLOCATE_PRESENT -DROCKSDB_MALLOC_USABLE_SIZE -DROCKSDB_RANGESYNC_PRESENT -DROCKSDB_SCHED_GETCPU_PRESENT -DROCKSDB_SUPPORT_THREAD_LOCAL -DHAVE_SSE42"
+CXXFLAGS+=" $CFLAGS"
+
+EXEC_LDFLAGS=" $SNAPPY_LIBS $ZLIB_LIBS $LZ4_LIBS $ZSTD_LIBS $GFLAGS_LIBS $NUMA_LIB $TBB_LIBS"
+EXEC_LDFLAGS+=" -B$BINUTILS/gold"
+EXEC_LDFLAGS+=" -Wl,--dynamic-linker,/usr/local/fbcode/platform007/lib/ld.so"
+EXEC_LDFLAGS+=" $LIBUNWIND"
+EXEC_LDFLAGS+=" -Wl,-rpath=/usr/local/fbcode/platform007/lib"
+# required by libtbb
+EXEC_LDFLAGS+=" -ldl"
+
+PLATFORM_LDFLAGS="$LIBGCC_LIBS $GLIBC_LIBS $STDLIBS -lgcc -lstdc++"
+
+EXEC_LDFLAGS_SHARED="$SNAPPY_LIBS $ZLIB_LIBS $LZ4_LIBS $ZSTD_LIBS $GFLAGS_LIBS $TBB_LIBS"
+
+VALGRIND_VER="$VALGRIND_BASE/bin/"
+
+export CC CXX AR CFLAGS CXXFLAGS EXEC_LDFLAGS EXEC_LDFLAGS_SHARED VALGRIND_VER JEMALLOC_LIB JEMALLOC_INCLUDE CLANG_ANALYZER CLANG_SCAN_BUILD 
@@ -47,7 +47,6 @@ fi
 #     ln -s `git rev-parse --show-toplevel`/build_tools/format-diff.sh $PRE_COMMIT_SCRIPT_PATH
 #   fi
 # fi
-
 set -e

 uncommitted_code=`git diff HEAD`
@@ -55,7 +54,6 @@ uncommitted_code=`git diff HEAD`
 # If there's no uncommitted changes, we assume user are doing post-commit
 # format check, in which case we'll check the modified lines from latest commit.
 # Otherwise, we'll check format of the uncommitted code only.
-format_last_commit=0
 if [ -z "$uncommitted_code" ]
 then
  # Check the format of last commit
@@ -22,4 +22,4 @@ echo ""
 echo "-----------------------------------------------------------------------------"
 echo "|                         Installation Completed                            |"
 echo "-----------------------------------------------------------------------------"
-echo "Please run `. ~/bash_profile` to be able to compile with gflags"
+echo "Please run \`. ~/.bash_profile\` to be able to compile with gflags"
@@ -5,13 +5,18 @@
 #  of patent rights can be found in the PATENTS file in the same directory.

 set -e
+if [ -z "$GIT" ]
+then
+  GIT="git"
+fi
+
 # Print out the colored progress info so that it can be brainlessly 
 # distinguished by users.
 function title() {
  echo -e "\033[1;32m$*\033[0m"
 }

-usage="Create new rocksdb version and prepare it for the release process\n"
+usage="Create new RocksDB version and prepare it for the release process\n"
 usage+="USAGE: ./make_new_version.sh <version>"

 # -- Pre-check
@@ -23,18 +28,19 @@ fi
 ROCKSDB_VERSION=$1

 GIT_BRANCH=`git rev-parse --abbrev-ref HEAD`
+echo $GIT_BRANCH
+
 if [ $GIT_BRANCH != "master" ]; then
  echo "Error: Current branch is '$GIT_BRANCH', Please switch to master branch."
+  exit 1
 fi

 title "Adding new tag for this release ..."
-git tag -a "$ROCKSDB_VERSION.fb" -m "Rocksdb $ROCKSDB_VERSION"
+BRANCH="$ROCKSDB_VERSION.fb"
+$GIT co -b $BRANCH

 # Setting up the proxy for remote repo access
-export http_proxy=http://172.31.255.99:8080
-export https_proxy="$http_proxy";
+title "Pushing new branch to remote repo ..."
+git push origin --set-upstream $BRANCH

-title "Pushing new tag to remote repo ..."
-proxycmd.sh git push origin --tags
-
-title "Done!"
+title "Branch $BRANCH is pushed to github;"
@@ -109,7 +109,6 @@ make release
    --cache_numshardbits=6 \
    --table_cache_numshardbits=4 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -117,6 +116,26 @@ make release
    --sync=0 \
    --threads=16 > ${STAT_FILE}.readrandom

+# measure readrandom with 6GB block cache and tailing iterator
+./db_bench \
+    --benchmarks=readrandom \
+    --db=$DATA_DIR \
+    --use_existing_db=1 \
+    --bloom_bits=10 \
+    --num=$NUM \
+    --reads=$((NUM / 5)) \
+    --cache_size=6442450944 \
+    --cache_numshardbits=6 \
+    --table_cache_numshardbits=4 \
+    --open_files=55000 \
+    --use_tailing_iterator=1 \
+    --statistics=1 \
+    --histogram=1 \
+    --disable_data_sync=1 \
+    --disable_wal=1 \
+    --sync=0 \
+    --threads=16 > ${STAT_FILE}.readrandomtailing
+
 # measure readrandom with 100MB block cache
 ./db_bench \
    --benchmarks=readrandom \
@@ -129,7 +148,6 @@ make release
    --cache_numshardbits=6 \
    --table_cache_numshardbits=4 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -151,7 +169,6 @@ make release
    --table_cache_numshardbits=4 \
    --write_buffer_size=1000000000 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -210,7 +227,6 @@ make release
    --cache_numshardbits=6 \
    --table_cache_numshardbits=4 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --disable_auto_compactions=1 \
    --statistics=1 \
    --histogram=1 \
@@ -233,7 +249,6 @@ make release
    --cache_numshardbits=6 \
    --table_cache_numshardbits=4 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -253,7 +268,6 @@ make release
    --table_cache_numshardbits=4 \
    --write_buffer_size=1000000000 \
    --open_files=55000 \
-    --disable_seek_compaction=1 \
    --statistics=1 \
    --histogram=1 \
    --disable_data_sync=1 \
@@ -262,6 +276,75 @@ make release
    --value_size=10 \
    --threads=16 > ${STAT_FILE}.memtablefillreadrandom

+common_in_mem_args="--db=/dev/shm/rocksdb \
+    --num_levels=6 \
+    --key_size=20 \
+    --prefix_size=12 \
+    --keys_per_prefix=10 \
+    --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 \
+    --level0_slowdown_writes_trigger=16 \
+    --level0_stop_writes_trigger=24 \
+    --target_file_size_base=134217728 \
+    --max_bytes_for_level_base=1073741824 \
+    --disable_wal=0 \
+    --wal_dir=/dev/shm/rocksdb \
+    --sync=0 \
+    --disable_data_sync=1 \
+    --verify_checksum=1 \
+    --delete_obsolete_files_period_micros=314572800 \
+    --max_grandparent_overlap_factor=10 \
+    --use_plain_table=1 \
+    --open_files=-1 \
+    --mmap_read=1 \
+    --mmap_write=0 \
+    --memtablerep=prefix_hash \
+    --bloom_bits=10 \
+    --bloom_locality=1 \
+    --perf_level=0"
+
+# prepare a in-memory DB with 50M keys, total DB size is ~6G
+./db_bench \
+    $common_in_mem_args \
+    --statistics=0 \
+    --max_background_compactions=16 \
+    --max_background_flushes=16 \
+    --benchmarks=filluniquerandom \
+    --use_existing_db=0 \
+    --num=52428800 \
+    --threads=1 > /dev/null
+
+# Readwhilewriting
+./db_bench \
+    $common_in_mem_args \
+    --statistics=1 \
+    --max_background_compactions=4 \
+    --max_background_flushes=0 \
+    --benchmarks=readwhilewriting\
+    --use_existing_db=1 \
+    --duration=600 \
+    --threads=32 \
+    --writes_per_second=81920 > ${STAT_FILE}.readwhilewriting_in_ram
+
+# Seekrandomwhilewriting
+./db_bench \
+    $common_in_mem_args \
+    --statistics=1 \
+    --max_background_compactions=4 \
+    --max_background_flushes=0 \
+    --benchmarks=seekrandomwhilewriting \
+    --use_existing_db=1 \
+    --use_tailing_iterator=1 \
+    --duration=600 \
+    --threads=32 \
+    --writes_per_second=81920 > ${STAT_FILE}.seekwhilewriting_in_ram
+
+
 # send data to ods
 function send_to_ods {
  key="$1"
@@ -287,9 +370,9 @@ function send_benchmark_to_ods {
  file="$3"

  QPS=$(grep $bench $file | awk '{print $5}')
-  P50_MICROS=$(grep $bench $file -A 4 | tail -n1 | awk '{print $3}' )
-  P75_MICROS=$(grep $bench $file -A 4 | tail -n1 | awk '{print $5}' )
-  P99_MICROS=$(grep $bench $file -A 4 | tail -n1 | awk '{print $7}' )
+  P50_MICROS=$(grep $bench $file -A 6 | grep "Percentiles" | awk '{print $3}' )
+  P75_MICROS=$(grep $bench $file -A 6 | grep "Percentiles" | awk '{print $5}' )
+  P99_MICROS=$(grep $bench $file -A 6 | grep "Percentiles" | awk '{print $7}' )

  send_to_ods rocksdb.build.$bench_key.qps $QPS
  send_to_ods rocksdb.build.$bench_key.p50_micros $P50_MICROS
@@ -300,9 +383,12 @@ function send_benchmark_to_ods {
 send_benchmark_to_ods overwrite overwrite $STAT_FILE.overwrite
 send_benchmark_to_ods fillseq fillseq $STAT_FILE.fillseq
 send_benchmark_to_ods readrandom readrandom $STAT_FILE.readrandom
+send_benchmark_to_ods readrandom readrandom_tailing $STAT_FILE.readrandomtailing
 send_benchmark_to_ods readrandom readrandom_smallblockcache $STAT_FILE.readrandomsmallblockcache
 send_benchmark_to_ods readrandom readrandom_memtable_sst $STAT_FILE.readrandom_mem_sst
 send_benchmark_to_ods readrandom readrandom_fillunique_random $STAT_FILE.readrandom_filluniquerandom
 send_benchmark_to_ods fillrandom memtablefillrandom $STAT_FILE.memtablefillreadrandom
 send_benchmark_to_ods readrandom memtablereadrandom $STAT_FILE.memtablefillreadrandom
 send_benchmark_to_ods readwhilewriting readwhilewriting $STAT_FILE.readwhilewriting
+send_benchmark_to_ods readwhilewriting readwhilewriting_in_ram ${STAT_FILE}.readwhilewriting_in_ram
+send_benchmark_to_ods seekrandomwhilewriting seekwhilewriting_in_ram ${STAT_FILE}.seekwhilewriting_in_ram
@@ -44,6 +44,11 @@ $GCOV --preserve-paths --relative-only --no-output $GCNO_FILES 2>/dev/null |
  tee -a $RECENT_REPORT &&
 echo -e "Generated coverage report for recently updated files: $RECENT_REPORT\n"

+# Unless otherwise specified, we'll not generate html report by default
+if [ -z "$HTML" ]; then
+  exit 0
+fi
+
 # Generate the html report. If we cannot find lcov in this machine, we'll simply
 # skip this step.
 echo "Generating the html coverage report..."
@@ -9,16 +9,16 @@

 #include "db/builder.h"

-#include "db/filename.h"
 #include "db/dbformat.h"
+#include "db/filename.h"
 #include "db/merge_helper.h"
 #include "db/table_cache.h"
 #include "db/version_edit.h"
 #include "rocksdb/db.h"
-#include "rocksdb/table.h"
 #include "rocksdb/env.h"
 #include "rocksdb/iterator.h"
 #include "rocksdb/options.h"
+#include "rocksdb/table.h"
 #include "table/block_based_table_builder.h"
 #include "util/stop_watch.h"

@@ -26,25 +26,24 @@ namespace rocksdb {

 class TableFactory;

-TableBuilder* GetTableBuilder(const Options& options, WritableFile* file,
+TableBuilder* NewTableBuilder(const Options& options,
+                              const InternalKeyComparator& internal_comparator,
+                              WritableFile* file,
                              CompressionType compression_type) {
-  return options.table_factory->GetTableBuilder(options, file,
-                                                compression_type);
+  return options.table_factory->NewTableBuilder(options, internal_comparator,
+                                                file, compression_type);
 }

-Status BuildTable(const std::string& dbname,
-                  Env* env,
-                  const Options& options,
-                  const EnvOptions& soptions,
-                  TableCache* table_cache,
-                  Iterator* iter,
-                  FileMetaData* meta,
-                  const Comparator* user_comparator,
+Status BuildTable(const std::string& dbname, Env* env, const Options& options,
+                  const EnvOptions& soptions, TableCache* table_cache,
+                  Iterator* iter, FileMetaData* meta,
+                  const InternalKeyComparator& internal_comparator,
                  const SequenceNumber newest_snapshot,
                  const SequenceNumber earliest_seqno_in_memtable,
-                  const CompressionType compression) {
+                  const CompressionType compression,
+                  const Env::IOPriority io_priority) {
  Status s;
-  meta->file_size = 0;
+  meta->fd.file_size = 0;
  meta->smallest_seqno = meta->largest_seqno = 0;
  iter->SeekToFirst();

@@ -56,16 +55,18 @@ Status BuildTable(const std::string& dbname,
    purge = false;
  }

-  std::string fname = TableFileName(dbname, meta->number);
+  std::string fname = TableFileName(options.db_paths, meta->fd.GetNumber(),
+                                    meta->fd.GetPathId());
  if (iter->Valid()) {
    unique_ptr<WritableFile> file;
    s = env->NewWritableFile(fname, &file, soptions);
    if (!s.ok()) {
      return s;
    }
+    file->SetIOPriority(io_priority);

-    TableBuilder* builder = GetTableBuilder(options, file.get(),
-                                            compression);
+    TableBuilder* builder =
+        NewTableBuilder(options, internal_comparator, file.get(), compression);

    // the first key is the smallest key
    Slice key = iter->key();
@@ -73,8 +74,9 @@ Status BuildTable(const std::string& dbname,
    meta->smallest_seqno = GetInternalKeySeqno(key);
    meta->largest_seqno = meta->smallest_seqno;

-    MergeHelper merge(user_comparator, options.merge_operator.get(),
-                      options.info_log.get(),
+    MergeHelper merge(internal_comparator.user_comparator(),
+                      options.merge_operator.get(), options.info_log.get(),
+                      options.min_partial_merge_operands,
                      true /* internal key corruption is not ok */);

    if (purge) {
@@ -103,8 +105,8 @@ Status BuildTable(const std::string& dbname,
        // If the key is the same as the previous key (and it is not the
        // first key), then we skip it, since it is an older version.
        // Otherwise we output the key and mark it as the "new" previous key.
-        if (!is_first_key && !user_comparator->Compare(prev_ikey.user_key,
-                                                       this_ikey.user_key)) {
+        if (!is_first_key && !internal_comparator.user_comparator()->Compare(
+                                  prev_ikey.user_key, this_ikey.user_key)) {
          // seqno within the same key are in decreasing order
          assert(this_ikey.sequence < prev_ikey.sequence);
        } else {
@@ -178,8 +180,8 @@ Status BuildTable(const std::string& dbname,
    if (s.ok()) {
      s = builder->Finish();
      if (s.ok()) {
-        meta->file_size = builder->FileSize();
-        assert(meta->file_size > 0);
+        meta->fd.file_size = builder->FileSize();
+        assert(meta->fd.GetFileSize() > 0);
      }
    } else {
      builder->Abandon();
@@ -202,10 +204,8 @@ Status BuildTable(const std::string& dbname,

    if (s.ok()) {
      // Verify that the table is usable
-      Iterator* it = table_cache->NewIterator(ReadOptions(),
-                                              soptions,
-                                              meta->number,
-                                              meta->file_size);
+      Iterator* it = table_cache->NewIterator(ReadOptions(), soptions,
+                                              internal_comparator, meta->fd);
      s = it->status();
      delete it;
    }
@@ -216,7 +216,7 @@ Status BuildTable(const std::string& dbname,
    s = iter->status();
  }

-  if (s.ok() && meta->file_size > 0) {
+  if (s.ok() && meta->fd.GetFileSize() > 0) {
    // Keep it
  } else {
    env->DeleteFile(fname);
@@ -7,6 +7,7 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 #pragma once
 #include "rocksdb/comparator.h"
+#include "rocksdb/env.h"
 #include "rocksdb/status.h"
 #include "rocksdb/types.h"
 #include "rocksdb/options.h"
@@ -24,25 +25,23 @@ class VersionEdit;
 class TableBuilder;
 class WritableFile;

-
-extern TableBuilder* GetTableBuilder(const Options& options, WritableFile* file,
-                                     CompressionType compression_type);
+extern TableBuilder* NewTableBuilder(
+    const Options& options, const InternalKeyComparator& internal_comparator,
+    WritableFile* file, CompressionType compression_type);

 // Build a Table file from the contents of *iter.  The generated file
-// will be named according to meta->number.  On success, the rest of
+// will be named according to number specified in meta. On success, the rest of
 // *meta will be filled with metadata about the generated table.
 // If no data is present in *iter, meta->file_size will be set to
 // zero, and no Table file will be produced.
-extern Status BuildTable(const std::string& dbname,
-                         Env* env,
-                         const Options& options,
-                         const EnvOptions& soptions,
-                         TableCache* table_cache,
-                         Iterator* iter,
+extern Status BuildTable(const std::string& dbname, Env* env,
+                         const Options& options, const EnvOptions& soptions,
+                         TableCache* table_cache, Iterator* iter,
                         FileMetaData* meta,
-                         const Comparator* user_comparator,
+                         const InternalKeyComparator& internal_comparator,
                         const SequenceNumber newest_snapshot,
                         const SequenceNumber earliest_seqno_in_memtable,
-                         const CompressionType compression);
+                         const CompressionType compression,
+                         const Env::IOPriority io_priority = Env::IO_HIGH);

 }  // namespace rocksdb
@@ -75,6 +75,22 @@ static void CheckGet(
  Free(&val);
 }

+static void CheckGetCF(
+    rocksdb_t* db,
+    const rocksdb_readoptions_t* options,
+    rocksdb_column_family_handle_t* handle,
+    const char* key,
+    const char* expected) {
+  char* err = NULL;
+  size_t val_len;
+  char* val;
+  val = rocksdb_get_cf(db, options, handle, key, strlen(key), &val_len, &err);
+  CheckNoError(err);
+  CheckEqual(expected, val, val_len);
+  Free(&val);
+}
+
+
 static void CheckIter(rocksdb_iterator_t* iter,
                      const char* key, const char* val) {
  size_t len;
@@ -145,7 +161,7 @@ static char* FilterCreate(
  memcpy(result, "fake", 4);
  return result;
 }
-unsigned char FilterKeyMatch(
+static unsigned char FilterKeyMatch(
    void* arg,
    const char* key, size_t length,
    const char* filter, size_t filter_length) {
@@ -154,6 +170,92 @@ unsigned char FilterKeyMatch(
  return fake_filter_result;
 }

+// Custom compaction filter
+static void CFilterDestroy(void* arg) {}
+static const char* CFilterName(void* arg) { return "foo"; }
+static unsigned char CFilterFilter(void* arg, int level, const char* key,
+                                   size_t key_length,
+                                   const char* existing_value,
+                                   size_t value_length, char** new_value,
+                                   size_t* new_value_length,
+                                   unsigned char* value_changed) {
+  if (key_length == 3) {
+    if (memcmp(key, "bar", key_length) == 0) {
+      return 1;
+    } else if (memcmp(key, "baz", key_length) == 0) {
+      *value_changed = 1;
+      *new_value = "newbazvalue";
+      *new_value_length = 11;
+      return 0;
+    }
+  }
+  return 0;
+}
+
+static void CFilterFactoryDestroy(void* arg) {}
+static const char* CFilterFactoryName(void* arg) { return "foo"; }
+static rocksdb_compactionfilter_t* CFilterCreate(
+    void* arg, rocksdb_compactionfiltercontext_t* context) {
+  return rocksdb_compactionfilter_create(NULL, CFilterDestroy, CFilterFilter,
+                                         CFilterName);
+}
+
+static rocksdb_t* CheckCompaction(rocksdb_t* db, rocksdb_options_t* options,
+                                  rocksdb_readoptions_t* roptions,
+                                  rocksdb_writeoptions_t* woptions) {
+  char* err = NULL;
+  db = rocksdb_open(options, dbname, &err);
+  CheckNoError(err);
+  rocksdb_put(db, woptions, "foo", 3, "foovalue", 8, &err);
+  CheckNoError(err);
+  CheckGet(db, roptions, "foo", "foovalue");
+  rocksdb_put(db, woptions, "bar", 3, "barvalue", 8, &err);
+  CheckNoError(err);
+  CheckGet(db, roptions, "bar", "barvalue");
+  rocksdb_put(db, woptions, "baz", 3, "bazvalue", 8, &err);
+  CheckNoError(err);
+  CheckGet(db, roptions, "baz", "bazvalue");
+
+  // Force compaction
+  rocksdb_compact_range(db, NULL, 0, NULL, 0);
+  // should have filtered bar, but not foo
+  CheckGet(db, roptions, "foo", "foovalue");
+  CheckGet(db, roptions, "bar", NULL);
+  CheckGet(db, roptions, "baz", "newbazvalue");
+  return db;
+}
+
+// Custom merge operator
+static void MergeOperatorDestroy(void* arg) { }
+static const char* MergeOperatorName(void* arg) {
+  return "TestMergeOperator";
+}
+static char* MergeOperatorFullMerge(
+    void* arg,
+    const char* key, size_t key_length,
+    const char* existing_value, size_t existing_value_length,
+    const char* const* operands_list, const size_t* operands_list_length,
+    int num_operands,
+    unsigned char* success, size_t* new_value_length) {
+  *new_value_length = 4;
+  *success = 1;
+  char* result = malloc(4);
+  memcpy(result, "fake", 4);
+  return result;
+}
+static char* MergeOperatorPartialMerge(
+    void* arg,
+    const char* key, size_t key_length,
+    const char* const* operands_list, const size_t* operands_list_length,
+    int num_operands,
+    unsigned char* success, size_t* new_value_length) {
+  *new_value_length = 4;
+  *success = 1;
+  char* result = malloc(4);
+  memcpy(result, "fake", 4);
+  return result;
+}
+
 int main(int argc, char** argv) {
  rocksdb_t* db;
  rocksdb_comparator_t* cmp;
@@ -246,6 +348,24 @@ int main(int argc, char** argv) {
    rocksdb_writebatch_destroy(wb);
  }

+  StartPhase("writebatch_rep");
+  {
+    rocksdb_writebatch_t* wb1 = rocksdb_writebatch_create();
+    rocksdb_writebatch_put(wb1, "baz", 3, "d", 1);
+    rocksdb_writebatch_put(wb1, "quux", 4, "e", 1);
+    rocksdb_writebatch_delete(wb1, "quux", 4);
+    size_t repsize1 = 0;
+    const char* rep = rocksdb_writebatch_data(wb1, &repsize1);
+    rocksdb_writebatch_t* wb2 = rocksdb_writebatch_create_from(rep, repsize1);
+    CheckCondition(rocksdb_writebatch_count(wb1) ==
+                   rocksdb_writebatch_count(wb2));
+    size_t repsize2 = 0;
+    CheckCondition(
+        memcmp(rep, rocksdb_writebatch_data(wb2, &repsize2), repsize1) == 0);
+    rocksdb_writebatch_destroy(wb1);
+    rocksdb_writebatch_destroy(wb2);
+  }
+
  StartPhase("iter");
  {
    rocksdb_iterator_t* iter = rocksdb_create_iterator(db, roptions);
@@ -342,7 +462,7 @@ int main(int argc, char** argv) {
    rocksdb_filterpolicy_t* policy;
    if (run == 0) {
      policy = rocksdb_filterpolicy_create(
-          NULL, FilterDestroy, FilterCreate, FilterKeyMatch, FilterName);
+          NULL, FilterDestroy, FilterCreate, FilterKeyMatch, NULL, FilterName);
    } else {
      policy = rocksdb_filterpolicy_create_bloom(10);
    }
@@ -376,6 +496,192 @@ int main(int argc, char** argv) {
    rocksdb_filterpolicy_destroy(policy);
  }

+  StartPhase("compaction_filter");
+  {
+    rocksdb_options_t* options = rocksdb_options_create();
+    rocksdb_options_set_create_if_missing(options, 1);
+    rocksdb_compactionfilter_t* cfilter;
+    cfilter = rocksdb_compactionfilter_create(NULL, CFilterDestroy,
+                                              CFilterFilter, CFilterName);
+    // Create new database
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    rocksdb_options_set_compaction_filter(options, cfilter);
+    db = CheckCompaction(db, options, roptions, woptions);
+
+    rocksdb_options_set_compaction_filter(options, NULL);
+    rocksdb_compactionfilter_destroy(cfilter);
+    rocksdb_options_destroy(options);
+  }
+
+  StartPhase("compaction_filter_factory");
+  {
+    rocksdb_options_t* options = rocksdb_options_create();
+    rocksdb_options_set_create_if_missing(options, 1);
+    rocksdb_compactionfilterfactory_t* factory;
+    factory = rocksdb_compactionfilterfactory_create(
+        NULL, CFilterFactoryDestroy, CFilterCreate, CFilterFactoryName);
+    // Create new database
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    rocksdb_options_set_compaction_filter_factory(options, factory);
+    db = CheckCompaction(db, options, roptions, woptions);
+
+    rocksdb_options_set_compaction_filter_factory(options, NULL);
+    rocksdb_options_destroy(options);
+  }
+
+  StartPhase("merge_operator");
+  {
+    rocksdb_mergeoperator_t* merge_operator;
+    merge_operator = rocksdb_mergeoperator_create(
+        NULL, MergeOperatorDestroy, MergeOperatorFullMerge,
+        MergeOperatorPartialMerge, NULL, MergeOperatorName);
+    // Create new database
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    rocksdb_options_set_merge_operator(options, merge_operator);
+    db = rocksdb_open(options, dbname, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "foo", 3, "foovalue", 8, &err);
+    CheckNoError(err);
+    CheckGet(db, roptions, "foo", "foovalue");
+    rocksdb_merge(db, woptions, "foo", 3, "barvalue", 8, &err);
+    CheckNoError(err);
+    CheckGet(db, roptions, "foo", "fake");
+
+    // Merge of a non-existing value
+    rocksdb_merge(db, woptions, "bar", 3, "barvalue", 8, &err);
+    CheckNoError(err);
+    CheckGet(db, roptions, "bar", "fake");
+
+  }
+
+  StartPhase("columnfamilies");
+  {
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    CheckNoError(err)
+
+    rocksdb_options_t* db_options = rocksdb_options_create();
+    rocksdb_options_set_create_if_missing(db_options, 1);
+    db = rocksdb_open(db_options, dbname, &err);
+    CheckNoError(err)
+    rocksdb_column_family_handle_t* cfh;
+    cfh = rocksdb_create_column_family(db, db_options, "cf1", &err);
+    rocksdb_column_family_handle_destroy(cfh);
+    CheckNoError(err);
+    rocksdb_close(db);
+
+    size_t cflen;
+    char** column_fams = rocksdb_list_column_families(db_options, dbname, &cflen, &err);
+    CheckNoError(err);
+    CheckEqual("default", column_fams[0], 7);
+    CheckEqual("cf1", column_fams[1], 3);
+    CheckCondition(cflen == 2);
+    rocksdb_list_column_families_destroy(column_fams, cflen);
+
+    rocksdb_options_t* cf_options = rocksdb_options_create();
+
+    const char* cf_names[2] = {"default", "cf1"};
+    const rocksdb_options_t* cf_opts[2] = {cf_options, cf_options};
+    rocksdb_column_family_handle_t* handles[2];
+    db = rocksdb_open_column_families(db_options, dbname, 2, cf_names, cf_opts, handles, &err);
+    CheckNoError(err);
+
+    rocksdb_put_cf(db, woptions, handles[1], "foo", 3, "hello", 5, &err);
+    CheckNoError(err);
+
+    CheckGetCF(db, roptions, handles[1], "foo", "hello");
+
+    rocksdb_delete_cf(db, woptions, handles[1], "foo", 3, &err);
+    CheckNoError(err);
+
+    CheckGetCF(db, roptions, handles[1], "foo", NULL);
+
+    rocksdb_writebatch_t* wb = rocksdb_writebatch_create();
+    rocksdb_writebatch_put_cf(wb, handles[1], "baz", 3, "a", 1);
+    rocksdb_writebatch_clear(wb);
+    rocksdb_writebatch_put_cf(wb, handles[1], "bar", 3, "b", 1);
+    rocksdb_writebatch_put_cf(wb, handles[1], "box", 3, "c", 1);
+    rocksdb_writebatch_delete_cf(wb, handles[1], "bar", 3);
+    rocksdb_write(db, woptions, wb, &err);
+    CheckNoError(err);
+    CheckGetCF(db, roptions, handles[1], "baz", NULL);
+    CheckGetCF(db, roptions, handles[1], "bar", NULL);
+    CheckGetCF(db, roptions, handles[1], "box", "c");
+    rocksdb_writebatch_destroy(wb);
+
+    rocksdb_iterator_t* iter = rocksdb_create_iterator_cf(db, roptions, handles[1]);
+    CheckCondition(!rocksdb_iter_valid(iter));
+    rocksdb_iter_seek_to_first(iter);
+    CheckCondition(rocksdb_iter_valid(iter));
+
+    int i;
+    for (i = 0; rocksdb_iter_valid(iter) != 0; rocksdb_iter_next(iter)) {
+      i++;
+    }
+    CheckCondition(i == 1);
+    rocksdb_iter_get_error(iter, &err);
+    CheckNoError(err);
+    rocksdb_iter_destroy(iter);
+
+    rocksdb_drop_column_family(db, handles[1], &err);
+    CheckNoError(err);
+    for (i = 0; i < 2; i++) {
+      rocksdb_column_family_handle_destroy(handles[i]);
+    }
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    rocksdb_options_destroy(db_options);
+    rocksdb_options_destroy(cf_options);
+  }
+
+  StartPhase("prefix");
+  {
+    // Create new database
+    rocksdb_filterpolicy_t* policy = rocksdb_filterpolicy_create_bloom(10);
+    rocksdb_options_set_filter_policy(options, policy);
+    rocksdb_options_set_prefix_extractor(options, rocksdb_slicetransform_create_fixed_prefix(3));
+    rocksdb_options_set_hash_skip_list_rep(options, 5000, 4, 4);
+    rocksdb_options_set_plain_table_factory(options, 4, 10, 0.75, 16);
+
+    db = rocksdb_open(options, dbname, &err);
+    CheckNoError(err);
+
+    rocksdb_put(db, woptions, "foo1", 4, "foo", 3, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "foo2", 4, "foo", 3, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "foo3", 4, "foo", 3, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "bar1", 4, "bar", 3, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "bar2", 4, "bar", 3, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "bar3", 4, "bar", 3, &err);
+    CheckNoError(err);
+
+    rocksdb_iterator_t* iter = rocksdb_create_iterator(db, roptions);
+    CheckCondition(!rocksdb_iter_valid(iter));
+
+    rocksdb_iter_seek(iter, "bar", 3);
+    rocksdb_iter_get_error(iter, &err);
+    CheckNoError(err);
+    CheckCondition(rocksdb_iter_valid(iter));
+
+    CheckIter(iter, "bar1", "bar");
+    rocksdb_iter_next(iter);
+    CheckIter(iter, "bar2", "bar");
+    rocksdb_iter_next(iter);
+    CheckIter(iter, "bar3", "bar");
+    rocksdb_iter_get_error(iter, &err);
+    CheckNoError(err);
+    rocksdb_iter_destroy(iter);
+    rocksdb_filterpolicy_destroy(policy);
+  }
+
+
  StartPhase("cleanup");
  rocksdb_close(db);
  rocksdb_options_destroy(options);
@@ -0,0 +1,642 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include "db/column_family.h"
+
+#include <vector>
+#include <string>
+#include <algorithm>
+#include <limits>
+
+#include "db/db_impl.h"
+#include "db/version_set.h"
+#include "db/internal_stats.h"
+#include "db/compaction_picker.h"
+#include "db/table_properties_collector.h"
+#include "util/autovector.h"
+#include "util/hash_skiplist_rep.h"
+
+namespace rocksdb {
+
+ColumnFamilyHandleImpl::ColumnFamilyHandleImpl(ColumnFamilyData* cfd,
+                                               DBImpl* db, port::Mutex* mutex)
+    : cfd_(cfd), db_(db), mutex_(mutex) {
+  if (cfd_ != nullptr) {
+    cfd_->Ref();
+  }
+}
+
+ColumnFamilyHandleImpl::~ColumnFamilyHandleImpl() {
+  if (cfd_ != nullptr) {
+    DBImpl::DeletionState deletion_state;
+    mutex_->Lock();
+    if (cfd_->Unref()) {
+      delete cfd_;
+    }
+    db_->FindObsoleteFiles(deletion_state, false, true);
+    mutex_->Unlock();
+    if (deletion_state.HaveSomethingToDelete()) {
+      db_->PurgeObsoleteFiles(deletion_state);
+    }
+  }
+}
+
+uint32_t ColumnFamilyHandleImpl::GetID() const { return cfd()->GetID(); }
+
+namespace {
+// Fix user-supplied options to be reasonable
+template <class T, class V>
+static void ClipToRange(T* ptr, V minvalue, V maxvalue) {
+  if (static_cast<V>(*ptr) > maxvalue) *ptr = maxvalue;
+  if (static_cast<V>(*ptr) < minvalue) *ptr = minvalue;
+}
+}  // anonymous namespace
+
+ColumnFamilyOptions SanitizeOptions(const InternalKeyComparator* icmp,
+                                    const InternalFilterPolicy* ipolicy,
+                                    const ColumnFamilyOptions& src) {
+  ColumnFamilyOptions result = src;
+  result.comparator = icmp;
+  result.filter_policy = (src.filter_policy != nullptr) ? ipolicy : nullptr;
+#ifdef OS_MACOSX
+  // TODO(icanadi) make write_buffer_size uint64_t instead of size_t
+  ClipToRange(&result.write_buffer_size, ((size_t)64) << 10, ((size_t)1) << 30);
+#else
+  ClipToRange(&result.write_buffer_size,
+              ((size_t)64) << 10, ((size_t)64) << 30);
+#endif
+  // 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) {
+    result.arena_block_size = result.write_buffer_size / 10;
+  }
+  result.min_write_buffer_number_to_merge =
+      std::min(result.min_write_buffer_number_to_merge,
+               result.max_write_buffer_number - 1);
+  if (result.block_cache == nullptr && !result.no_block_cache) {
+    result.block_cache = NewLRUCache(8 << 20);
+  }
+  result.compression_per_level = src.compression_per_level;
+  if (result.block_size_deviation < 0 || result.block_size_deviation > 100) {
+    result.block_size_deviation = 0;
+  }
+  if (result.max_mem_compaction_level >= result.num_levels) {
+    result.max_mem_compaction_level = result.num_levels - 1;
+  }
+  if (result.soft_rate_limit > result.hard_rate_limit) {
+    result.soft_rate_limit = result.hard_rate_limit;
+  }
+  if (result.max_write_buffer_number < 2) {
+    result.max_write_buffer_number = 2;
+  }
+  if (!result.prefix_extractor) {
+    assert(result.memtable_factory);
+    Slice name = result.memtable_factory->Name();
+    if (name.compare("HashSkipListRepFactory") == 0 ||
+        name.compare("HashLinkListRepFactory") == 0) {
+      result.memtable_factory = std::make_shared<SkipListFactory>();
+    }
+  }
+
+  // -- Sanitize the table properties collector
+  // All user defined properties collectors will be wrapped by
+  // UserKeyTablePropertiesCollector since for them they only have the
+  // knowledge of the user keys; internal keys are invisible to them.
+  auto& collector_factories = result.table_properties_collector_factories;
+  for (size_t i = 0; i < result.table_properties_collector_factories.size();
+       ++i) {
+    assert(collector_factories[i]);
+    collector_factories[i] =
+        std::make_shared<UserKeyTablePropertiesCollectorFactory>(
+            collector_factories[i]);
+  }
+  // Add collector to collect internal key statistics
+  collector_factories.push_back(
+      std::make_shared<InternalKeyPropertiesCollectorFactory>());
+
+  if (result.compaction_style == kCompactionStyleFIFO) {
+    result.num_levels = 1;
+    // since we delete level0 files in FIFO compaction when there are too many
+    // of them, these options don't really mean anything
+    result.level0_file_num_compaction_trigger = std::numeric_limits<int>::max();
+    result.level0_slowdown_writes_trigger = std::numeric_limits<int>::max();
+    result.level0_stop_writes_trigger = std::numeric_limits<int>::max();
+  }
+
+  return result;
+}
+
+int SuperVersion::dummy = 0;
+void* const SuperVersion::kSVInUse = &SuperVersion::dummy;
+void* const SuperVersion::kSVObsolete = nullptr;
+
+SuperVersion::~SuperVersion() {
+  for (auto td : to_delete) {
+    delete td;
+  }
+}
+
+SuperVersion* SuperVersion::Ref() {
+  refs.fetch_add(1, std::memory_order_relaxed);
+  return this;
+}
+
+bool SuperVersion::Unref() {
+  // fetch_sub returns the previous value of ref
+  uint32_t previous_refs = refs.fetch_sub(1, std::memory_order_relaxed);
+  assert(previous_refs > 0);
+  return previous_refs == 1;
+}
+
+void SuperVersion::Cleanup() {
+  assert(refs.load(std::memory_order_relaxed) == 0);
+  imm->Unref(&to_delete);
+  MemTable* m = mem->Unref();
+  if (m != nullptr) {
+    to_delete.push_back(m);
+  }
+  current->Unref();
+}
+
+void SuperVersion::Init(MemTable* new_mem, MemTableListVersion* new_imm,
+                        Version* new_current) {
+  mem = new_mem;
+  imm = new_imm;
+  current = new_current;
+  mem->Ref();
+  imm->Ref();
+  current->Ref();
+  refs.store(1, std::memory_order_relaxed);
+}
+
+namespace {
+void SuperVersionUnrefHandle(void* ptr) {
+  // UnrefHandle is called when a thread exists or a ThreadLocalPtr gets
+  // destroyed. When former happens, the thread shouldn't see kSVInUse.
+  // When latter happens, we are in ~ColumnFamilyData(), no get should happen as
+  // well.
+  SuperVersion* sv = static_cast<SuperVersion*>(ptr);
+  if (sv->Unref()) {
+    sv->db_mutex->Lock();
+    sv->Cleanup();
+    sv->db_mutex->Unlock();
+    delete sv;
+  }
+}
+}  // anonymous namespace
+
+ColumnFamilyData::ColumnFamilyData(const std::string& dbname, uint32_t id,
+                                   const std::string& name,
+                                   Version* dummy_versions, Cache* table_cache,
+                                   const ColumnFamilyOptions& options,
+                                   const DBOptions* db_options,
+                                   const EnvOptions& storage_options,
+                                   ColumnFamilySet* column_family_set)
+    : id_(id),
+      name_(name),
+      dummy_versions_(dummy_versions),
+      current_(nullptr),
+      refs_(0),
+      dropped_(false),
+      internal_comparator_(options.comparator),
+      internal_filter_policy_(options.filter_policy),
+      options_(*db_options, SanitizeOptions(&internal_comparator_,
+                                            &internal_filter_policy_, options)),
+      mem_(nullptr),
+      imm_(options_.min_write_buffer_number_to_merge),
+      super_version_(nullptr),
+      super_version_number_(0),
+      local_sv_(new ThreadLocalPtr(&SuperVersionUnrefHandle)),
+      next_(nullptr),
+      prev_(nullptr),
+      log_number_(0),
+      need_slowdown_for_num_level0_files_(false),
+      column_family_set_(column_family_set) {
+  Ref();
+
+  // if dummy_versions is nullptr, then this is a dummy column family.
+  if (dummy_versions != nullptr) {
+    internal_stats_.reset(new InternalStats(
+        options_.num_levels, db_options->env, db_options->statistics.get()));
+    table_cache_.reset(new TableCache(&options_, storage_options, table_cache));
+    if (options_.compaction_style == kCompactionStyleUniversal) {
+      compaction_picker_.reset(
+          new UniversalCompactionPicker(&options_, &internal_comparator_));
+    } else if (options_.compaction_style == kCompactionStyleLevel) {
+      compaction_picker_.reset(
+          new LevelCompactionPicker(&options_, &internal_comparator_));
+    } else {
+      assert(options_.compaction_style == kCompactionStyleFIFO);
+      compaction_picker_.reset(
+          new FIFOCompactionPicker(&options_, &internal_comparator_));
+    }
+
+    Log(options_.info_log, "Options for column family \"%s\":\n",
+        name.c_str());
+    const ColumnFamilyOptions* cf_options = &options_;
+    cf_options->Dump(options_.info_log.get());
+  }
+
+  RecalculateWriteStallConditions();
+}
+
+// DB mutex held
+ColumnFamilyData::~ColumnFamilyData() {
+  assert(refs_ == 0);
+  // remove from linked list
+  auto prev = prev_;
+  auto next = next_;
+  prev->next_ = next;
+  next->prev_ = prev;
+
+  // it's nullptr for dummy CFD
+  if (column_family_set_ != nullptr) {
+    // remove from column_family_set
+    column_family_set_->RemoveColumnFamily(this);
+  }
+
+  if (current_ != nullptr) {
+    current_->Unref();
+  }
+
+  if (super_version_ != nullptr) {
+    // Release SuperVersion reference kept in ThreadLocalPtr.
+    // This must be done outside of mutex_ since unref handler can lock mutex.
+    super_version_->db_mutex->Unlock();
+    local_sv_.reset();
+    super_version_->db_mutex->Lock();
+
+    bool is_last_reference __attribute__((unused));
+    is_last_reference = super_version_->Unref();
+    assert(is_last_reference);
+    super_version_->Cleanup();
+    delete super_version_;
+    super_version_ = nullptr;
+  }
+
+  if (dummy_versions_ != nullptr) {
+    // List must be empty
+    assert(dummy_versions_->next_ == dummy_versions_);
+    delete dummy_versions_;
+  }
+
+  if (mem_ != nullptr) {
+    delete mem_->Unref();
+  }
+  autovector<MemTable*> to_delete;
+  imm_.current()->Unref(&to_delete);
+  for (MemTable* m : to_delete) {
+    delete m;
+  }
+}
+
+void ColumnFamilyData::RecalculateWriteStallConditions() {
+  need_wait_for_num_memtables_ =
+    (imm()->size() == options()->max_write_buffer_number - 1);
+
+  if (current_ != nullptr) {
+    need_wait_for_num_level0_files_ =
+      (current_->NumLevelFiles(0) >= options()->level0_stop_writes_trigger);
+  } else {
+    need_wait_for_num_level0_files_ = false;
+  }
+
+  RecalculateWriteStallRateLimitsConditions();
+}
+
+void ColumnFamilyData::RecalculateWriteStallRateLimitsConditions() {
+  if (current_ != nullptr) {
+    exceeds_hard_rate_limit_ =
+        (options()->hard_rate_limit > 1.0 &&
+         current_->MaxCompactionScore() > options()->hard_rate_limit);
+
+    exceeds_soft_rate_limit_ =
+        (options()->soft_rate_limit > 0.0 &&
+         current_->MaxCompactionScore() > options()->soft_rate_limit);
+  } else {
+    exceeds_hard_rate_limit_ = false;
+    exceeds_soft_rate_limit_ = false;
+  }
+}
+
+const EnvOptions* ColumnFamilyData::soptions() const {
+  return &(column_family_set_->storage_options_);
+}
+
+void ColumnFamilyData::SetCurrent(Version* current) {
+  current_ = current;
+  need_slowdown_for_num_level0_files_ =
+      (options_.level0_slowdown_writes_trigger >= 0 &&
+       current_->NumLevelFiles(0) >= options_.level0_slowdown_writes_trigger);
+}
+
+void ColumnFamilyData::CreateNewMemtable() {
+  assert(current_ != nullptr);
+  if (mem_ != nullptr) {
+    delete mem_->Unref();
+  }
+  mem_ = new MemTable(internal_comparator_, options_);
+  mem_->Ref();
+}
+
+Compaction* ColumnFamilyData::PickCompaction(LogBuffer* log_buffer) {
+  auto result = compaction_picker_->PickCompaction(current_, log_buffer);
+  RecalculateWriteStallRateLimitsConditions();
+  return result;
+}
+
+Compaction* ColumnFamilyData::CompactRange(int input_level, int output_level,
+                                           const InternalKey* begin,
+                                           const InternalKey* end,
+                                           InternalKey** compaction_end) {
+  return compaction_picker_->CompactRange(current_, input_level, output_level,
+                                          begin, end, compaction_end);
+}
+
+SuperVersion* ColumnFamilyData::GetReferencedSuperVersion(
+    port::Mutex* db_mutex) {
+  SuperVersion* sv = nullptr;
+  if (LIKELY(column_family_set_->db_options_->allow_thread_local)) {
+    sv = GetThreadLocalSuperVersion(db_mutex);
+    sv->Ref();
+    if (!ReturnThreadLocalSuperVersion(sv)) {
+      sv->Unref();
+    }
+  } else {
+    db_mutex->Lock();
+    sv = super_version_->Ref();
+    db_mutex->Unlock();
+  }
+  return sv;
+}
+
+SuperVersion* ColumnFamilyData::GetThreadLocalSuperVersion(
+    port::Mutex* db_mutex) {
+  SuperVersion* sv = nullptr;
+  // The SuperVersion is cached in thread local storage to avoid acquiring
+  // mutex when SuperVersion does not change since the last use. When a new
+  // SuperVersion is installed, the compaction or flush thread cleans up
+  // cached SuperVersion in all existing thread local storage. To avoid
+  // acquiring mutex for this operation, we use atomic Swap() on the thread
+  // local pointer to guarantee exclusive access. If the thread local pointer
+  // is being used while a new SuperVersion is installed, the cached
+  // SuperVersion can become stale. In that case, the background thread would
+  // have swapped in kSVObsolete. We re-check the value at when returning
+  // SuperVersion back to thread local, with an atomic compare and swap.
+  // The superversion will need to be released if detected to be stale.
+  void* ptr = local_sv_->Swap(SuperVersion::kSVInUse);
+  // Invariant:
+  // (1) Scrape (always) installs kSVObsolete in ThreadLocal storage
+  // (2) the Swap above (always) installs kSVInUse, ThreadLocal storage
+  // should only keep kSVInUse before ReturnThreadLocalSuperVersion call
+  // (if no Scrape happens).
+  assert(ptr != SuperVersion::kSVInUse);
+  sv = static_cast<SuperVersion*>(ptr);
+  if (sv == SuperVersion::kSVObsolete ||
+      sv->version_number != super_version_number_.load()) {
+    RecordTick(options_.statistics.get(), NUMBER_SUPERVERSION_ACQUIRES);
+    SuperVersion* sv_to_delete = nullptr;
+
+    if (sv && sv->Unref()) {
+      RecordTick(options_.statistics.get(), NUMBER_SUPERVERSION_CLEANUPS);
+      db_mutex->Lock();
+      // NOTE: underlying resources held by superversion (sst files) might
+      // not be released until the next background job.
+      sv->Cleanup();
+      sv_to_delete = sv;
+    } else {
+      db_mutex->Lock();
+    }
+    sv = super_version_->Ref();
+    db_mutex->Unlock();
+
+    delete sv_to_delete;
+  }
+  assert(sv != nullptr);
+  return sv;
+}
+
+bool ColumnFamilyData::ReturnThreadLocalSuperVersion(SuperVersion* sv) {
+  assert(sv != nullptr);
+  // Put the SuperVersion back
+  void* expected = SuperVersion::kSVInUse;
+  if (local_sv_->CompareAndSwap(static_cast<void*>(sv), expected)) {
+    // When we see kSVInUse in the ThreadLocal, we are sure ThreadLocal
+    // storage has not been altered and no Scrape has happend. The
+    // SuperVersion is still current.
+    return true;
+  } else {
+    // ThreadLocal scrape happened in the process of this GetImpl call (after
+    // thread local Swap() at the beginning and before CompareAndSwap()).
+    // This means the SuperVersion it holds is obsolete.
+    assert(expected == SuperVersion::kSVObsolete);
+  }
+  return false;
+}
+
+SuperVersion* ColumnFamilyData::InstallSuperVersion(
+    SuperVersion* new_superversion, port::Mutex* db_mutex) {
+  new_superversion->db_mutex = db_mutex;
+  new_superversion->Init(mem_, imm_.current(), current_);
+  SuperVersion* old_superversion = super_version_;
+  super_version_ = new_superversion;
+  ++super_version_number_;
+  super_version_->version_number = super_version_number_;
+  // Reset SuperVersions cached in thread local storage
+  if (column_family_set_->db_options_->allow_thread_local) {
+    ResetThreadLocalSuperVersions();
+  }
+
+  RecalculateWriteStallConditions();
+
+  if (old_superversion != nullptr && old_superversion->Unref()) {
+    old_superversion->Cleanup();
+    return old_superversion;  // will let caller delete outside of mutex
+  }
+  return nullptr;
+}
+
+void ColumnFamilyData::ResetThreadLocalSuperVersions() {
+  autovector<void*> sv_ptrs;
+  local_sv_->Scrape(&sv_ptrs, SuperVersion::kSVObsolete);
+  for (auto ptr : sv_ptrs) {
+    assert(ptr);
+    if (ptr == SuperVersion::kSVInUse) {
+      continue;
+    }
+    auto sv = static_cast<SuperVersion*>(ptr);
+    if (sv->Unref()) {
+      sv->Cleanup();
+      delete sv;
+    }
+  }
+}
+
+ColumnFamilySet::ColumnFamilySet(const std::string& dbname,
+                                 const DBOptions* db_options,
+                                 const EnvOptions& storage_options,
+                                 Cache* table_cache)
+    : max_column_family_(0),
+      dummy_cfd_(new ColumnFamilyData(dbname, 0, "", nullptr, nullptr,
+                                      ColumnFamilyOptions(), db_options,
+                                      storage_options_, nullptr)),
+      default_cfd_cache_(nullptr),
+      db_name_(dbname),
+      db_options_(db_options),
+      storage_options_(storage_options),
+      table_cache_(table_cache),
+      spin_lock_(ATOMIC_FLAG_INIT) {
+  // initialize linked list
+  dummy_cfd_->prev_ = dummy_cfd_;
+  dummy_cfd_->next_ = dummy_cfd_;
+}
+
+ColumnFamilySet::~ColumnFamilySet() {
+  while (column_family_data_.size() > 0) {
+    // cfd destructor will delete itself from column_family_data_
+    auto cfd = column_family_data_.begin()->second;
+    cfd->Unref();
+    delete cfd;
+  }
+  dummy_cfd_->Unref();
+  delete dummy_cfd_;
+}
+
+ColumnFamilyData* ColumnFamilySet::GetDefault() const {
+  assert(default_cfd_cache_ != nullptr);
+  return default_cfd_cache_;
+}
+
+ColumnFamilyData* ColumnFamilySet::GetColumnFamily(uint32_t id) const {
+  auto cfd_iter = column_family_data_.find(id);
+  if (cfd_iter != column_family_data_.end()) {
+    return cfd_iter->second;
+  } else {
+    return nullptr;
+  }
+}
+
+ColumnFamilyData* ColumnFamilySet::GetColumnFamily(const std::string& name)
+    const {
+  auto cfd_iter = column_families_.find(name);
+  if (cfd_iter != column_families_.end()) {
+    auto cfd = GetColumnFamily(cfd_iter->second);
+    assert(cfd != nullptr);
+    return cfd;
+  } else {
+    return nullptr;
+  }
+}
+
+uint32_t ColumnFamilySet::GetNextColumnFamilyID() {
+  return ++max_column_family_;
+}
+
+uint32_t ColumnFamilySet::GetMaxColumnFamily() { return max_column_family_; }
+
+void ColumnFamilySet::UpdateMaxColumnFamily(uint32_t new_max_column_family) {
+  max_column_family_ = std::max(new_max_column_family, max_column_family_);
+}
+
+size_t ColumnFamilySet::NumberOfColumnFamilies() const {
+  return column_families_.size();
+}
+
+// under a DB mutex
+ColumnFamilyData* ColumnFamilySet::CreateColumnFamily(
+    const std::string& name, uint32_t id, Version* dummy_versions,
+    const ColumnFamilyOptions& options) {
+  assert(column_families_.find(name) == column_families_.end());
+  ColumnFamilyData* new_cfd =
+      new ColumnFamilyData(db_name_, id, name, dummy_versions, table_cache_,
+                           options, db_options_, storage_options_, this);
+  Lock();
+  column_families_.insert({name, id});
+  column_family_data_.insert({id, new_cfd});
+  Unlock();
+  max_column_family_ = std::max(max_column_family_, id);
+  // add to linked list
+  new_cfd->next_ = dummy_cfd_;
+  auto prev = dummy_cfd_->prev_;
+  new_cfd->prev_ = prev;
+  prev->next_ = new_cfd;
+  dummy_cfd_->prev_ = new_cfd;
+  if (id == 0) {
+    default_cfd_cache_ = new_cfd;
+  }
+  return new_cfd;
+}
+
+void ColumnFamilySet::Lock() {
+  // spin lock
+  while (spin_lock_.test_and_set(std::memory_order_acquire)) {
+  }
+}
+
+void ColumnFamilySet::Unlock() { spin_lock_.clear(std::memory_order_release); }
+
+// REQUIRES: DB mutex held
+void ColumnFamilySet::FreeDeadColumnFamilies() {
+  autovector<ColumnFamilyData*> to_delete;
+  for (auto cfd = dummy_cfd_->next_; cfd != dummy_cfd_; cfd = cfd->next_) {
+    if (cfd->refs_ == 0) {
+      to_delete.push_back(cfd);
+    }
+  }
+  for (auto cfd : to_delete) {
+    // this is very rare, so it's not a problem that we do it under a mutex
+    delete cfd;
+  }
+}
+
+// under a DB mutex
+void ColumnFamilySet::RemoveColumnFamily(ColumnFamilyData* cfd) {
+  auto cfd_iter = column_family_data_.find(cfd->GetID());
+  assert(cfd_iter != column_family_data_.end());
+  Lock();
+  column_family_data_.erase(cfd_iter);
+  column_families_.erase(cfd->GetName());
+  Unlock();
+}
+
+bool ColumnFamilyMemTablesImpl::Seek(uint32_t column_family_id) {
+  if (column_family_id == 0) {
+    // optimization for common case
+    current_ = column_family_set_->GetDefault();
+  } else {
+    // maybe outside of db mutex, should lock
+    column_family_set_->Lock();
+    current_ = column_family_set_->GetColumnFamily(column_family_id);
+    column_family_set_->Unlock();
+  }
+  handle_.SetCFD(current_);
+  return current_ != nullptr;
+}
+
+uint64_t ColumnFamilyMemTablesImpl::GetLogNumber() const {
+  assert(current_ != nullptr);
+  return current_->GetLogNumber();
+}
+
+MemTable* ColumnFamilyMemTablesImpl::GetMemTable() const {
+  assert(current_ != nullptr);
+  return current_->mem();
+}
+
+const Options* ColumnFamilyMemTablesImpl::GetOptions() const {
+  assert(current_ != nullptr);
+  return current_->options();
+}
+
+ColumnFamilyHandle* ColumnFamilyMemTablesImpl::GetColumnFamilyHandle() {
+  assert(current_ != nullptr);
+  return &handle_;
+}
+
+}  // namespace rocksdb
@@ -0,0 +1,459 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#pragma once
+
+#include <unordered_map>
+#include <string>
+#include <vector>
+#include <atomic>
+
+#include "rocksdb/options.h"
+#include "rocksdb/db.h"
+#include "rocksdb/env.h"
+#include "db/memtable_list.h"
+#include "db/write_batch_internal.h"
+#include "db/table_cache.h"
+#include "util/thread_local.h"
+
+namespace rocksdb {
+
+class Version;
+class VersionSet;
+class MemTable;
+class MemTableListVersion;
+class CompactionPicker;
+class Compaction;
+class InternalKey;
+class InternalStats;
+class ColumnFamilyData;
+class DBImpl;
+class LogBuffer;
+
+// ColumnFamilyHandleImpl is the class that clients use to access different
+// column families. It has non-trivial destructor, which gets called when client
+// is done using the column family
+class ColumnFamilyHandleImpl : public ColumnFamilyHandle {
+ public:
+  // create while holding the mutex
+  ColumnFamilyHandleImpl(ColumnFamilyData* cfd, DBImpl* db, port::Mutex* mutex);
+  // destroy without mutex
+  virtual ~ColumnFamilyHandleImpl();
+  virtual ColumnFamilyData* cfd() const { return cfd_; }
+
+  virtual uint32_t GetID() const;
+
+ private:
+  ColumnFamilyData* cfd_;
+  DBImpl* db_;
+  port::Mutex* mutex_;
+};
+
+// Does not ref-count ColumnFamilyData
+// We use this dummy ColumnFamilyHandleImpl because sometimes MemTableInserter
+// calls DBImpl methods. When this happens, MemTableInserter need access to
+// ColumnFamilyHandle (same as the client would need). In that case, we feed
+// MemTableInserter dummy ColumnFamilyHandle and enable it to call DBImpl
+// methods
+class ColumnFamilyHandleInternal : public ColumnFamilyHandleImpl {
+ public:
+  ColumnFamilyHandleInternal()
+      : ColumnFamilyHandleImpl(nullptr, nullptr, nullptr) {}
+
+  void SetCFD(ColumnFamilyData* cfd) { internal_cfd_ = cfd; }
+  virtual ColumnFamilyData* cfd() const override { return internal_cfd_; }
+
+ private:
+  ColumnFamilyData* internal_cfd_;
+};
+
+// holds references to memtable, all immutable memtables and version
+struct SuperVersion {
+  MemTable* mem;
+  MemTableListVersion* imm;
+  Version* current;
+  std::atomic<uint32_t> refs;
+  // We need to_delete because during Cleanup(), imm->Unref() returns
+  // all memtables that we need to free through this vector. We then
+  // delete all those memtables outside of mutex, during destruction
+  autovector<MemTable*> to_delete;
+  // Version number of the current SuperVersion
+  uint64_t version_number;
+  port::Mutex* db_mutex;
+
+  // should be called outside the mutex
+  SuperVersion() = default;
+  ~SuperVersion();
+  SuperVersion* Ref();
+
+  bool Unref();
+
+  // call these two methods with db mutex held
+  // Cleanup unrefs mem, imm and current. Also, it stores all memtables
+  // that needs to be deleted in to_delete vector. Unrefing those
+  // objects needs to be done in the mutex
+  void Cleanup();
+  void Init(MemTable* new_mem, MemTableListVersion* new_imm,
+            Version* new_current);
+
+  // The value of dummy is not actually used. kSVInUse takes its address as a
+  // mark in the thread local storage to indicate the SuperVersion is in use
+  // by thread. This way, the value of kSVInUse is guaranteed to have no
+  // conflict with SuperVersion object address and portable on different
+  // platform.
+  static int dummy;
+  static void* const kSVInUse;
+  static void* const kSVObsolete;
+};
+
+extern ColumnFamilyOptions SanitizeOptions(const InternalKeyComparator* icmp,
+                                           const InternalFilterPolicy* ipolicy,
+                                           const ColumnFamilyOptions& src);
+
+class ColumnFamilySet;
+
+// This class keeps all the data that a column family needs. It's mosly dumb and
+// used just to provide access to metadata.
+// Most methods require DB mutex held, unless otherwise noted
+class ColumnFamilyData {
+ public:
+  ~ColumnFamilyData();
+
+  // thread-safe
+  uint32_t GetID() const { return id_; }
+  // thread-safe
+  const std::string& GetName() const { return name_; }
+
+  void Ref() { ++refs_; }
+  // will just decrease reference count to 0, but will not delete it. returns
+  // true if the ref count was decreased to zero. in that case, it can be
+  // deleted by the caller immediatelly, or later, by calling
+  // FreeDeadColumnFamilies()
+  bool Unref() {
+    assert(refs_ > 0);
+    return --refs_ == 0;
+  }
+
+  // This can only be called from single-threaded VersionSet::LogAndApply()
+  // After dropping column family no other operation on that column family
+  // will be executed. All the files and memory will be, however, kept around
+  // until client drops the column family handle. That way, client can still
+  // access data from dropped column family.
+  // Column family can be dropped and still alive. In that state:
+  // *) Column family is not included in the iteration.
+  // *) Compaction and flush is not executed on the dropped column family.
+  // *) Client can continue writing and reading from column family. However, all
+  // writes stay in the current memtable.
+  // When the dropped column family is unreferenced, then we:
+  // *) delete all memory associated with that column family
+  // *) delete all the files associated with that column family
+  void SetDropped() {
+    // can't drop default CF
+    assert(id_ != 0);
+    dropped_ = true;
+  }
+  bool IsDropped() const { return dropped_; }
+
+  // thread-safe
+  int NumberLevels() const { return options_.num_levels; }
+
+  void SetLogNumber(uint64_t log_number) { log_number_ = log_number; }
+  uint64_t GetLogNumber() const { return log_number_; }
+
+  // thread-safe
+  const Options* options() const { return &options_; }
+  const EnvOptions* soptions() const;
+
+  InternalStats* internal_stats() { return internal_stats_.get(); }
+
+  MemTableList* imm() { return &imm_; }
+  MemTable* mem() { return mem_; }
+  Version* current() { return current_; }
+  Version* dummy_versions() { return dummy_versions_; }
+  void SetMemtable(MemTable* new_mem) { mem_ = new_mem; }
+  void SetCurrent(Version* current);
+  void CreateNewMemtable();
+
+  TableCache* table_cache() const { return table_cache_.get(); }
+
+  // See documentation in compaction_picker.h
+  Compaction* PickCompaction(LogBuffer* log_buffer);
+  Compaction* CompactRange(int input_level, int output_level,
+                           const InternalKey* begin, const InternalKey* end,
+                           InternalKey** compaction_end);
+
+  CompactionPicker* compaction_picker() { return compaction_picker_.get(); }
+  // thread-safe
+  const Comparator* user_comparator() const {
+    return internal_comparator_.user_comparator();
+  }
+  // thread-safe
+  const InternalKeyComparator& internal_comparator() const {
+    return internal_comparator_;
+  }
+
+  SuperVersion* GetSuperVersion() { return super_version_; }
+  // thread-safe
+  // Return a already referenced SuperVersion to be used safely.
+  SuperVersion* GetReferencedSuperVersion(port::Mutex* db_mutex);
+  // thread-safe
+  // Get SuperVersion stored in thread local storage. If it does not exist,
+  // get a reference from a current SuperVersion.
+  SuperVersion* GetThreadLocalSuperVersion(port::Mutex* db_mutex);
+  // Try to return SuperVersion back to thread local storage. Retrun true on
+  // success and false on failure. It fails when the thread local storage
+  // contains anything other than SuperVersion::kSVInUse flag.
+  bool ReturnThreadLocalSuperVersion(SuperVersion* sv);
+  // thread-safe
+  uint64_t GetSuperVersionNumber() const {
+    return super_version_number_.load();
+  }
+  // will return a pointer to SuperVersion* if previous SuperVersion
+  // if its reference count is zero and needs deletion or nullptr if not
+  // As argument takes a pointer to allocated SuperVersion to enable
+  // the clients to allocate SuperVersion outside of mutex.
+  SuperVersion* InstallSuperVersion(SuperVersion* new_superversion,
+                                    port::Mutex* db_mutex);
+
+  void ResetThreadLocalSuperVersions();
+
+  // A Flag indicating whether write needs to slowdown because of there are
+  // too many number of level0 files.
+  bool NeedSlowdownForNumLevel0Files() const {
+    return need_slowdown_for_num_level0_files_;
+  }
+
+  bool NeedWaitForNumLevel0Files() const {
+    return need_wait_for_num_level0_files_;
+  }
+
+  bool NeedWaitForNumMemtables() const {
+    return need_wait_for_num_memtables_;
+  }
+
+  bool ExceedsSoftRateLimit() const {
+    return exceeds_soft_rate_limit_;
+  }
+
+  bool ExceedsHardRateLimit() const {
+    return exceeds_hard_rate_limit_;
+  }
+
+ private:
+  friend class ColumnFamilySet;
+  ColumnFamilyData(const std::string& dbname, uint32_t id,
+                   const std::string& name, Version* dummy_versions,
+                   Cache* table_cache, const ColumnFamilyOptions& options,
+                   const DBOptions* db_options,
+                   const EnvOptions& storage_options,
+                   ColumnFamilySet* column_family_set);
+
+  // Recalculate some small conditions, which are changed only during
+  // compaction, adding new memtable and/or
+  // recalculation of compaction score. These values are used in
+  // DBImpl::MakeRoomForWrite function to decide, if it need to make
+  // a write stall
+  void RecalculateWriteStallConditions();
+  void RecalculateWriteStallRateLimitsConditions();
+
+  uint32_t id_;
+  const std::string name_;
+  Version* dummy_versions_;  // Head of circular doubly-linked list of versions.
+  Version* current_;         // == dummy_versions->prev_
+
+  int refs_;                   // outstanding references to ColumnFamilyData
+  bool dropped_;               // true if client dropped it
+
+  const InternalKeyComparator internal_comparator_;
+  const InternalFilterPolicy internal_filter_policy_;
+
+  Options const options_;
+
+  std::unique_ptr<TableCache> table_cache_;
+
+  std::unique_ptr<InternalStats> internal_stats_;
+
+  MemTable* mem_;
+  MemTableList imm_;
+  SuperVersion* super_version_;
+
+  // An ordinal representing the current SuperVersion. Updated by
+  // InstallSuperVersion(), i.e. incremented every time super_version_
+  // changes.
+  std::atomic<uint64_t> super_version_number_;
+
+  // Thread's local copy of SuperVersion pointer
+  // This needs to be destructed before mutex_
+  std::unique_ptr<ThreadLocalPtr> local_sv_;
+
+  // pointers for a circular linked list. we use it to support iterations
+  // that can be concurrent with writes
+  ColumnFamilyData* next_;
+  ColumnFamilyData* prev_;
+
+  // This is the earliest log file number that contains data from this
+  // Column Family. All earlier log files must be ignored and not
+  // recovered from
+  uint64_t log_number_;
+
+  // A flag indicating whether we should delay writes because
+  // we have too many level 0 files
+  bool need_slowdown_for_num_level0_files_;
+
+  // These 4 variables are updated only after compaction,
+  // adding new memtable, flushing memtables to files
+  // and/or add recalculation of compaction score.
+  // That's why theirs values are cached in ColumnFamilyData.
+  // Recalculation is made by RecalculateWriteStallConditions and
+  // RecalculateWriteStallRateLimitsConditions function. They are used
+  // in DBImpl::MakeRoomForWrite function to decide, if it need
+  // to sleep during write operation
+  bool need_wait_for_num_memtables_;
+
+  bool need_wait_for_num_level0_files_;
+
+  bool exceeds_hard_rate_limit_;
+
+  bool exceeds_soft_rate_limit_;
+
+  // An object that keeps all the compaction stats
+  // and picks the next compaction
+  std::unique_ptr<CompactionPicker> compaction_picker_;
+
+  ColumnFamilySet* column_family_set_;
+};
+
+// ColumnFamilySet has interesting thread-safety requirements
+// * CreateColumnFamily() or RemoveColumnFamily() -- need to protect by DB
+// mutex. Inside, column_family_data_ and column_families_ will be protected
+// by Lock() and Unlock(). CreateColumnFamily() should ONLY be called from
+// VersionSet::LogAndApply() in the normal runtime. It is also called
+// during Recovery and in DumpManifest(). RemoveColumnFamily() is called
+// from ColumnFamilyData destructor
+// * Iteration -- hold DB mutex, but you can release it in the body of
+// iteration. If you release DB mutex in body, reference the column
+// family before the mutex and unreference after you unlock, since the column
+// family might get dropped when the DB mutex is released
+// * GetDefault() -- thread safe
+// * GetColumnFamily() -- either inside of DB mutex or call Lock() <-> Unlock()
+// * GetNextColumnFamilyID(), GetMaxColumnFamily(), UpdateMaxColumnFamily(),
+// NumberOfColumnFamilies -- inside of DB mutex
+class ColumnFamilySet {
+ public:
+  // ColumnFamilySet supports iteration
+  class iterator {
+   public:
+    explicit iterator(ColumnFamilyData* cfd)
+        : current_(cfd) {}
+    iterator& operator++() {
+      // dummy is never dead or dropped, so this will never be infinite
+      do {
+        current_ = current_->next_;
+      } while (current_->refs_ == 0 || current_->IsDropped());
+      return *this;
+    }
+    bool operator!=(const iterator& other) {
+      return this->current_ != other.current_;
+    }
+    ColumnFamilyData* operator*() { return current_; }
+
+   private:
+    ColumnFamilyData* current_;
+  };
+
+  ColumnFamilySet(const std::string& dbname, const DBOptions* db_options,
+                  const EnvOptions& storage_options, Cache* table_cache);
+  ~ColumnFamilySet();
+
+  ColumnFamilyData* GetDefault() const;
+  // GetColumnFamily() calls return nullptr if column family is not found
+  ColumnFamilyData* GetColumnFamily(uint32_t id) const;
+  ColumnFamilyData* GetColumnFamily(const std::string& name) const;
+  // this call will return the next available column family ID. it guarantees
+  // that there is no column family with id greater than or equal to the
+  // returned value in the current running instance or anytime in RocksDB
+  // instance history.
+  uint32_t GetNextColumnFamilyID();
+  uint32_t GetMaxColumnFamily();
+  void UpdateMaxColumnFamily(uint32_t new_max_column_family);
+  size_t NumberOfColumnFamilies() const;
+
+  ColumnFamilyData* CreateColumnFamily(const std::string& name, uint32_t id,
+                                       Version* dummy_version,
+                                       const ColumnFamilyOptions& options);
+
+  iterator begin() { return iterator(dummy_cfd_->next_); }
+  iterator end() { return iterator(dummy_cfd_); }
+
+  void Lock();
+  void Unlock();
+
+  // REQUIRES: DB mutex held
+  // Don't call while iterating over ColumnFamilySet
+  void FreeDeadColumnFamilies();
+
+ private:
+  friend class ColumnFamilyData;
+  // helper function that gets called from cfd destructor
+  // REQUIRES: DB mutex held
+  void RemoveColumnFamily(ColumnFamilyData* cfd);
+
+  // column_families_ and column_family_data_ need to be protected:
+  // * when mutating: 1. DB mutex locked first, 2. spinlock locked second
+  // * when reading, either: 1. lock DB mutex, or 2. lock spinlock
+  //  (if both, respect the ordering to avoid deadlock!)
+  std::unordered_map<std::string, uint32_t> column_families_;
+  std::unordered_map<uint32_t, ColumnFamilyData*> column_family_data_;
+
+  uint32_t max_column_family_;
+  ColumnFamilyData* dummy_cfd_;
+  // We don't hold the refcount here, since default column family always exists
+  // We are also not responsible for cleaning up default_cfd_cache_. This is
+  // just a cache that makes common case (accessing default column family)
+  // faster
+  ColumnFamilyData* default_cfd_cache_;
+
+  const std::string db_name_;
+  const DBOptions* const db_options_;
+  const EnvOptions storage_options_;
+  Cache* table_cache_;
+  std::atomic_flag spin_lock_;
+};
+
+// We use ColumnFamilyMemTablesImpl to provide WriteBatch a way to access
+// memtables of different column families (specified by ID in the write batch)
+class ColumnFamilyMemTablesImpl : public ColumnFamilyMemTables {
+ public:
+  explicit ColumnFamilyMemTablesImpl(ColumnFamilySet* column_family_set)
+      : column_family_set_(column_family_set), current_(nullptr) {}
+
+  // sets current_ to ColumnFamilyData with column_family_id
+  // returns false if column family doesn't exist
+  bool Seek(uint32_t column_family_id) override;
+
+  // Returns log number of the selected column family
+  uint64_t GetLogNumber() const override;
+
+  // REQUIRES: Seek() called first
+  virtual MemTable* GetMemTable() const override;
+
+  // Returns options for selected column family
+  // REQUIRES: Seek() called first
+  virtual const Options* GetOptions() const override;
+
+  // Returns column family handle for the selected column family
+  virtual ColumnFamilyHandle* GetColumnFamilyHandle() override;
+
+ private:
+  ColumnFamilySet* column_family_set_;
+  ColumnFamilyData* current_;
+  ColumnFamilyHandleInternal handle_;
+};
+
+}  // namespace rocksdb
@@ -0,0 +1,945 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include <algorithm>
+#include <vector>
+#include <string>
+
+#include "db/db_impl.h"
+#include "rocksdb/env.h"
+#include "rocksdb/db.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+#include "util/coding.h"
+#include "utilities/merge_operators.h"
+
+namespace rocksdb {
+
+namespace {
+std::string RandomString(Random* rnd, int len) {
+  std::string r;
+  test::RandomString(rnd, len, &r);
+  return r;
+}
+}  // anonymous namespace
+
+// counts how many operations were performed
+class EnvCounter : public EnvWrapper {
+ public:
+  explicit EnvCounter(Env* base)
+      : EnvWrapper(base), num_new_writable_file_(0) {}
+  int GetNumberOfNewWritableFileCalls() {
+    return num_new_writable_file_;
+  }
+  Status NewWritableFile(const std::string& f, unique_ptr<WritableFile>* r,
+                         const EnvOptions& soptions) {
+    ++num_new_writable_file_;
+    return EnvWrapper::NewWritableFile(f, r, soptions);
+  }
+
+ private:
+  int num_new_writable_file_;
+};
+
+class ColumnFamilyTest {
+ public:
+  ColumnFamilyTest() : rnd_(139) {
+    env_ = new EnvCounter(Env::Default());
+    dbname_ = test::TmpDir() + "/column_family_test";
+    db_options_.create_if_missing = true;
+    db_options_.env = env_;
+    DestroyDB(dbname_, Options(db_options_, column_family_options_));
+  }
+
+  ~ColumnFamilyTest() {
+    delete env_;
+  }
+
+  void Close() {
+    for (auto h : handles_) {
+      delete h;
+    }
+    handles_.clear();
+    names_.clear();
+    delete db_;
+    db_ = nullptr;
+  }
+
+  Status TryOpen(std::vector<std::string> cf,
+                 std::vector<ColumnFamilyOptions> options = {}) {
+    std::vector<ColumnFamilyDescriptor> column_families;
+    names_.clear();
+    for (size_t i = 0; i < cf.size(); ++i) {
+      column_families.push_back(ColumnFamilyDescriptor(
+          cf[i], options.size() == 0 ? column_family_options_ : options[i]));
+      names_.push_back(cf[i]);
+    }
+    return DB::Open(db_options_, dbname_, column_families, &handles_, &db_);
+  }
+
+  Status OpenReadOnly(std::vector<std::string> cf,
+                         std::vector<ColumnFamilyOptions> options = {}) {
+    std::vector<ColumnFamilyDescriptor> column_families;
+    names_.clear();
+    for (size_t i = 0; i < cf.size(); ++i) {
+      column_families.push_back(ColumnFamilyDescriptor(
+          cf[i], options.size() == 0 ? column_family_options_ : options[i]));
+      names_.push_back(cf[i]);
+    }
+    return DB::OpenForReadOnly(db_options_, dbname_, column_families, &handles_,
+                               &db_);
+  }
+
+  void AssertOpenReadOnly(std::vector<std::string> cf,
+                    std::vector<ColumnFamilyOptions> options = {}) {
+    ASSERT_OK(OpenReadOnly(cf, options));
+  }
+
+
+  void Open(std::vector<std::string> cf,
+            std::vector<ColumnFamilyOptions> options = {}) {
+    ASSERT_OK(TryOpen(cf, options));
+  }
+
+  void Open() {
+    Open({"default"});
+  }
+
+  DBImpl* dbfull() { return reinterpret_cast<DBImpl*>(db_); }
+
+  int GetProperty(int cf, std::string property) {
+    std::string value;
+    ASSERT_TRUE(dbfull()->GetProperty(handles_[cf], property, &value));
+    return std::stoi(value);
+  }
+
+  void Destroy() {
+    for (auto h : handles_) {
+      delete h;
+    }
+    handles_.clear();
+    names_.clear();
+    delete db_;
+    db_ = nullptr;
+    ASSERT_OK(DestroyDB(dbname_, Options(db_options_, column_family_options_)));
+  }
+
+  void CreateColumnFamilies(
+      const std::vector<std::string>& cfs,
+      const std::vector<ColumnFamilyOptions> options = {}) {
+    int cfi = handles_.size();
+    handles_.resize(cfi + cfs.size());
+    names_.resize(cfi + cfs.size());
+    for (size_t i = 0; i < cfs.size(); ++i) {
+      ASSERT_OK(db_->CreateColumnFamily(
+          options.size() == 0 ? column_family_options_ : options[i], cfs[i],
+          &handles_[cfi]));
+      names_[cfi] = cfs[i];
+      cfi++;
+    }
+  }
+
+  void Reopen(const std::vector<ColumnFamilyOptions> options = {}) {
+    std::vector<std::string> names;
+    for (auto name : names_) {
+      if (name != "") {
+        names.push_back(name);
+      }
+    }
+    Close();
+    assert(options.size() == 0 || names.size() == options.size());
+    Open(names, options);
+  }
+
+  void CreateColumnFamiliesAndReopen(const std::vector<std::string>& cfs) {
+    CreateColumnFamilies(cfs);
+    Reopen();
+  }
+
+  void DropColumnFamilies(const std::vector<int>& cfs) {
+    for (auto cf : cfs) {
+      ASSERT_OK(db_->DropColumnFamily(handles_[cf]));
+      delete handles_[cf];
+      handles_[cf] = nullptr;
+      names_[cf] = "";
+    }
+  }
+
+  void PutRandomData(int cf, int num, int key_value_size) {
+    for (int i = 0; i < num; ++i) {
+      // 10 bytes for key, rest is value
+      ASSERT_OK(Put(cf, test::RandomKey(&rnd_, 10),
+                    RandomString(&rnd_, key_value_size - 10)));
+    }
+  }
+
+  void WaitForFlush(int cf) {
+    ASSERT_OK(dbfull()->TEST_WaitForFlushMemTable(handles_[cf]));
+  }
+
+  void WaitForCompaction() { ASSERT_OK(dbfull()->TEST_WaitForCompact()); }
+
+  Status Put(int cf, const std::string& key, const std::string& value) {
+    return db_->Put(WriteOptions(), handles_[cf], Slice(key), Slice(value));
+  }
+  Status Merge(int cf, const std::string& key, const std::string& value) {
+    return db_->Merge(WriteOptions(), handles_[cf], Slice(key), Slice(value));
+  }
+  Status Flush(int cf) {
+    return db_->Flush(FlushOptions(), handles_[cf]);
+  }
+
+  std::string Get(int cf, const std::string& key) {
+    ReadOptions options;
+    options.verify_checksums = true;
+    std::string result;
+    Status s = db_->Get(options, handles_[cf], Slice(key), &result);
+    if (s.IsNotFound()) {
+      result = "NOT_FOUND";
+    } else if (!s.ok()) {
+      result = s.ToString();
+    }
+    return result;
+  }
+
+  void CompactAll(int cf) {
+    ASSERT_OK(db_->CompactRange(handles_[cf], nullptr, nullptr));
+  }
+
+  void Compact(int cf, const Slice& start, const Slice& limit) {
+    ASSERT_OK(db_->CompactRange(handles_[cf], &start, &limit));
+  }
+
+  int NumTableFilesAtLevel(int level, int cf) {
+    return GetProperty(cf,
+                       "rocksdb.num-files-at-level" + std::to_string(level));
+  }
+
+  // Return spread of files per level
+  std::string FilesPerLevel(int cf) {
+    std::string result;
+    int last_non_zero_offset = 0;
+    for (int level = 0; level < dbfull()->NumberLevels(handles_[cf]); level++) {
+      int f = NumTableFilesAtLevel(level, cf);
+      char buf[100];
+      snprintf(buf, sizeof(buf), "%s%d", (level ? "," : ""), f);
+      result += buf;
+      if (f > 0) {
+        last_non_zero_offset = result.size();
+      }
+    }
+    result.resize(last_non_zero_offset);
+    return result;
+  }
+
+  int CountLiveFiles() {
+    std::vector<LiveFileMetaData> metadata;
+    db_->GetLiveFilesMetaData(&metadata);
+    return static_cast<int>(metadata.size());
+  }
+
+  // Do n memtable flushes, each of which produces an sstable
+  // covering the range [small,large].
+  void MakeTables(int cf, int n, const std::string& small,
+                  const std::string& large) {
+    for (int i = 0; i < n; i++) {
+      ASSERT_OK(Put(cf, small, "begin"));
+      ASSERT_OK(Put(cf, large, "end"));
+      ASSERT_OK(db_->Flush(FlushOptions(), handles_[cf]));
+    }
+  }
+
+  int CountLiveLogFiles() {
+    int micros_wait_for_log_deletion = 20000;
+    env_->SleepForMicroseconds(micros_wait_for_log_deletion);
+    int ret = 0;
+    VectorLogPtr wal_files;
+    Status s;
+    // GetSortedWalFiles is a flakey function -- it gets all the wal_dir
+    // children files and then later checks for their existance. if some of the
+    // log files doesn't exist anymore, it reports an error. it does all of this
+    // without DB mutex held, so if a background process deletes the log file
+    // while the function is being executed, it returns an error. We retry the
+    // function 10 times to avoid the error failing the test
+    for (int retries = 0; retries < 10; ++retries) {
+      wal_files.clear();
+      s = db_->GetSortedWalFiles(wal_files);
+      if (s.ok()) {
+        break;
+      }
+    }
+    ASSERT_OK(s);
+    for (const auto& wal : wal_files) {
+      if (wal->Type() == kAliveLogFile) {
+        ++ret;
+      }
+    }
+    return ret;
+  }
+
+  void AssertNumberOfImmutableMemtables(std::vector<int> num_per_cf) {
+    assert(num_per_cf.size() == handles_.size());
+
+    for (size_t i = 0; i < num_per_cf.size(); ++i) {
+      ASSERT_EQ(num_per_cf[i],
+                GetProperty(i, "rocksdb.num-immutable-mem-table"));
+    }
+  }
+
+  void CopyFile(const std::string& source, const std::string& destination,
+                uint64_t size = 0) {
+    const EnvOptions soptions;
+    unique_ptr<SequentialFile> srcfile;
+    ASSERT_OK(env_->NewSequentialFile(source, &srcfile, soptions));
+    unique_ptr<WritableFile> destfile;
+    ASSERT_OK(env_->NewWritableFile(destination, &destfile, soptions));
+
+    if (size == 0) {
+      // default argument means copy everything
+      ASSERT_OK(env_->GetFileSize(source, &size));
+    }
+
+    char buffer[4096];
+    Slice slice;
+    while (size > 0) {
+      uint64_t one = std::min(uint64_t(sizeof(buffer)), size);
+      ASSERT_OK(srcfile->Read(one, &slice, buffer));
+      ASSERT_OK(destfile->Append(slice));
+      size -= slice.size();
+    }
+    ASSERT_OK(destfile->Close());
+  }
+
+  std::vector<ColumnFamilyHandle*> handles_;
+  std::vector<std::string> names_;
+  ColumnFamilyOptions column_family_options_;
+  DBOptions db_options_;
+  std::string dbname_;
+  DB* db_ = nullptr;
+  EnvCounter* env_;
+  Random rnd_;
+};
+
+TEST(ColumnFamilyTest, DontReuseColumnFamilyID) {
+  for (int iter = 0; iter < 3; ++iter) {
+    Open();
+    CreateColumnFamilies({"one", "two", "three"});
+    for (size_t i = 0; i < handles_.size(); ++i) {
+      auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(handles_[i]);
+      ASSERT_EQ(i, cfh->GetID());
+    }
+    if (iter == 1) {
+      Reopen();
+    }
+    DropColumnFamilies({3});
+    Reopen();
+    if (iter == 2) {
+      // this tests if max_column_family is correctly persisted with
+      // WriteSnapshot()
+      Reopen();
+    }
+    CreateColumnFamilies({"three2"});
+    // ID 3 that was used for dropped column family "three" should not be reused
+    auto cfh3 = reinterpret_cast<ColumnFamilyHandleImpl*>(handles_[3]);
+    ASSERT_EQ(4U, cfh3->GetID());
+    Close();
+    Destroy();
+  }
+}
+
+
+TEST(ColumnFamilyTest, AddDrop) {
+  Open();
+  CreateColumnFamilies({"one", "two", "three"});
+  ASSERT_EQ("NOT_FOUND", Get(1, "fodor"));
+  ASSERT_EQ("NOT_FOUND", Get(2, "fodor"));
+  DropColumnFamilies({2});
+  ASSERT_EQ("NOT_FOUND", Get(1, "fodor"));
+  CreateColumnFamilies({"four"});
+  ASSERT_EQ("NOT_FOUND", Get(3, "fodor"));
+  ASSERT_OK(Put(1, "fodor", "mirko"));
+  ASSERT_EQ("mirko", Get(1, "fodor"));
+  ASSERT_EQ("NOT_FOUND", Get(3, "fodor"));
+  Close();
+  ASSERT_TRUE(TryOpen({"default"}).IsInvalidArgument());
+  Open({"default", "one", "three", "four"});
+  DropColumnFamilies({1});
+  Reopen();
+  Close();
+
+  std::vector<std::string> families;
+  ASSERT_OK(DB::ListColumnFamilies(db_options_, dbname_, &families));
+  sort(families.begin(), families.end());
+  ASSERT_TRUE(families ==
+              std::vector<std::string>({"default", "four", "three"}));
+}
+
+TEST(ColumnFamilyTest, DropTest) {
+  // first iteration - dont reopen DB before dropping
+  // second iteration - reopen DB before dropping
+  for (int iter = 0; iter < 2; ++iter) {
+    Open({"default"});
+    CreateColumnFamiliesAndReopen({"pikachu"});
+    for (int i = 0; i < 100; ++i) {
+      ASSERT_OK(Put(1, std::to_string(i), "bar" + std::to_string(i)));
+    }
+    ASSERT_OK(Flush(1));
+
+    if (iter == 1) {
+      Reopen();
+    }
+    ASSERT_EQ("bar1", Get(1, "1"));
+
+    ASSERT_EQ(CountLiveFiles(), 1);
+    DropColumnFamilies({1});
+    // make sure that all files are deleted when we drop the column family
+    ASSERT_EQ(CountLiveFiles(), 0);
+    Destroy();
+  }
+}
+
+TEST(ColumnFamilyTest, WriteBatchFailure) {
+  Open();
+  CreateColumnFamiliesAndReopen({"one", "two"});
+  WriteBatch batch;
+  batch.Put(handles_[1], Slice("non-existing"), Slice("column-family"));
+  ASSERT_OK(db_->Write(WriteOptions(), &batch));
+  DropColumnFamilies({1});
+  Status s = db_->Write(WriteOptions(), &batch);
+  ASSERT_TRUE(s.IsInvalidArgument());
+  Close();
+}
+
+TEST(ColumnFamilyTest, ReadWrite) {
+  Open();
+  CreateColumnFamiliesAndReopen({"one", "two"});
+  ASSERT_OK(Put(0, "foo", "v1"));
+  ASSERT_OK(Put(0, "bar", "v2"));
+  ASSERT_OK(Put(1, "mirko", "v3"));
+  ASSERT_OK(Put(0, "foo", "v2"));
+  ASSERT_OK(Put(2, "fodor", "v5"));
+
+  for (int iter = 0; iter <= 3; ++iter) {
+    ASSERT_EQ("v2", Get(0, "foo"));
+    ASSERT_EQ("v2", Get(0, "bar"));
+    ASSERT_EQ("v3", Get(1, "mirko"));
+    ASSERT_EQ("v5", Get(2, "fodor"));
+    ASSERT_EQ("NOT_FOUND", Get(0, "fodor"));
+    ASSERT_EQ("NOT_FOUND", Get(1, "fodor"));
+    ASSERT_EQ("NOT_FOUND", Get(2, "foo"));
+    if (iter <= 1) {
+      Reopen();
+    }
+  }
+  Close();
+}
+
+TEST(ColumnFamilyTest, IgnoreRecoveredLog) {
+  std::string backup_logs = dbname_ + "/backup_logs";
+
+  // delete old files in backup_logs directory
+  ASSERT_OK(env_->CreateDirIfMissing(dbname_));
+  ASSERT_OK(env_->CreateDirIfMissing(backup_logs));
+  std::vector<std::string> old_files;
+  env_->GetChildren(backup_logs, &old_files);
+  for (auto& file : old_files) {
+    if (file != "." && file != "..") {
+      env_->DeleteFile(backup_logs + "/" + file);
+    }
+  }
+
+  column_family_options_.merge_operator =
+      MergeOperators::CreateUInt64AddOperator();
+  db_options_.wal_dir = dbname_ + "/logs";
+  Destroy();
+  Open();
+  CreateColumnFamilies({"cf1", "cf2"});
+
+  // fill up the DB
+  std::string one, two, three;
+  PutFixed64(&one, 1);
+  PutFixed64(&two, 2);
+  PutFixed64(&three, 3);
+  ASSERT_OK(Merge(0, "foo", one));
+  ASSERT_OK(Merge(1, "mirko", one));
+  ASSERT_OK(Merge(0, "foo", one));
+  ASSERT_OK(Merge(2, "bla", one));
+  ASSERT_OK(Merge(2, "fodor", one));
+  ASSERT_OK(Merge(0, "bar", one));
+  ASSERT_OK(Merge(2, "bla", one));
+  ASSERT_OK(Merge(1, "mirko", two));
+  ASSERT_OK(Merge(1, "franjo", one));
+
+  // copy the logs to backup
+  std::vector<std::string> logs;
+  env_->GetChildren(db_options_.wal_dir, &logs);
+  for (auto& log : logs) {
+    if (log != ".." && log != ".") {
+      CopyFile(db_options_.wal_dir + "/" + log, backup_logs + "/" + log);
+    }
+  }
+
+  // recover the DB
+  Close();
+
+  // 1. check consistency
+  // 2. copy the logs from backup back to WAL dir. if the recovery happens
+  // again on the same log files, this should lead to incorrect results
+  // due to applying merge operator twice
+  // 3. check consistency
+  for (int iter = 0; iter < 2; ++iter) {
+    // assert consistency
+    Open({"default", "cf1", "cf2"});
+    ASSERT_EQ(two, Get(0, "foo"));
+    ASSERT_EQ(one, Get(0, "bar"));
+    ASSERT_EQ(three, Get(1, "mirko"));
+    ASSERT_EQ(one, Get(1, "franjo"));
+    ASSERT_EQ(one, Get(2, "fodor"));
+    ASSERT_EQ(two, Get(2, "bla"));
+    Close();
+
+    if (iter == 0) {
+      // copy the logs from backup back to wal dir
+      for (auto& log : logs) {
+        if (log != ".." && log != ".") {
+          CopyFile(backup_logs + "/" + log, db_options_.wal_dir + "/" + log);
+        }
+      }
+    }
+  }
+}
+
+TEST(ColumnFamilyTest, FlushTest) {
+  Open();
+  CreateColumnFamiliesAndReopen({"one", "two"});
+  ASSERT_OK(Put(0, "foo", "v1"));
+  ASSERT_OK(Put(0, "bar", "v2"));
+  ASSERT_OK(Put(1, "mirko", "v3"));
+  ASSERT_OK(Put(0, "foo", "v2"));
+  ASSERT_OK(Put(2, "fodor", "v5"));
+  for (int i = 0; i < 3; ++i) {
+    Flush(i);
+  }
+  Reopen();
+
+  for (int iter = 0; iter <= 2; ++iter) {
+    ASSERT_EQ("v2", Get(0, "foo"));
+    ASSERT_EQ("v2", Get(0, "bar"));
+    ASSERT_EQ("v3", Get(1, "mirko"));
+    ASSERT_EQ("v5", Get(2, "fodor"));
+    ASSERT_EQ("NOT_FOUND", Get(0, "fodor"));
+    ASSERT_EQ("NOT_FOUND", Get(1, "fodor"));
+    ASSERT_EQ("NOT_FOUND", Get(2, "foo"));
+    if (iter <= 1) {
+      Reopen();
+    }
+  }
+  Close();
+}
+
+// Makes sure that obsolete log files get deleted
+TEST(ColumnFamilyTest, LogDeletionTest) {
+  db_options_.max_total_wal_size = std::numeric_limits<uint64_t>::max();
+  column_family_options_.write_buffer_size = 100000;  // 100KB
+  Open();
+  CreateColumnFamilies({"one", "two", "three", "four"});
+  // Each bracket is one log file. if number is in (), it means
+  // we don't need it anymore (it's been flushed)
+  // []
+  ASSERT_EQ(CountLiveLogFiles(), 0);
+  PutRandomData(0, 1, 100);
+  // [0]
+  PutRandomData(1, 1, 100);
+  // [0, 1]
+  PutRandomData(1, 1000, 100);
+  WaitForFlush(1);
+  // [0, (1)] [1]
+  ASSERT_EQ(CountLiveLogFiles(), 2);
+  PutRandomData(0, 1, 100);
+  // [0, (1)] [0, 1]
+  ASSERT_EQ(CountLiveLogFiles(), 2);
+  PutRandomData(2, 1, 100);
+  // [0, (1)] [0, 1, 2]
+  PutRandomData(2, 1000, 100);
+  WaitForFlush(2);
+  // [0, (1)] [0, 1, (2)] [2]
+  ASSERT_EQ(CountLiveLogFiles(), 3);
+  PutRandomData(2, 1000, 100);
+  WaitForFlush(2);
+  // [0, (1)] [0, 1, (2)] [(2)] [2]
+  ASSERT_EQ(CountLiveLogFiles(), 4);
+  PutRandomData(3, 1, 100);
+  // [0, (1)] [0, 1, (2)] [(2)] [2, 3]
+  PutRandomData(1, 1, 100);
+  // [0, (1)] [0, 1, (2)] [(2)] [1, 2, 3]
+  ASSERT_EQ(CountLiveLogFiles(), 4);
+  PutRandomData(1, 1000, 100);
+  WaitForFlush(1);
+  // [0, (1)] [0, (1), (2)] [(2)] [(1), 2, 3] [1]
+  ASSERT_EQ(CountLiveLogFiles(), 5);
+  PutRandomData(0, 1000, 100);
+  WaitForFlush(0);
+  // [(0), (1)] [(0), (1), (2)] [(2)] [(1), 2, 3] [1, (0)] [0]
+  // delete obsolete logs -->
+  // [(1), 2, 3] [1, (0)] [0]
+  ASSERT_EQ(CountLiveLogFiles(), 3);
+  PutRandomData(0, 1000, 100);
+  WaitForFlush(0);
+  // [(1), 2, 3] [1, (0)], [(0)] [0]
+  ASSERT_EQ(CountLiveLogFiles(), 4);
+  PutRandomData(1, 1000, 100);
+  WaitForFlush(1);
+  // [(1), 2, 3] [(1), (0)] [(0)] [0, (1)] [1]
+  ASSERT_EQ(CountLiveLogFiles(), 5);
+  PutRandomData(2, 1000, 100);
+  WaitForFlush(2);
+  // [(1), (2), 3] [(1), (0)] [(0)] [0, (1)] [1, (2)], [2]
+  ASSERT_EQ(CountLiveLogFiles(), 6);
+  PutRandomData(3, 1000, 100);
+  WaitForFlush(3);
+  // [(1), (2), (3)] [(1), (0)] [(0)] [0, (1)] [1, (2)], [2, (3)] [3]
+  // delete obsolete logs -->
+  // [0, (1)] [1, (2)], [2, (3)] [3]
+  ASSERT_EQ(CountLiveLogFiles(), 4);
+  Close();
+}
+
+// Makes sure that obsolete log files get deleted
+TEST(ColumnFamilyTest, DifferentWriteBufferSizes) {
+  // disable flushing stale column families
+  db_options_.max_total_wal_size = std::numeric_limits<uint64_t>::max();
+  Open();
+  CreateColumnFamilies({"one", "two", "three"});
+  ColumnFamilyOptions default_cf, one, two, three;
+  // setup options. all column families have max_write_buffer_number setup to 10
+  // "default" -> 100KB memtable, start flushing immediatelly
+  // "one" -> 200KB memtable, start flushing with two immutable memtables
+  // "two" -> 1MB memtable, start flushing with three immutable memtables
+  // "three" -> 90KB memtable, start flushing with four immutable memtables
+  default_cf.write_buffer_size = 100000;
+  default_cf.max_write_buffer_number = 10;
+  default_cf.min_write_buffer_number_to_merge = 1;
+  one.write_buffer_size = 200000;
+  one.max_write_buffer_number = 10;
+  one.min_write_buffer_number_to_merge = 2;
+  two.write_buffer_size = 1000000;
+  two.max_write_buffer_number = 10;
+  two.min_write_buffer_number_to_merge = 3;
+  three.write_buffer_size = 90000;
+  three.max_write_buffer_number = 10;
+  three.min_write_buffer_number_to_merge = 4;
+
+  Reopen({default_cf, one, two, three});
+
+  int micros_wait_for_flush = 10000;
+  PutRandomData(0, 100, 1000);
+  WaitForFlush(0);
+  AssertNumberOfImmutableMemtables({0, 0, 0, 0});
+  ASSERT_EQ(CountLiveLogFiles(), 1);
+  PutRandomData(1, 200, 1000);
+  env_->SleepForMicroseconds(micros_wait_for_flush);
+  AssertNumberOfImmutableMemtables({0, 1, 0, 0});
+  ASSERT_EQ(CountLiveLogFiles(), 2);
+  PutRandomData(2, 1000, 1000);
+  env_->SleepForMicroseconds(micros_wait_for_flush);
+  AssertNumberOfImmutableMemtables({0, 1, 1, 0});
+  ASSERT_EQ(CountLiveLogFiles(), 3);
+  PutRandomData(2, 1000, 1000);
+  env_->SleepForMicroseconds(micros_wait_for_flush);
+  AssertNumberOfImmutableMemtables({0, 1, 2, 0});
+  ASSERT_EQ(CountLiveLogFiles(), 4);
+  PutRandomData(3, 90, 1000);
+  env_->SleepForMicroseconds(micros_wait_for_flush);
+  AssertNumberOfImmutableMemtables({0, 1, 2, 1});
+  ASSERT_EQ(CountLiveLogFiles(), 5);
+  PutRandomData(3, 90, 1000);
+  env_->SleepForMicroseconds(micros_wait_for_flush);
+  AssertNumberOfImmutableMemtables({0, 1, 2, 2});
+  ASSERT_EQ(CountLiveLogFiles(), 6);
+  PutRandomData(3, 90, 1000);
+  env_->SleepForMicroseconds(micros_wait_for_flush);
+  AssertNumberOfImmutableMemtables({0, 1, 2, 3});
+  ASSERT_EQ(CountLiveLogFiles(), 7);
+  PutRandomData(0, 100, 1000);
+  WaitForFlush(0);
+  AssertNumberOfImmutableMemtables({0, 1, 2, 3});
+  ASSERT_EQ(CountLiveLogFiles(), 8);
+  PutRandomData(2, 100, 10000);
+  WaitForFlush(2);
+  AssertNumberOfImmutableMemtables({0, 1, 0, 3});
+  ASSERT_EQ(CountLiveLogFiles(), 9);
+  PutRandomData(3, 90, 1000);
+  WaitForFlush(3);
+  AssertNumberOfImmutableMemtables({0, 1, 0, 0});
+  ASSERT_EQ(CountLiveLogFiles(), 10);
+  PutRandomData(3, 90, 1000);
+  env_->SleepForMicroseconds(micros_wait_for_flush);
+  AssertNumberOfImmutableMemtables({0, 1, 0, 1});
+  ASSERT_EQ(CountLiveLogFiles(), 11);
+  PutRandomData(1, 200, 1000);
+  WaitForFlush(1);
+  AssertNumberOfImmutableMemtables({0, 0, 0, 1});
+  ASSERT_EQ(CountLiveLogFiles(), 5);
+  PutRandomData(3, 90*6, 1000);
+  WaitForFlush(3);
+  AssertNumberOfImmutableMemtables({0, 0, 0, 0});
+  ASSERT_EQ(CountLiveLogFiles(), 12);
+  PutRandomData(0, 100, 1000);
+  WaitForFlush(0);
+  AssertNumberOfImmutableMemtables({0, 0, 0, 0});
+  ASSERT_EQ(CountLiveLogFiles(), 12);
+  PutRandomData(2, 3*100, 10000);
+  WaitForFlush(2);
+  AssertNumberOfImmutableMemtables({0, 0, 0, 0});
+  ASSERT_EQ(CountLiveLogFiles(), 12);
+  PutRandomData(1, 2*200, 1000);
+  WaitForFlush(1);
+  AssertNumberOfImmutableMemtables({0, 0, 0, 0});
+  ASSERT_EQ(CountLiveLogFiles(), 7);
+  Close();
+}
+
+TEST(ColumnFamilyTest, DifferentMergeOperators) {
+  Open();
+  CreateColumnFamilies({"first", "second"});
+  ColumnFamilyOptions default_cf, first, second;
+  first.merge_operator = MergeOperators::CreateUInt64AddOperator();
+  second.merge_operator = MergeOperators::CreateStringAppendOperator();
+  Reopen({default_cf, first, second});
+
+  std::string one, two, three;
+  PutFixed64(&one, 1);
+  PutFixed64(&two, 2);
+  PutFixed64(&three, 3);
+
+  ASSERT_OK(Put(0, "foo", two));
+  ASSERT_OK(Put(0, "foo", one));
+  ASSERT_TRUE(Merge(0, "foo", two).IsNotSupported());
+  ASSERT_EQ(Get(0, "foo"), one);
+
+  ASSERT_OK(Put(1, "foo", two));
+  ASSERT_OK(Put(1, "foo", one));
+  ASSERT_OK(Merge(1, "foo", two));
+  ASSERT_EQ(Get(1, "foo"), three);
+
+  ASSERT_OK(Put(2, "foo", two));
+  ASSERT_OK(Put(2, "foo", one));
+  ASSERT_OK(Merge(2, "foo", two));
+  ASSERT_EQ(Get(2, "foo"), one + "," + two);
+  Close();
+}
+
+TEST(ColumnFamilyTest, DifferentCompactionStyles) {
+  Open();
+  CreateColumnFamilies({"one", "two"});
+  ColumnFamilyOptions default_cf, one, two;
+  db_options_.max_open_files = 20;  // only 10 files in file cache
+  db_options_.disableDataSync = true;
+
+  default_cf.compaction_style = kCompactionStyleLevel;
+  default_cf.num_levels = 3;
+  default_cf.write_buffer_size = 64 << 10;  // 64KB
+  default_cf.target_file_size_base = 30 << 10;
+  default_cf.filter_policy = nullptr;
+  default_cf.no_block_cache = true;
+  default_cf.source_compaction_factor = 100;
+
+  one.compaction_style = kCompactionStyleUniversal;
+  // trigger compaction if there are >= 4 files
+  one.level0_file_num_compaction_trigger = 4;
+  one.write_buffer_size = 100000;
+
+  two.compaction_style = kCompactionStyleLevel;
+  two.num_levels = 4;
+  two.max_mem_compaction_level = 0;
+  two.level0_file_num_compaction_trigger = 3;
+  two.write_buffer_size = 100000;
+
+  Reopen({default_cf, one, two});
+
+  // SETUP column family "one" -- universal style
+  for (int i = 0; i < one.level0_file_num_compaction_trigger - 1; ++i) {
+    PutRandomData(1, 11, 10000);
+    WaitForFlush(1);
+    ASSERT_EQ(std::to_string(i + 1), FilesPerLevel(1));
+  }
+
+  // SETUP column family "two" -- level style with 4 levels
+  for (int i = 0; i < two.level0_file_num_compaction_trigger - 1; ++i) {
+    PutRandomData(2, 15, 10000);
+    WaitForFlush(2);
+    ASSERT_EQ(std::to_string(i + 1), FilesPerLevel(2));
+  }
+
+  // TRIGGER compaction "one"
+  PutRandomData(1, 12, 10000);
+
+  // TRIGGER compaction "two"
+  PutRandomData(2, 10, 10000);
+
+  // WAIT for compactions
+  WaitForCompaction();
+
+  // VERIFY compaction "one"
+  ASSERT_EQ("1", FilesPerLevel(1));
+
+  // VERIFY compaction "two"
+  ASSERT_EQ("0,1", FilesPerLevel(2));
+  CompactAll(2);
+  ASSERT_EQ("0,1", FilesPerLevel(2));
+
+  Close();
+}
+
+namespace {
+std::string IterStatus(Iterator* iter) {
+  std::string result;
+  if (iter->Valid()) {
+    result = iter->key().ToString() + "->" + iter->value().ToString();
+  } else {
+    result = "(invalid)";
+  }
+  return result;
+}
+}  // anonymous namespace
+
+TEST(ColumnFamilyTest, NewIteratorsTest) {
+  // iter == 0 -- no tailing
+  // iter == 2 -- tailing
+  for (int iter = 0; iter < 2; ++iter) {
+    Open();
+    CreateColumnFamiliesAndReopen({"one", "two"});
+    ASSERT_OK(Put(0, "a", "b"));
+    ASSERT_OK(Put(1, "b", "a"));
+    ASSERT_OK(Put(2, "c", "m"));
+    ASSERT_OK(Put(2, "v", "t"));
+    std::vector<Iterator*> iterators;
+    ReadOptions options;
+    options.tailing = (iter == 1);
+    ASSERT_OK(db_->NewIterators(options, handles_, &iterators));
+
+    for (auto it : iterators) {
+      it->SeekToFirst();
+    }
+    ASSERT_EQ(IterStatus(iterators[0]), "a->b");
+    ASSERT_EQ(IterStatus(iterators[1]), "b->a");
+    ASSERT_EQ(IterStatus(iterators[2]), "c->m");
+
+    ASSERT_OK(Put(1, "x", "x"));
+
+    for (auto it : iterators) {
+      it->Next();
+    }
+
+    ASSERT_EQ(IterStatus(iterators[0]), "(invalid)");
+    if (iter == 0) {
+      // no tailing
+      ASSERT_EQ(IterStatus(iterators[1]), "(invalid)");
+    } else {
+      // tailing
+      ASSERT_EQ(IterStatus(iterators[1]), "x->x");
+    }
+    ASSERT_EQ(IterStatus(iterators[2]), "v->t");
+
+    for (auto it : iterators) {
+      delete it;
+    }
+    Destroy();
+  }
+}
+
+TEST(ColumnFamilyTest, ReadOnlyDBTest) {
+  Open();
+  CreateColumnFamiliesAndReopen({"one", "two", "three", "four"});
+  ASSERT_OK(Put(1, "foo", "bla"));
+  ASSERT_OK(Put(2, "foo", "blabla"));
+  ASSERT_OK(Put(3, "foo", "blablabla"));
+  ASSERT_OK(Put(4, "foo", "blablablabla"));
+
+  DropColumnFamilies({2});
+  Close();
+  // open only a subset of column families
+  AssertOpenReadOnly({"default", "one", "four"});
+  ASSERT_EQ("NOT_FOUND", Get(0, "foo"));
+  ASSERT_EQ("bla", Get(1, "foo"));
+  ASSERT_EQ("blablablabla", Get(2, "foo"));
+
+  Close();
+  // can't open dropped column family
+  Status s = OpenReadOnly({"default", "one", "two"});
+  ASSERT_TRUE(!s.ok());
+
+  // Can't open without specifying default column family
+  s = OpenReadOnly({"one", "four"});
+  ASSERT_TRUE(!s.ok());
+}
+
+TEST(ColumnFamilyTest, DontRollEmptyLogs) {
+  Open();
+  CreateColumnFamiliesAndReopen({"one", "two", "three", "four"});
+
+  for (size_t i = 0; i < handles_.size(); ++i) {
+    PutRandomData(i, 10, 100);
+  }
+  int num_writable_file_start = env_->GetNumberOfNewWritableFileCalls();
+  // this will trigger the flushes
+  ASSERT_OK(db_->Write(WriteOptions(), nullptr));
+
+  for (int i = 0; i < 4; ++i) {
+    dbfull()->TEST_WaitForFlushMemTable(handles_[i]);
+  }
+  int total_new_writable_files =
+      env_->GetNumberOfNewWritableFileCalls() - num_writable_file_start;
+  ASSERT_EQ(static_cast<size_t>(total_new_writable_files), handles_.size() + 1);
+  Close();
+}
+
+TEST(ColumnFamilyTest, FlushStaleColumnFamilies) {
+  Open();
+  CreateColumnFamilies({"one", "two"});
+  ColumnFamilyOptions default_cf, one, two;
+  default_cf.write_buffer_size = 100000;  // small write buffer size
+  default_cf.disable_auto_compactions = true;
+  one.disable_auto_compactions = true;
+  two.disable_auto_compactions = true;
+  db_options_.max_total_wal_size = 210000;
+
+  Reopen({default_cf, one, two});
+
+  PutRandomData(2, 1, 10);  // 10 bytes
+  for (int i = 0; i < 2; ++i) {
+    PutRandomData(0, 100, 1000);  // flush
+    WaitForFlush(0);
+    ASSERT_EQ(i + 1, CountLiveFiles());
+  }
+  // third flush. now, CF [two] should be detected as stale and flushed
+  // column family 1 should not be flushed since it's empty
+  PutRandomData(0, 100, 1000);  // flush
+  WaitForFlush(0);
+  WaitForFlush(2);
+  // 3 files for default column families, 1 file for column family [two], zero
+  // files for column family [one], because it's empty
+  ASSERT_EQ(4, CountLiveFiles());
+  Close();
+}
+
+TEST(ColumnFamilyTest, CreateMissingColumnFamilies) {
+  Status s = TryOpen({"one", "two"});
+  ASSERT_TRUE(!s.ok());
+  db_options_.create_missing_column_families = true;
+  s = TryOpen({"default", "one", "two"});
+  ASSERT_TRUE(s.ok());
+  Close();
+}
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  return rocksdb::test::RunAllTests();
+}
@@ -9,12 +9,19 @@

 #include "db/compaction.h"

+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
+#include <vector>
+
+#include "db/column_family.h"
+#include "util/logging.h"
+
 namespace rocksdb {

 static uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
  uint64_t sum = 0;
  for (size_t i = 0; i < files.size() && files[i]; i++) {
-    sum += files[i]->file_size;
+    sum += files[i]->fd.GetFileSize();
  }
  return sum;
 }
@@ -22,15 +29,20 @@ static uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
 Compaction::Compaction(Version* input_version, int level, int out_level,
                       uint64_t target_file_size,
                       uint64_t max_grandparent_overlap_bytes,
-                       bool seek_compaction, bool enable_compression)
+                       uint32_t output_path_id,
+                       CompressionType output_compression, bool seek_compaction,
+                       bool deletion_compaction)
    : level_(level),
      out_level_(out_level),
      max_output_file_size_(target_file_size),
      max_grandparent_overlap_bytes_(max_grandparent_overlap_bytes),
      input_version_(input_version),
      number_levels_(input_version_->NumberLevels()),
+      cfd_(input_version_->cfd_),
+      output_path_id_(output_path_id),
+      output_compression_(output_compression),
      seek_compaction_(seek_compaction),
-      enable_compression_(enable_compression),
+      deletion_compaction_(deletion_compaction),
      grandparent_index_(0),
      seen_key_(false),
      overlapped_bytes_(0),
@@ -39,10 +51,13 @@ Compaction::Compaction(Version* input_version, int level, int out_level,
      score_(0),
      bottommost_level_(false),
      is_full_compaction_(false),
+      is_manual_compaction_(false),
      level_ptrs_(std::vector<size_t>(number_levels_)) {

+  cfd_->Ref();
  input_version_->Ref();
  edit_ = new VersionEdit();
+  edit_->SetColumnFamily(cfd_->GetID());
  for (int i = 0; i < number_levels_; i++) {
    level_ptrs_[i] = 0;
  }
@@ -53,6 +68,11 @@ Compaction::~Compaction() {
  if (input_version_ != nullptr) {
    input_version_->Unref();
  }
+  if (cfd_ != nullptr) {
+    if (cfd_->Unref()) {
+      delete cfd_;
+    }
+  }
 }

 bool Compaction::IsTrivialMove() const {
@@ -67,21 +87,23 @@ bool Compaction::IsTrivialMove() const {
          TotalFileSize(grandparents_) <= max_grandparent_overlap_bytes_);
 }

+bool Compaction::IsDeletionCompaction() const { return deletion_compaction_; }
+
 void Compaction::AddInputDeletions(VersionEdit* edit) {
  for (int which = 0; which < 2; which++) {
    for (size_t i = 0; i < inputs_[which].size(); i++) {
-      edit->DeleteFile(level_ + which, inputs_[which][i]->number);
+      edit->DeleteFile(level_ + which, inputs_[which][i]->fd.GetNumber());
    }
  }
 }

 bool Compaction::IsBaseLevelForKey(const Slice& user_key) {
-  if (input_version_->vset_->options_->compaction_style ==
-      kCompactionStyleUniversal) {
+  assert(cfd_->options()->compaction_style != kCompactionStyleFIFO);
+  if (cfd_->options()->compaction_style == kCompactionStyleUniversal) {
    return bottommost_level_;
  }
  // Maybe use binary search to find right entry instead of linear search?
-  const Comparator* user_cmp = input_version_->vset_->icmp_.user_comparator();
+  const Comparator* user_cmp = cfd_->user_comparator();
  for (int lvl = level_ + 2; lvl < number_levels_; lvl++) {
    const std::vector<FileMetaData*>& files = input_version_->files_[lvl];
    for (; level_ptrs_[lvl] < files.size(); ) {
@@ -102,12 +124,12 @@ bool Compaction::IsBaseLevelForKey(const Slice& user_key) {

 bool Compaction::ShouldStopBefore(const Slice& internal_key) {
  // Scan to find earliest grandparent file that contains key.
-  const InternalKeyComparator* icmp = &input_version_->vset_->icmp_;
+  const InternalKeyComparator* icmp = &cfd_->internal_comparator();
  while (grandparent_index_ < grandparents_.size() &&
      icmp->Compare(internal_key,
                    grandparents_[grandparent_index_]->largest.Encode()) > 0) {
    if (seen_key_) {
-      overlapped_bytes_ += grandparents_[grandparent_index_]->file_size;
+      overlapped_bytes_ += grandparents_[grandparent_index_]->fd.GetFileSize();
    }
    assert(grandparent_index_ + 1 >= grandparents_.size() ||
           icmp->Compare(grandparents_[grandparent_index_]->largest.Encode(),
@@ -140,8 +162,8 @@ void Compaction::MarkFilesBeingCompacted(bool value) {

 // Is this compaction producing files at the bottommost level?
 void Compaction::SetupBottomMostLevel(bool isManual) {
-  if (input_version_->vset_->options_->compaction_style  ==
-         kCompactionStyleUniversal) {
+  assert(cfd_->options()->compaction_style != kCompactionStyleFIFO);
+  if (cfd_->options()->compaction_style == kCompactionStyleUniversal) {
    // If universal compaction style is used and manual
    // compaction is occuring, then we are guaranteed that
    // all files will be picked in a single compaction
@@ -154,8 +176,7 @@ void Compaction::SetupBottomMostLevel(bool isManual) {
    return;
  }
  bottommost_level_ = true;
-  int num_levels = input_version_->vset_->NumberLevels();
-  for (int i = output_level() + 1; i < num_levels; i++) {
+  for (int i = output_level() + 1; i < number_levels_; i++) {
    if (input_version_->NumLevelFiles(i) > 0) {
      bottommost_level_ = false;
      break;
@@ -168,47 +189,83 @@ void Compaction::ReleaseInputs() {
    input_version_->Unref();
    input_version_ = nullptr;
  }
+  if (cfd_ != nullptr) {
+    if (cfd_->Unref()) {
+      delete cfd_;
+    }
+    cfd_ = nullptr;
+  }
+}
+
+void Compaction::ReleaseCompactionFiles(Status status) {
+  cfd_->compaction_picker()->ReleaseCompactionFiles(this, status);
 }

 void Compaction::ResetNextCompactionIndex() {
  input_version_->ResetNextCompactionIndex(level_);
 }

-static void InputSummary(std::vector<FileMetaData*>& files, char* output,
-                         int len) {
+namespace {
+int InputSummary(const std::vector<FileMetaData*>& files, char* output,
+                 int len) {
+  *output = '\0';
  int write = 0;
  for (unsigned int i = 0; i < files.size(); i++) {
    int sz = len - write;
-    int ret = snprintf(output + write, sz, "%lu(%lu) ",
-        (unsigned long)files.at(i)->number,
-        (unsigned long)files.at(i)->file_size);
-    if (ret < 0 || ret >= sz)
-      break;
+    int ret;
+    char sztxt[16];
+    AppendHumanBytes(files.at(i)->fd.GetFileSize(), sztxt, 16);
+    ret = snprintf(output + write, sz, "%" PRIu64 "(%s) ",
+                   files.at(i)->fd.GetNumber(), sztxt);
+    if (ret < 0 || ret >= sz) break;
    write += ret;
  }
+  // if files.size() is non-zero, overwrite the last space
+  return write - !!files.size();
 }
+}  // namespace

 void Compaction::Summary(char* output, int len) {
-  int write = snprintf(output, len,
-      "Base version %lu Base level %d, seek compaction:%d, inputs:",
-      (unsigned long)input_version_->GetVersionNumber(),
-      level_,
-      seek_compaction_);
-  if (write < 0 || write > len) {
+  int write =
+      snprintf(output, len, "Base version %" PRIu64
+                            " Base level %d, seek compaction:%d, inputs: [",
+               input_version_->GetVersionNumber(), level_, seek_compaction_);
+  if (write < 0 || write >= len) {
    return;
  }

-  char level_low_summary[100];
-  InputSummary(inputs_[0], level_low_summary, sizeof(level_low_summary));
-  char level_up_summary[100];
-  if (inputs_[1].size()) {
-    InputSummary(inputs_[1], level_up_summary, sizeof(level_up_summary));
-  } else {
-    level_up_summary[0] = '\0';
+  write += InputSummary(inputs_[0], output + write, len - write);
+  if (write < 0 || write >= len) {
+    return;
  }

-  snprintf(output + write, len - write, "[%s],[%s]",
-      level_low_summary, level_up_summary);
+  write += snprintf(output + write, len - write, "], [");
+  if (write < 0 || write >= len) {
+    return;
+  }
+
+  write += InputSummary(inputs_[1], output + write, len - write);
+  if (write < 0 || write >= len) {
+    return;
+  }
+
+  snprintf(output + write, len - write, "]");
+}
+
+uint64_t Compaction::OutputFilePreallocationSize() {
+  uint64_t preallocation_size = 0;
+
+  if (cfd_->options()->compaction_style == kCompactionStyleLevel) {
+    preallocation_size =
+        cfd_->compaction_picker()->MaxFileSizeForLevel(output_level());
+  } else {
+    for (const auto& f : inputs_[0]) {
+      preallocation_size += f->fd.GetFileSize();
+    }
+  }
+  // Over-estimate slightly so we don't end up just barely crossing
+  // the threshold
+  return preallocation_size * 1.1;
 }

 }  // namespace rocksdb
@@ -13,6 +13,7 @@
 namespace rocksdb {

 class Version;
+class ColumnFamilyData;

 // A Compaction encapsulates information about a compaction.
 class Compaction {
@@ -36,6 +37,8 @@ class Compaction {
  // Returns input version of the compaction
  Version* input_version() const { return input_version_; }

+  ColumnFamilyData* column_family_data() const { return cfd_; }
+
  // Return the ith input file at "level()+which" ("which" must be 0 or 1).
  FileMetaData* input(int which, int i) const { return inputs_[which][i]; }

@@ -44,13 +47,19 @@ class Compaction {
  // Maximum size of files to build during this compaction.
  uint64_t MaxOutputFileSize() const { return max_output_file_size_; }

-  // Whether compression will be enabled for compaction outputs
-  bool enable_compression() const { return enable_compression_; }
+  // What compression for output
+  CompressionType OutputCompressionType() const { return output_compression_; }

-  // Is this a trivial compaction that can be implemented by just
+  // Whether need to write output file to second DB path.
+  uint32_t GetOutputPathId() const { return output_path_id_; }
+
+    // Is this a trivial compaction that can be implemented by just
  // moving a single input file to the next level (no merging or splitting)
  bool IsTrivialMove() const;

+  // If true, just delete all files in inputs_[0]
+  bool IsDeletionCompaction() const;
+
  // Add all inputs to this compaction as delete operations to *edit.
  void AddInputDeletions(VersionEdit* edit);

@@ -67,6 +76,10 @@ class Compaction {
  // is successful.
  void ReleaseInputs();

+  // Clear all files to indicate that they are not being compacted
+  // Delete this compaction from the list of running compactions.
+  void ReleaseCompactionFiles(Status status);
+
  void Summary(char* output, int len);

  // Return the score that was used to pick this compaction run.
@@ -78,14 +91,24 @@ class Compaction {
  // Does this compaction include all sst files?
  bool IsFullCompaction() { return is_full_compaction_; }

+  // Was this compaction triggered manually by the client?
+  bool IsManualCompaction() { return is_manual_compaction_; }
+
+  // Returns a number of byte that the output file should be preallocated to
+  // In level compaction, that is max_file_size_. In universal compaction, that
+  // is the sum of all input file sizes
+  uint64_t OutputFilePreallocationSize();
+
 private:
  friend class CompactionPicker;
  friend class UniversalCompactionPicker;
+  friend class FIFOCompactionPicker;
  friend class LevelCompactionPicker;

  Compaction(Version* input_version, int level, int out_level,
             uint64_t target_file_size, uint64_t max_grandparent_overlap_bytes,
-             bool seek_compaction = false, bool enable_compression = true);
+             uint32_t output_path_id, CompressionType output_compression,
+             bool seek_compaction = false, bool deletion_compaction = false);

  int level_;
  int out_level_; // levels to which output files are stored
@@ -94,9 +117,13 @@ class Compaction {
  Version* input_version_;
  VersionEdit* edit_;
  int number_levels_;
+  ColumnFamilyData* cfd_;

+  uint32_t output_path_id_;
+  CompressionType output_compression_;
  bool seek_compaction_;
-  bool enable_compression_;
+  // if true, just delete files in inputs_[0]
+  bool deletion_compaction_;

  // Each compaction reads inputs from "level_" and "level_+1"
  std::vector<FileMetaData*> inputs_[2];      // The two sets of inputs
@@ -117,6 +144,9 @@ class Compaction {
  // Does this compaction include all sst files?
  bool is_full_compaction_;

+  // Is this compaction requested by the client?
+  bool is_manual_compaction_;
+
  // level_ptrs_ holds indices into input_version_->levels_: our state
  // is that we are positioned at one of the file ranges for each
  // higher level than the ones involved in this compaction (i.e. for
@@ -9,17 +9,46 @@

 #include "db/compaction_picker.h"

+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include <limits>
+#include "db/filename.h"
+#include "util/log_buffer.h"
 #include "util/statistics.h"

 namespace rocksdb {

 namespace {
+// Determine compression type, based on user options, level of the output
+// file and whether compression is disabled.
+// 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 Options& options, int level,
+                                   const bool enable_compression = true) {
+  if (!enable_compression) {
+    // disable compression
+    return kNoCompression;
+  }
+  // If the use has specified a different compression level for each level,
+  // then pick the compresison for that level.
+  if (!options.compression_per_level.empty()) {
+    const int n = 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 options.compression_per_level[std::max(0, std::min(level, n))];
+  } else {
+    return options.compression;
+  }
+}

-uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
+uint64_t TotalCompensatedFileSize(const std::vector<FileMetaData*>& files) {
  uint64_t sum = 0;
  for (size_t i = 0; i < files.size() && files[i]; i++) {
-    sum += files[i]->file_size;
+    sum += files[i]->compensated_file_size;
  }
  return sum;
 }
@@ -77,7 +106,7 @@ void CompactionPicker::SizeBeingCompacted(std::vector<uint64_t>& sizes) {
    for (auto c : compactions_in_progress_[level]) {
      assert(c->level() == level);
      for (int i = 0; i < c->num_input_files(0); i++) {
-        total += c->input(0,i)->file_size;
+        total += c->input(0, i)->compensated_file_size;
      }
    }
    sizes[level] = total;
@@ -177,7 +206,12 @@ bool CompactionPicker::ExpandWhileOverlapping(Compaction* c) {
  // If, after the expansion, there are files that are already under
  // compaction, then we must drop/cancel this compaction.
  int parent_index = -1;
-  if (FilesInCompaction(c->inputs_[0]) ||
+  if (c->inputs_[0].empty()) {
+    Log(options_->info_log,
+        "[%s] ExpandWhileOverlapping() failure because zero input files",
+        c->column_family_data()->GetName().c_str());
+  }
+  if (c->inputs_[0].empty() || FilesInCompaction(c->inputs_[0]) ||
      (c->level() != c->output_level() &&
       ParentRangeInCompaction(c->input_version_, &smallest, &largest, level,
                               &parent_index))) {
@@ -253,9 +287,9 @@ void CompactionPicker::SetupOtherInputs(Compaction* c) {
    std::vector<FileMetaData*> expanded0;
    c->input_version_->GetOverlappingInputs(
        level, &all_start, &all_limit, &expanded0, c->base_index_, nullptr);
-    const uint64_t inputs0_size = TotalFileSize(c->inputs_[0]);
-    const uint64_t inputs1_size = TotalFileSize(c->inputs_[1]);
-    const uint64_t expanded0_size = TotalFileSize(expanded0);
+    const uint64_t inputs0_size = TotalCompensatedFileSize(c->inputs_[0]);
+    const uint64_t inputs1_size = TotalCompensatedFileSize(c->inputs_[1]);
+    const uint64_t expanded0_size = TotalCompensatedFileSize(expanded0);
    uint64_t limit = ExpandedCompactionByteSizeLimit(level);
    if (expanded0.size() > c->inputs_[0].size() &&
        inputs1_size + expanded0_size < limit &&
@@ -270,17 +304,12 @@ void CompactionPicker::SetupOtherInputs(Compaction* c) {
      if (expanded1.size() == c->inputs_[1].size() &&
          !FilesInCompaction(expanded1)) {
        Log(options_->info_log,
-            "Expanding@%lu %lu+%lu (%lu+%lu bytes) to %lu+%lu (%lu+%lu bytes)"
-            "\n",
-            (unsigned long)level,
-            (unsigned long)(c->inputs_[0].size()),
-            (unsigned long)(c->inputs_[1].size()),
-            (unsigned long)inputs0_size,
-            (unsigned long)inputs1_size,
-            (unsigned long)(expanded0.size()),
-            (unsigned long)(expanded1.size()),
-            (unsigned long)expanded0_size,
-            (unsigned long)inputs1_size);
+            "[%s] Expanding@%d %zu+%zu (%" PRIu64 "+%" PRIu64
+            " bytes) to %zu+%zu (%" PRIu64 "+%" PRIu64 "bytes)\n",
+            c->column_family_data()->GetName().c_str(), level,
+            c->inputs_[0].size(), c->inputs_[1].size(), inputs0_size,
+            inputs1_size, expanded0.size(), expanded1.size(), expanded0_size,
+            inputs1_size);
        smallest = new_start;
        largest = new_limit;
        c->inputs_[0] = expanded0;
@@ -304,6 +333,9 @@ Compaction* CompactionPicker::CompactRange(Version* version, int input_level,
                                           const InternalKey* begin,
                                           const InternalKey* end,
                                           InternalKey** compaction_end) {
+  // CompactionPickerFIFO has its own implementation of compact range
+  assert(options_->compaction_style != kCompactionStyleFIFO);
+
  std::vector<FileMetaData*> inputs;
  bool covering_the_whole_range = true;

@@ -327,7 +359,7 @@ Compaction* CompactionPicker::CompactRange(Version* version, int input_level,
        MaxFileSizeForLevel(input_level) * options_->source_compaction_factor;
    uint64_t total = 0;
    for (size_t i = 0; i + 1 < inputs.size(); ++i) {
-      uint64_t s = inputs[i]->file_size;
+      uint64_t s = inputs[i]->compensated_file_size;
      total += s;
      if (total >= limit) {
        **compaction_end = inputs[i + 1]->smallest;
@@ -339,12 +371,15 @@ Compaction* CompactionPicker::CompactRange(Version* version, int input_level,
  }
  Compaction* c = new Compaction(version, input_level, output_level,
                                 MaxFileSizeForLevel(output_level),
-                                 MaxGrandParentOverlapBytes(input_level));
+                                 MaxGrandParentOverlapBytes(input_level), 0,
+                                 GetCompressionType(*options_, output_level));

  c->inputs_[0] = inputs;
  if (ExpandWhileOverlapping(c) == false) {
    delete c;
-    Log(options_->info_log, "Could not compact due to expansion failure.\n");
+    Log(options_->info_log,
+        "[%s] Could not compact due to expansion failure.\n",
+        version->cfd_->GetName().c_str());
    return nullptr;
  }

@@ -361,10 +396,14 @@ Compaction* CompactionPicker::CompactRange(Version* version, int input_level,

  // Is this compaction creating a file at the bottommost level
  c->SetupBottomMostLevel(true);
+
+  c->is_manual_compaction_ = true;
+
  return c;
 }

-Compaction* LevelCompactionPicker::PickCompaction(Version* version) {
+Compaction* LevelCompactionPicker::PickCompaction(Version* version,
+                                                  LogBuffer* log_buffer) {
  Compaction* c = nullptr;
  int level = -1;

@@ -372,7 +411,7 @@ Compaction* LevelCompactionPicker::PickCompaction(Version* version) {
  // and also in LogAndApply(), otherwise the values could be stale.
  std::vector<uint64_t> size_being_compacted(NumberLevels() - 1);
  SizeBeingCompacted(size_being_compacted);
-  version->Finalize(size_being_compacted);
+  version->ComputeCompactionScore(size_being_compacted);

  // We prefer compactions triggered by too much data in a level over
  // the compactions triggered by seeks.
@@ -393,31 +432,6 @@ Compaction* LevelCompactionPicker::PickCompaction(Version* version) {
    }
  }

-  // Find compactions needed by seeks
-  FileMetaData* f = version->file_to_compact_;
-  if (c == nullptr && f != nullptr && !f->being_compacted) {
-
-    level = version->file_to_compact_level_;
-    int parent_index = -1;
-
-    // Only allow one level 0 compaction at a time.
-    // Do not pick this file if its parents at level+1 are being compacted.
-    if (level != 0 || compactions_in_progress_[0].empty()) {
-      if (!ParentRangeInCompaction(version, &f->smallest, &f->largest, level,
-                                   &parent_index)) {
-        c = new Compaction(version, level, level + 1,
-                           MaxFileSizeForLevel(level + 1),
-                           MaxGrandParentOverlapBytes(level), true);
-        c->inputs_[0].push_back(f);
-        c->parent_index_ = parent_index;
-        c->input_version_->file_to_compact_ = nullptr;
-        if (ExpandWhileOverlapping(c) == false) {
-          return nullptr;
-        }
-      }
-    }
-  }
-
  if (c == nullptr) {
    return nullptr;
  }
@@ -478,7 +492,8 @@ Compaction* LevelCompactionPicker::PickCompactionBySize(Version* version,
  assert(level >= 0);
  assert(level + 1 < NumberLevels());
  c = new Compaction(version, level, level + 1, MaxFileSizeForLevel(level + 1),
-                     MaxGrandParentOverlapBytes(level));
+                     MaxGrandParentOverlapBytes(level), 0,
+                     GetCompressionType(*options_, level + 1));
  c->score_ = score;

  // Pick the largest file in this level that is not already
@@ -493,11 +508,12 @@ Compaction* LevelCompactionPicker::PickCompactionBySize(Version* version,
    int index = file_size[i];
    FileMetaData* f = c->input_version_->files_[level][index];

-    // check to verify files are arranged in descending size
+    // Check to verify files are arranged in descending compensated size.
    assert((i == file_size.size() - 1) ||
           (i >= Version::number_of_files_to_sort_ - 1) ||
-           (f->file_size >=
-            c->input_version_->files_[level][file_size[i + 1]]->file_size));
+           (f->compensated_file_size >=
+            c->input_version_->files_[level][file_size[i + 1]]->
+                compensated_file_size));

    // do not pick a file to compact if it is being compacted
    // from n-1 level.
@@ -510,10 +526,6 @@ Compaction* LevelCompactionPicker::PickCompactionBySize(Version* version,
      nextIndex = i;
    }

-    //if (i > Version::number_of_files_to_sort_) {
-    //  Log(options_->info_log, "XXX Looking at index %d", i);
-    //}
-
    // Do not pick this file if its parents at level+1 are being compacted.
    // Maybe we can avoid redoing this work in SetupOtherInputs
    int parent_index = -1;
@@ -541,37 +553,49 @@ Compaction* LevelCompactionPicker::PickCompactionBySize(Version* version,
 // Universal style of compaction. Pick files that are contiguous in
 // time-range to compact.
 //
-Compaction* UniversalCompactionPicker::PickCompaction(Version* version) {
+Compaction* UniversalCompactionPicker::PickCompaction(Version* version,
+                                                      LogBuffer* log_buffer) {
  int level = 0;
  double score = version->compaction_score_[0];

  if ((version->files_[level].size() <
       (unsigned int)options_->level0_file_num_compaction_trigger)) {
-    Log(options_->info_log, "Universal: nothing to do\n");
+    LogToBuffer(log_buffer, "[%s] Universal: nothing to do\n",
+                version->cfd_->GetName().c_str());
    return nullptr;
  }
  Version::FileSummaryStorage tmp;
-  Log(options_->info_log, "Universal: candidate files(%lu): %s\n",
-      version->files_[level].size(),
-      version->LevelFileSummary(&tmp, 0));
+  LogToBuffer(log_buffer, "[%s] Universal: candidate files(%zu): %s\n",
+              version->cfd_->GetName().c_str(), version->files_[level].size(),
+              version->LevelFileSummary(&tmp, 0));

  // Check for size amplification first.
-  Compaction* c = PickCompactionUniversalSizeAmp(version, score);
-  if (c == nullptr) {
-
+  Compaction* c;
+  if ((c = PickCompactionUniversalSizeAmp(version, score, log_buffer)) !=
+      nullptr) {
+    LogToBuffer(log_buffer, "[%s] Universal: compacting for size amp\n",
+                version->cfd_->GetName().c_str());
+  } else {
    // Size amplification is within limits. Try reducing read
    // amplification while maintaining file size ratios.
    unsigned int ratio = options_->compaction_options_universal.size_ratio;
-    c = PickCompactionUniversalReadAmp(version, score, ratio, UINT_MAX);

-    // Size amplification and file size ratios are within configured limits.
-    // If max read amplification is exceeding configured limits, then force
-    // compaction without looking at filesize ratios and try to reduce
-    // the number of files to fewer than level0_file_num_compaction_trigger.
-    if (c == nullptr) {
+    if ((c = PickCompactionUniversalReadAmp(version, score, ratio, UINT_MAX,
+                                            log_buffer)) != nullptr) {
+      LogToBuffer(log_buffer, "[%s] Universal: compacting for size ratio\n",
+                  version->cfd_->GetName().c_str());
+    } else {
+      // Size amplification and file size ratios are within configured limits.
+      // If max read amplification is exceeding configured limits, then force
+      // compaction without looking at filesize ratios and try to reduce
+      // the number of files to fewer than level0_file_num_compaction_trigger.
      unsigned int num_files = version->files_[level].size() -
                               options_->level0_file_num_compaction_trigger;
-      c = PickCompactionUniversalReadAmp(version, score, UINT_MAX, num_files);
+      if ((c = PickCompactionUniversalReadAmp(
+               version, score, UINT_MAX, num_files, log_buffer)) != nullptr) {
+        LogToBuffer(log_buffer, "[%s] Universal: compacting for file num\n",
+                    version->cfd_->GetName().c_str());
+      }
    }
  }
  if (c == nullptr) {
@@ -589,15 +613,9 @@ Compaction* UniversalCompactionPicker::PickCompaction(Version* version) {
    newerfile = f;
  }

-  // The files are sorted from newest first to oldest last.
-  std::vector<int>& file_by_time = c->input_version_->files_by_size_[level];
-
  // Is the earliest file part of this compaction?
-  int last_index = file_by_time[file_by_time.size()-1];
-  FileMetaData* last_file = c->input_version_->files_[level][last_index];
-  if (c->inputs_[0][c->inputs_[0].size()-1] == last_file) {
-    c->bottommost_level_ = true;
-  }
+  FileMetaData* last_file = c->input_version_->files_[level].back();
+  c->bottommost_level_ = c->inputs_[0].back() == last_file;

  // update statistics
  MeasureTime(options_->statistics.get(), NUM_FILES_IN_SINGLE_COMPACTION,
@@ -623,7 +641,7 @@ Compaction* UniversalCompactionPicker::PickCompaction(Version* version) {
 //
 Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
    Version* version, double score, unsigned int ratio,
-    unsigned int max_number_of_files_to_compact) {
+    unsigned int max_number_of_files_to_compact, LogBuffer* log_buffer) {
  int level = 0;

  unsigned int min_merge_width =
@@ -632,12 +650,12 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
    options_->compaction_options_universal.max_merge_width;

  // The files are sorted from newest first to oldest last.
-  std::vector<int>& file_by_time = version->files_by_size_[level];
+  const auto& files = version->files_[level];
+
  FileMetaData* f = nullptr;
  bool done = false;
  int start_index = 0;
-  unsigned int candidate_count;
-  assert(file_by_time.size() == version->files_[level].size());
+  unsigned int candidate_count = 0;

  unsigned int max_files_to_compact = std::min(max_merge_width,
                                       max_number_of_files_to_compact);
@@ -645,50 +663,67 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(

  // Considers a candidate file only if it is smaller than the
  // total size accumulated so far.
-  for (unsigned int loop = 0; loop < file_by_time.size(); loop++) {
+  for (unsigned int loop = 0; loop < files.size(); loop++) {

    candidate_count = 0;

    // Skip files that are already being compacted
-    for (f = nullptr; loop < file_by_time.size(); loop++) {
-      int index = file_by_time[loop];
-      f = version->files_[level][index];
+    for (f = nullptr; loop < files.size(); loop++) {
+      f = files[loop];

      if (!f->being_compacted) {
        candidate_count = 1;
        break;
      }
-      Log(options_->info_log,
-          "Universal: file %lu[%d] being compacted, skipping",
-          (unsigned long)f->number, loop);
+      LogToBuffer(log_buffer, "[%s] Universal: file %" PRIu64
+                              "[%d] being compacted, skipping",
+                  version->cfd_->GetName().c_str(), f->fd.GetNumber(), loop);
      f = nullptr;
    }

    // This file is not being compacted. Consider it as the
    // first candidate to be compacted.
-    uint64_t candidate_size =  f != nullptr? f->file_size : 0;
+    uint64_t candidate_size =  f != nullptr? f->compensated_file_size : 0;
    if (f != nullptr) {
-      Log(options_->info_log, "Universal: Possible candidate file %lu[%d].",
-          (unsigned long)f->number, loop);
+      LogToBuffer(
+          log_buffer, "[%s] Universal: Possible candidate file %s[%d].",
+          version->cfd_->GetName().c_str(),
+          FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(), loop);
    }

    // Check if the suceeding files need compaction.
-    for (unsigned int i = loop+1;
-         candidate_count < max_files_to_compact && i < file_by_time.size();
-         i++) {
-      int index = file_by_time[i];
-      FileMetaData* f = version->files_[level][index];
+    for (unsigned int i = loop + 1;
+         candidate_count < max_files_to_compact && i < files.size(); i++) {
+      FileMetaData* f = files[i];
      if (f->being_compacted) {
        break;
      }
-      // pick files if the total candidate file size (increased by the
+      // Pick files if the total/last candidate file size (increased by the
      // specified ratio) is still larger than the next candidate file.
+      // candidate_size is the total size of files picked so far with the
+      // default kCompactionStopStyleTotalSize; with
+      // kCompactionStopStyleSimilarSize, it's simply the size of the last
+      // picked file.
      uint64_t sz = (candidate_size * (100L + ratio)) /100;
-      if (sz < f->file_size) {
+      if (sz < f->fd.GetFileSize()) {
        break;
      }
+      if (options_->compaction_options_universal.stop_style == kCompactionStopStyleSimilarSize) {
+        // Similar-size stopping rule: also check the last picked file isn't
+        // far larger than the next candidate file.
+        sz = (f->fd.GetFileSize() * (100L + ratio)) / 100;
+        if (sz < candidate_size) {
+          // If the small file we've encountered begins a run of similar-size
+          // files, we'll pick them up on a future iteration of the outer
+          // loop. If it's some lonely straggler, it'll eventually get picked
+          // by the last-resort read amp strategy which disregards size ratios.
+          break;
+        }
+        candidate_size = f->compensated_file_size;
+      } else { // default kCompactionStopStyleTotalSize
+        candidate_size += f->compensated_file_size;
+      }
      candidate_count++;
-      candidate_size += f->file_size;
    }

    // Found a series of consecutive files that need compaction.
@@ -698,15 +733,14 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
      break;
    } else {
      for (unsigned int i = loop;
-           i < loop + candidate_count && i < file_by_time.size(); i++) {
-       int index = file_by_time[i];
-       FileMetaData* f = version->files_[level][index];
-       Log(options_->info_log,
-           "Universal: Skipping file %lu[%d] with size %lu %d\n",
-           (unsigned long)f->number,
-           i,
-           (unsigned long)f->file_size,
-           f->being_compacted);
+           i < loop + candidate_count && i < files.size(); i++) {
+        FileMetaData* f = files[i];
+        LogToBuffer(log_buffer, "[%s] Universal: Skipping file %" PRIu64
+                                "[%d] with size %" PRIu64
+                                " (compensated size %" PRIu64 ") %d\n",
+                    version->cfd_->GetName().c_str(), f->fd.GetNumber(), i,
+                    f->fd.GetFileSize(), f->compensated_file_size,
+                    f->being_compacted);
      }
    }
  }
@@ -722,28 +756,29 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
  if (ratio_to_compress >= 0) {
    uint64_t total_size = version->NumLevelBytes(level);
    uint64_t older_file_size = 0;
-    for (unsigned int i = file_by_time.size() - 1; i >= first_index_after;
-        i--) {
-      older_file_size += version->files_[level][file_by_time[i]]->file_size;
+    for (unsigned int i = files.size() - 1;
+         i >= first_index_after; i--) {
+      older_file_size += files[i]->fd.GetFileSize();
      if (older_file_size * 100L >= total_size * (long) ratio_to_compress) {
        enable_compression = false;
        break;
      }
    }
  }
-  Compaction* c =
-      new Compaction(version, level, level, MaxFileSizeForLevel(level),
-                     LLONG_MAX, false, enable_compression);
+  Compaction* c = new Compaction(
+      version, level, level, MaxFileSizeForLevel(level), LLONG_MAX, 0,
+      GetCompressionType(*options_, level, enable_compression));
  c->score_ = score;

  for (unsigned int i = start_index; i < first_index_after; i++) {
-    int index = file_by_time[i];
-    FileMetaData* f = c->input_version_->files_[level][index];
+    FileMetaData* f = c->input_version_->files_[level][i];
    c->inputs_[0].push_back(f);
-    Log(options_->info_log, "Universal: Picking file %lu[%d] with size %lu\n",
-        (unsigned long)f->number,
-        i,
-        (unsigned long)f->file_size);
+    LogToBuffer(log_buffer,
+                "[%s] Universal: Picking file %s[%d] "
+                "with size %" PRIu64 " (compensated size %" PRIu64 ")\n",
+                version->cfd_->GetName().c_str(),
+                FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(),
+                i, f->fd.GetFileSize(), f->compensated_file_size);
  }
  return c;
 }
@@ -755,7 +790,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
 // min_merge_width and max_merge_width).
 //
 Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
-    Version* version, double score) {
+    Version* version, double score, LogBuffer* log_buffer) {
  int level = 0;

  // percentage flexibilty while reducing size amplification
@@ -763,8 +798,7 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
                     max_size_amplification_percent;

  // The files are sorted from newest first to oldest last.
-  std::vector<int>& file_by_time = version->files_by_size_[level];
-  assert(file_by_time.size() == version->files_[level].size());
+  const auto& files = version->files_[level];

  unsigned int candidate_count = 0;
  uint64_t candidate_size = 0;
@@ -772,42 +806,39 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
  FileMetaData* f = nullptr;

  // Skip files that are already being compacted
-  for (unsigned int loop = 0; loop < file_by_time.size() - 1; loop++) {
-    int index = file_by_time[loop];
-    f = version->files_[level][index];
+  for (unsigned int loop = 0; loop < files.size() - 1; loop++) {
+    f = files[loop];
    if (!f->being_compacted) {
      start_index = loop;         // Consider this as the first candidate.
      break;
    }
-    Log(options_->info_log, "Universal: skipping file %lu[%d] compacted %s",
-        (unsigned long)f->number,
-        loop,
-        " cannot be a candidate to reduce size amp.\n");
+    LogToBuffer(log_buffer, "[%s] Universal: skipping file %s[%d] compacted %s",
+                version->cfd_->GetName().c_str(),
+                FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(),
+                loop, " cannot be a candidate to reduce size amp.\n");
    f = nullptr;
  }
  if (f == nullptr) {
    return nullptr;             // no candidate files
  }

-  Log(options_->info_log, "Universal: First candidate file %lu[%d] %s",
-      (unsigned long)f->number,
-      start_index,
-      " to reduce size amp.\n");
+  LogToBuffer(log_buffer, "[%s] Universal: First candidate file %s[%d] %s",
+              version->cfd_->GetName().c_str(),
+              FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(),
+              start_index, " to reduce size amp.\n");

  // keep adding up all the remaining files
-  for (unsigned int loop = start_index; loop < file_by_time.size() - 1;
-       loop++) {
-    int index = file_by_time[loop];
-    f = version->files_[level][index];
+  for (unsigned int loop = start_index; loop < files.size() - 1; loop++) {
+    f = files[loop];
    if (f->being_compacted) {
-      Log(options_->info_log,
-          "Universal: Possible candidate file %lu[%d] %s.",
-          (unsigned long)f->number,
-          loop,
+      LogToBuffer(
+          log_buffer, "[%s] Universal: Possible candidate file %s[%d] %s.",
+          version->cfd_->GetName().c_str(),
+          FormatFileNumber(f->fd.GetNumber(), f->fd.GetPathId()).c_str(), loop,
          " is already being compacted. No size amp reduction possible.\n");
      return nullptr;
    }
-    candidate_size += f->file_size;
+    candidate_size += f->compensated_file_size;
    candidate_count++;
  }
  if (candidate_count == 0) {
@@ -815,43 +846,108 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
  }

  // size of earliest file
-  int index = file_by_time[file_by_time.size() - 1];
-  uint64_t earliest_file_size = version->files_[level][index]->file_size;
+  uint64_t earliest_file_size = files.back()->fd.GetFileSize();

  // size amplification = percentage of additional size
  if (candidate_size * 100 < ratio * earliest_file_size) {
-    Log(options_->info_log,
-        "Universal: size amp not needed. newer-files-total-size %lu "
-        "earliest-file-size %lu",
-        (unsigned long)candidate_size,
-        (unsigned long)earliest_file_size);
+    LogToBuffer(
+        log_buffer,
+        "[%s] Universal: size amp not needed. newer-files-total-size %" PRIu64
+        "earliest-file-size %" PRIu64,
+        version->cfd_->GetName().c_str(), candidate_size, earliest_file_size);
    return nullptr;
  } else {
-    Log(options_->info_log,
-        "Universal: size amp needed. newer-files-total-size %lu "
-        "earliest-file-size %lu",
-        (unsigned long)candidate_size,
-        (unsigned long)earliest_file_size);
+    LogToBuffer(
+        log_buffer,
+        "[%s] Universal: size amp needed. newer-files-total-size %" PRIu64
+        "earliest-file-size %" PRIu64,
+        version->cfd_->GetName().c_str(), candidate_size, earliest_file_size);
  }
-  assert(start_index >= 0 && start_index < file_by_time.size() - 1);
+  assert(start_index >= 0 && start_index < files.size() - 1);

  // create a compaction request
  // We always compact all the files, so always compress.
  Compaction* c =
      new Compaction(version, level, level, MaxFileSizeForLevel(level),
-                     LLONG_MAX, false, true);
+                     LLONG_MAX, 0, GetCompressionType(*options_, level));
  c->score_ = score;
-  for (unsigned int loop = start_index; loop < file_by_time.size(); loop++) {
-    int index = file_by_time[loop];
-    f = c->input_version_->files_[level][index];
+  for (unsigned int loop = start_index; loop < files.size(); loop++) {
+    f = c->input_version_->files_[level][loop];
    c->inputs_[0].push_back(f);
-    Log(options_->info_log,
-        "Universal: size amp picking file %lu[%d] with size %lu",
-        (unsigned long)f->number,
-        index,
-        (unsigned long)f->file_size);
+    LogToBuffer(log_buffer,
+        "[%s] Universal: size amp picking file %" PRIu64 "[%d] "
+        "with size %" PRIu64 " (compensated size %" PRIu64 ")",
+        version->cfd_->GetName().c_str(),
+        f->fd.GetNumber(), loop,
+        f->fd.GetFileSize(), f->compensated_file_size);
  }
  return c;
 }

+Compaction* FIFOCompactionPicker::PickCompaction(Version* version,
+                                                 LogBuffer* log_buffer) {
+  assert(version->NumberLevels() == 1);
+  uint64_t total_size = 0;
+  for (const auto& file : version->files_[0]) {
+    total_size += file->compensated_file_size;
+  }
+
+  if (total_size <= options_->compaction_options_fifo.max_table_files_size ||
+      version->files_[0].size() == 0) {
+    // total size not exceeded
+    LogToBuffer(log_buffer,
+                "[%s] FIFO compaction: nothing to do. Total size %" PRIu64
+                ", max size %" PRIu64 "\n",
+                version->cfd_->GetName().c_str(), total_size,
+                options_->compaction_options_fifo.max_table_files_size);
+    return nullptr;
+  }
+
+  if (compactions_in_progress_[0].size() > 0) {
+    LogToBuffer(log_buffer,
+                "[%s] FIFO compaction: Already executing compaction. No need "
+                "to run parallel compactions since compactions are very fast",
+                version->cfd_->GetName().c_str());
+    return nullptr;
+  }
+
+  Compaction* c = new Compaction(version, 0, 0, 0, 0, 0, kNoCompression, false,
+                                 true /* is deletion compaction */);
+  // delete old files (FIFO)
+  for (auto ritr = version->files_[0].rbegin();
+       ritr != version->files_[0].rend(); ++ritr) {
+    auto f = *ritr;
+    total_size -= f->compensated_file_size;
+    c->inputs_[0].push_back(f);
+    char tmp_fsize[16];
+    AppendHumanBytes(f->fd.GetFileSize(), tmp_fsize, sizeof(tmp_fsize));
+    LogToBuffer(log_buffer, "[%s] FIFO compaction: picking file %" PRIu64
+                            " with size %s for deletion",
+                version->cfd_->GetName().c_str(), f->fd.GetNumber(), tmp_fsize);
+    if (total_size <= options_->compaction_options_fifo.max_table_files_size) {
+      break;
+    }
+  }
+
+  c->MarkFilesBeingCompacted(true);
+  compactions_in_progress_[0].insert(c);
+
+  return c;
+}
+
+Compaction* FIFOCompactionPicker::CompactRange(Version* version,
+                                               int input_level,
+                                               int output_level,
+                                               const InternalKey* begin,
+                                               const InternalKey* end,
+                                               InternalKey** compaction_end) {
+  assert(input_level == 0);
+  assert(output_level == 0);
+  *compaction_end = nullptr;
+  LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL, options_->info_log.get());
+  auto c = PickCompaction(version, &log_buffer);
+  log_buffer.FlushBufferToLog();
+  return c;
+}
+
 }  // namespace rocksdb
@@ -12,6 +12,7 @@
 #include "db/compaction.h"
 #include "rocksdb/status.h"
 #include "rocksdb/options.h"
+#include "rocksdb/env.h"

 #include <vector>
 #include <memory>
@@ -19,6 +20,7 @@

 namespace rocksdb {

+class LogBuffer;
 class Compaction;
 class Version;

@@ -31,7 +33,8 @@ class CompactionPicker {
  // Returns nullptr if there is no compaction to be done.
  // Otherwise returns a pointer to a heap-allocated object that
  // describes the compaction.  Caller should delete the result.
-  virtual Compaction* PickCompaction(Version* version) = 0;
+  virtual Compaction* PickCompaction(Version* version,
+                                     LogBuffer* log_buffer) = 0;

  // Return a compaction object for compacting the range [begin,end] in
  // the specified level.  Returns nullptr if there is nothing in that
@@ -44,9 +47,10 @@ class CompactionPicker {
  // compaction_end will be set to nullptr.
  // Client is responsible for compaction_end storage -- when called,
  // *compaction_end should point to valid InternalKey!
-  Compaction* CompactRange(Version* version, int input_level, int output_level,
-                           const InternalKey* begin, const InternalKey* end,
-                           InternalKey** compaction_end);
+  virtual Compaction* CompactRange(Version* version, int input_level,
+                                   int output_level, const InternalKey* begin,
+                                   const InternalKey* end,
+                                   InternalKey** compaction_end);

  // Free up the files that participated in a compaction
  void ReleaseCompactionFiles(Compaction* c, Status status);
@@ -116,6 +120,7 @@ class CompactionPicker {
  std::unique_ptr<uint64_t[]> level_max_bytes_;

  const Options* const options_;
+
 private:
  int num_levels_;

@@ -127,16 +132,19 @@ class UniversalCompactionPicker : public CompactionPicker {
  UniversalCompactionPicker(const Options* options,
                            const InternalKeyComparator* icmp)
      : CompactionPicker(options, icmp) {}
-  virtual Compaction* PickCompaction(Version* version) override;
+  virtual Compaction* PickCompaction(Version* version,
+                                     LogBuffer* log_buffer) override;

 private:
  // Pick Universal compaction to limit read amplification
  Compaction* PickCompactionUniversalReadAmp(Version* version, double score,
                                             unsigned int ratio,
-                                             unsigned int num_files);
+                                             unsigned int num_files,
+                                             LogBuffer* log_buffer);

  // Pick Universal compaction to limit space amplification.
-  Compaction* PickCompactionUniversalSizeAmp(Version* version, double score);
+  Compaction* PickCompactionUniversalSizeAmp(Version* version, double score,
+                                             LogBuffer* log_buffer);
 };

 class LevelCompactionPicker : public CompactionPicker {
@@ -144,7 +152,8 @@ class LevelCompactionPicker : public CompactionPicker {
  LevelCompactionPicker(const Options* options,
                        const InternalKeyComparator* icmp)
      : CompactionPicker(options, icmp) {}
-  virtual Compaction* PickCompaction(Version* version) override;
+  virtual Compaction* PickCompaction(Version* version,
+                                     LogBuffer* log_buffer) override;

 private:
  // For the specfied level, pick a compaction.
@@ -154,4 +163,19 @@ class LevelCompactionPicker : public CompactionPicker {
  Compaction* PickCompactionBySize(Version* version, int level, double score);
 };

+class FIFOCompactionPicker : public CompactionPicker {
+ public:
+  FIFOCompactionPicker(const Options* options,
+                       const InternalKeyComparator* icmp)
+      : CompactionPicker(options, icmp) {}
+
+  virtual Compaction* PickCompaction(Version* version,
+                                     LogBuffer* log_buffer) override;
+
+  virtual Compaction* CompactRange(Version* version, int input_level,
+                                   int output_level, const InternalKey* begin,
+                                   const InternalKey* end,
+                                   InternalKey** compaction_end) override;
+};
+
 }  // namespace rocksdb
@@ -40,7 +40,7 @@ class CorruptionTest {
  CorruptionTest() {
    tiny_cache_ = NewLRUCache(100);
    options_.env = &env_;
-    dbname_ = test::TmpDir() + "/db_test";
+    dbname_ = test::TmpDir() + "/corruption_test";
    DestroyDB(dbname_, options_);

    db_ = nullptr;
@@ -95,7 +95,12 @@ class CorruptionTest {
    int bad_values = 0;
    int correct = 0;
    std::string value_space;
-    Iterator* iter = db_->NewIterator(ReadOptions());
+    // Do not verify checksums. If we verify checksums then the
+    // db itself will raise errors because data is corrupted.
+    // Instead, we want the reads to be successful and this test
+    // will detect whether the appropriate corruptions have
+    // occured.
+    Iterator* iter = db_->NewIterator(ReadOptions(false, true));
    for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
      uint64_t key;
      Slice in(iter->key());
@@ -122,24 +127,7 @@ class CorruptionTest {
    ASSERT_GE(max_expected, correct);
  }

-  void Corrupt(FileType filetype, int offset, int bytes_to_corrupt) {
-    // Pick file to corrupt
-    std::vector<std::string> filenames;
-    ASSERT_OK(env_.GetChildren(dbname_, &filenames));
-    uint64_t number;
-    FileType type;
-    std::string fname;
-    int picked_number = -1;
-    for (unsigned int i = 0; i < filenames.size(); i++) {
-      if (ParseFileName(filenames[i], &number, &type) &&
-          type == filetype &&
-          int(number) > picked_number) {  // Pick latest file
-        fname = dbname_ + "/" + filenames[i];
-        picked_number = number;
-      }
-    }
-    ASSERT_TRUE(!fname.empty()) << filetype;
-
+  void CorruptFile(const std::string fname, int offset, int bytes_to_corrupt) {
    struct stat sbuf;
    if (stat(fname.c_str(), &sbuf) != 0) {
      const char* msg = strerror(errno);
@@ -172,6 +160,42 @@ class CorruptionTest {
    ASSERT_TRUE(s.ok()) << s.ToString();
  }

+  void Corrupt(FileType filetype, int offset, int bytes_to_corrupt) {
+    // Pick file to corrupt
+    std::vector<std::string> filenames;
+    ASSERT_OK(env_.GetChildren(dbname_, &filenames));
+    uint64_t number;
+    FileType type;
+    std::string fname;
+    int picked_number = -1;
+    for (unsigned int i = 0; i < filenames.size(); i++) {
+      if (ParseFileName(filenames[i], &number, &type) &&
+          type == filetype &&
+          static_cast<int>(number) > picked_number) {  // Pick latest file
+        fname = dbname_ + "/" + filenames[i];
+        picked_number = number;
+      }
+    }
+    ASSERT_TRUE(!fname.empty()) << filetype;
+
+    CorruptFile(fname, offset, bytes_to_corrupt);
+  }
+
+  // corrupts exactly one file at level `level`. if no file found at level,
+  // asserts
+  void CorruptTableFileAtLevel(int level, int offset, int bytes_to_corrupt) {
+    std::vector<LiveFileMetaData> metadata;
+    db_->GetLiveFilesMetaData(&metadata);
+    for (const auto& m : metadata) {
+      if (m.level == level) {
+        CorruptFile(dbname_ + "/" + m.name, offset, bytes_to_corrupt);
+        return;
+      }
+    }
+    ASSERT_TRUE(false) << "no file found at level";
+  }
+
+
  int Property(const std::string& name) {
    std::string property;
    int result;
@@ -321,30 +345,35 @@ TEST(CorruptionTest, CompactionInputError) {
 TEST(CorruptionTest, CompactionInputErrorParanoid) {
  Options options;
  options.paranoid_checks = true;
-  options.write_buffer_size = 1048576;
+  options.write_buffer_size = 131072;
+  options.max_write_buffer_number = 2;
  Reopen(&options);
  DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);

-  // Fill levels >= 1 so memtable compaction outputs to level 1
+  // Fill levels >= 1 so memtable flush outputs to level 0
  for (int level = 1; level < dbi->NumberLevels(); level++) {
    dbi->Put(WriteOptions(), "", "begin");
    dbi->Put(WriteOptions(), "~", "end");
    dbi->TEST_FlushMemTable();
  }

+  options.max_mem_compaction_level = 0;
+  Reopen(&options);
+
+  dbi = reinterpret_cast<DBImpl*>(db_);
  Build(10);
  dbi->TEST_FlushMemTable();
  dbi->TEST_WaitForCompact();
  ASSERT_EQ(1, Property("rocksdb.num-files-at-level0"));

-  Corrupt(kTableFile, 100, 1);
+  CorruptTableFileAtLevel(0, 100, 1);
  Check(9, 9);

  // Write must eventually fail because of corrupted table
  Status s;
  std::string tmp1, tmp2;
  bool failed = false;
-  for (int i = 0; i < 10000 && s.ok(); i++) {
+  for (int i = 0; i < 10000; i++) {
    s = db_->Put(WriteOptions(), Key(i, &tmp1), Value(i, &tmp2));
    if (!s.ok()) {
      failed = true;
@@ -371,6 +400,39 @@ TEST(CorruptionTest, UnrelatedKeys) {
  ASSERT_EQ(Value(1000, &tmp2).ToString(), v);
 }

+TEST(CorruptionTest, FileSystemStateCorrupted) {
+  for (int iter = 0; iter < 2; ++iter) {
+    Options options;
+    options.paranoid_checks = true;
+    options.create_if_missing = true;
+    Reopen(&options);
+    Build(10);
+    ASSERT_OK(db_->Flush(FlushOptions()));
+    DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
+    std::vector<LiveFileMetaData> metadata;
+    dbi->GetLiveFilesMetaData(&metadata);
+    ASSERT_GT(metadata.size(), size_t(0));
+    std::string filename = dbname_ + metadata[0].name;
+
+    delete db_;
+    db_ = nullptr;
+
+    if (iter == 0) {  // corrupt file size
+      unique_ptr<WritableFile> file;
+      env_.NewWritableFile(filename, &file, EnvOptions());
+      file->Append(Slice("corrupted sst"));
+      file.reset();
+    } else {  // delete the file
+      env_.DeleteFile(filename);
+    }
+
+    Status x = TryReopen(&options);
+    ASSERT_TRUE(x.IsCorruption());
+    DestroyDB(dbname_, options_);
+    Reopen(&options);
+  }
+}
+
 }  // namespace rocksdb

 int main(int argc, char** argv) {
@@ -7,6 +7,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

+#ifndef ROCKSDB_LITE
+
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include <algorithm>
 #include <string>
 #include <stdint.h>
@@ -17,6 +21,7 @@
 #include "rocksdb/env.h"
 #include "port/port.h"
 #include "util/mutexlock.h"
+#include "util/sync_point.h"

 namespace rocksdb {

@@ -24,8 +29,11 @@ Status DBImpl::DisableFileDeletions() {
  MutexLock l(&mutex_);
  ++disable_delete_obsolete_files_;
  if (disable_delete_obsolete_files_ == 1) {
-    // if not, it has already been disabled, so don't log anything
    Log(options_.info_log, "File Deletions Disabled");
+  } else {
+    Log(options_.info_log,
+        "File Deletions Disabled, but already disabled. Counter: %d",
+        disable_delete_obsolete_files_);
  }
  return Status::OK();
 }
@@ -45,6 +53,10 @@ Status DBImpl::EnableFileDeletions(bool force) {
      Log(options_.info_log, "File Deletions Enabled");
      should_purge_files = true;
      FindObsoleteFiles(deletion_state, true);
+    } else {
+      Log(options_.info_log,
+          "File Deletions Enable, but not really enabled. Counter: %d",
+          disable_delete_obsolete_files_);
    }
  }
  if (should_purge_files)  {
@@ -60,21 +72,36 @@ Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,

  *manifest_file_size = 0;

+  mutex_.Lock();
+
  if (flush_memtable) {
    // flush all dirty data to disk.
-    Status status =  Flush(FlushOptions());
+    Status status;
+    for (auto cfd : *versions_->GetColumnFamilySet()) {
+      cfd->Ref();
+      mutex_.Unlock();
+      status = FlushMemTable(cfd, FlushOptions());
+      mutex_.Lock();
+      cfd->Unref();
+      if (!status.ok()) {
+        break;
+      }
+    }
+    versions_->GetColumnFamilySet()->FreeDeadColumnFamilies();
+
    if (!status.ok()) {
+      mutex_.Unlock();
      Log(options_.info_log, "Cannot Flush data %s\n",
          status.ToString().c_str());
      return status;
    }
  }

-  MutexLock l(&mutex_);
-
  // Make a set of all of the live *.sst files
-  std::set<uint64_t> live;
-  versions_->current()->AddLiveFiles(&live);
+  std::vector<FileDescriptor> live;
+  for (auto cfd : *versions_->GetColumnFamilySet()) {
+    cfd->current()->AddLiveFiles(&live);
+  }

  ret.clear();
  ret.reserve(live.size() + 2); //*.sst + CURRENT + MANIFEST
@@ -82,7 +109,7 @@ Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
  // create names of the live files. The names are not absolute
  // paths, instead they are relative to dbname_;
  for (auto live_file : live) {
-    ret.push_back(TableFileName("", live_file));
+    ret.push_back(MakeTableFileName("", live_file.GetNumber()));
  }

  ret.push_back(CurrentFileName(""));
@@ -91,24 +118,62 @@ Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
  // find length of manifest file while holding the mutex lock
  *manifest_file_size = versions_->ManifestFileSize();

+  mutex_.Unlock();
  return Status::OK();
 }

 Status DBImpl::GetSortedWalFiles(VectorLogPtr& files) {
-  // First get sorted files in archive dir, then append sorted files from main
-  // dir to maintain sorted order
-
-  // list wal files in archive dir.
+  // First get sorted files in db dir, then get sorted files from archived
+  // dir, to avoid a race condition where a log file is moved to archived
+  // dir in between.
  Status s;
+  // list wal files in main db dir.
+  VectorLogPtr logs;
+  s = GetSortedWalsOfType(options_.wal_dir, logs, kAliveLogFile);
+  if (!s.ok()) {
+    return s;
+  }
+
+  // Reproduce the race condition where a log file is moved
+  // to archived dir, between these two sync points, used in
+  // (DBTest,TransactionLogIteratorRace)
+  TEST_SYNC_POINT("DBImpl::GetSortedWalFiles:1");
+  TEST_SYNC_POINT("DBImpl::GetSortedWalFiles:2");
+
+  files.clear();
+  // list wal files in archive dir.
  std::string archivedir = ArchivalDirectory(options_.wal_dir);
  if (env_->FileExists(archivedir)) {
-    s = AppendSortedWalsOfType(archivedir, files, kArchivedLogFile);
+    s = GetSortedWalsOfType(archivedir, files, kArchivedLogFile);
    if (!s.ok()) {
      return s;
    }
  }
-  // list wal files in main db dir.
-  return AppendSortedWalsOfType(options_.wal_dir, files, kAliveLogFile);
+
+  uint64_t latest_archived_log_number = 0;
+  if (!files.empty()) {
+    latest_archived_log_number = files.back()->LogNumber();
+    Log(options_.info_log, "Latest Archived log: %" PRIu64,
+        latest_archived_log_number);
+  }
+
+  files.reserve(files.size() + logs.size());
+  for (auto& log : logs) {
+    if (log->LogNumber() > latest_archived_log_number) {
+      files.push_back(std::move(log));
+    } else {
+      // When the race condition happens, we could see the
+      // same log in both db dir and archived dir. Simply
+      // ignore the one in db dir. Note that, if we read
+      // archived dir first, we would have missed the log file.
+      Log(options_.info_log, "%s already moved to archive",
+          log->PathName().c_str());
+    }
+  }
+
+  return s;
 }

 }
+
+#endif  // ROCKSDB_LITE
@@ -7,23 +7,31 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 #pragma once
+
 #include <atomic>
 #include <deque>
+#include <limits>
 #include <set>
 #include <utility>
 #include <vector>
+#include <string>
+
 #include "db/dbformat.h"
 #include "db/log_writer.h"
 #include "db/snapshot.h"
+#include "db/column_family.h"
 #include "db/version_edit.h"
+#include "memtable_list.h"
+#include "port/port.h"
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "rocksdb/memtablerep.h"
 #include "rocksdb/transaction_log.h"
-#include "port/port.h"
-#include "util/stats_logger.h"
-#include "memtablelist.h"
 #include "util/autovector.h"
+#include "util/stats_logger.h"
+#include "util/stop_watch.h"
+#include "util/thread_local.h"
+#include "db/internal_stats.h"

 namespace rocksdb {

@@ -32,47 +40,88 @@ class TableCache;
 class Version;
 class VersionEdit;
 class VersionSet;
+class CompactionFilterV2;
+class Arena;

 class DBImpl : public DB {
 public:
-  DBImpl(const Options& options, const std::string& dbname);
+  DBImpl(const DBOptions& options, const std::string& dbname);
  virtual ~DBImpl();

  // Implementations of the DB interface
-  virtual Status Put(const WriteOptions&, const Slice& key, const Slice& value);
-  virtual Status Merge(const WriteOptions&, const Slice& key,
+  using DB::Put;
+  virtual Status Put(const WriteOptions& options,
+                     ColumnFamilyHandle* column_family, const Slice& key,
+                     const Slice& value);
+  using DB::Merge;
+  virtual Status Merge(const WriteOptions& options,
+                       ColumnFamilyHandle* column_family, const Slice& key,
                       const Slice& value);
-  virtual Status Delete(const WriteOptions&, const Slice& key);
+  using DB::Delete;
+  virtual Status Delete(const WriteOptions& options,
+                        ColumnFamilyHandle* column_family, const Slice& key);
+  using DB::Write;
  virtual Status Write(const WriteOptions& options, WriteBatch* updates);
+  using DB::Get;
  virtual Status Get(const ReadOptions& options,
-                     const Slice& key,
+                     ColumnFamilyHandle* column_family, const Slice& key,
                     std::string* value);
-  virtual std::vector<Status> MultiGet(const ReadOptions& options,
-                                       const std::vector<Slice>& keys,
-                                       std::vector<std::string>* values);
+  using DB::MultiGet;
+  virtual std::vector<Status> MultiGet(
+      const ReadOptions& options,
+      const std::vector<ColumnFamilyHandle*>& column_family,
+      const std::vector<Slice>& keys, std::vector<std::string>* values);
+
+  virtual Status CreateColumnFamily(const ColumnFamilyOptions& options,
+                                    const std::string& column_family,
+                                    ColumnFamilyHandle** handle);
+  virtual Status DropColumnFamily(ColumnFamilyHandle* column_family);

  // Returns false if key doesn't exist in the database and true if it may.
  // If value_found is not passed in as null, then return the value if found in
  // memory. On return, if value was found, then value_found will be set to true
  // , otherwise false.
+  using DB::KeyMayExist;
  virtual bool KeyMayExist(const ReadOptions& options,
-                           const Slice& key,
-                           std::string* value,
-                           bool* value_found = nullptr);
-  virtual Iterator* NewIterator(const ReadOptions&);
+                           ColumnFamilyHandle* column_family, const Slice& key,
+                           std::string* value, bool* value_found = nullptr);
+  using DB::NewIterator;
+  virtual Iterator* NewIterator(const ReadOptions& options,
+                                ColumnFamilyHandle* column_family);
+  virtual Status NewIterators(
+      const ReadOptions& options,
+      const std::vector<ColumnFamilyHandle*>& column_families,
+      std::vector<Iterator*>* iterators);
  virtual const Snapshot* GetSnapshot();
  virtual void ReleaseSnapshot(const Snapshot* snapshot);
-  virtual bool GetProperty(const Slice& property, std::string* value);
-  virtual void GetApproximateSizes(const Range* range, int n, uint64_t* sizes);
-  virtual Status CompactRange(const Slice* begin, const Slice* end,
+  using DB::GetProperty;
+  virtual bool GetProperty(ColumnFamilyHandle* column_family,
+                           const Slice& property, std::string* value);
+  using DB::GetApproximateSizes;
+  virtual void GetApproximateSizes(ColumnFamilyHandle* column_family,
+                                   const Range* range, int n, uint64_t* sizes);
+  using DB::CompactRange;
+  virtual Status CompactRange(ColumnFamilyHandle* column_family,
+                              const Slice* begin, const Slice* end,
                              bool reduce_level = false, int target_level = -1);
-  virtual int NumberLevels();
-  virtual int MaxMemCompactionLevel();
-  virtual int Level0StopWriteTrigger();
+
+  using DB::NumberLevels;
+  virtual int NumberLevels(ColumnFamilyHandle* column_family);
+  using DB::MaxMemCompactionLevel;
+  virtual int MaxMemCompactionLevel(ColumnFamilyHandle* column_family);
+  using DB::Level0StopWriteTrigger;
+  virtual int Level0StopWriteTrigger(ColumnFamilyHandle* column_family);
  virtual const std::string& GetName() const;
  virtual Env* GetEnv() const;
-  virtual const Options& GetOptions() const;
-  virtual Status Flush(const FlushOptions& options);
+  using DB::GetOptions;
+  virtual const Options& GetOptions(ColumnFamilyHandle* column_family) const;
+  using DB::Flush;
+  virtual Status Flush(const FlushOptions& options,
+                       ColumnFamilyHandle* column_family);
+
+  virtual SequenceNumber GetLatestSequenceNumber() const;
+
+#ifndef ROCKSDB_LITE
  virtual Status DisableFileDeletions();
  virtual Status EnableFileDeletions(bool force);
  // All the returned filenames start with "/"
@@ -80,33 +129,39 @@ class DBImpl : public DB {
                              uint64_t* manifest_file_size,
                              bool flush_memtable = true);
  virtual Status GetSortedWalFiles(VectorLogPtr& files);
-  virtual SequenceNumber GetLatestSequenceNumber() const;
-  virtual Status GetUpdatesSince(SequenceNumber seq_number,
-                                 unique_ptr<TransactionLogIterator>* iter);
+
+  virtual Status GetUpdatesSince(
+      SequenceNumber seq_number, unique_ptr<TransactionLogIterator>* iter,
+      const TransactionLogIterator::ReadOptions&
+          read_options = TransactionLogIterator::ReadOptions());
  virtual Status DeleteFile(std::string name);

-  virtual void GetLiveFilesMetaData(
-    std::vector<LiveFileMetaData> *metadata);
+  virtual void GetLiveFilesMetaData(std::vector<LiveFileMetaData>* metadata);
+#endif  // ROCKSDB_LITE
+
+  // checks if all live files exist on file system and that their file sizes
+  // match to our in-memory records
+  virtual Status CheckConsistency();

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

-  Status RunManualCompaction(int input_level,
-                             int output_level,
-                             const Slice* begin,
+  Status RunManualCompaction(ColumnFamilyData* cfd, int input_level,
+                             int output_level, const Slice* begin,
                             const Slice* end);

+#ifndef ROCKSDB_LITE
  // Extra methods (for testing) that are not in the public DB interface
+  // Implemented in db_impl_debug.cc

  // Compact any files in the named level that overlap [*begin, *end]
-  Status TEST_CompactRange(int level,
-                           const Slice* begin,
-                           const Slice* end);
+  Status TEST_CompactRange(int level, const Slice* begin, const Slice* end,
+                           ColumnFamilyHandle* column_family = nullptr);

  // Force current memtable contents to be flushed.
-  Status TEST_FlushMemTable();
+  Status TEST_FlushMemTable(bool wait = true);

  // Wait for memtable compaction
-  Status TEST_WaitForFlushMemTable();
+  Status TEST_WaitForFlushMemTable(ColumnFamilyHandle* column_family = nullptr);

  // Wait for any compaction
  Status TEST_WaitForCompact();
@@ -114,14 +169,13 @@ class DBImpl : public DB {
  // Return an internal iterator over the current state of the database.
  // The keys of this iterator are internal keys (see format.h).
  // The returned iterator should be deleted when no longer needed.
-  Iterator* TEST_NewInternalIterator();
+  Iterator* TEST_NewInternalIterator(ColumnFamilyHandle* column_family =
+                                         nullptr);

  // Return the maximum overlapping data (in bytes) at next level for any
  // file at a level >= 1.
-  int64_t TEST_MaxNextLevelOverlappingBytes();
-
-  // Simulate a db crash, no elegant closing of database.
-  void TEST_Destroy_DBImpl();
+  int64_t TEST_MaxNextLevelOverlappingBytes(ColumnFamilyHandle* column_family =
+                                                nullptr);

  // Return the current manifest file no.
  uint64_t TEST_Current_Manifest_FileNo();
@@ -137,38 +191,30 @@ class DBImpl : public DB {
    default_interval_to_delete_obsolete_WAL_ = default_interval_to_delete_obsolete_WAL;
  }

-  // holds references to memtable, all immutable memtables and version
-  struct SuperVersion {
-    MemTable* mem;
-    MemTableListVersion* imm;
-    Version* current;
-    std::atomic<uint32_t> refs;
-    // We need to_delete because during Cleanup(), imm->Unref() returns
-    // all memtables that we need to free through this vector. We then
-    // delete all those memtables outside of mutex, during destruction
-    std::vector<MemTable*> to_delete;
+  void TEST_GetFilesMetaData(ColumnFamilyHandle* column_family,
+                             std::vector<std::vector<FileMetaData>>* metadata);

-    // should be called outside the mutex
-    explicit SuperVersion(const int num_memtables = 0);
-    ~SuperVersion();
-    SuperVersion* Ref();
-    // Returns true if this was the last reference and caller should
-    // call Clenaup() and delete the object
-    bool Unref();
+  Status TEST_ReadFirstRecord(const WalFileType type, const uint64_t number,
+                              SequenceNumber* sequence);

-    // call these two methods with db mutex held
-    // Cleanup unrefs mem, imm and current. Also, it stores all memtables
-    // that needs to be deleted in to_delete vector. Unrefing those
-    // objects needs to be done in the mutex
-    void Cleanup();
-    void Init(MemTable* new_mem, MemTableListVersion* new_imm,
-              Version* new_current);
+  Status TEST_ReadFirstLine(const std::string& fname, SequenceNumber* sequence);
+#endif  // NDEBUG
+
+  // Structure to store information for candidate files to delete.
+  struct CandidateFileInfo {
+    std::string file_name;
+    uint32_t path_id;
+    CandidateFileInfo(std::string name, uint32_t path)
+        : file_name(name), path_id(path) {}
+    bool operator==(const CandidateFileInfo& other) const {
+      return file_name == other.file_name && path_id == other.path_id;
+    }
  };

  // needed for CleanupIteratorState
  struct DeletionState {
    inline bool HaveSomethingToDelete() const {
-      return  all_files.size() ||
+      return  candidate_files.size() ||
        sst_delete_files.size() ||
        log_delete_files.size();
    }
@@ -176,10 +222,10 @@ class DBImpl : public DB {
    // a list of all files that we'll consider deleting
    // (every once in a while this is filled up with all files
    // in the DB directory)
-    std::vector<std::string> all_files;
+    std::vector<CandidateFileInfo> candidate_files;

    // the list of all live sst files that cannot be deleted
-    std::vector<uint64_t> sst_live;
+    std::vector<FileDescriptor> sst_live;

    // a list of sst files that we need to delete
    std::vector<FileMetaData*> sst_delete_files;
@@ -188,25 +234,23 @@ class DBImpl : public DB {
    std::vector<uint64_t> log_delete_files;

    // a list of memtables to be free
-    std::vector<MemTable *> memtables_to_free;
+    autovector<MemTable*> memtables_to_free;

-    SuperVersion* superversion_to_free; // if nullptr nothing to free
+    autovector<SuperVersion*> superversions_to_free;

-    SuperVersion* new_superversion; // if nullptr no new superversion
+    SuperVersion* new_superversion;  // if nullptr no new superversion

    // the current manifest_file_number, log_number and prev_log_number
    // that corresponds to the set of files in 'live'.
-    uint64_t manifest_file_number, log_number, prev_log_number;
+    uint64_t manifest_file_number, pending_manifest_file_number, log_number,
+        prev_log_number;

-    explicit DeletionState(const int num_memtables = 0,
-                           bool create_superversion = false) {
+    explicit DeletionState(bool create_superversion = false) {
      manifest_file_number = 0;
+      pending_manifest_file_number = 0;
      log_number = 0;
      prev_log_number = 0;
-      memtables_to_free.reserve(num_memtables);
-      superversion_to_free = nullptr;
-      new_superversion =
-          create_superversion ? new SuperVersion(num_memtables) : nullptr;
+      new_superversion = create_superversion ? new SuperVersion() : nullptr;
    }

    ~DeletionState() {
@@ -214,8 +258,10 @@ class DBImpl : public DB {
      for (auto m : memtables_to_free) {
        delete m;
      }
-      // free superversion. if nullptr, this will be noop
-      delete superversion_to_free;
+      // free superversions
+      for (auto s : superversions_to_free) {
+        delete s;
+      }
      // if new_superversion was not used, it will be non-nullptr and needs
      // to be freed here
      delete new_superversion;
@@ -223,7 +269,7 @@ class DBImpl : public DB {
  };

  // Returns the list of live files in 'live' and the list
-  // of all files in the filesystem in 'all_files'.
+  // of all files in the filesystem in 'candidate_files'.
  // If force == false and the last call was less than
  // options_.delete_obsolete_files_period_micros microseconds ago,
  // it will not fill up the deletion_state
@@ -237,35 +283,36 @@ class DBImpl : public DB {
  // It is not necessary to hold the mutex when invoking this method.
  void PurgeObsoleteFiles(DeletionState& deletion_state);

+  ColumnFamilyHandle* DefaultColumnFamily() const;
+
 protected:
  Env* const env_;
  const std::string dbname_;
  unique_ptr<VersionSet> versions_;
-  const InternalKeyComparator internal_comparator_;
-  const Options options_;  // options_.comparator == &internal_comparator_
+  const DBOptions options_;

-  const Comparator* user_comparator() const {
-    return internal_comparator_.user_comparator();
-  }
-
-  MemTable* GetMemTable() {
-    return mem_;
-  }
-
-  Iterator* NewInternalIterator(const ReadOptions&,
-                                SequenceNumber* latest_snapshot);
+  Iterator* NewInternalIterator(const ReadOptions&, ColumnFamilyData* cfd,
+                                SuperVersion* super_version,
+                                Arena* arena = nullptr);

 private:
  friend class DB;
+  friend class InternalStats;
+#ifndef ROCKSDB_LITE
  friend class TailingIterator;
+  friend class ForwardIterator;
+#endif
+  friend struct SuperVersion;
  struct CompactionState;
  struct Writer;

  Status NewDB();

  // Recover the descriptor from persistent storage.  May do a significant
-  // amount of work to recover recently logged updates.
-  Status Recover(bool read_only = false, bool error_if_log_file_exist = false);
+  // amount of work to recover recently logged updates.  Any changes to
+  // be made to the descriptor are added to *edit.
+  Status Recover(const std::vector<ColumnFamilyDescriptor>& column_families,
+                 bool read_only = false, bool error_if_log_file_exist = false);

  void MaybeIgnoreError(Status* s) const;

@@ -276,8 +323,9 @@ class DBImpl : public DB {

  // Flush the in-memory write buffer to storage.  Switches to a new
  // log-file/memtable and writes a new descriptor iff successful.
-  Status FlushMemTableToOutputFile(bool* madeProgress,
-                                   DeletionState& deletion_state);
+  Status FlushMemTableToOutputFile(ColumnFamilyData* cfd, bool* madeProgress,
+                                   DeletionState& deletion_state,
+                                   LogBuffer* log_buffer);

  Status RecoverLogFile(uint64_t log_number, SequenceNumber* max_sequence,
                        bool read_only);
@@ -287,97 +335,134 @@ class DBImpl : public DB {
  // database is opened) and is heavyweight because it holds the mutex
  // for the entire period. The second method WriteLevel0Table supports
  // concurrent flush memtables to storage.
-  Status WriteLevel0TableForRecovery(MemTable* mem, VersionEdit* edit);
-  Status WriteLevel0Table(std::vector<MemTable*> &mems, VersionEdit* edit,
-                                uint64_t* filenumber);
+  Status WriteLevel0TableForRecovery(ColumnFamilyData* cfd, MemTable* mem,
+                                     VersionEdit* edit);
+  Status WriteLevel0Table(ColumnFamilyData* cfd, autovector<MemTable*>& mems,
+                          VersionEdit* edit, uint64_t* filenumber,
+                          LogBuffer* log_buffer);

  uint64_t SlowdownAmount(int n, double bottom, double top);
-  // MakeRoomForWrite will return superversion_to_free through an arugment,
-  // which the caller needs to delete. We do it because caller can delete
-  // the superversion outside of mutex
-  Status MakeRoomForWrite(bool force /* compact even if there is room? */,
-                          SuperVersion** superversion_to_free);
+
+  // TODO(icanadi) free superversion_to_free and old_log outside of mutex
+  Status MakeRoomForWrite(ColumnFamilyData* cfd,
+                          bool force /* flush even if there is room? */,
+                          autovector<SuperVersion*>* superversions_to_free,
+                          autovector<log::Writer*>* logs_to_free,
+                          uint64_t expiration_time);
+
  void BuildBatchGroup(Writer** last_writer,
                       autovector<WriteBatch*>* write_batch_group);

  // Force current memtable contents to be flushed.
-  Status FlushMemTable(const FlushOptions& options);
+  Status FlushMemTable(ColumnFamilyData* cfd, const FlushOptions& options);

  // Wait for memtable flushed
-  Status WaitForFlushMemTable();
+  Status WaitForFlushMemTable(ColumnFamilyData* cfd);
+
+  void RecordFlushIOStats();
+  void RecordCompactionIOStats();

  void MaybeScheduleLogDBDeployStats();
+
+#ifndef ROCKSDB_LITE
  static void BGLogDBDeployStats(void* db);
  void LogDBDeployStats();
+#endif  // ROCKSDB_LITE

  void MaybeScheduleFlushOrCompaction();
  static void BGWorkCompaction(void* db);
  static void BGWorkFlush(void* db);
  void BackgroundCallCompaction();
  void BackgroundCallFlush();
-  Status BackgroundCompaction(bool* madeProgress,DeletionState& deletion_state);
-  Status BackgroundFlush(bool* madeProgress, DeletionState& deletion_state);
+  Status BackgroundCompaction(bool* madeProgress, DeletionState& deletion_state,
+                              LogBuffer* log_buffer);
+  Status BackgroundFlush(bool* madeProgress, DeletionState& deletion_state,
+                         LogBuffer* log_buffer);
  void CleanupCompaction(CompactionState* compact, Status status);
  Status DoCompactionWork(CompactionState* compact,
-                          DeletionState& deletion_state);
+                          DeletionState& deletion_state,
+                          LogBuffer* log_buffer);
+
+  // This function is called as part of compaction. It enables Flush process to
+  // preempt compaction, since it's higher prioirty
+  // Returns: micros spent executing
+  uint64_t CallFlushDuringCompaction(ColumnFamilyData* cfd,
+                                     DeletionState& deletion_state,
+                                     LogBuffer* log_buffer);
+
+  // Call compaction filter if is_compaction_v2 is not true. Then iterate
+  // through input and compact the kv-pairs
+  Status ProcessKeyValueCompaction(
+    bool is_snapshot_supported,
+    SequenceNumber visible_at_tip,
+    SequenceNumber earliest_snapshot,
+    SequenceNumber latest_snapshot,
+    DeletionState& deletion_state,
+    bool bottommost_level,
+    int64_t& imm_micros,
+    Iterator* input,
+    CompactionState* compact,
+    bool is_compaction_v2,
+    LogBuffer* log_buffer);
+
+  // Call compaction_filter_v2->Filter() on kv-pairs in compact
+  void CallCompactionFilterV2(CompactionState* compact,
+    CompactionFilterV2* compaction_filter_v2);

  Status OpenCompactionOutputFile(CompactionState* compact);
  Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
-  Status InstallCompactionResults(CompactionState* compact);
+  Status InstallCompactionResults(CompactionState* compact,
+                                  LogBuffer* log_buffer);
  void AllocateCompactionOutputFileNumbers(CompactionState* compact);
  void ReleaseCompactionUnusedFileNumbers(CompactionState* compact);

+#ifdef ROCKSDB_LITE
+  void PurgeObsoleteWALFiles() {
+    // this function is used for archiving WAL files. we don't need this in
+    // ROCKSDB_LITE
+  }
+#else
  void PurgeObsoleteWALFiles();

-  Status AppendSortedWalsOfType(const std::string& path,
-                                VectorLogPtr& log_files,
-                                WalFileType type);
+  Status GetSortedWalsOfType(const std::string& path,
+                             VectorLogPtr& log_files,
+                             WalFileType type);

  // Requires: all_logs should be sorted with earliest log file first
  // Retains all log files in all_logs which contain updates with seq no.
  // Greater Than or Equal to the requested SequenceNumber.
  Status RetainProbableWalFiles(VectorLogPtr& all_logs,
                                const SequenceNumber target);
-  //  return true if
-  bool CheckWalFileExistsAndEmpty(const WalFileType type,
-                                  const uint64_t number);

  Status ReadFirstRecord(const WalFileType type, const uint64_t number,
-                         WriteBatch* const result);
+                         SequenceNumber* sequence);

-  Status ReadFirstLine(const std::string& fname, WriteBatch* const batch);
+  Status ReadFirstLine(const std::string& fname, SequenceNumber* sequence);
+#endif  // ROCKSDB_LITE

  void PrintStatistics();

  // dump rocksdb.stats to LOG
  void MaybeDumpStats();

+  // Return true if the current db supports snapshot.  If the current
+  // DB does not support snapshot, then calling GetSnapshot() will always
+  // return nullptr.
+  //
+  // @see GetSnapshot()
+  virtual bool IsSnapshotSupported() const;
+
  // Return the minimum empty level that could hold the total data in the
  // input level. Return the input level, if such level could not be found.
-  int FindMinimumEmptyLevelFitting(int level);
+  int FindMinimumEmptyLevelFitting(ColumnFamilyData* cfd, int level);

  // Move the files in the input level to the target level.
  // If target_level < 0, automatically calculate the minimum level that could
  // hold the data set.
-  Status ReFitLevel(int level, int target_level = -1);
-
-  // Returns the current SuperVersion number.
-  uint64_t CurrentVersionNumber() const;
-
-  // Returns a pair of iterators (mutable-only and immutable-only) used
-  // internally by TailingIterator and stores CurrentVersionNumber() in
-  // *superversion_number. These iterators are always up-to-date, i.e. can
-  // be used to read new data.
-  std::pair<Iterator*, Iterator*> GetTailingIteratorPair(
-    const ReadOptions& options,
-    uint64_t* superversion_number);
-
-  // Constant after construction
-  const InternalFilterPolicy internal_filter_policy_;
-  bool owns_info_log_;
+  Status ReFitLevel(ColumnFamilyData* cfd, int level, int target_level = -1);

  // table_cache_ provides its own synchronization
-  unique_ptr<TableCache> table_cache_;
+  std::shared_ptr<Cache> table_cache_;

  // Lock over the persistent DB state.  Non-nullptr iff successfully acquired.
  FileLock* db_lock_;
@@ -385,19 +470,37 @@ class DBImpl : public DB {
  // State below is protected by mutex_
  port::Mutex mutex_;
  port::AtomicPointer shutting_down_;
-  port::CondVar bg_cv_;          // Signalled when background work finishes
-  MemTableRepFactory* mem_rep_factory_;
-  MemTable* mem_;
-  MemTableList imm_;             // Memtable that are not changing
+  // This condition variable is signaled on these conditions:
+  // * whenever bg_compaction_scheduled_ goes down to 0
+  // * if bg_manual_only_ > 0, whenever a compaction finishes, even if it hasn't
+  // made any progress
+  // * whenever a compaction made any progress
+  // * whenever bg_flush_scheduled_ value decreases (i.e. whenever a flush is
+  // done, even if it didn't make any progress)
+  // * whenever there is an error in background flush or compaction
+  // * whenever bg_logstats_scheduled_ turns to false
+  port::CondVar bg_cv_;
  uint64_t logfile_number_;
  unique_ptr<log::Writer> log_;
-
-  SuperVersion* super_version_;
-
-  // An ordinal representing the current SuperVersion. Updated by
-  // InstallSuperVersion(), i.e. incremented every time super_version_
-  // changes.
-  std::atomic<uint64_t> super_version_number_;
+  bool log_empty_;
+  ColumnFamilyHandleImpl* default_cf_handle_;
+  unique_ptr<ColumnFamilyMemTablesImpl> column_family_memtables_;
+  struct LogFileNumberSize {
+    explicit LogFileNumberSize(uint64_t _number)
+        : number(_number), size(0), getting_flushed(false) {}
+    void AddSize(uint64_t new_size) { size += new_size; }
+    uint64_t number;
+    uint64_t size;
+    bool getting_flushed;
+  };
+  std::deque<LogFileNumberSize> alive_log_files_;
+  uint64_t total_log_size_;
+  // only used for dynamically adjusting max_total_wal_size. it is a sum of
+  // [write_buffer_size * max_write_buffer_number] over all column families
+  uint64_t max_total_in_memory_state_;
+  // If true, we have only one (default) column family. We use this to optimize
+  // some code-paths
+  bool single_column_family_mode_;

  std::string host_name_;

@@ -409,9 +512,18 @@ class DBImpl : public DB {

  SnapshotList snapshots_;

+  // cache for ReadFirstRecord() calls
+  std::unordered_map<uint64_t, SequenceNumber> read_first_record_cache_;
+  port::Mutex read_first_record_cache_mutex_;
+
  // Set of table files to protect from deletion because they are
  // part of ongoing compactions.
-  std::set<uint64_t> pending_outputs_;
+  // map from pending file number ID to their path IDs.
+  FileNumToPathIdMap pending_outputs_;
+
+  // At least one compaction or flush job is pending but not yet scheduled
+  // because of the max background thread limit.
+  bool bg_schedule_needed_;

  // count how many background compactions are running or have been scheduled
  int bg_compaction_scheduled_;
@@ -429,6 +541,7 @@ class DBImpl : public DB {

  // Information for a manual compaction
  struct ManualCompaction {
+    ColumnFamilyData* cfd;
    int input_level;
    int output_level;
    bool done;
@@ -468,90 +581,10 @@ class DBImpl : public DB {
  // enabled and archive size_limit is disabled.
  uint64_t default_interval_to_delete_obsolete_WAL_;

-  // These count the number of microseconds for which MakeRoomForWrite stalls.
-  uint64_t stall_level0_slowdown_;
-  uint64_t stall_memtable_compaction_;
-  uint64_t stall_level0_num_files_;
-  std::vector<uint64_t> stall_leveln_slowdown_;
-  uint64_t stall_level0_slowdown_count_;
-  uint64_t stall_memtable_compaction_count_;
-  uint64_t stall_level0_num_files_count_;
-  std::vector<uint64_t> stall_leveln_slowdown_count_;
-
-  // Time at which this instance was started.
-  const uint64_t started_at_;
-
  bool flush_on_destroy_; // Used when disableWAL is true.

-  // Per level compaction stats.  stats_[level] stores the stats for
-  // compactions that produced data for the specified "level".
-  struct CompactionStats {
-    uint64_t micros;
-
-    // Bytes read from level N during compaction between levels N and N+1
-    int64_t bytes_readn;
-
-    // Bytes read from level N+1 during compaction between levels N and N+1
-    int64_t bytes_readnp1;
-
-    // Total bytes written during compaction between levels N and N+1
-    int64_t bytes_written;
-
-    // Files read from level N during compaction between levels N and N+1
-    int     files_in_leveln;
-
-    // Files read from level N+1 during compaction between levels N and N+1
-    int     files_in_levelnp1;
-
-    // Files written during compaction between levels N and N+1
-    int     files_out_levelnp1;
-
-    // Number of compactions done
-    int     count;
-
-    CompactionStats() : micros(0), bytes_readn(0), bytes_readnp1(0),
-                        bytes_written(0), files_in_leveln(0),
-                        files_in_levelnp1(0), files_out_levelnp1(0),
-                        count(0) { }
-
-    void Add(const CompactionStats& c) {
-      this->micros += c.micros;
-      this->bytes_readn += c.bytes_readn;
-      this->bytes_readnp1 += c.bytes_readnp1;
-      this->bytes_written += c.bytes_written;
-      this->files_in_leveln += c.files_in_leveln;
-      this->files_in_levelnp1 += c.files_in_levelnp1;
-      this->files_out_levelnp1 += c.files_out_levelnp1;
-      this->count += 1;
-    }
-  };
-
-  std::vector<CompactionStats> stats_;
-
-  // Used to compute per-interval statistics
-  struct StatsSnapshot {
-    uint64_t compaction_bytes_read_;     // Bytes read by compaction
-    uint64_t compaction_bytes_written_;  // Bytes written by compaction
-    uint64_t ingest_bytes_;              // Bytes written by user
-    uint64_t wal_bytes_;                 // Bytes written to WAL
-    uint64_t wal_synced_;                // Number of times WAL is synced
-    uint64_t write_with_wal_;            // Number of writes that request WAL
-    // These count the number of writes processed by the calling thread or
-    // another thread.
-    uint64_t write_other_;
-    uint64_t write_self_;
-    double   seconds_up_;
-
-    StatsSnapshot() : compaction_bytes_read_(0), compaction_bytes_written_(0),
-                      ingest_bytes_(0), wal_bytes_(0), wal_synced_(0),
-                      write_with_wal_(0), write_other_(0), write_self_(0),
-                      seconds_up_(0) {}
-  };
-
-  // Counters from the previous time per-interval stats were computed
-  StatsSnapshot last_stats_;
-
  static const int KEEP_LOG_FILE_NUM = 1000;
+  static const uint64_t kNoTimeOut = std::numeric_limits<uint64_t>::max();
  std::string db_absolute_path_;

  // count of the number of contiguous delaying writes
@@ -566,6 +599,9 @@ class DBImpl : public DB {
  // Guard against multiple concurrent refitting
  bool refitting_level_;

+  // Indicate DB was opened successfully
+  bool opened_successfully_;
+
  // No copying allowed
  DBImpl(const DBImpl&);
  void operator=(const DBImpl&);
@@ -580,23 +616,23 @@ class DBImpl : public DB {
    std::vector<SequenceNumber>& snapshots,
    SequenceNumber* prev_snapshot);

-  // will return a pointer to SuperVersion* if previous SuperVersion
-  // if its reference count is zero and needs deletion or nullptr if not
-  // As argument takes a pointer to allocated SuperVersion
-  // Foreground threads call this function directly (they don't carry
-  // deletion state and have to handle their own creation and deletion
-  // of SuperVersion)
-  SuperVersion* InstallSuperVersion(SuperVersion* new_superversion);
  // Background threads call this function, which is just a wrapper around
-  // the InstallSuperVersion() function above. Background threads carry
+  // the cfd->InstallSuperVersion() function. Background threads carry
  // deletion_state which can have new_superversion already allocated.
-  void InstallSuperVersion(DeletionState& deletion_state);
+  void InstallSuperVersion(ColumnFamilyData* cfd,
+                           DeletionState& deletion_state);
+
+#ifndef ROCKSDB_LITE
+  using DB::GetPropertiesOfAllTables;
+  virtual Status GetPropertiesOfAllTables(ColumnFamilyHandle* column_family,
+                                          TablePropertiesCollection* props)
+      override;
+#endif  // ROCKSDB_LITE

  // Function that Get and KeyMayExist call with no_io true or false
  // Note: 'value_found' from KeyMayExist propagates here
-  Status GetImpl(const ReadOptions& options,
-                 const Slice& key,
-                 std::string* value,
+  Status GetImpl(const ReadOptions& options, ColumnFamilyHandle* column_family,
+                 const Slice& key, std::string* value,
                 bool* value_found = nullptr);
 };

@@ -606,17 +642,6 @@ extern Options SanitizeOptions(const std::string& db,
                               const InternalKeyComparator* icmp,
                               const InternalFilterPolicy* ipolicy,
                               const Options& src);
-
-
-// Determine compression type, based on user options, level of the output
-// file and whether compression is disabled.
-// 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 Options& options, int level,
-                                   const bool enable_compression);
-
-// Determine compression type for L0 file written by memtable flush.
-CompressionType GetCompressionFlush(const Options& options);
+extern DBOptions SanitizeOptions(const std::string& db, const DBOptions& src);

 }  // namespace rocksdb
@@ -0,0 +1,133 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef ROCKSDB_LITE
+
+#include "db/db_impl.h"
+
+namespace rocksdb {
+
+void DBImpl::TEST_PurgeObsoleteteWAL() { PurgeObsoleteWALFiles(); }
+
+uint64_t DBImpl::TEST_GetLevel0TotalSize() {
+  MutexLock l(&mutex_);
+  return default_cf_handle_->cfd()->current()->NumLevelBytes(0);
+}
+
+Iterator* DBImpl::TEST_NewInternalIterator(ColumnFamilyHandle* column_family) {
+  ColumnFamilyData* cfd;
+  if (column_family == nullptr) {
+    cfd = default_cf_handle_->cfd();
+  } else {
+    auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
+    cfd = cfh->cfd();
+  }
+
+  mutex_.Lock();
+  SuperVersion* super_version = cfd->GetSuperVersion()->Ref();
+  mutex_.Unlock();
+  ReadOptions roptions;
+  return NewInternalIterator(roptions, cfd, super_version);
+}
+
+int64_t DBImpl::TEST_MaxNextLevelOverlappingBytes(
+    ColumnFamilyHandle* column_family) {
+  ColumnFamilyData* cfd;
+  if (column_family == nullptr) {
+    cfd = default_cf_handle_->cfd();
+  } else {
+    auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
+    cfd = cfh->cfd();
+  }
+  MutexLock l(&mutex_);
+  return cfd->current()->MaxNextLevelOverlappingBytes();
+}
+
+void DBImpl::TEST_GetFilesMetaData(
+    ColumnFamilyHandle* column_family,
+    std::vector<std::vector<FileMetaData>>* metadata) {
+  auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
+  auto cfd = cfh->cfd();
+  MutexLock l(&mutex_);
+  metadata->resize(NumberLevels());
+  for (int level = 0; level < NumberLevels(); level++) {
+    const std::vector<FileMetaData*>& files = cfd->current()->files_[level];
+
+    (*metadata)[level].clear();
+    for (const auto& f : files) {
+      (*metadata)[level].push_back(*f);
+    }
+  }
+}
+
+uint64_t DBImpl::TEST_Current_Manifest_FileNo() {
+  return versions_->ManifestFileNumber();
+}
+
+Status DBImpl::TEST_CompactRange(int level, const Slice* begin,
+                                 const Slice* end,
+                                 ColumnFamilyHandle* column_family) {
+  ColumnFamilyData* cfd;
+  if (column_family == nullptr) {
+    cfd = default_cf_handle_->cfd();
+  } else {
+    auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
+    cfd = cfh->cfd();
+  }
+  int output_level =
+      (cfd->options()->compaction_style == kCompactionStyleUniversal ||
+       cfd->options()->compaction_style == kCompactionStyleFIFO)
+          ? level
+          : level + 1;
+  return RunManualCompaction(cfd, level, output_level, begin, end);
+}
+
+Status DBImpl::TEST_FlushMemTable(bool wait) {
+  FlushOptions fo;
+  fo.wait = wait;
+  return FlushMemTable(default_cf_handle_->cfd(), fo);
+}
+
+Status DBImpl::TEST_WaitForFlushMemTable(ColumnFamilyHandle* column_family) {
+  ColumnFamilyData* cfd;
+  if (column_family == nullptr) {
+    cfd = default_cf_handle_->cfd();
+  } else {
+    auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
+    cfd = cfh->cfd();
+  }
+  return WaitForFlushMemTable(cfd);
+}
+
+Status DBImpl::TEST_WaitForCompact() {
+  // 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.
+
+  MutexLock l(&mutex_);
+  while ((bg_compaction_scheduled_ || bg_flush_scheduled_) && bg_error_.ok()) {
+    bg_cv_.Wait();
+  }
+  return bg_error_;
+}
+
+Status DBImpl::TEST_ReadFirstRecord(const WalFileType type,
+                                    const uint64_t number,
+                                    SequenceNumber* sequence) {
+  return ReadFirstRecord(type, number, sequence);
+}
+
+Status DBImpl::TEST_ReadFirstLine(const std::string& fname,
+                                  SequenceNumber* sequence) {
+  return ReadFirstLine(fname, sequence);
+}
+}  // namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -42,8 +42,8 @@

 namespace rocksdb {

-DBImplReadOnly::DBImplReadOnly(const Options& options,
-    const std::string& dbname)
+DBImplReadOnly::DBImplReadOnly(const DBOptions& options,
+                               const std::string& dbname)
    : DBImpl(options, dbname) {
  Log(options_.info_log, "Opening the db in read only mode");
 }
@@ -53,47 +53,100 @@ DBImplReadOnly::~DBImplReadOnly() {

 // Implementations of the DB interface
 Status DBImplReadOnly::Get(const ReadOptions& options,
-                   const Slice& key,
-                   std::string* value) {
+                           ColumnFamilyHandle* column_family, const Slice& key,
+                           std::string* value) {
  Status s;
-  MemTable* mem = GetMemTable();
-  Version* current = versions_->current();
  SequenceNumber snapshot = versions_->LastSequence();
+  auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
+  auto cfd = cfh->cfd();
+  SuperVersion* super_version = cfd->GetSuperVersion();
  MergeContext merge_context;
  LookupKey lkey(key, snapshot);
-  if (mem->Get(lkey, value, &s, merge_context, options_)) {
+  if (super_version->mem->Get(lkey, value, &s, merge_context,
+                              *cfd->options())) {
  } else {
-    Version::GetStats stats;
-    current->Get(options, lkey, value, &s, &merge_context, &stats, options_);
+    super_version->current->Get(options, lkey, value, &s, &merge_context);
  }
  return s;
 }

-Iterator* DBImplReadOnly::NewIterator(const ReadOptions& options) {
-  SequenceNumber latest_snapshot;
-  Iterator* internal_iter = NewInternalIterator(options, &latest_snapshot);
+Iterator* DBImplReadOnly::NewIterator(const ReadOptions& options,
+                                      ColumnFamilyHandle* column_family) {
+  auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
+  auto cfd = cfh->cfd();
+  SuperVersion* super_version = cfd->GetSuperVersion()->Ref();
+  SequenceNumber latest_snapshot = versions_->LastSequence();
+  Iterator* internal_iter = NewInternalIterator(options, cfd, super_version);
  return NewDBIterator(
-    &dbname_, env_, options_,  user_comparator(),internal_iter,
+      env_, *cfd->options(), cfd->user_comparator(), internal_iter,
      (options.snapshot != nullptr
-      ? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
-      : latest_snapshot));
+           ? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
+           : latest_snapshot));
 }

-
 Status DB::OpenForReadOnly(const Options& options, const std::string& dbname,
-                DB** dbptr, bool error_if_log_file_exist) {
+                           DB** dbptr, bool error_if_log_file_exist) {
  *dbptr = nullptr;

-  DBImplReadOnly* impl = new DBImplReadOnly(options, dbname);
+  DBOptions db_options(options);
+  ColumnFamilyOptions cf_options(options);
+  std::vector<ColumnFamilyDescriptor> column_families;
+  column_families.push_back(
+      ColumnFamilyDescriptor(kDefaultColumnFamilyName, cf_options));
+  std::vector<ColumnFamilyHandle*> handles;
+
+  Status s =
+      DB::OpenForReadOnly(db_options, dbname, column_families, &handles, dbptr);
+  if (s.ok()) {
+    assert(handles.size() == 1);
+    // i can delete the handle since DBImpl is always holding a
+    // reference to default column family
+    delete handles[0];
+  }
+  return s;
+}
+
+Status DB::OpenForReadOnly(
+    const DBOptions& db_options, const std::string& dbname,
+    const std::vector<ColumnFamilyDescriptor>& column_families,
+    std::vector<ColumnFamilyHandle*>* handles, DB** dbptr,
+    bool error_if_log_file_exist) {
+  *dbptr = nullptr;
+  handles->clear();
+
+  DBImplReadOnly* impl = new DBImplReadOnly(db_options, dbname);
  impl->mutex_.Lock();
-  Status s = impl->Recover(true /* read only */, error_if_log_file_exist);
+  Status s = impl->Recover(column_families, true /* read only */,
+                           error_if_log_file_exist);
+  if (s.ok()) {
+    // set column family handles
+    for (auto cf : column_families) {
+      auto cfd =
+          impl->versions_->GetColumnFamilySet()->GetColumnFamily(cf.name);
+      if (cfd == nullptr) {
+        s = Status::InvalidArgument("Column family not found: ", cf.name);
+        break;
+      }
+      handles->push_back(new ColumnFamilyHandleImpl(cfd, impl, &impl->mutex_));
+    }
+  }
+  if (s.ok()) {
+    for (auto cfd : *impl->versions_->GetColumnFamilySet()) {
+      delete cfd->InstallSuperVersion(new SuperVersion(), &impl->mutex_);
+    }
+  }
  impl->mutex_.Unlock();
  if (s.ok()) {
    *dbptr = impl;
  } else {
+    for (auto h : *handles) {
+      delete h;
+    }
+    handles->clear();
    delete impl;
  }
  return s;
 }

-}
+
+}   // namespace rocksdb
@@ -12,6 +12,8 @@

 #include <deque>
 #include <set>
+#include <vector>
+#include <string>
 #include "db/dbformat.h"
 #include "db/log_writer.h"
 #include "db/snapshot.h"
@@ -23,57 +25,79 @@
 namespace rocksdb {

 class DBImplReadOnly : public DBImpl {
-public:
-  DBImplReadOnly(const Options& options, const std::string& dbname);
- virtual ~DBImplReadOnly();
+ public:
+  DBImplReadOnly(const DBOptions& options, const std::string& dbname);
+  virtual ~DBImplReadOnly();

- // Implementations of the DB interface
- virtual Status Get(const ReadOptions& options,
-                    const Slice& key,
-                    std::string* value);
+  // Implementations of the DB interface
+  using DB::Get;
+  virtual Status Get(const ReadOptions& options,
+                     ColumnFamilyHandle* column_family, const Slice& key,
+                     std::string* value);

- // TODO: Implement ReadOnly MultiGet?
+  // TODO: Implement ReadOnly MultiGet?

- virtual Iterator* NewIterator(const ReadOptions&);
+  using DBImpl::NewIterator;
+  virtual Iterator* NewIterator(const ReadOptions&,
+                                ColumnFamilyHandle* column_family);

- virtual Status Put(const WriteOptions&, const Slice& key, const Slice& value) {
-   return Status::NotSupported("Not supported operation in read only mode.");
- }
- virtual Status Merge(const WriteOptions&, const Slice& key,
-                      const Slice& value) {
-   return Status::NotSupported("Not supported operation in read only mode.");
- }
- virtual Status Delete(const WriteOptions&, const Slice& key) {
-   return Status::NotSupported("Not supported operation in read only mode.");
- }
- virtual Status Write(const WriteOptions& options, WriteBatch* updates) {
-   return Status::NotSupported("Not supported operation in read only mode.");
- }
- virtual Status CompactRange(const Slice* begin, const Slice* end,
-                             bool reduce_level = false, int target_level = -1) {
-   return Status::NotSupported("Not supported operation in read only mode.");
- }
- virtual Status DisableFileDeletions() {
-   return Status::NotSupported("Not supported operation in read only mode.");
- }
- virtual Status EnableFileDeletions(bool force) {
-   return Status::NotSupported("Not supported operation in read only mode.");
- }
- virtual Status GetLiveFiles(std::vector<std::string>&,
-                             uint64_t* manifest_file_size,
-                             bool flush_memtable = true) {
-   return Status::NotSupported("Not supported operation in read only mode.");
- }
- virtual Status Flush(const FlushOptions& options) {
-   return Status::NotSupported("Not supported operation in read only mode.");
- }
+  virtual Status NewIterators(
+      const ReadOptions& options,
+      const std::vector<ColumnFamilyHandle*>& column_family,
+      std::vector<Iterator*>* iterators) {
+   // TODO
+    return Status::NotSupported("Not supported yet.");
+  }

-private:
- friend class DB;
+  using DBImpl::Put;
+  virtual Status Put(const WriteOptions& options,
+                     ColumnFamilyHandle* column_family, const Slice& key,
+                     const Slice& value) {
+    return Status::NotSupported("Not supported operation in read only mode.");
+  }
+  using DBImpl::Merge;
+  virtual Status Merge(const WriteOptions& options,
+                       ColumnFamilyHandle* column_family, const Slice& key,
+                       const Slice& value) {
+    return Status::NotSupported("Not supported operation in read only mode.");
+  }
+  using DBImpl::Delete;
+  virtual Status Delete(const WriteOptions& options,
+                        ColumnFamilyHandle* column_family, const Slice& key) {
+    return Status::NotSupported("Not supported operation in read only mode.");
+  }
+  virtual Status Write(const WriteOptions& options, WriteBatch* updates) {
+    return Status::NotSupported("Not supported operation in read only mode.");
+  }
+  using DBImpl::CompactRange;
+  virtual Status CompactRange(ColumnFamilyHandle* column_family,
+                              const Slice* begin, const Slice* end,
+                              bool reduce_level = false,
+                              int target_level = -1) {
+    return Status::NotSupported("Not supported operation in read only mode.");
+  }
+  virtual Status DisableFileDeletions() {
+    return Status::NotSupported("Not supported operation in read only mode.");
+  }
+  virtual Status EnableFileDeletions(bool force) {
+    return Status::NotSupported("Not supported operation in read only mode.");
+  }
+  virtual Status GetLiveFiles(std::vector<std::string>&,
+                              uint64_t* manifest_file_size,
+                              bool flush_memtable = true) {
+    return Status::NotSupported("Not supported operation in read only mode.");
+  }
+  using DBImpl::Flush;
+  virtual Status Flush(const FlushOptions& options,
+                       ColumnFamilyHandle* column_family) {
+    return Status::NotSupported("Not supported operation in read only mode.");
+  }

- // No copying allowed
- DBImplReadOnly(const DBImplReadOnly&);
- void operator=(const DBImplReadOnly&);
+ private:
+  friend class DB;
+
+  // No copying allowed
+  DBImplReadOnly(const DBImplReadOnly&);
+  void operator=(const DBImplReadOnly&);
 };
-
 }
@@ -18,6 +18,7 @@
 #include "rocksdb/iterator.h"
 #include "rocksdb/merge_operator.h"
 #include "port/port.h"
+#include "util/arena.h"
 #include "util/logging.h"
 #include "util/mutexlock.h"
 #include "util/perf_context_imp.h"
@@ -37,8 +38,6 @@ static void DumpInternalIter(Iterator* iter) {
 }
 #endif

-namespace {
-
 // Memtables and sstables that make the DB representation contain
 // (userkey,seq,type) => uservalue entries.  DBIter
 // combines multiple entries for the same userkey found in the DB
@@ -57,9 +56,9 @@ class DBIter: public Iterator {
    kReverse
  };

-  DBIter(const std::string* dbname, Env* env, const Options& options,
-         const Comparator* cmp, Iterator* iter, SequenceNumber s)
-      : dbname_(dbname),
+  DBIter(Env* env, const Options& options, const Comparator* cmp,
+         Iterator* iter, SequenceNumber s, bool arena_mode)
+      : arena_mode_(arena_mode),
        env_(env),
        logger_(options.info_log.get()),
        user_comparator_(cmp),
@@ -75,12 +74,20 @@ class DBIter: public Iterator {
  }
  virtual ~DBIter() {
    RecordTick(statistics_, NO_ITERATORS, -1);
-    delete iter_;
+    if (!arena_mode_) {
+      delete iter_;
+    } else {
+      iter_->~Iterator();
+    }
+  }
+  virtual void SetIter(Iterator* iter) {
+    assert(iter_ == nullptr);
+    iter_ = iter;
  }
  virtual bool Valid() const { return valid_; }
  virtual Slice key() const {
    assert(valid_);
-    return saved_key_;
+    return saved_key_.GetKey();
  }
  virtual Slice value() const {
    assert(valid_);
@@ -102,15 +109,12 @@ class DBIter: public Iterator {
  virtual void SeekToLast();

 private:
-  void FindNextUserEntry(bool skipping);
+  inline void FindNextUserEntry(bool skipping);
+  void FindNextUserEntryInternal(bool skipping);
  void FindPrevUserEntry();
  bool ParseKey(ParsedInternalKey* key);
  void MergeValuesNewToOld();

-  inline void SaveKey(const Slice& k, std::string* dst) {
-    dst->assign(k.data(), k.size());
-  }
-
  inline void ClearSavedValue() {
    if (saved_value_.capacity() > 1048576) {
      std::string empty;
@@ -120,18 +124,17 @@ class DBIter: public Iterator {
    }
  }

-  const std::string* const dbname_;
+  bool arena_mode_;
  Env* const env_;
  Logger* logger_;
  const Comparator* const user_comparator_;
  const MergeOperator* const user_merge_operator_;
-  Iterator* const iter_;
+  Iterator* iter_;
  SequenceNumber const sequence_;

  Status status_;
-  std::string saved_key_;     // == current key when direction_==kReverse
+  IterKey saved_key_;   // == current key when direction_==kReverse
  std::string saved_value_;   // == current raw value when direction_==kReverse
-  std::string skip_key_;
  Direction direction_;
  bool valid_;
  bool current_entry_is_merged_;
@@ -169,7 +172,7 @@ void DBIter::Next() {
    }
    if (!iter_->Valid()) {
      valid_ = false;
-      saved_key_.clear();
+      saved_key_.Clear();
      return;
    }
  }
@@ -191,7 +194,14 @@ void DBIter::Next() {
 //
 // NOTE: In between, saved_key_ can point to a user key that has
 //       a delete marker
-void DBIter::FindNextUserEntry(bool skipping) {
+inline void DBIter::FindNextUserEntry(bool skipping) {
+  PERF_TIMER_AUTO(find_next_user_entry_time);
+  FindNextUserEntryInternal(skipping);
+  PERF_TIMER_STOP(find_next_user_entry_time);
+}
+
+// Actual implementation of DBIter::FindNextUserEntry()
+void DBIter::FindNextUserEntryInternal(bool skipping) {
  // Loop until we hit an acceptable entry to yield
  assert(iter_->Valid());
  assert(direction_ == kForward);
@@ -201,32 +211,32 @@ void DBIter::FindNextUserEntry(bool skipping) {
    ParsedInternalKey ikey;
    if (ParseKey(&ikey) && ikey.sequence <= sequence_) {
      if (skipping &&
-          user_comparator_->Compare(ikey.user_key, saved_key_) <= 0) {
+          user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) <= 0) {
        num_skipped++; // skip this entry
-        BumpPerfCount(&perf_context.internal_key_skipped_count);
+        PERF_COUNTER_ADD(internal_key_skipped_count, 1);
      } else {
        skipping = false;
        switch (ikey.type) {
          case kTypeDeletion:
            // Arrange to skip all upcoming entries for this key since
            // they are hidden by this deletion.
-            SaveKey(ikey.user_key, &saved_key_);
+            saved_key_.SetKey(ikey.user_key);
            skipping = true;
            num_skipped = 0;
-            BumpPerfCount(&perf_context.internal_delete_skipped_count);
+            PERF_COUNTER_ADD(internal_delete_skipped_count, 1);
            break;
          case kTypeValue:
            valid_ = true;
-            SaveKey(ikey.user_key, &saved_key_);
+            saved_key_.SetKey(ikey.user_key);
            return;
          case kTypeMerge:
            // By now, we are sure the current ikey is going to yield a value
-            SaveKey(ikey.user_key, &saved_key_);
+            saved_key_.SetKey(ikey.user_key);
            current_entry_is_merged_ = true;
            valid_ = true;
            MergeValuesNewToOld();  // Go to a different state machine
            return;
-          case kTypeLogData:
+          default:
            assert(false);
            break;
        }
@@ -239,8 +249,8 @@ void DBIter::FindNextUserEntry(bool skipping) {
    if (skipping && num_skipped > max_skip_) {
      num_skipped = 0;
      std::string last_key;
-      AppendInternalKey(&last_key,
-        ParsedInternalKey(Slice(saved_key_), 0, kValueTypeForSeek));
+      AppendInternalKey(&last_key, ParsedInternalKey(saved_key_.GetKey(), 0,
+                                                     kValueTypeForSeek));
      iter_->Seek(last_key);
      RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
    } else {
@@ -275,7 +285,7 @@ void DBIter::MergeValuesNewToOld() {
      continue;
    }

-    if (user_comparator_->Compare(ikey.user_key, saved_key_) != 0) {
+    if (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) != 0) {
      // hit the next user key, stop right here
      break;
    }
@@ -304,21 +314,6 @@ void DBIter::MergeValuesNewToOld() {
      // when complete, add result to operands and continue.
      const Slice& value = iter_->value();
      operands.push_front(value.ToString());
-      while(operands.size() >= 2) {
-        // Call user associative-merge until it returns false
-        if (user_merge_operator_->PartialMerge(ikey.user_key,
-                                               Slice(operands[0]),
-                                               Slice(operands[1]),
-                                               &merge_result,
-                                               logger_)) {
-          operands.pop_front();
-          swap(operands.front(), merge_result);
-        } else {
-          // Associative merge returns false ==> stack the operands
-          break;
-        }
-      }
-
    }
  }

@@ -326,7 +321,7 @@ void DBIter::MergeValuesNewToOld() {
  // a deletion marker.
  // feed null as the existing value to the merge operator, such that
  // client can differentiate this scenario and do things accordingly.
-  user_merge_operator_->FullMerge(saved_key_, nullptr, operands,
+  user_merge_operator_->FullMerge(saved_key_.GetKey(), nullptr, operands,
                                  &saved_value_, logger_);
 }

@@ -345,17 +340,17 @@ void DBIter::Prev() {
    // iter_ is pointing at the current entry.  Scan backwards until
    // the key changes so we can use the normal reverse scanning code.
    assert(iter_->Valid());  // Otherwise valid_ would have been false
-    SaveKey(ExtractUserKey(iter_->key()), &saved_key_);
+    saved_key_.SetKey(ExtractUserKey(iter_->key()));
    while (true) {
      iter_->Prev();
      if (!iter_->Valid()) {
        valid_ = false;
-        saved_key_.clear();
+        saved_key_.Clear();
        ClearSavedValue();
        return;
      }
      if (user_comparator_->Compare(ExtractUserKey(iter_->key()),
-                                    saved_key_) < 0) {
+                                    saved_key_.GetKey()) < 0) {
        break;
      }
    }
@@ -370,42 +365,46 @@ void DBIter::FindPrevUserEntry() {
  uint64_t num_skipped = 0;

  ValueType value_type = kTypeDeletion;
+  bool saved_key_valid = true;
  if (iter_->Valid()) {
    do {
      ParsedInternalKey ikey;
-      bool saved_key_cleared = false;
      if (ParseKey(&ikey) && ikey.sequence <= sequence_) {
        if ((value_type != kTypeDeletion) &&
-            user_comparator_->Compare(ikey.user_key, saved_key_) < 0) {
+            user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) < 0) {
          // We encountered a non-deleted value in entries for previous keys,
          break;
        }
        value_type = ikey.type;
        if (value_type == kTypeDeletion) {
-          saved_key_.clear();
+          saved_key_.Clear();
          ClearSavedValue();
-          saved_key_cleared = true;
+          saved_key_valid = false;
        } else {
          Slice raw_value = iter_->value();
          if (saved_value_.capacity() > raw_value.size() + 1048576) {
            std::string empty;
            swap(empty, saved_value_);
          }
-          SaveKey(ExtractUserKey(iter_->key()), &saved_key_);
+          saved_key_.SetKey(ExtractUserKey(iter_->key()));
          saved_value_.assign(raw_value.data(), raw_value.size());
        }
+      } else {
+        // In the case of ikey.sequence > sequence_, we might have already
+        // iterated to a different user key.
+        saved_key_valid = false;
      }
      num_skipped++;
      // If we have sequentially iterated via numerous keys and still not
      // found the prev user-key, then it is better to seek so that we can
      // avoid too many key comparisons. We seek to the first occurence of
      // our current key by looking for max sequence number.
-      if (!saved_key_cleared && num_skipped > max_skip_) {
+      if (saved_key_valid && num_skipped > max_skip_) {
        num_skipped = 0;
        std::string last_key;
-        AppendInternalKey(&last_key,
-          ParsedInternalKey(Slice(saved_key_), kMaxSequenceNumber,
-                            kValueTypeForSeek));
+        AppendInternalKey(&last_key, ParsedInternalKey(saved_key_.GetKey(),
+                                                       kMaxSequenceNumber,
+                                                       kValueTypeForSeek));
        iter_->Seek(last_key);
        RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
      } else {
@@ -417,7 +416,7 @@ void DBIter::FindPrevUserEntry() {
  if (value_type == kTypeDeletion) {
    // End
    valid_ = false;
-    saved_key_.clear();
+    saved_key_.Clear();
    ClearSavedValue();
    direction_ = kForward;
  } else {
@@ -426,13 +425,15 @@ void DBIter::FindPrevUserEntry() {
 }

 void DBIter::Seek(const Slice& target) {
-  direction_ = kForward;
-  ClearSavedValue();
-  saved_key_.clear();
-  AppendInternalKey(
-      &saved_key_, ParsedInternalKey(target, sequence_, kValueTypeForSeek));
-  iter_->Seek(saved_key_);
+  saved_key_.Clear();
+  // now savved_key is used to store internal key.
+  saved_key_.SetInternalKey(target, sequence_);
+  PERF_TIMER_AUTO(seek_internal_seek_time);
+  iter_->Seek(saved_key_.GetKey());
+  PERF_TIMER_STOP(seek_internal_seek_time);
  if (iter_->Valid()) {
+    direction_ = kForward;
+    ClearSavedValue();
    FindNextUserEntry(false /*not skipping */);
  } else {
    valid_ = false;
@@ -442,7 +443,9 @@ void DBIter::Seek(const Slice& target) {
 void DBIter::SeekToFirst() {
  direction_ = kForward;
  ClearSavedValue();
+  PERF_TIMER_AUTO(seek_internal_seek_time);
  iter_->SeekToFirst();
+  PERF_TIMER_STOP(seek_internal_seek_time);
  if (iter_->Valid()) {
    FindNextUserEntry(false /* not skipping */);
  } else {
@@ -461,21 +464,54 @@ void DBIter::SeekToLast() {

  direction_ = kReverse;
  ClearSavedValue();
+  PERF_TIMER_AUTO(seek_internal_seek_time);
  iter_->SeekToLast();
+  PERF_TIMER_STOP(seek_internal_seek_time);
  FindPrevUserEntry();
 }

-}  // anonymous namespace
+Iterator* NewDBIterator(Env* env, const Options& options,
+                        const Comparator* user_key_comparator,
+                        Iterator* internal_iter,
+                        const SequenceNumber& sequence) {
+  return new DBIter(env, options, user_key_comparator, internal_iter, sequence,
+                    false);
+}

-Iterator* NewDBIterator(
-    const std::string* dbname,
-    Env* env,
-    const Options& options,
-    const Comparator *user_key_comparator,
-    Iterator* internal_iter,
+ArenaWrappedDBIter::~ArenaWrappedDBIter() { db_iter_->~DBIter(); }
+
+void ArenaWrappedDBIter::SetDBIter(DBIter* iter) { db_iter_ = iter; }
+
+void ArenaWrappedDBIter::SetIterUnderDBIter(Iterator* iter) {
+  static_cast<DBIter*>(db_iter_)->SetIter(iter);
+}
+
+inline bool ArenaWrappedDBIter::Valid() const { return db_iter_->Valid(); }
+inline void ArenaWrappedDBIter::SeekToFirst() { db_iter_->SeekToFirst(); }
+inline void ArenaWrappedDBIter::SeekToLast() { db_iter_->SeekToLast(); }
+inline void ArenaWrappedDBIter::Seek(const Slice& target) {
+  db_iter_->Seek(target);
+}
+inline void ArenaWrappedDBIter::Next() { db_iter_->Next(); }
+inline void ArenaWrappedDBIter::Prev() { db_iter_->Prev(); }
+inline Slice ArenaWrappedDBIter::key() const { return db_iter_->key(); }
+inline Slice ArenaWrappedDBIter::value() const { return db_iter_->value(); }
+inline Status ArenaWrappedDBIter::status() const { return db_iter_->status(); }
+void ArenaWrappedDBIter::RegisterCleanup(CleanupFunction function, void* arg1,
+                                         void* arg2) {
+  db_iter_->RegisterCleanup(function, arg1, arg2);
+}
+
+ArenaWrappedDBIter* NewArenaWrappedDbIterator(
+    Env* env, const Options& options, const Comparator* user_key_comparator,
    const SequenceNumber& sequence) {
-  return new DBIter(dbname, env, options, user_key_comparator,
-                    internal_iter, sequence);
+  ArenaWrappedDBIter* iter = new ArenaWrappedDBIter();
+  Arena* arena = iter->GetArena();
+  auto mem = arena->AllocateAligned(sizeof(DBIter));
+  DBIter* db_iter = new (mem)
+      DBIter(env, options, user_key_comparator, nullptr, sequence, true);
+  iter->SetDBIter(db_iter);
+  return iter;
 }

 }  // namespace rocksdb
@@ -11,18 +11,63 @@
 #include <stdint.h>
 #include "rocksdb/db.h"
 #include "db/dbformat.h"
+#include "util/arena.h"
+#include "util/autovector.h"

 namespace rocksdb {

+class Arena;
+class DBIter;
+
 // Return a new iterator that converts internal keys (yielded by
 // "*internal_iter") that were live at the specified "sequence" number
 // into appropriate user keys.
 extern Iterator* NewDBIterator(
-    const std::string* dbname,
    Env* env,
    const Options& options,
    const Comparator *user_key_comparator,
    Iterator* internal_iter,
    const SequenceNumber& sequence);

+// A wrapper iterator which wraps DB Iterator and the arena, with which the DB
+// iterator is supposed be allocated. This class is used as an entry point of
+// a iterator hierarchy whose memory can be allocated inline. In that way,
+// accessing the iterator tree can be more cache friendly. It is also faster
+// to allocate.
+class ArenaWrappedDBIter : public Iterator {
+ public:
+  virtual ~ArenaWrappedDBIter();
+
+  // Get the arena to be used to allocate memory for DBIter to be wrapped,
+  // as well as child iterators in it.
+  virtual Arena* GetArena() { return &arena_; }
+
+  // Set the DB Iterator to be wrapped
+
+  virtual void SetDBIter(DBIter* iter);
+
+  // Set the internal iterator wrapped inside the DB Iterator. Usually it is
+  // a merging iterator.
+  virtual void SetIterUnderDBIter(Iterator* iter);
+  virtual bool Valid() const override;
+  virtual void SeekToFirst() override;
+  virtual void SeekToLast() override;
+  virtual void Seek(const Slice& target) override;
+  virtual void Next() override;
+  virtual void Prev() override;
+  virtual Slice key() const override;
+  virtual Slice value() const override;
+  virtual Status status() const override;
+  void RegisterCleanup(CleanupFunction function, void* arg1, void* arg2);
+
+ private:
+  DBIter* db_iter_;
+  Arena arena_;
+};
+
+// Generate the arena wrapped iterator class.
+extern ArenaWrappedDBIter* NewArenaWrappedDbIterator(
+    Env* env, const Options& options, const Comparator* user_key_comparator,
+    const SequenceNumber& sequence);
+
 }  // namespace rocksdb
@@ -20,7 +20,8 @@
 namespace rocksdb {

 void DBImpl::MaybeScheduleLogDBDeployStats() {
-
+// we did say maybe
+#ifndef ROCKSDB_LITE
  // There is a lock in the actual logger.
  if (!logger_ || options_.db_stats_log_interval < 0
      || host_name_.empty()) {
@@ -65,7 +66,7 @@ void DBImpl::LogDBDeployStats() {

  uint64_t file_total_size = 0;
  uint32_t file_total_num = 0;
-  Version* current = versions_->current();
+  Version* current = default_cf_handle_->cfd()->current();
  for (int i = 0; i < current->NumberLevels(); i++) {
    file_total_num += current->NumLevelFiles(i);
    file_total_size += current->NumLevelBytes(i);
@@ -89,6 +90,6 @@ void DBImpl::LogDBDeployStats() {
  bg_logstats_scheduled_ = false;
  bg_cv_.SignalAll();
  mutex_.Unlock();
+#endif
 }
-
 }
@@ -6,16 +6,16 @@
 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
+#include "db/dbformat.h"

 #include <stdio.h>
-#include "db/dbformat.h"
 #include "port/port.h"
 #include "util/coding.h"
 #include "util/perf_context_imp.h"

 namespace rocksdb {

-static uint64_t PackSequenceAndType(uint64_t seq, ValueType t) {
+uint64_t PackSequenceAndType(uint64_t seq, ValueType t) {
  assert(seq <= kMaxSequenceNumber);
  assert(t <= kValueTypeForSeek);
  return (seq << 8) | t;
@@ -59,7 +59,7 @@ int InternalKeyComparator::Compare(const Slice& akey, const Slice& bkey) const {
  //    decreasing sequence number
  //    decreasing type (though sequence# should be enough to disambiguate)
  int r = user_comparator_->Compare(ExtractUserKey(akey), ExtractUserKey(bkey));
-  BumpPerfCount(&perf_context.user_key_comparison_count);
+  PERF_COUNTER_ADD(user_key_comparison_count, 1);
  if (r == 0) {
    const uint64_t anum = DecodeFixed64(akey.data() + akey.size() - 8);
    const uint64_t bnum = DecodeFixed64(bkey.data() + bkey.size() - 8);
@@ -72,6 +72,28 @@ int InternalKeyComparator::Compare(const Slice& akey, const Slice& bkey) const {
  return r;
 }

+int InternalKeyComparator::Compare(const ParsedInternalKey& a,
+                                   const ParsedInternalKey& b) const {
+  // Order by:
+  //    increasing user key (according to user-supplied comparator)
+  //    decreasing sequence number
+  //    decreasing type (though sequence# should be enough to disambiguate)
+  int r = user_comparator_->Compare(a.user_key, b.user_key);
+  PERF_COUNTER_ADD(user_key_comparison_count, 1);
+  if (r == 0) {
+    if (a.sequence > b.sequence) {
+      r = -1;
+    } else if (a.sequence < b.sequence) {
+      r = +1;
+    } else if (a.type > b.type) {
+      r = -1;
+    } else if (a.type < b.type) {
+      r = +1;
+    }
+  }
+  return r;
+}
+
 void InternalKeyComparator::FindShortestSeparator(
      std::string* start,
      const Slice& limit) const {
@@ -13,6 +13,7 @@
 #include "rocksdb/db.h"
 #include "rocksdb/filter_policy.h"
 #include "rocksdb/slice.h"
+#include "rocksdb/slice_transform.h"
 #include "rocksdb/table.h"
 #include "rocksdb/types.h"
 #include "util/coding.h"
@@ -25,12 +26,21 @@ class InternalKey;
 // Value types encoded as the last component of internal keys.
 // DO NOT CHANGE THESE ENUM VALUES: they are embedded in the on-disk
 // data structures.
-enum ValueType {
+// The highest bit of the value type needs to be reserved to SST tables
+// for them to do more flexible encoding.
+enum ValueType : unsigned char {
  kTypeDeletion = 0x0,
  kTypeValue = 0x1,
  kTypeMerge = 0x2,
-  kTypeLogData = 0x3
+  // Following types are used only in write ahead logs. They are not used in
+  // memtables or sst files:
+  kTypeLogData = 0x3,
+  kTypeColumnFamilyDeletion = 0x4,
+  kTypeColumnFamilyValue = 0x5,
+  kTypeColumnFamilyMerge = 0x6,
+  kMaxValue = 0x7F
 };
+
 // kValueTypeForSeek defines the ValueType that should be passed when
 // constructing a ParsedInternalKey object for seeking to a particular
 // sequence number (since we sort sequence numbers in decreasing order
@@ -60,6 +70,8 @@ inline size_t InternalKeyEncodingLength(const ParsedInternalKey& key) {
  return key.user_key.size() + 8;
 }

+extern uint64_t PackSequenceAndType(uint64_t seq, ValueType t);
+
 // Append the serialization of "key" to *result.
 extern void AppendInternalKey(std::string* result,
                              const ParsedInternalKey& key);
@@ -96,6 +108,7 @@ class InternalKeyComparator : public Comparator {
    name_("rocksdb.InternalKeyComparator:" +
          std::string(user_comparator_->Name())) {
  }
+  virtual ~InternalKeyComparator() {}

  virtual const char* Name() const;
  virtual int Compare(const Slice& a, const Slice& b) const;
@@ -107,6 +120,7 @@ class InternalKeyComparator : public Comparator {
  const Comparator* user_comparator() const { return user_comparator_; }

  int Compare(const InternalKey& a, const InternalKey& b) const;
+  int Compare(const ParsedInternalKey& a, const ParsedInternalKey& b) const;
 };

 // Filter policy wrapper that converts from internal keys to user keys
@@ -132,6 +146,11 @@ class InternalKey {
    AppendInternalKey(&rep_, ParsedInternalKey(user_key, s, t));
  }

+  bool Valid() const {
+    ParsedInternalKey parsed;
+    return ParseInternalKey(Slice(rep_), &parsed);
+  }
+
  void DecodeFrom(const Slice& s) { rep_.assign(s.data(), s.size()); }
  Slice Encode() const {
    assert(!rep_.empty());
@@ -163,6 +182,7 @@ inline bool ParseInternalKey(const Slice& internal_key,
  unsigned char c = num & 0xff;
  result->sequence = num >> 8;
  result->type = static_cast<ValueType>(c);
+  assert(result->type <= ValueType::kMaxValue);
  result->user_key = Slice(internal_key.data(), n - 8);
  return (c <= static_cast<unsigned char>(kValueTypeForSeek));
 }
@@ -226,4 +246,128 @@ inline LookupKey::~LookupKey() {
  if (start_ != space_) delete[] start_;
 }

+class IterKey {
+ public:
+  IterKey() : key_(space_), buf_size_(sizeof(space_)), key_size_(0) {}
+
+  ~IterKey() { ResetBuffer(); }
+
+  Slice GetKey() const { return Slice(key_, key_size_); }
+
+  void Clear() { key_size_ = 0; }
+
+  void SetKey(const Slice& key) {
+    size_t size = key.size();
+    EnlargeBufferIfNeeded(size);
+    memcpy(key_, key.data(), size);
+    key_size_ = size;
+  }
+
+  void SetInternalKey(const Slice& key_prefix, const Slice& user_key,
+                      SequenceNumber s,
+                      ValueType value_type = kValueTypeForSeek) {
+    size_t psize = key_prefix.size();
+    size_t usize = user_key.size();
+    EnlargeBufferIfNeeded(psize + usize + sizeof(uint64_t));
+    if (psize > 0) {
+      memcpy(key_, key_prefix.data(), psize);
+    }
+    memcpy(key_ + psize, user_key.data(), usize);
+    EncodeFixed64(key_ + usize + psize, PackSequenceAndType(s, value_type));
+    key_size_ = psize + usize + sizeof(uint64_t);
+  }
+
+  void SetInternalKey(const Slice& user_key, SequenceNumber s,
+                      ValueType value_type = kValueTypeForSeek) {
+    SetInternalKey(Slice(), user_key, s, value_type);
+  }
+
+  void Reserve(size_t size) {
+    EnlargeBufferIfNeeded(size);
+    key_size_ = size;
+  }
+
+  void SetInternalKey(const ParsedInternalKey& parsed_key) {
+    SetInternalKey(Slice(), parsed_key);
+  }
+
+  void SetInternalKey(const Slice& key_prefix,
+                      const ParsedInternalKey& parsed_key_suffix) {
+    SetInternalKey(key_prefix, parsed_key_suffix.user_key,
+                   parsed_key_suffix.sequence, parsed_key_suffix.type);
+  }
+
+  void EncodeLengthPrefixedKey(const Slice& key) {
+    auto size = key.size();
+    EnlargeBufferIfNeeded(size + VarintLength(size));
+    char* ptr = EncodeVarint32(key_, size);
+    memcpy(ptr, key.data(), size);
+  }
+
+ private:
+  char* key_;
+  size_t buf_size_;
+  size_t key_size_;
+  char space_[32];  // Avoid allocation for short keys
+
+  void ResetBuffer() {
+    if (key_ != nullptr && key_ != space_) {
+      delete[] key_;
+    }
+    key_ = space_;
+    buf_size_ = sizeof(space_);
+    key_size_ = 0;
+  }
+
+  // Enlarge the buffer size if needed based on key_size.
+  // By default, static allocated buffer is used. Once there is a key
+  // larger than the static allocated buffer, another buffer is dynamically
+  // allocated, until a larger key buffer is requested. In that case, we
+  // reallocate buffer and delete the old one.
+  void EnlargeBufferIfNeeded(size_t key_size) {
+    // If size is smaller than buffer size, continue using current buffer,
+    // or the static allocated one, as default
+    if (key_size > buf_size_) {
+      // Need to enlarge the buffer.
+      ResetBuffer();
+      key_ = new char[key_size];
+      buf_size_ = key_size;
+    }
+  }
+
+  // No copying allowed
+  IterKey(const IterKey&) = delete;
+  void operator=(const IterKey&) = delete;
+};
+
+class InternalKeySliceTransform : public SliceTransform {
+ public:
+  explicit InternalKeySliceTransform(const SliceTransform* transform)
+      : transform_(transform) {}
+
+  virtual const char* Name() const { return transform_->Name(); }
+
+  virtual Slice Transform(const Slice& src) const {
+    auto user_key = ExtractUserKey(src);
+    return transform_->Transform(user_key);
+  }
+
+  virtual bool InDomain(const Slice& src) const {
+    auto user_key = ExtractUserKey(src);
+    return transform_->InDomain(user_key);
+  }
+
+  virtual bool InRange(const Slice& dst) const {
+    auto user_key = ExtractUserKey(dst);
+    return transform_->InRange(user_key);
+  }
+
+  const SliceTransform* user_prefix_extractor() const { return transform_; }
+
+ private:
+  // Like comparator, InternalKeySliceTransform will not take care of the
+  // deletion of transform_
+  const SliceTransform* const transform_;
+};
+
 }  // namespace rocksdb
@@ -0,0 +1,202 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include "db/file_indexer.h"
+#include <algorithm>
+#include "rocksdb/comparator.h"
+#include "db/version_edit.h"
+
+namespace rocksdb {
+
+FileIndexer::FileIndexer(const uint32_t num_levels,
+                         const Comparator* ucmp)
+  : num_levels_(num_levels),
+    ucmp_(ucmp),
+    next_level_index_(num_levels),
+    level_rb_(num_levels, -1) {
+}
+
+
+uint32_t FileIndexer::NumLevelIndex() {
+  return next_level_index_.size();
+}
+
+uint32_t FileIndexer::LevelIndexSize(uint32_t level) {
+  return next_level_index_[level].size();
+}
+
+void FileIndexer::GetNextLevelIndex(
+    const uint32_t level, const uint32_t file_index, const int cmp_smallest,
+    const int cmp_largest, int32_t* left_bound, int32_t* right_bound) {
+  assert(level > 0);
+
+  // Last level, no hint
+  if (level == num_levels_ - 1) {
+    *left_bound = 0;
+    *right_bound = -1;
+    return;
+  }
+
+  assert(level < num_levels_ - 1);
+  assert(static_cast<int32_t>(file_index) <= level_rb_[level]);
+
+  const auto& index = next_level_index_[level][file_index];
+
+  if (cmp_smallest < 0) {
+    *left_bound = (level > 0 && file_index > 0) ?
+      next_level_index_[level][file_index - 1].largest_lb : 0;
+    *right_bound = index.smallest_rb;
+  } else if (cmp_smallest == 0) {
+    *left_bound = index.smallest_lb;
+    *right_bound = index.smallest_rb;
+  } else if (cmp_smallest > 0 && cmp_largest < 0) {
+    *left_bound = index.smallest_lb;
+    *right_bound = index.largest_rb;
+  } else if (cmp_largest == 0) {
+    *left_bound = index.largest_lb;
+    *right_bound = index.largest_rb;
+  } else if (cmp_largest > 0) {
+    *left_bound = index.largest_lb;
+    *right_bound = level_rb_[level + 1];
+  } else {
+    assert(false);
+  }
+
+  assert(*left_bound >= 0);
+  assert(*left_bound <= *right_bound + 1);
+  assert(*right_bound <= level_rb_[level + 1]);
+}
+
+void FileIndexer::ClearIndex() {
+  for (uint32_t level = 1; level < num_levels_; ++level) {
+    next_level_index_[level].clear();
+  }
+}
+
+void FileIndexer::UpdateIndex(std::vector<FileMetaData*>* const files) {
+  if (files == nullptr) {
+    return;
+  }
+
+  // L1 - Ln-1
+  for (uint32_t level = 1; level < num_levels_ - 1; ++level) {
+    const auto& upper_files = files[level];
+    const int32_t upper_size = upper_files.size();
+    const auto& lower_files = files[level + 1];
+    level_rb_[level] = upper_files.size() - 1;
+    if (upper_size == 0) {
+      continue;
+    }
+    auto& index = next_level_index_[level];
+    index.resize(upper_size);
+
+    CalculateLB(upper_files, lower_files, &index,
+        [this](const FileMetaData* a, const FileMetaData* b) -> int {
+          return ucmp_->Compare(a->smallest.user_key(), b->largest.user_key());
+        },
+        [](IndexUnit* index, int32_t f_idx) {
+          index->smallest_lb = f_idx;
+        });
+    CalculateLB(upper_files, lower_files, &index,
+        [this](const FileMetaData* a, const FileMetaData* b) -> int {
+          return ucmp_->Compare(a->largest.user_key(), b->largest.user_key());
+        },
+        [](IndexUnit* index, int32_t f_idx) {
+          index->largest_lb = f_idx;
+        });
+    CalculateRB(upper_files, lower_files, &index,
+        [this](const FileMetaData* a, const FileMetaData* b) -> int {
+          return ucmp_->Compare(a->smallest.user_key(), b->smallest.user_key());
+        },
+        [](IndexUnit* index, int32_t f_idx) {
+          index->smallest_rb = f_idx;
+        });
+    CalculateRB(upper_files, lower_files, &index,
+        [this](const FileMetaData* a, const FileMetaData* b) -> int {
+          return ucmp_->Compare(a->largest.user_key(), b->smallest.user_key());
+        },
+        [](IndexUnit* index, int32_t f_idx) {
+          index->largest_rb = f_idx;
+        });
+  }
+  level_rb_[num_levels_ - 1] = files[num_levels_ - 1].size() - 1;
+}
+
+void FileIndexer::CalculateLB(const std::vector<FileMetaData*>& upper_files,
+    const std::vector<FileMetaData*>& lower_files,
+    std::vector<IndexUnit>* index,
+    std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
+    std::function<void(IndexUnit*, int32_t)> set_index) {
+  const int32_t upper_size = upper_files.size();
+  const int32_t lower_size = lower_files.size();
+  int32_t upper_idx = 0;
+  int32_t lower_idx = 0;
+  while (upper_idx < upper_size && lower_idx < lower_size) {
+    int cmp = cmp_op(upper_files[upper_idx], lower_files[lower_idx]);
+
+    if (cmp == 0) {
+      set_index(&(*index)[upper_idx], lower_idx);
+      ++upper_idx;
+      ++lower_idx;
+    } else if (cmp > 0) {
+      // Lower level's file (largest) is smaller, a key won't hit in that
+      // file. Move to next lower file
+      ++lower_idx;
+    } else {
+      // Lower level's file becomes larger, update the index, and
+      // move to the next upper file
+      set_index(&(*index)[upper_idx], lower_idx);
+      ++upper_idx;
+    }
+  }
+
+  while (upper_idx < upper_size) {
+    // Lower files are exhausted, that means the remaining upper files are
+    // greater than any lower files. Set the index to be the lower level size.
+    set_index(&(*index)[upper_idx], lower_size);
+    ++upper_idx;
+  }
+}
+
+void FileIndexer::CalculateRB(const std::vector<FileMetaData*>& upper_files,
+    const std::vector<FileMetaData*>& lower_files,
+    std::vector<IndexUnit>* index,
+    std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
+    std::function<void(IndexUnit*, int32_t)> set_index) {
+  const int32_t upper_size = upper_files.size();
+  const int32_t lower_size = lower_files.size();
+  int32_t upper_idx = upper_size - 1;
+  int32_t lower_idx = lower_size - 1;
+  while (upper_idx >= 0 && lower_idx >= 0) {
+    int cmp = cmp_op(upper_files[upper_idx], lower_files[lower_idx]);
+
+    if (cmp == 0) {
+      set_index(&(*index)[upper_idx], lower_idx);
+      --upper_idx;
+      --lower_idx;
+    } else if (cmp < 0) {
+      // Lower level's file (smallest) is larger, a key won't hit in that
+      // file. Move to next lower file.
+      --lower_idx;
+    } else {
+      // Lower level's file becomes smaller, update the index, and move to
+      // the next the upper file
+      set_index(&(*index)[upper_idx], lower_idx);
+      --upper_idx;
+    }
+  }
+  while (upper_idx >= 0) {
+    // Lower files are exhausted, that means the remaining upper files are
+    // smaller than any lower files. Set it to -1.
+    set_index(&(*index)[upper_idx], -1);
+    --upper_idx;
+  }
+}
+
+}  // namespace rocksdb
@@ -0,0 +1,129 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#pragma once
+#include <cstdint>
+#include <functional>
+#include <limits>
+#include <vector>
+
+namespace rocksdb {
+
+class Comparator;
+struct FileMetaData;
+
+// The file tree structure in Version is prebuilt and the range of each file
+// is known. On Version::Get(), it uses binary search to find a potential file
+// and then check if a target key can be found in the file by comparing the key
+// to each file's smallest and largest key. The results of these comparisions
+// can be reused beyond checking if a key falls into a file's range.
+// With some pre-calculated knowledge, each key comparision that has been done
+// can serve as a hint to narrow down further searches: if a key compared to
+// be smaller than a file's smallest or largest, that comparison can be used
+// to find out the right bound of next binary search. Similarly, if a key
+// compared to be larger than a file's smallest or largest, it can be utilized
+// to find out the left bound of next binary search.
+// With these hints: it can greatly reduce the range of binary search,
+// especially for bottom levels, given that one file most likely overlaps with
+// only N files from level below (where N is max_bytes_for_level_multiplier).
+// So on level L, we will only look at ~N files instead of N^L files on the
+// naive approach.
+class FileIndexer {
+ public:
+  FileIndexer(const uint32_t num_levels, const Comparator* ucmp);
+
+  uint32_t NumLevelIndex();
+
+  uint32_t LevelIndexSize(uint32_t level);
+
+  // Return a file index range in the next level to search for a key based on
+  // smallest and largest key comparision for the current file specified by
+  // level and file_index. When *left_index < *right_index, both index should
+  // be valid and fit in the vector size.
+  void GetNextLevelIndex(
+    const uint32_t level, const uint32_t file_index, const int cmp_smallest,
+    const int cmp_largest, int32_t* left_bound, int32_t* right_bound);
+
+  void ClearIndex();
+
+  void UpdateIndex(std::vector<FileMetaData*>* const files);
+
+  enum {
+    kLevelMaxIndex = std::numeric_limits<int32_t>::max()
+  };
+
+ private:
+  const uint32_t num_levels_;
+  const Comparator* ucmp_;
+
+  struct IndexUnit {
+    IndexUnit()
+      : smallest_lb(0), largest_lb(0), smallest_rb(-1), largest_rb(-1) {}
+    // During file search, a key is compared against smallest and largest
+    // from a FileMetaData. It can have 3 possible outcomes:
+    // (1) key is smaller than smallest, implying it is also smaller than
+    //     larger. Precalculated index based on "smallest < smallest" can
+    //     be used to provide right bound.
+    // (2) key is in between smallest and largest.
+    //     Precalculated index based on "smallest > greatest" can be used to
+    //     provide left bound.
+    //     Precalculated index based on "largest < smallest" can be used to
+    //     provide right bound.
+    // (3) key is larger than largest, implying it is also larger than smallest.
+    //     Precalculated index based on "largest > largest" can be used to
+    //     provide left bound.
+    //
+    // As a result, we will need to do:
+    // Compare smallest (<=) and largest keys from upper level file with
+    // smallest key from lower level to get a right bound.
+    // Compare smallest (>=) and largest keys from upper level file with
+    // largest key from lower level to get a left bound.
+    //
+    // Example:
+    //    level 1:              [50 - 60]
+    //    level 2:        [1 - 40], [45 - 55], [58 - 80]
+    // A key 35, compared to be less than 50, 3rd file on level 2 can be
+    // skipped according to rule (1). LB = 0, RB = 1.
+    // A key 53, sits in the middle 50 and 60. 1st file on level 2 can be
+    // skipped according to rule (2)-a, but the 3rd file cannot be skipped
+    // because 60 is greater than 58. LB = 1, RB = 2.
+    // A key 70, compared to be larger than 60. 1st and 2nd file can be skipped
+    // according to rule (3). LB = 2, RB = 2.
+    //
+    // Point to a left most file in a lower level that may contain a key,
+    // which compares greater than smallest of a FileMetaData (upper level)
+    int32_t smallest_lb;
+    // Point to a left most file in a lower level that may contain a key,
+    // which compares greater than largest of a FileMetaData (upper level)
+    int32_t largest_lb;
+    // Point to a right most file in a lower level that may contain a key,
+    // which compares smaller than smallest of a FileMetaData (upper level)
+    int32_t smallest_rb;
+    // Point to a right most file in a lower level that may contain a key,
+    // which compares smaller than largest of a FileMetaData (upper level)
+    int32_t largest_rb;
+  };
+
+  void CalculateLB(const std::vector<FileMetaData*>& upper_files,
+    const std::vector<FileMetaData*>& lower_files,
+    std::vector<IndexUnit>* index,
+    std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
+    std::function<void(IndexUnit*, int32_t)> set_index);
+
+  void CalculateRB(const std::vector<FileMetaData*>& upper_files,
+    const std::vector<FileMetaData*>& lower_files,
+    std::vector<IndexUnit>* index,
+    std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
+    std::function<void(IndexUnit*, int32_t)> set_index);
+
+  std::vector<std::vector<IndexUnit>> next_level_index_;
+  std::vector<int32_t> level_rb_;
+};
+
+}  // namespace rocksdb
@@ -0,0 +1,330 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include <string>
+#include "db/file_indexer.h"
+#include "db/dbformat.h"
+#include "db/version_edit.h"
+#include "rocksdb/comparator.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+namespace rocksdb {
+
+class IntComparator : public Comparator {
+ public:
+  int Compare(const Slice& a, const Slice& b) const {
+    assert(a.size() == 8);
+    assert(b.size() == 8);
+    return *reinterpret_cast<const int64_t*>(a.data()) -
+      *reinterpret_cast<const int64_t*>(b.data());
+  }
+
+  const char* Name() const {
+    return "IntComparator";
+  }
+
+  void FindShortestSeparator(std::string* start, const Slice& limit) const {}
+
+  void FindShortSuccessor(std::string* key) const {}
+};
+
+
+struct FileIndexerTest {
+ public:
+  FileIndexerTest() :
+    kNumLevels(4), indexer(kNumLevels, &ucmp),
+    files(new std::vector<FileMetaData*>[kNumLevels]) {
+  }
+
+  ~FileIndexerTest() {
+    Reset();
+    delete[] files;
+  }
+
+  void AddFile(int level, int64_t smallest, int64_t largest) {
+    auto* f = new FileMetaData();
+    f->smallest = IntKey(smallest);
+    f->largest = IntKey(largest);
+    files[level].push_back(f);
+  }
+
+  InternalKey IntKey(int64_t v) {
+    return InternalKey(Slice(reinterpret_cast<char*>(&v), 8), 0, kTypeValue);
+  }
+
+  void Reset() {
+    for (uint32_t i = 0; i < kNumLevels; ++i) {
+      for (auto* f : files[i]) {
+        delete f;
+      }
+      files[i].clear();
+    }
+    indexer.ClearIndex();
+  }
+
+  void GetNextLevelIndex(const uint32_t level, const uint32_t file_index,
+      const int cmp_smallest, const int cmp_largest, int32_t* left_index,
+      int32_t* right_index) {
+    *left_index = 100;
+    *right_index = 100;
+    indexer.GetNextLevelIndex(level, file_index, cmp_smallest, cmp_largest,
+        left_index, right_index);
+  }
+
+  const uint32_t kNumLevels;
+  IntComparator ucmp;
+  FileIndexer indexer;
+
+  std::vector<FileMetaData*>* files;
+};
+
+TEST(FileIndexerTest, next_level_hint) {
+  for (uint32_t i = 0; i < kNumLevels; ++i) {
+    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
+  }
+
+  // Case 1: no overlap, files are on the left of next level files
+  // level 1
+  AddFile(1, 100, 200);
+  AddFile(1, 300, 400);
+  AddFile(1, 500, 600);
+  // level 2
+  AddFile(2, 1500, 1600);
+  AddFile(2, 1601, 1699);
+  AddFile(2, 1700, 1800);
+  // level 3
+  AddFile(3, 2500, 2600);
+  AddFile(3, 2601, 2699);
+  AddFile(3, 2700, 2800);
+  indexer.UpdateIndex(files);
+  int32_t left = 100;
+  int32_t right = 100;
+  for (uint32_t level = 1; level < 3; ++level) {
+    for (uint32_t f = 0; f < 3; ++f) {
+      GetNextLevelIndex(level, f, -1, -1, &left, &right);
+      ASSERT_EQ(0, left);
+      ASSERT_EQ(-1, right);
+      GetNextLevelIndex(level, f, 0, -1, &left, &right);
+      ASSERT_EQ(0, left);
+      ASSERT_EQ(-1, right);
+      GetNextLevelIndex(level, f, 1, -1, &left, &right);
+      ASSERT_EQ(0, left);
+      ASSERT_EQ(-1, right);
+      GetNextLevelIndex(level, f, 1, 0, &left, &right);
+      ASSERT_EQ(0, left);
+      ASSERT_EQ(-1, right);
+      GetNextLevelIndex(level, f, 1, 1, &left, &right);
+      ASSERT_EQ(0, left);
+      ASSERT_EQ(2, right);
+    }
+  }
+
+  // Case 2: no overlap, files are on the right of next level files
+  Reset();
+  for (uint32_t i = 1; i < kNumLevels; ++i) {
+    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
+  }
+  // level 1
+  AddFile(1, 2100, 2200);
+  AddFile(1, 2300, 2400);
+  AddFile(1, 2500, 2600);
+  // level 2
+  AddFile(2, 1500, 1600);
+  AddFile(2, 1501, 1699);
+  AddFile(2, 1700, 1800);
+  // level 3
+  AddFile(3, 500, 600);
+  AddFile(3, 501, 699);
+  AddFile(3, 700, 800);
+  indexer.UpdateIndex(files);
+  for (uint32_t level = 1; level < 3; ++level) {
+    for (uint32_t f = 0; f < 3; ++f) {
+      GetNextLevelIndex(level, f, -1, -1, &left, &right);
+      ASSERT_EQ(f == 0 ? 0 : 3, left);
+      ASSERT_EQ(2, right);
+      GetNextLevelIndex(level, f, 0, -1, &left, &right);
+      ASSERT_EQ(3, left);
+      ASSERT_EQ(2, right);
+      GetNextLevelIndex(level, f, 1, -1, &left, &right);
+      ASSERT_EQ(3, left);
+      ASSERT_EQ(2, right);
+      GetNextLevelIndex(level, f, 1, -1, &left, &right);
+      ASSERT_EQ(3, left);
+      ASSERT_EQ(2, right);
+      GetNextLevelIndex(level, f, 1, 0, &left, &right);
+      ASSERT_EQ(3, left);
+      ASSERT_EQ(2, right);
+      GetNextLevelIndex(level, f, 1, 1, &left, &right);
+      ASSERT_EQ(3, left);
+      ASSERT_EQ(2, right);
+    }
+  }
+
+  // Case 3: empty L2
+  Reset();
+  for (uint32_t i = 1; i < kNumLevels; ++i) {
+    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
+  }
+  // level 1
+  AddFile(1, 2100, 2200);
+  AddFile(1, 2300, 2400);
+  AddFile(1, 2500, 2600);
+  // level 3
+  AddFile(3, 500, 600);
+  AddFile(3, 501, 699);
+  AddFile(3, 700, 800);
+  indexer.UpdateIndex(files);
+  for (uint32_t f = 0; f < 3; ++f) {
+    GetNextLevelIndex(1, f, -1, -1, &left, &right);
+    ASSERT_EQ(0, left);
+    ASSERT_EQ(-1, right);
+    GetNextLevelIndex(1, f, 0, -1, &left, &right);
+    ASSERT_EQ(0, left);
+    ASSERT_EQ(-1, right);
+    GetNextLevelIndex(1, f, 1, -1, &left, &right);
+    ASSERT_EQ(0, left);
+    ASSERT_EQ(-1, right);
+    GetNextLevelIndex(1, f, 1, -1, &left, &right);
+    ASSERT_EQ(0, left);
+    ASSERT_EQ(-1, right);
+    GetNextLevelIndex(1, f, 1, 0, &left, &right);
+    ASSERT_EQ(0, left);
+    ASSERT_EQ(-1, right);
+    GetNextLevelIndex(1, f, 1, 1, &left, &right);
+    ASSERT_EQ(0, left);
+    ASSERT_EQ(-1, right);
+  }
+
+
+  // Case 4: mixed
+  Reset();
+  for (uint32_t i = 1; i < kNumLevels; ++i) {
+    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
+  }
+  // level 1
+  AddFile(1, 100, 200);
+  AddFile(1, 250, 400);
+  AddFile(1, 450, 500);
+  // level 2
+  AddFile(2, 100, 150);  // 0
+  AddFile(2, 200, 250);  // 1
+  AddFile(2, 251, 300);  // 2
+  AddFile(2, 301, 350);  // 3
+  AddFile(2, 500, 600);  // 4
+  // level 3
+  AddFile(3, 0, 50);
+  AddFile(3, 100, 200);
+  AddFile(3, 201, 250);
+  indexer.UpdateIndex(files);
+  // level 1, 0
+  GetNextLevelIndex(1, 0, -1, -1, &left, &right);
+  ASSERT_EQ(0, left);
+  ASSERT_EQ(0, right);
+  GetNextLevelIndex(1, 0, 0, -1, &left, &right);
+  ASSERT_EQ(0, left);
+  ASSERT_EQ(0, right);
+  GetNextLevelIndex(1, 0, 1, -1, &left, &right);
+  ASSERT_EQ(0, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(1, 0, 1, 0, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(1, 0, 1, 1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(4, right);
+  // level 1, 1
+  GetNextLevelIndex(1, 1, -1, -1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(1, 1, 0, -1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(1, 1, 1, -1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(3, right);
+  GetNextLevelIndex(1, 1, 1, 0, &left, &right);
+  ASSERT_EQ(4, left);
+  ASSERT_EQ(3, right);
+  GetNextLevelIndex(1, 1, 1, 1, &left, &right);
+  ASSERT_EQ(4, left);
+  ASSERT_EQ(4, right);
+  // level 1, 2
+  GetNextLevelIndex(1, 2, -1, -1, &left, &right);
+  ASSERT_EQ(4, left);
+  ASSERT_EQ(3, right);
+  GetNextLevelIndex(1, 2, 0, -1, &left, &right);
+  ASSERT_EQ(4, left);
+  ASSERT_EQ(3, right);
+  GetNextLevelIndex(1, 2, 1, -1, &left, &right);
+  ASSERT_EQ(4, left);
+  ASSERT_EQ(4, right);
+  GetNextLevelIndex(1, 2, 1, 0, &left, &right);
+  ASSERT_EQ(4, left);
+  ASSERT_EQ(4, right);
+  GetNextLevelIndex(1, 2, 1, 1, &left, &right);
+  ASSERT_EQ(4, left);
+  ASSERT_EQ(4, right);
+  // level 2, 0
+  GetNextLevelIndex(2, 0, -1, -1, &left, &right);
+  ASSERT_EQ(0, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(2, 0, 0, -1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(2, 0, 1, -1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(2, 0, 1, 0, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(2, 0, 1, 1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(2, right);
+  // level 2, 1
+  GetNextLevelIndex(2, 1, -1, -1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(2, 1, 0, -1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(1, right);
+  GetNextLevelIndex(2, 1, 1, -1, &left, &right);
+  ASSERT_EQ(1, left);
+  ASSERT_EQ(2, right);
+  GetNextLevelIndex(2, 1, 1, 0, &left, &right);
+  ASSERT_EQ(2, left);
+  ASSERT_EQ(2, right);
+  GetNextLevelIndex(2, 1, 1, 1, &left, &right);
+  ASSERT_EQ(2, left);
+  ASSERT_EQ(2, right);
+  // level 2, [2 - 4], no overlap
+  for (uint32_t f = 2; f <= 4; ++f) {
+    GetNextLevelIndex(2, f, -1, -1, &left, &right);
+    ASSERT_EQ(f == 2 ? 2 : 3, left);
+    ASSERT_EQ(2, right);
+    GetNextLevelIndex(2, f, 0, -1, &left, &right);
+    ASSERT_EQ(3, left);
+    ASSERT_EQ(2, right);
+    GetNextLevelIndex(2, f, 1, -1, &left, &right);
+    ASSERT_EQ(3, left);
+    ASSERT_EQ(2, right);
+    GetNextLevelIndex(2, f, 1, 0, &left, &right);
+    ASSERT_EQ(3, left);
+    ASSERT_EQ(2, right);
+    GetNextLevelIndex(2, f, 1, 1, &left, &right);
+    ASSERT_EQ(3, left);
+    ASSERT_EQ(2, right);
+  }
+}
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  return rocksdb::test::RunAllTests();
+}
@@ -11,6 +11,7 @@

 #include <ctype.h>
 #include <stdio.h>
+#include <vector>
 #include "db/dbformat.h"
 #include "rocksdb/env.h"
 #include "util/logging.h"
@@ -44,10 +45,6 @@ static int FlattenPath(const std::string& path, char* dest, int len) {
  return write_idx;
 }

-// A utility routine: write "data" to the named file and Sync() it.
-extern Status WriteStringToFileSync(Env* env, const Slice& data,
-                                    const std::string& fname);
-
 static std::string MakeFileName(const std::string& name, uint64_t number,
                                const char* suffix) {
  char buf[100];
@@ -70,9 +67,28 @@ std::string ArchivedLogFileName(const std::string& name, uint64_t number) {
  return MakeFileName(name + "/" + ARCHIVAL_DIR, number, "log");
 }

-std::string TableFileName(const std::string& name, uint64_t number) {
+std::string MakeTableFileName(const std::string& path, uint64_t number) {
+  return MakeFileName(path, number, "sst");
+}
+
+std::string TableFileName(const std::vector<std::string> db_paths,
+                          uint64_t number, uint32_t path_id) {
  assert(number > 0);
-  return MakeFileName(name, number, "sst");
+  std::string path;
+  if (path_id >= db_paths.size()) {
+    path = db_paths.back();
+  } else {
+    path = db_paths[path_id];
+  }
+  return MakeTableFileName(path, number);
+}
+
+std::string FormatFileNumber(uint64_t number, uint32_t path_id) {
+  if (path_id == 0) {
+    return std::to_string(number);
+  } else {
+    return std::to_string(number) + "(path " + std::to_string(path_id) + ")";
+  }
 }

 std::string DescriptorFileName(const std::string& dbname, uint64_t number) {
@@ -92,7 +108,6 @@ std::string LockFileName(const std::string& dbname) {
 }

 std::string TempFileName(const std::string& dbname, uint64_t number) {
-  assert(number >= 0);
  return MakeFileName(dbname, number, "dbtmp");
 }

@@ -231,18 +246,23 @@ bool ParseFileName(const std::string& fname,
 }

 Status SetCurrentFile(Env* env, const std::string& dbname,
-                      uint64_t descriptor_number) {
+                      uint64_t descriptor_number,
+                      Directory* directory_to_fsync) {
  // Remove leading "dbname/" and add newline to manifest file name
  std::string manifest = DescriptorFileName(dbname, descriptor_number);
  Slice contents = manifest;
  assert(contents.starts_with(dbname + "/"));
  contents.remove_prefix(dbname.size() + 1);
  std::string tmp = TempFileName(dbname, descriptor_number);
-  Status s = WriteStringToFileSync(env, contents.ToString() + "\n", tmp);
+  Status s = WriteStringToFile(env, contents.ToString() + "\n", tmp, true);
  if (s.ok()) {
    s = env->RenameFile(tmp, CurrentFileName(dbname));
  }
-  if (!s.ok()) {
+  if (s.ok()) {
+    if (directory_to_fsync != nullptr) {
+      directory_to_fsync->Fsync();
+    }
+  } else {
    env->DeleteFile(tmp);
  }
  return s;
@@ -253,7 +273,7 @@ Status SetIdentityFile(Env* env, const std::string& dbname) {
  assert(!id.empty());
  // Reserve the filename dbname/000000.dbtmp for the temporary identity file
  std::string tmp = TempFileName(dbname, 0);
-  Status s = WriteStringToFileSync(env, id, tmp);
+  Status s = WriteStringToFile(env, id, tmp, true);
  if (s.ok()) {
    s = env->RenameFile(tmp, IdentityFileName(dbname));
  }
@@ -11,7 +11,9 @@

 #pragma once
 #include <stdint.h>
+#include <unordered_map>
 #include <string>
+#include <vector>
 #include "rocksdb/slice.h"
 #include "rocksdb/status.h"
 #include "rocksdb/transaction_log.h"
@@ -20,6 +22,7 @@
 namespace rocksdb {

 class Env;
+class Directory;

 enum FileType {
  kLogFile,
@@ -33,6 +36,9 @@ enum FileType {
  kIdentityFile
 };

+// map from file number to path ID.
+typedef std::unordered_map<uint64_t, uint32_t> FileNumToPathIdMap;
+
 // Return the name of the log file with the specified number
 // in the db named by "dbname".  The result will be prefixed with
 // "dbname".
@@ -47,10 +53,15 @@ extern std::string ArchivalDirectory(const std::string& dbname);
 extern std::string ArchivedLogFileName(const std::string& dbname,
                                       uint64_t num);

+extern std::string MakeTableFileName(const std::string& name, uint64_t number);
+
 // Return the name of the sstable with the specified number
 // in the db named by "dbname".  The result will be prefixed with
 // "dbname".
-extern std::string TableFileName(const std::string& dbname, uint64_t number);
+extern std::string TableFileName(const std::vector<std::string> db_paths,
+                                 uint64_t number, uint32_t path_id);
+
+extern std::string FormatFileNumber(uint64_t number, uint32_t path_id);

 // Return the name of the descriptor file for the db named by
 // "dbname" and the specified incarnation number.  The result will be
@@ -100,7 +111,8 @@ extern bool ParseFileName(const std::string& filename,
 // Make the CURRENT file point to the descriptor file with the
 // specified number.
 extern Status SetCurrentFile(Env* env, const std::string& dbname,
-                             uint64_t descriptor_number);
+                             uint64_t descriptor_number,
+                             Directory* directory_to_fsync);

 // Make the IDENTITY file for the db
 extern Status SetIdentityFile(Env* env, const std::string& dbname);
@@ -108,7 +108,9 @@ TEST(FileNameTest, Construction) {
  ASSERT_EQ(192U, number);
  ASSERT_EQ(kLogFile, type);

-  fname = TableFileName("bar", 200);
+  fname = TableFileName({"bar"}, 200, 0);
+  std::string fname1 = TableFileName({"foo", "bar"}, 200, 1);
+  ASSERT_EQ(fname, fname1);
  ASSERT_EQ("bar/", std::string(fname.data(), 4));
  ASSERT_TRUE(ParseFileName(fname.c_str() + 4, &number, &type));
  ASSERT_EQ(200U, number);
@@ -0,0 +1,460 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+
+#ifndef ROCKSDB_LITE
+#include "db/forward_iterator.h"
+
+#include <string>
+#include <utility>
+#include <limits>
+#include "db/db_impl.h"
+#include "db/db_iter.h"
+#include "db/column_family.h"
+#include "rocksdb/env.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/slice_transform.h"
+#include "table/merger.h"
+#include "db/dbformat.h"
+
+namespace rocksdb {
+
+// Usage:
+//     LevelIterator iter;
+//     iter.SetFileIndex(file_index);
+//     iter.Seek(target);
+//     iter.Next()
+class LevelIterator : public Iterator {
+ public:
+  LevelIterator(const ColumnFamilyData* const cfd,
+      const ReadOptions& read_options,
+      const std::vector<FileMetaData*>& files)
+    : cfd_(cfd), read_options_(read_options), files_(files), valid_(false),
+      file_index_(std::numeric_limits<uint32_t>::max()) {}
+
+  void SetFileIndex(uint32_t file_index) {
+    assert(file_index < files_.size());
+    if (file_index != file_index_) {
+      file_index_ = file_index;
+      file_iter_.reset(cfd_->table_cache()->NewIterator(
+          read_options_, *(cfd_->soptions()), cfd_->internal_comparator(),
+          files_[file_index_]->fd, nullptr /* table_reader_ptr */, false));
+    }
+    valid_ = false;
+  }
+  void SeekToLast() override {
+    status_ = Status::NotSupported("LevelIterator::SeekToLast()");
+    valid_ = false;
+  }
+  void Prev() {
+    status_ = Status::NotSupported("LevelIterator::Prev()");
+    valid_ = false;
+  }
+  bool Valid() const override {
+    return valid_;
+  }
+  void SeekToFirst() override {
+    SetFileIndex(0);
+    file_iter_->SeekToFirst();
+    valid_ = file_iter_->Valid();
+  }
+  void Seek(const Slice& internal_key) override {
+    assert(file_iter_ != nullptr);
+    file_iter_->Seek(internal_key);
+    valid_ = file_iter_->Valid();
+    assert(valid_);
+  }
+  void Next() override {
+    assert(valid_);
+    file_iter_->Next();
+    while (!file_iter_->Valid()) {
+      if (file_index_ + 1 >= files_.size()) {
+        valid_ = false;
+        return;
+      }
+      SetFileIndex(file_index_ + 1);
+      file_iter_->SeekToFirst();
+    }
+    valid_ = file_iter_->Valid();
+  }
+  Slice key() const override {
+    assert(valid_);
+    return file_iter_->key();
+  }
+  Slice value() const override {
+    assert(valid_);
+    return file_iter_->value();
+  }
+  Status status() const override {
+    if (!status_.ok()) {
+      return status_;
+    } else if (file_iter_ && !file_iter_->status().ok()) {
+      return file_iter_->status();
+    }
+    return Status::OK();
+  }
+
+ private:
+  const ColumnFamilyData* const cfd_;
+  const ReadOptions& read_options_;
+  const std::vector<FileMetaData*>& files_;
+
+  bool valid_;
+  uint32_t file_index_;
+  Status status_;
+  std::unique_ptr<Iterator> file_iter_;
+};
+
+ForwardIterator::ForwardIterator(DBImpl* db, const ReadOptions& read_options,
+                                 ColumnFamilyData* cfd)
+    : db_(db),
+      read_options_(read_options),
+      cfd_(cfd),
+      prefix_extractor_(cfd->options()->prefix_extractor.get()),
+      user_comparator_(cfd->user_comparator()),
+      immutable_min_heap_(MinIterComparator(&cfd_->internal_comparator())),
+      sv_(nullptr),
+      mutable_iter_(nullptr),
+      current_(nullptr),
+      valid_(false),
+      is_prev_set_(false) {}
+
+ForwardIterator::~ForwardIterator() {
+  Cleanup();
+}
+
+void ForwardIterator::Cleanup() {
+  delete mutable_iter_;
+  for (auto* m : imm_iters_) {
+    delete m;
+  }
+  imm_iters_.clear();
+  for (auto* f : l0_iters_) {
+    delete f;
+  }
+  l0_iters_.clear();
+  for (auto* l : level_iters_) {
+    delete l;
+  }
+  level_iters_.clear();
+
+  if (sv_ != nullptr && sv_->Unref()) {
+    DBImpl::DeletionState deletion_state;
+    db_->mutex_.Lock();
+    sv_->Cleanup();
+    db_->FindObsoleteFiles(deletion_state, false, true);
+    db_->mutex_.Unlock();
+    delete sv_;
+    if (deletion_state.HaveSomethingToDelete()) {
+      db_->PurgeObsoleteFiles(deletion_state);
+    }
+  }
+}
+
+bool ForwardIterator::Valid() const {
+  return valid_;
+}
+
+void ForwardIterator::SeekToFirst() {
+  if (sv_ == nullptr ||
+      sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
+    RebuildIterators();
+  }
+  SeekInternal(Slice(), true);
+}
+
+void ForwardIterator::Seek(const Slice& internal_key) {
+  if (sv_ == nullptr ||
+      sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
+    RebuildIterators();
+  }
+  SeekInternal(internal_key, false);
+}
+
+void ForwardIterator::SeekInternal(const Slice& internal_key,
+                                   bool seek_to_first) {
+  // mutable
+  seek_to_first ? mutable_iter_->SeekToFirst() :
+                  mutable_iter_->Seek(internal_key);
+
+  // immutable
+  // TODO(ljin): NeedToSeekImmutable has negative impact on performance
+  // if it turns to need to seek immutable often. We probably want to have
+  // an option to turn it off.
+  if (seek_to_first || NeedToSeekImmutable(internal_key)) {
+    {
+      auto tmp = MinIterHeap(MinIterComparator(&cfd_->internal_comparator()));
+      immutable_min_heap_.swap(tmp);
+    }
+    for (auto* m : imm_iters_) {
+      seek_to_first ? m->SeekToFirst() : m->Seek(internal_key);
+      if (m->Valid()) {
+        immutable_min_heap_.push(m);
+      }
+    }
+
+    Slice user_key;
+    if (!seek_to_first) {
+      user_key = ExtractUserKey(internal_key);
+    }
+    auto* files = sv_->current->files_;
+    for (uint32_t i = 0; i < files[0].size(); ++i) {
+      if (seek_to_first) {
+        l0_iters_[i]->SeekToFirst();
+      } else {
+        // If the target key passes over the larget key, we are sure Next()
+        // won't go over this file.
+        if (user_comparator_->Compare(user_key,
+              files[0][i]->largest.user_key()) > 0) {
+          continue;
+        }
+        l0_iters_[i]->Seek(internal_key);
+      }
+      if (l0_iters_[i]->Valid()) {
+        immutable_min_heap_.push(l0_iters_[i]);
+      }
+    }
+
+    int32_t search_left_bound = 0;
+    int32_t search_right_bound = FileIndexer::kLevelMaxIndex;
+    for (int32_t level = 1; level < sv_->current->NumberLevels(); ++level) {
+      if (files[level].empty()) {
+        search_left_bound = 0;
+        search_right_bound = FileIndexer::kLevelMaxIndex;
+        continue;
+      }
+      assert(level_iters_[level - 1] != nullptr);
+      uint32_t f_idx = 0;
+      if (!seek_to_first) {
+        // TODO(ljin): remove before committing
+        // f_idx = FindFileInRange(
+        //    files[level], internal_key, 0, files[level].size());
+
+        if (search_left_bound == search_right_bound) {
+          f_idx = search_left_bound;
+        } else if (search_left_bound < search_right_bound) {
+          f_idx = FindFileInRange(
+              files[level], internal_key, search_left_bound,
+              search_right_bound == FileIndexer::kLevelMaxIndex ?
+                files[level].size() : search_right_bound);
+        } else {
+          // search_left_bound > search_right_bound
+          // There are only 2 cases this can happen:
+          // (1) target key is smaller than left most file
+          // (2) target key is larger than right most file
+          assert(search_left_bound == (int32_t)files[level].size() ||
+                 search_right_bound == -1);
+          if (search_right_bound == -1) {
+            assert(search_left_bound == 0);
+            f_idx = 0;
+          } else {
+            sv_->current->file_indexer_.GetNextLevelIndex(
+                level, files[level].size() - 1,
+                1, 1, &search_left_bound, &search_right_bound);
+            continue;
+          }
+        }
+
+        // Prepare hints for the next level
+        if (f_idx < files[level].size()) {
+          int cmp_smallest = user_comparator_->Compare(
+              user_key, files[level][f_idx]->smallest.user_key());
+          int cmp_largest = -1;
+          if (cmp_smallest >= 0) {
+            cmp_smallest = user_comparator_->Compare(
+                user_key, files[level][f_idx]->smallest.user_key());
+          }
+          sv_->current->file_indexer_.GetNextLevelIndex(level, f_idx,
+              cmp_smallest, cmp_largest,
+              &search_left_bound, &search_right_bound);
+        } else {
+          sv_->current->file_indexer_.GetNextLevelIndex(
+              level, files[level].size() - 1,
+              1, 1, &search_left_bound, &search_right_bound);
+        }
+      }
+
+      // Seek
+      if (f_idx < files[level].size()) {
+        level_iters_[level - 1]->SetFileIndex(f_idx);
+        seek_to_first ? level_iters_[level - 1]->SeekToFirst() :
+                        level_iters_[level - 1]->Seek(internal_key);
+        if (level_iters_[level - 1]->Valid()) {
+          immutable_min_heap_.push(level_iters_[level - 1]);
+        }
+      }
+    }
+
+    if (seek_to_first || immutable_min_heap_.empty()) {
+      is_prev_set_ = false;
+    } else {
+      prev_key_.SetKey(internal_key);
+      is_prev_set_ = true;
+    }
+  }
+
+  UpdateCurrent();
+}
+
+void ForwardIterator::Next() {
+  assert(valid_);
+
+  if (sv_ == nullptr ||
+      sv_ ->version_number != cfd_->GetSuperVersionNumber()) {
+    std::string current_key = key().ToString();
+    Slice old_key(current_key.data(), current_key.size());
+
+    RebuildIterators();
+    SeekInternal(old_key, false);
+    if (!valid_ || key().compare(old_key) != 0) {
+      return;
+    }
+  } else if (current_ != mutable_iter_) {
+    // It is going to advance immutable iterator
+    prev_key_.SetKey(current_->key());
+    is_prev_set_ = true;
+  }
+
+  current_->Next();
+  if (current_->Valid() && current_ != mutable_iter_) {
+    immutable_min_heap_.push(current_);
+  }
+  UpdateCurrent();
+}
+
+Slice ForwardIterator::key() const {
+  assert(valid_);
+  return current_->key();
+}
+
+Slice ForwardIterator::value() const {
+  assert(valid_);
+  return current_->value();
+}
+
+Status ForwardIterator::status() const {
+  if (!status_.ok()) {
+    return status_;
+  } else if (!mutable_iter_->status().ok()) {
+    return mutable_iter_->status();
+  }
+
+  for (auto *it : imm_iters_) {
+    if (it && !it->status().ok()) {
+      return it->status();
+    }
+  }
+  for (auto *it : l0_iters_) {
+    if (it && !it->status().ok()) {
+      return it->status();
+    }
+  }
+  for (auto *it : level_iters_) {
+    if (it && !it->status().ok()) {
+      return it->status();
+    }
+  }
+
+  return Status::OK();
+}
+
+void ForwardIterator::RebuildIterators() {
+  // Clean up
+  Cleanup();
+  // New
+  sv_ = cfd_->GetReferencedSuperVersion(&(db_->mutex_));
+  mutable_iter_ = sv_->mem->NewIterator(read_options_);
+  sv_->imm->AddIterators(read_options_, &imm_iters_);
+  const auto& l0_files = sv_->current->files_[0];
+  l0_iters_.reserve(l0_files.size());
+  for (const auto* l0 : l0_files) {
+    l0_iters_.push_back(cfd_->table_cache()->NewIterator(
+        read_options_, *cfd_->soptions(), cfd_->internal_comparator(), l0->fd));
+  }
+  level_iters_.reserve(sv_->current->NumberLevels() - 1);
+  for (int32_t level = 1; level < sv_->current->NumberLevels(); ++level) {
+    if (sv_->current->files_[level].empty()) {
+      level_iters_.push_back(nullptr);
+    } else {
+      level_iters_.push_back(new LevelIterator(cfd_, read_options_,
+          sv_->current->files_[level]));
+    }
+  }
+
+  current_ = nullptr;
+  is_prev_set_ = false;
+}
+
+void ForwardIterator::UpdateCurrent() {
+  if (immutable_min_heap_.empty() && !mutable_iter_->Valid()) {
+    current_ = nullptr;
+  } else if (immutable_min_heap_.empty()) {
+    current_ = mutable_iter_;
+  } else if (!mutable_iter_->Valid()) {
+    current_ = immutable_min_heap_.top();
+    immutable_min_heap_.pop();
+  } else {
+    current_ = immutable_min_heap_.top();
+    assert(current_ != nullptr);
+    assert(current_->Valid());
+    int cmp = cfd_->internal_comparator().InternalKeyComparator::Compare(
+        mutable_iter_->key(), current_->key());
+    assert(cmp != 0);
+    if (cmp > 0) {
+      immutable_min_heap_.pop();
+    } else {
+      current_ = mutable_iter_;
+    }
+  }
+  valid_ = (current_ != nullptr);
+  if (!status_.ok()) {
+    status_ = Status::OK();
+  }
+}
+
+bool ForwardIterator::NeedToSeekImmutable(const Slice& target) {
+  if (!is_prev_set_) {
+    return true;
+  }
+  Slice prev_key = prev_key_.GetKey();
+  if (prefix_extractor_ && prefix_extractor_->Transform(target).compare(
+    prefix_extractor_->Transform(prev_key)) != 0) {
+    return true;
+  }
+  if (cfd_->internal_comparator().InternalKeyComparator::Compare(
+        prev_key, target) >= 0) {
+    return true;
+  }
+  if (immutable_min_heap_.empty() ||
+      cfd_->internal_comparator().InternalKeyComparator::Compare(
+          target, current_ == mutable_iter_ ? immutable_min_heap_.top()->key()
+                                            : current_->key()) > 0) {
+    return true;
+  }
+  return false;
+}
+
+uint32_t ForwardIterator::FindFileInRange(
+    const std::vector<FileMetaData*>& files, const Slice& internal_key,
+    uint32_t left, uint32_t right) {
+  while (left < right) {
+    uint32_t mid = (left + right) / 2;
+    const FileMetaData* f = files[mid];
+    if (cfd_->internal_comparator().InternalKeyComparator::Compare(
+          f->largest.Encode(), internal_key) < 0) {
+      // Key at "mid.largest" is < "target".  Therefore all
+      // files at or before "mid" are uninteresting.
+      left = mid + 1;
+    } else {
+      // Key at "mid.largest" is >= "target".  Therefore all files
+      // after "mid" are uninteresting.
+      right = mid;
+    }
+  }
+  return right;
+}
+
+}  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE
@@ -0,0 +1,105 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+#pragma once
+
+#ifndef ROCKSDB_LITE
+
+#include <string>
+#include <vector>
+#include <queue>
+
+#include "rocksdb/db.h"
+#include "rocksdb/iterator.h"
+#include "rocksdb/options.h"
+#include "db/dbformat.h"
+
+namespace rocksdb {
+
+class DBImpl;
+class Env;
+struct SuperVersion;
+class ColumnFamilyData;
+class LevelIterator;
+struct FileMetaData;
+
+class MinIterComparator {
+ public:
+  explicit MinIterComparator(const Comparator* comparator) :
+    comparator_(comparator) {}
+
+  bool operator()(Iterator* a, Iterator* b) {
+    return comparator_->Compare(a->key(), b->key()) > 0;
+  }
+ private:
+  const Comparator* comparator_;
+};
+
+typedef std::priority_queue<Iterator*,
+          std::vector<Iterator*>,
+          MinIterComparator> MinIterHeap;
+
+/**
+ * ForwardIterator is a special type of iterator that only supports Seek()
+ * and Next(). It is expected to perform better than TailingIterator by
+ * removing the encapsulation and making all information accessible within
+ * the iterator. At the current implementation, snapshot is taken at the
+ * time Seek() is called. The Next() followed do not see new values after.
+ */
+class ForwardIterator : public Iterator {
+ public:
+  ForwardIterator(DBImpl* db, const ReadOptions& read_options,
+                  ColumnFamilyData* cfd);
+  virtual ~ForwardIterator();
+
+  void SeekToLast() override {
+    status_ = Status::NotSupported("ForwardIterator::SeekToLast()");
+    valid_ = false;
+  }
+  void Prev() {
+    status_ = Status::NotSupported("ForwardIterator::Prev");
+    valid_ = false;
+  }
+
+  virtual bool Valid() const override;
+  void SeekToFirst() override;
+  virtual void Seek(const Slice& target) override;
+  virtual void Next() override;
+  virtual Slice key() const override;
+  virtual Slice value() const override;
+  virtual Status status() const override;
+
+ private:
+  void Cleanup();
+  void RebuildIterators();
+  void SeekInternal(const Slice& internal_key, bool seek_to_first);
+  void UpdateCurrent();
+  bool NeedToSeekImmutable(const Slice& internal_key);
+  uint32_t FindFileInRange(
+    const std::vector<FileMetaData*>& files, const Slice& internal_key,
+    uint32_t left, uint32_t right);
+
+  DBImpl* const db_;
+  const ReadOptions read_options_;
+  ColumnFamilyData* const cfd_;
+  const SliceTransform* const prefix_extractor_;
+  const Comparator* user_comparator_;
+  MinIterHeap immutable_min_heap_;
+
+  SuperVersion* sv_;
+  Iterator* mutable_iter_;
+  std::vector<Iterator*> imm_iters_;
+  std::vector<Iterator*> l0_iters_;
+  std::vector<LevelIterator*> level_iters_;
+  Iterator* current_;
+  // internal iterator status
+  Status status_;
+  bool valid_;
+
+  IterKey prev_key_;
+  bool is_prev_set_;
+};
+
+}  // namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -0,0 +1,369 @@
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include "db/internal_stats.h"
+#include "db/column_family.h"
+
+#include <vector>
+
+namespace rocksdb {
+
+DBPropertyType GetPropertyType(const Slice& property) {
+  Slice in = property;
+  Slice prefix("rocksdb.");
+  if (!in.starts_with(prefix)) return kUnknown;
+  in.remove_prefix(prefix.size());
+
+  if (in.starts_with("num-files-at-level")) {
+    return kNumFilesAtLevel;
+  } else if (in == "levelstats") {
+    return kLevelStats;
+  } else if (in == "stats") {
+    return kStats;
+  } else if (in == "sstables") {
+    return kSsTables;
+  } else if (in == "num-immutable-mem-table") {
+    return kNumImmutableMemTable;
+  } else if (in == "mem-table-flush-pending") {
+    return kMemtableFlushPending;
+  } else if (in == "compaction-pending") {
+    return kCompactionPending;
+  } else if (in == "background-errors") {
+    return kBackgroundErrors;
+  } else if (in == "cur-size-active-mem-table") {
+    return kCurSizeActiveMemTable;
+  } else if (in == "num-entries-active-mem-table") {
+    return kNumEntriesInMutableMemtable;
+  } else if (in == "num-entries-imm-mem-tables") {
+    return kNumEntriesInImmutableMemtable;
+  }
+  return kUnknown;
+}
+
+bool InternalStats::GetProperty(DBPropertyType property_type,
+                                const Slice& property, std::string* value,
+                                ColumnFamilyData* cfd) {
+  Version* current = cfd->current();
+  Slice in = property;
+
+  switch (property_type) {
+    case kNumFilesAtLevel: {
+      in.remove_prefix(strlen("rocksdb.num-files-at-level"));
+      uint64_t level;
+      bool ok = ConsumeDecimalNumber(&in, &level) && in.empty();
+      if (!ok || (int)level >= number_levels_) {
+        return false;
+      } else {
+        char buf[100];
+        snprintf(buf, sizeof(buf), "%d",
+                 current->NumLevelFiles(static_cast<int>(level)));
+        *value = buf;
+        return true;
+      }
+    }
+    case kLevelStats: {
+      char buf[1000];
+      snprintf(buf, sizeof(buf),
+               "Level Files Size(MB)\n"
+               "--------------------\n");
+      value->append(buf);
+
+      for (int level = 0; level < number_levels_; level++) {
+        snprintf(buf, sizeof(buf), "%3d %8d %8.0f\n", level,
+                 current->NumLevelFiles(level),
+                 current->NumLevelBytes(level) / 1048576.0);
+        value->append(buf);
+      }
+      return true;
+    }
+    case kStats: {
+      char buf[1000];
+
+      uint64_t wal_bytes = 0;
+      uint64_t wal_synced = 0;
+      uint64_t user_bytes_written = 0;
+      uint64_t write_other = 0;
+      uint64_t write_self = 0;
+      uint64_t write_with_wal = 0;
+      uint64_t total_bytes_written = 0;
+      uint64_t total_bytes_read = 0;
+      uint64_t micros_up = env_->NowMicros() - started_at_;
+      // Add "+1" to make sure seconds_up is > 0 and avoid NaN later
+      double seconds_up = (micros_up + 1) / 1000000.0;
+      uint64_t total_slowdown = 0;
+      uint64_t total_slowdown_count = 0;
+      uint64_t interval_bytes_written = 0;
+      uint64_t interval_bytes_read = 0;
+      uint64_t interval_bytes_new = 0;
+      double interval_seconds_up = 0;
+
+      if (statistics_) {
+        wal_bytes = statistics_->getTickerCount(WAL_FILE_BYTES);
+        wal_synced = statistics_->getTickerCount(WAL_FILE_SYNCED);
+        user_bytes_written = statistics_->getTickerCount(BYTES_WRITTEN);
+        write_other = statistics_->getTickerCount(WRITE_DONE_BY_OTHER);
+        write_self = statistics_->getTickerCount(WRITE_DONE_BY_SELF);
+        write_with_wal = statistics_->getTickerCount(WRITE_WITH_WAL);
+      }
+
+      snprintf(
+          buf, sizeof(buf),
+          "                               Compactions\n"
+          "Level  Files Size(MB) Score Time(sec)  Read(MB) Write(MB)    Rn(MB) "
+          " "
+          "Rnp1(MB)  Wnew(MB) RW-Amplify Read(MB/s) Write(MB/s)      Rn     "
+          "Rnp1 "
+          "    Wnp1     NewW    Count   msComp   msStall  Ln-stall Stall-cnt\n"
+          "--------------------------------------------------------------------"
+          "--"
+          "--------------------------------------------------------------------"
+          "--"
+          "----------------------------------------------------------------\n");
+      value->append(buf);
+      for (int level = 0; level < number_levels_; level++) {
+        int files = current->NumLevelFiles(level);
+        if (compaction_stats_[level].micros > 0 || files > 0) {
+          int64_t bytes_read = compaction_stats_[level].bytes_readn +
+                               compaction_stats_[level].bytes_readnp1;
+          int64_t bytes_new = compaction_stats_[level].bytes_written -
+                              compaction_stats_[level].bytes_readnp1;
+          double amplify =
+              (compaction_stats_[level].bytes_readn == 0)
+                  ? 0.0
+                  : (compaction_stats_[level].bytes_written +
+                     compaction_stats_[level].bytes_readnp1 +
+                     compaction_stats_[level].bytes_readn) /
+                        (double)compaction_stats_[level].bytes_readn;
+
+          total_bytes_read += bytes_read;
+          total_bytes_written += compaction_stats_[level].bytes_written;
+
+          uint64_t stalls = level == 0 ? (stall_counts_[LEVEL0_SLOWDOWN] +
+                                          stall_counts_[LEVEL0_NUM_FILES] +
+                                          stall_counts_[MEMTABLE_COMPACTION])
+                                       : stall_leveln_slowdown_count_[level];
+
+          double stall_us = level == 0 ? (stall_micros_[LEVEL0_SLOWDOWN] +
+                                          stall_micros_[LEVEL0_NUM_FILES] +
+                                          stall_micros_[MEMTABLE_COMPACTION])
+                                       : stall_leveln_slowdown_[level];
+
+          snprintf(buf, sizeof(buf),
+                   "%3d %8d %8.0f %5.1f %9.0f %9.0f %9.0f %9.0f %9.0f %9.0f "
+                   "%10.1f %9.1f %11.1f %8d %8d %8d %8d %8d %8d %9.1f %9.1f "
+                   "%9lu\n",
+                   level, files, current->NumLevelBytes(level) / 1048576.0,
+                   current->NumLevelBytes(level) /
+                       cfd->compaction_picker()->MaxBytesForLevel(level),
+                   compaction_stats_[level].micros / 1e6,
+                   bytes_read / 1048576.0,
+                   compaction_stats_[level].bytes_written / 1048576.0,
+                   compaction_stats_[level].bytes_readn / 1048576.0,
+                   compaction_stats_[level].bytes_readnp1 / 1048576.0,
+                   bytes_new / 1048576.0, amplify,
+                   // +1 to avoid division by 0
+                   (bytes_read / 1048576.0) /
+                       ((compaction_stats_[level].micros + 1) / 1000000.0),
+                   (compaction_stats_[level].bytes_written / 1048576.0) /
+                       ((compaction_stats_[level].micros + 1) / 1000000.0),
+                   compaction_stats_[level].files_in_leveln,
+                   compaction_stats_[level].files_in_levelnp1,
+                   compaction_stats_[level].files_out_levelnp1,
+                   compaction_stats_[level].files_out_levelnp1 -
+                       compaction_stats_[level].files_in_levelnp1,
+                   compaction_stats_[level].count,
+                   (int)((double)compaction_stats_[level].micros / 1000.0 /
+                         (compaction_stats_[level].count + 1)),
+                   (double)stall_us / 1000.0 / (stalls + 1),
+                   stall_us / 1000000.0, (unsigned long)stalls);
+          total_slowdown += stall_leveln_slowdown_[level];
+          total_slowdown_count += stall_leveln_slowdown_count_[level];
+          value->append(buf);
+        }
+      }
+
+      interval_bytes_new = user_bytes_written - last_stats_.ingest_bytes_;
+      interval_bytes_read =
+          total_bytes_read - last_stats_.compaction_bytes_read_;
+      interval_bytes_written =
+          total_bytes_written - last_stats_.compaction_bytes_written_;
+      interval_seconds_up = seconds_up - last_stats_.seconds_up_;
+
+      snprintf(buf, sizeof(buf), "Uptime(secs): %.1f total, %.1f interval\n",
+               seconds_up, interval_seconds_up);
+      value->append(buf);
+
+      snprintf(buf, sizeof(buf),
+               "Writes cumulative: %llu total, %llu batches, "
+               "%.1f per batch, %.2f ingest GB\n",
+               (unsigned long long)(write_other + write_self),
+               (unsigned long long)write_self,
+               (write_other + write_self) / (double)(write_self + 1),
+               user_bytes_written / (1048576.0 * 1024));
+      value->append(buf);
+
+      snprintf(buf, sizeof(buf),
+               "WAL cumulative: %llu WAL writes, %llu WAL syncs, "
+               "%.2f writes per sync, %.2f GB written\n",
+               (unsigned long long)write_with_wal,
+               (unsigned long long)wal_synced,
+               write_with_wal / (double)(wal_synced + 1),
+               wal_bytes / (1048576.0 * 1024));
+      value->append(buf);
+
+      snprintf(buf, sizeof(buf),
+               "Compaction IO cumulative (GB): "
+               "%.2f new, %.2f read, %.2f write, %.2f read+write\n",
+               user_bytes_written / (1048576.0 * 1024),
+               total_bytes_read / (1048576.0 * 1024),
+               total_bytes_written / (1048576.0 * 1024),
+               (total_bytes_read + total_bytes_written) / (1048576.0 * 1024));
+      value->append(buf);
+
+      snprintf(
+          buf, sizeof(buf),
+          "Compaction IO cumulative (MB/sec): "
+          "%.1f new, %.1f read, %.1f write, %.1f read+write\n",
+          user_bytes_written / 1048576.0 / seconds_up,
+          total_bytes_read / 1048576.0 / seconds_up,
+          total_bytes_written / 1048576.0 / seconds_up,
+          (total_bytes_read + total_bytes_written) / 1048576.0 / seconds_up);
+      value->append(buf);
+
+      // +1 to avoid divide by 0 and NaN
+      snprintf(
+          buf, sizeof(buf),
+          "Amplification cumulative: %.1f write, %.1f compaction\n",
+          (double)(total_bytes_written + wal_bytes) / (user_bytes_written + 1),
+          (double)(total_bytes_written + total_bytes_read + wal_bytes) /
+              (user_bytes_written + 1));
+      value->append(buf);
+
+      uint64_t interval_write_other = write_other - last_stats_.write_other_;
+      uint64_t interval_write_self = write_self - last_stats_.write_self_;
+
+      snprintf(buf, sizeof(buf),
+               "Writes interval: %llu total, %llu batches, "
+               "%.1f per batch, %.1f ingest MB\n",
+               (unsigned long long)(interval_write_other + interval_write_self),
+               (unsigned long long)interval_write_self,
+               (double)(interval_write_other + interval_write_self) /
+                   (interval_write_self + 1),
+               (user_bytes_written - last_stats_.ingest_bytes_) / 1048576.0);
+      value->append(buf);
+
+      uint64_t interval_write_with_wal =
+          write_with_wal - last_stats_.write_with_wal_;
+
+      uint64_t interval_wal_synced = wal_synced - last_stats_.wal_synced_;
+      uint64_t interval_wal_bytes = wal_bytes - last_stats_.wal_bytes_;
+
+      snprintf(buf, sizeof(buf),
+               "WAL interval: %llu WAL writes, %llu WAL syncs, "
+               "%.2f writes per sync, %.2f MB written\n",
+               (unsigned long long)interval_write_with_wal,
+               (unsigned long long)interval_wal_synced,
+               interval_write_with_wal / (double)(interval_wal_synced + 1),
+               interval_wal_bytes / (1048576.0 * 1024));
+      value->append(buf);
+
+      snprintf(buf, sizeof(buf),
+               "Compaction IO interval (MB): "
+               "%.2f new, %.2f read, %.2f write, %.2f read+write\n",
+               interval_bytes_new / 1048576.0, interval_bytes_read / 1048576.0,
+               interval_bytes_written / 1048576.0,
+               (interval_bytes_read + interval_bytes_written) / 1048576.0);
+      value->append(buf);
+
+      snprintf(buf, sizeof(buf),
+               "Compaction IO interval (MB/sec): "
+               "%.1f new, %.1f read, %.1f write, %.1f read+write\n",
+               interval_bytes_new / 1048576.0 / interval_seconds_up,
+               interval_bytes_read / 1048576.0 / interval_seconds_up,
+               interval_bytes_written / 1048576.0 / interval_seconds_up,
+               (interval_bytes_read + interval_bytes_written) / 1048576.0 /
+                   interval_seconds_up);
+      value->append(buf);
+
+      // +1 to avoid divide by 0 and NaN
+      snprintf(
+          buf, sizeof(buf),
+          "Amplification interval: %.1f write, %.1f compaction\n",
+          (double)(interval_bytes_written + interval_wal_bytes) /
+              (interval_bytes_new + 1),
+          (double)(interval_bytes_written + interval_bytes_read + interval_wal_bytes) /
+              (interval_bytes_new + 1));
+      value->append(buf);
+
+      snprintf(buf, sizeof(buf),
+               "Stalls(secs): %.3f level0_slowdown, %.3f level0_numfiles, "
+               "%.3f memtable_compaction, %.3f leveln_slowdown\n",
+               stall_micros_[LEVEL0_SLOWDOWN] / 1000000.0,
+               stall_micros_[LEVEL0_NUM_FILES] / 1000000.0,
+               stall_micros_[MEMTABLE_COMPACTION] / 1000000.0,
+               total_slowdown / 1000000.0);
+      value->append(buf);
+
+      snprintf(buf, sizeof(buf),
+               "Stalls(count): %lu level0_slowdown, %lu level0_numfiles, "
+               "%lu memtable_compaction, %lu leveln_slowdown\n",
+               (unsigned long)stall_counts_[LEVEL0_SLOWDOWN],
+               (unsigned long)stall_counts_[LEVEL0_NUM_FILES],
+               (unsigned long)stall_counts_[MEMTABLE_COMPACTION],
+               (unsigned long)total_slowdown_count);
+      value->append(buf);
+
+      last_stats_.compaction_bytes_read_ = total_bytes_read;
+      last_stats_.compaction_bytes_written_ = total_bytes_written;
+      last_stats_.ingest_bytes_ = user_bytes_written;
+      last_stats_.seconds_up_ = seconds_up;
+      last_stats_.wal_bytes_ = wal_bytes;
+      last_stats_.wal_synced_ = wal_synced;
+      last_stats_.write_with_wal_ = write_with_wal;
+      last_stats_.write_other_ = write_other;
+      last_stats_.write_self_ = write_self;
+
+      return true;
+    }
+    case kSsTables:
+      *value = current->DebugString();
+      return true;
+    case kNumImmutableMemTable:
+      *value = std::to_string(cfd->imm()->size());
+      return true;
+    case kMemtableFlushPending:
+      // Return number of mem tables that are ready to flush (made immutable)
+      *value = std::to_string(cfd->imm()->IsFlushPending() ? 1 : 0);
+      return true;
+    case kCompactionPending:
+      // 1 if the system already determines at least one compacdtion is needed.
+      // 0 otherwise,
+      *value = std::to_string(current->NeedsCompaction() ? 1 : 0);
+      return true;
+    case kBackgroundErrors:
+      // Accumulated number of  errors in background flushes or compactions.
+      *value = std::to_string(GetBackgroundErrorCount());
+      return true;
+    case kCurSizeActiveMemTable:
+      // Current size of the active memtable
+      *value = std::to_string(cfd->mem()->ApproximateMemoryUsage());
+      return true;
+    case kNumEntriesInMutableMemtable:
+      // Current size of the active memtable
+      *value = std::to_string(cfd->mem()->GetNumEntries());
+      return true;
+    case kNumEntriesInImmutableMemtable:
+      // Current size of the active memtable
+      *value = std::to_string(cfd->imm()->current()->GetTotalNumEntries());
+      return true;
+    default:
+      return false;
+  }
+}
+
+}  // namespace rocksdb
@@ -0,0 +1,187 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+
+#pragma once
+#include "rocksdb/statistics.h"
+#include "util/statistics.h"
+#include "db/version_set.h"
+
+#include <vector>
+#include <string>
+
+class ColumnFamilyData;
+
+namespace rocksdb {
+
+class MemTableList;
+class DBImpl;
+
+enum DBPropertyType {
+  kNumFilesAtLevel,  // Number of files at a specific level
+  kLevelStats,       // Return number of files and total sizes of each level
+  kStats,            // Return general statitistics of DB
+  kSsTables,         // Return a human readable string of current SST files
+  kNumImmutableMemTable,   // Return number of immutable mem tables
+  kMemtableFlushPending,   // Return 1 if mem table flushing is pending,
+                           // otherwise 0.
+  kCompactionPending,      // Return 1 if a compaction is pending. Otherwise 0.
+  kBackgroundErrors,       // Return accumulated background errors encountered.
+  kCurSizeActiveMemTable,  // Return current size of the active memtable
+  kNumEntriesInMutableMemtable,    // Return number of entries in the mutable
+                                   // memtable.
+  kNumEntriesInImmutableMemtable,  // Return sum of number of entries in all
+                                   // the immutable mem tables.
+  kUnknown,
+};
+
+extern DBPropertyType GetPropertyType(const Slice& property);
+
+class InternalStats {
+ public:
+  enum WriteStallType {
+    LEVEL0_SLOWDOWN,
+    MEMTABLE_COMPACTION,
+    LEVEL0_NUM_FILES,
+    WRITE_STALLS_ENUM_MAX,
+  };
+
+  InternalStats(int num_levels, Env* env, Statistics* statistics)
+      : compaction_stats_(num_levels),
+        stall_micros_(WRITE_STALLS_ENUM_MAX, 0),
+        stall_counts_(WRITE_STALLS_ENUM_MAX, 0),
+        stall_leveln_slowdown_(num_levels, 0),
+        stall_leveln_slowdown_count_(num_levels, 0),
+        bg_error_count_(0),
+        number_levels_(num_levels),
+        statistics_(statistics),
+        env_(env),
+        started_at_(env->NowMicros()) {}
+
+  // Per level compaction stats.  compaction_stats_[level] stores the stats for
+  // compactions that produced data for the specified "level".
+  struct CompactionStats {
+    uint64_t micros;
+
+    // Bytes read from level N during compaction between levels N and N+1
+    int64_t bytes_readn;
+
+    // Bytes read from level N+1 during compaction between levels N and N+1
+    int64_t bytes_readnp1;
+
+    // Total bytes written during compaction between levels N and N+1
+    int64_t bytes_written;
+
+    // Files read from level N during compaction between levels N and N+1
+    int files_in_leveln;
+
+    // Files read from level N+1 during compaction between levels N and N+1
+    int files_in_levelnp1;
+
+    // Files written during compaction between levels N and N+1
+    int files_out_levelnp1;
+
+    // Number of compactions done
+    int count;
+
+    CompactionStats()
+        : micros(0),
+          bytes_readn(0),
+          bytes_readnp1(0),
+          bytes_written(0),
+          files_in_leveln(0),
+          files_in_levelnp1(0),
+          files_out_levelnp1(0),
+          count(0) {}
+
+    void Add(const CompactionStats& c) {
+      this->micros += c.micros;
+      this->bytes_readn += c.bytes_readn;
+      this->bytes_readnp1 += c.bytes_readnp1;
+      this->bytes_written += c.bytes_written;
+      this->files_in_leveln += c.files_in_leveln;
+      this->files_in_levelnp1 += c.files_in_levelnp1;
+      this->files_out_levelnp1 += c.files_out_levelnp1;
+      this->count += 1;
+    }
+  };
+
+  void AddCompactionStats(int level, const CompactionStats& stats) {
+    compaction_stats_[level].Add(stats);
+  }
+
+  void RecordWriteStall(WriteStallType write_stall_type, uint64_t micros) {
+    stall_micros_[write_stall_type] += micros;
+    ++stall_counts_[write_stall_type];
+  }
+
+  void RecordLevelNSlowdown(int level, uint64_t micros) {
+    stall_leveln_slowdown_[level] += micros;
+    ++stall_leveln_slowdown_count_[level];
+  }
+
+  uint64_t GetBackgroundErrorCount() const { return bg_error_count_; }
+
+  uint64_t BumpAndGetBackgroundErrorCount() { return ++bg_error_count_; }
+
+  bool GetProperty(DBPropertyType property_type, const Slice& property,
+                   std::string* value, ColumnFamilyData* cfd);
+
+ private:
+  std::vector<CompactionStats> compaction_stats_;
+
+  // Used to compute per-interval statistics
+  struct StatsSnapshot {
+    uint64_t compaction_bytes_read_;     // Bytes read by compaction
+    uint64_t compaction_bytes_written_;  // Bytes written by compaction
+    uint64_t ingest_bytes_;              // Bytes written by user
+    uint64_t wal_bytes_;                 // Bytes written to WAL
+    uint64_t wal_synced_;                // Number of times WAL is synced
+    uint64_t write_with_wal_;            // Number of writes that request WAL
+    // These count the number of writes processed by the calling thread or
+    // another thread.
+    uint64_t write_other_;
+    uint64_t write_self_;
+    double seconds_up_;
+
+    StatsSnapshot()
+        : compaction_bytes_read_(0),
+          compaction_bytes_written_(0),
+          ingest_bytes_(0),
+          wal_bytes_(0),
+          wal_synced_(0),
+          write_with_wal_(0),
+          write_other_(0),
+          write_self_(0),
+          seconds_up_(0) {}
+  };
+
+  // Counters from the previous time per-interval stats were computed
+  StatsSnapshot last_stats_;
+
+  // These count the number of microseconds for which MakeRoomForWrite stalls.
+  std::vector<uint64_t> stall_micros_;
+  std::vector<uint64_t> stall_counts_;
+  std::vector<uint64_t> stall_leveln_slowdown_;
+  std::vector<uint64_t> stall_leveln_slowdown_count_;
+
+  // Total number of background errors encountered. Every time a flush task
+  // or compaction task fails, this counter is incremented. The failure can
+  // be caused by any possible reason, including file system errors, out of
+  // resources, or input file corruption. Failing when retrying the same flush
+  // or compaction will cause the counter to increase too.
+  uint64_t bg_error_count_;
+
+  int number_levels_;
+  Statistics* statistics_;
+  Env* env_;
+  uint64_t started_at_;
+};
+
+}  // namespace rocksdb
@@ -0,0 +1,79 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+
+
+#include <vector>
+
+#include "util/testharness.h"
+#include "util/benchharness.h"
+#include "db/version_set.h"
+#include "util/mutexlock.h"
+
+namespace rocksdb {
+
+std::string MakeKey(unsigned int num) {
+  char buf[30];
+  snprintf(buf, sizeof(buf), "%016u", num);
+  return std::string(buf);
+}
+
+void BM_LogAndApply(int iters, int num_base_files) {
+  VersionSet* vset;
+  ColumnFamilyData* default_cfd;
+  uint64_t fnum = 1;
+  port::Mutex mu;
+  MutexLock l(&mu);
+
+  BENCHMARK_SUSPEND {
+    std::string dbname = test::TmpDir() + "/rocksdb_test_benchmark";
+    ASSERT_OK(DestroyDB(dbname, Options()));
+
+    DB* db = nullptr;
+    Options opts;
+    opts.create_if_missing = true;
+    Status s = DB::Open(opts, dbname, &db);
+    ASSERT_OK(s);
+    ASSERT_TRUE(db != nullptr);
+
+    delete db;
+    db = nullptr;
+
+    Options options;
+    EnvOptions sopt;
+    vset = new VersionSet(dbname, &options, sopt, nullptr);
+    std::vector<ColumnFamilyDescriptor> dummy;
+    dummy.push_back(ColumnFamilyDescriptor());
+    ASSERT_OK(vset->Recover(dummy));
+    default_cfd = vset->GetColumnFamilySet()->GetDefault();
+    VersionEdit vbase;
+    for (int i = 0; i < num_base_files; i++) {
+      InternalKey start(MakeKey(2 * fnum), 1, kTypeValue);
+      InternalKey limit(MakeKey(2 * fnum + 1), 1, kTypeDeletion);
+      vbase.AddFile(2, ++fnum, 0, 1 /* file size */, start, limit, 1, 1);
+    }
+    ASSERT_OK(vset->LogAndApply(default_cfd, &vbase, &mu));
+  }
+
+  for (int i = 0; i < iters; i++) {
+    VersionEdit vedit;
+    vedit.DeleteFile(2, fnum);
+    InternalKey start(MakeKey(2 * fnum), 1, kTypeValue);
+    InternalKey limit(MakeKey(2 * fnum + 1), 1, kTypeDeletion);
+    vedit.AddFile(2, ++fnum, 0, 1 /* file size */, start, limit, 1, 1);
+    vset->LogAndApply(default_cfd, &vedit, &mu);
+  }
+}
+
+BENCHMARK_NAMED_PARAM(BM_LogAndApply, 1000_iters_1_file, 1000, 1)
+BENCHMARK_NAMED_PARAM(BM_LogAndApply, 1000_iters_100_files, 1000, 100)
+BENCHMARK_NAMED_PARAM(BM_LogAndApply, 1000_iters_10000_files, 1000, 10000)
+BENCHMARK_NAMED_PARAM(BM_LogAndApply, 100_iters_100000_files, 100, 100000)
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  rocksdb::benchmark::RunBenchmarks();
+  return 0;
+}
@@ -17,7 +17,6 @@ namespace log {
 enum RecordType {
  // Zero is reserved for preallocated files
  kZeroType = 0,
-
  kFullType = 1,

  // For fragments
@@ -140,7 +140,9 @@ bool Reader::ReadRecord(Slice* record, std::string* scratch) {

      case kEof:
        if (in_fragmented_record) {
-          ReportCorruption(scratch->size(), "partial record without end(3)");
+          // This can be caused by the writer dying immediately after
+          //  writing a physical record but before completing the next; don't
+          //  treat it as a corruption, just ignore the entire logical record.
          scratch->clear();
        }
        return false;
@@ -264,13 +266,12 @@ unsigned int Reader::ReadPhysicalRecord(Slice* result) {
          eof_offset_ = buffer_.size();
        }
        continue;
-      } else if (buffer_.size() == 0) {
-        // End of file
-        return kEof;
      } else {
-        size_t drop_size = buffer_.size();
+        // Note that if buffer_ is non-empty, we have a truncated header at the
+        //  end of the file, which can be caused by the writer crashing in the
+        //  middle of writing the header. Instead of considering this an error,
+        //  just report EOF.
        buffer_.clear();
-        ReportCorruption(drop_size, "truncated record at end of file");
        return kEof;
      }
    }
@@ -284,14 +285,22 @@ unsigned int Reader::ReadPhysicalRecord(Slice* result) {
    if (kHeaderSize + length > buffer_.size()) {
      size_t drop_size = buffer_.size();
      buffer_.clear();
-      ReportCorruption(drop_size, "bad record length");
-      return kBadRecord;
+      if (!eof_) {
+        ReportCorruption(drop_size, "bad record length");
+        return kBadRecord;
+      }
+      // If the end of the file has been reached without reading |length| bytes
+      // of payload, assume the writer died in the middle of writing the record.
+      // Don't report a corruption.
+      return kEof;
    }

    if (type == kZeroType && length == 0) {
      // Skip zero length record without reporting any drops since
      // such records are produced by the mmap based writing code in
      // env_posix.cc that preallocates file regions.
+      // NOTE: this should never happen in DB written by new RocksDB versions,
+      // since we turn off mmap writes to manifest and log files
      buffer_.clear();
      return kBadRecord;
    }
@@ -446,20 +446,32 @@ TEST(LogTest, BadRecordType) {
  ASSERT_EQ("OK", MatchError("unknown record type"));
 }

-TEST(LogTest, TruncatedTrailingRecord) {
+TEST(LogTest, TruncatedTrailingRecordIsIgnored) {
  Write("foo");
  ShrinkSize(4);   // Drop all payload as well as a header byte
  ASSERT_EQ("EOF", Read());
-  ASSERT_EQ((unsigned int)(kHeaderSize - 1), DroppedBytes());
-  ASSERT_EQ("OK", MatchError("truncated record at end of file"));
+  // Truncated last record is ignored, not treated as an error
+  ASSERT_EQ(0U, DroppedBytes());
+  ASSERT_EQ("", ReportMessage());
 }

 TEST(LogTest, BadLength) {
+  const int kPayloadSize = kBlockSize - kHeaderSize;
+  Write(BigString("bar", kPayloadSize));
+  Write("foo");
+  // Least significant size byte is stored in header[4].
+  IncrementByte(4, 1);
+  ASSERT_EQ("foo", Read());
+  ASSERT_EQ(kBlockSize, DroppedBytes());
+  ASSERT_EQ("OK", MatchError("bad record length"));
+}
+
+TEST(LogTest, BadLengthAtEndIsIgnored) {
  Write("foo");
  ShrinkSize(1);
  ASSERT_EQ("EOF", Read());
-  ASSERT_EQ((unsigned int)(kHeaderSize + 2), DroppedBytes());
-  ASSERT_EQ("OK", MatchError("bad record length"));
+  ASSERT_EQ(0U, DroppedBytes());
+  ASSERT_EQ("", ReportMessage());
 }

 TEST(LogTest, ChecksumMismatch) {
@@ -510,6 +522,24 @@ TEST(LogTest, UnexpectedFirstType) {
  ASSERT_EQ("OK", MatchError("partial record without end"));
 }

+TEST(LogTest, MissingLastIsIgnored) {
+  Write(BigString("bar", kBlockSize));
+  // Remove the LAST block, including header.
+  ShrinkSize(14);
+  ASSERT_EQ("EOF", Read());
+  ASSERT_EQ("", ReportMessage());
+  ASSERT_EQ(0U, DroppedBytes());
+}
+
+TEST(LogTest, PartialLastIsIgnored) {
+  Write(BigString("bar", kBlockSize));
+  // Cause a bad record length in the LAST block.
+  ShrinkSize(1);
+  ASSERT_EQ("EOF", Read());
+  ASSERT_EQ("", ReportMessage());
+  ASSERT_EQ(0U, DroppedBytes());
+}
+
 TEST(LogTest, ErrorJoinsRecords) {
  // Consider two fragmented records:
  //    first(R1) last(R1) first(R2) last(R2)
@@ -10,6 +10,8 @@
 #include "db/memtable.h"

 #include <memory>
+#include <algorithm>
+#include <limits>

 #include "db/dbformat.h"
 #include "db/merge_context.h"
@@ -17,52 +19,137 @@
 #include "rocksdb/env.h"
 #include "rocksdb/iterator.h"
 #include "rocksdb/merge_operator.h"
+#include "rocksdb/slice_transform.h"
+#include "table/merger.h"
+#include "util/arena.h"
 #include "util/coding.h"
-#include "util/mutexlock.h"
 #include "util/murmurhash.h"
+#include "util/mutexlock.h"
+#include "util/perf_context_imp.h"
 #include "util/statistics.h"
-
-namespace std {
-template <>
-struct hash<rocksdb::Slice> {
-  size_t operator()(const rocksdb::Slice& slice) const {
-    return MurmurHash(slice.data(), slice.size(), 0);
-  }
-};
-}
+#include "util/stop_watch.h"

 namespace rocksdb {

 MemTable::MemTable(const InternalKeyComparator& cmp, const Options& options)
    : comparator_(cmp),
      refs_(0),
-      arena_impl_(options.arena_block_size),
-      table_(options.memtable_factory->CreateMemTableRep(comparator_,
-                                                         &arena_impl_)),
+      kArenaBlockSize(OptimizeBlockSize(options.arena_block_size)),
+      kWriteBufferSize(options.write_buffer_size),
+      arena_(options.arena_block_size),
+      table_(options.memtable_factory->CreateMemTableRep(
+          comparator_, &arena_, options.prefix_extractor.get(),
+          options.info_log.get())),
+      num_entries_(0),
      flush_in_progress_(false),
      flush_completed_(false),
      file_number_(0),
      first_seqno_(0),
      mem_next_logfile_number_(0),
-      mem_logfile_number_(0),
      locks_(options.inplace_update_support ? options.inplace_update_num_locks
-                                            : 0) {}
+                                            : 0),
+      prefix_extractor_(options.prefix_extractor.get()),
+      should_flush_(ShouldFlushNow()) {
+  // if should_flush_ == true without an entry inserted, something must have
+  // gone wrong already.
+  assert(!should_flush_);
+  if (prefix_extractor_ && options.memtable_prefix_bloom_bits > 0) {
+    prefix_bloom_.reset(new DynamicBloom(
+        &arena_,
+        options.memtable_prefix_bloom_bits, options.bloom_locality,
+        options.memtable_prefix_bloom_probes, nullptr,
+        options.memtable_prefix_bloom_huge_page_tlb_size,
+        options.info_log.get()));
+  }
+}

 MemTable::~MemTable() {
  assert(refs_ == 0);
 }

 size_t MemTable::ApproximateMemoryUsage() {
-  return arena_impl_.ApproximateMemoryUsage() +
-         table_->ApproximateMemoryUsage();
+  size_t arena_usage = arena_.ApproximateMemoryUsage();
+  size_t table_usage = table_->ApproximateMemoryUsage();
+  // let MAX_USAGE =  std::numeric_limits<size_t>::max()
+  // then if arena_usage + total_usage >= MAX_USAGE, return MAX_USAGE.
+  // the following variation is to avoid numeric overflow.
+  if (arena_usage >= std::numeric_limits<size_t>::max() - table_usage) {
+    return std::numeric_limits<size_t>::max();
+  }
+  // otherwise, return the actual usage
+  return arena_usage + table_usage;
 }

-int MemTable::KeyComparator::operator()(const char* aptr, const char* bptr)
+bool MemTable::ShouldFlushNow() const {
+  // In a lot of times, we cannot allocate arena blocks that exactly matches the
+  // buffer size. Thus we have to decide if we should over-allocate or
+  // under-allocate.
+  // This constant avariable can be interpreted as: if we still have more than
+  // "kAllowOverAllocationRatio * kArenaBlockSize" space left, we'd try to over
+  // allocate one more block.
+  const double kAllowOverAllocationRatio = 0.6;
+
+  // If arena still have room for new block allocation, we can safely say it
+  // shouldn't flush.
+  auto allocated_memory =
+      table_->ApproximateMemoryUsage() + arena_.MemoryAllocatedBytes();
+
+  // if we can still allocate one more block without exceeding the
+  // over-allocation ratio, then we should not flush.
+  if (allocated_memory + kArenaBlockSize <
+      kWriteBufferSize + kArenaBlockSize * kAllowOverAllocationRatio) {
+    return false;
+  }
+
+  // if user keeps adding entries that exceeds kWriteBufferSize, we need to
+  // flush earlier even though we still have much available memory left.
+  if (allocated_memory >
+      kWriteBufferSize + kArenaBlockSize * kAllowOverAllocationRatio) {
+    return true;
+  }
+
+  // In this code path, Arena has already allocated its "last block", which
+  // means the total allocatedmemory size is either:
+  //  (1) "moderately" over allocated the memory (no more than `0.6 * arena
+  // block size`. Or,
+  //  (2) the allocated memory is less than write buffer size, but we'll stop
+  // here since if we allocate a new arena block, we'll over allocate too much
+  // more (half of the arena block size) memory.
+  //
+  // In either case, to avoid over-allocate, the last block will stop allocation
+  // when its usage reaches a certain ratio, which we carefully choose "0.75
+  // full" as the stop condition because it addresses the following issue with
+  // great simplicity: What if the next inserted entry's size is
+  // bigger than AllocatedAndUnused()?
+  //
+  // The answer is: if the entry size is also bigger than 0.25 *
+  // kArenaBlockSize, a dedicated block will be allocated for it; otherwise
+  // arena will anyway skip the AllocatedAndUnused() and allocate a new, empty
+  // and regular block. In either case, we *overly* over-allocated.
+  //
+  // Therefore, setting the last block to be at most "0.75 full" avoids both
+  // cases.
+  //
+  // NOTE: the average percentage of waste space of this approach can be counted
+  // as: "arena block size * 0.25 / write buffer size". User who specify a small
+  // write buffer size and/or big arena block size may suffer.
+  return arena_.AllocatedAndUnused() < kArenaBlockSize / 4;
+}
+
+int MemTable::KeyComparator::operator()(const char* prefix_len_key1,
+                                        const char* prefix_len_key2) const {
+  // Internal keys are encoded as length-prefixed strings.
+  Slice k1 = GetLengthPrefixedSlice(prefix_len_key1);
+  Slice k2 = GetLengthPrefixedSlice(prefix_len_key2);
+  return comparator.Compare(k1, k2);
+}
+
+int MemTable::KeyComparator::operator()(const char* prefix_len_key,
+                                        const Slice& key)
    const {
  // Internal keys are encoded as length-prefixed strings.
-  Slice a = GetLengthPrefixedSlice(aptr);
-  Slice b = GetLengthPrefixedSlice(bptr);
-  return comparator.Compare(a, b);
+  Slice a = GetLengthPrefixedSlice(prefix_len_key);
+  return comparator.Compare(a, key);
 }

 Slice MemTableRep::UserKey(const char* key) const {
@@ -70,10 +157,15 @@ Slice MemTableRep::UserKey(const char* key) const {
  return Slice(slice.data(), slice.size() - 8);
 }

+KeyHandle MemTableRep::Allocate(const size_t len, char** buf) {
+  *buf = arena_->Allocate(len);
+  return static_cast<KeyHandle>(*buf);
+}
+
 // Encode a suitable internal key target for "target" and return it.
 // Uses *scratch as scratch space, and the returned pointer will point
 // into this scratch space.
-static const char* EncodeKey(std::string* scratch, const Slice& target) {
+const char* EncodeKey(std::string* scratch, const Slice& target) {
  scratch->clear();
  PutVarint32(scratch, target.size());
  scratch->append(target.data(), target.size());
@@ -82,27 +174,62 @@ static const char* EncodeKey(std::string* scratch, const Slice& target) {

 class MemTableIterator: public Iterator {
 public:
-  MemTableIterator(MemTableRep* table, const ReadOptions& options)
-    : iter_() {
-    if (options.prefix) {
-      iter_.reset(table->GetPrefixIterator(*options.prefix));
-    } else if (options.prefix_seek) {
-      iter_.reset(table->GetDynamicPrefixIterator());
+  MemTableIterator(const MemTable& mem, const ReadOptions& options,
+                   bool enforce_total_order, Arena* arena)
+      : bloom_(nullptr),
+        prefix_extractor_(mem.prefix_extractor_),
+        valid_(false),
+        arena_mode_(arena != nullptr) {
+    if (prefix_extractor_ != nullptr && !enforce_total_order) {
+      bloom_ = mem.prefix_bloom_.get();
+      iter_ = mem.table_->GetDynamicPrefixIterator(arena);
    } else {
-      iter_.reset(table->GetIterator());
+      iter_ = mem.table_->GetIterator(arena);
    }
  }

-  virtual bool Valid() const { return iter_->Valid(); }
-  virtual void Seek(const Slice& k) { iter_->Seek(EncodeKey(&tmp_, k)); }
-  virtual void SeekToFirst() { iter_->SeekToFirst(); }
-  virtual void SeekToLast() { iter_->SeekToLast(); }
-  virtual void Next() { iter_->Next(); }
-  virtual void Prev() { iter_->Prev(); }
+  ~MemTableIterator() {
+    if (arena_mode_) {
+      iter_->~Iterator();
+    } else {
+      delete iter_;
+    }
+  }
+
+  virtual bool Valid() const { return valid_; }
+  virtual void Seek(const Slice& k) {
+    if (bloom_ != nullptr &&
+        !bloom_->MayContain(prefix_extractor_->Transform(ExtractUserKey(k)))) {
+      valid_ = false;
+      return;
+    }
+    iter_->Seek(k, nullptr);
+    valid_ = iter_->Valid();
+  }
+  virtual void SeekToFirst() {
+    iter_->SeekToFirst();
+    valid_ = iter_->Valid();
+  }
+  virtual void SeekToLast() {
+    iter_->SeekToLast();
+    valid_ = iter_->Valid();
+  }
+  virtual void Next() {
+    assert(Valid());
+    iter_->Next();
+    valid_ = iter_->Valid();
+  }
+  virtual void Prev() {
+    assert(Valid());
+    iter_->Prev();
+    valid_ = iter_->Valid();
+  }
  virtual Slice key() const {
+    assert(Valid());
    return GetLengthPrefixedSlice(iter_->key());
  }
  virtual Slice value() const {
+    assert(Valid());
    Slice key_slice = GetLengthPrefixedSlice(iter_->key());
    return GetLengthPrefixedSlice(key_slice.data() + key_slice.size());
  }
@@ -110,24 +237,35 @@ class MemTableIterator: public Iterator {
  virtual Status status() const { return Status::OK(); }

 private:
-  std::unique_ptr<MemTableRep::Iterator> iter_;
-  std::string tmp_;       // For passing to EncodeKey
+  DynamicBloom* bloom_;
+  const SliceTransform* const prefix_extractor_;
+  MemTableRep::Iterator* iter_;
+  bool valid_;
+  bool arena_mode_;

  // No copying allowed
  MemTableIterator(const MemTableIterator&);
  void operator=(const MemTableIterator&);
 };

-Iterator* MemTable::NewIterator(const ReadOptions& options) {
-  return new MemTableIterator(table_.get(), options);
+Iterator* MemTable::NewIterator(const ReadOptions& options,
+                                bool enforce_total_order, Arena* arena) {
+  if (arena == nullptr) {
+    return new MemTableIterator(*this, options, enforce_total_order, nullptr);
+  } else {
+    auto mem = arena->AllocateAligned(sizeof(MemTableIterator));
+    return new (mem)
+        MemTableIterator(*this, options, enforce_total_order, arena);
+  }
 }

 port::RWMutex* MemTable::GetLock(const Slice& key) {
-  return &locks_[std::hash<Slice>()(key) % locks_.size()];
+  static murmur_hash hash;
+  return &locks_[hash(key) % locks_.size()];
 }

 void MemTable::Add(SequenceNumber s, ValueType type,
-                   const Slice& key,
+                   const Slice& key, /* user key */
                   const Slice& value) {
  // Format of an entry is concatenation of:
  //  key_size     : varint32 of internal_key.size()
@@ -140,7 +278,9 @@ void MemTable::Add(SequenceNumber s, ValueType type,
  const size_t encoded_len =
      VarintLength(internal_key_size) + internal_key_size +
      VarintLength(val_size) + val_size;
-  char* buf = arena_impl_.Allocate(encoded_len);
+  char* buf = nullptr;
+  KeyHandle handle = table_->Allocate(encoded_len, &buf);
+  assert(buf != nullptr);
  char* p = EncodeVarint32(buf, internal_key_size);
  memcpy(p, key.data(), key_size);
  p += key_size;
@@ -148,132 +288,174 @@ void MemTable::Add(SequenceNumber s, ValueType type,
  p += 8;
  p = EncodeVarint32(p, val_size);
  memcpy(p, value.data(), val_size);
-  assert((p + val_size) - buf == (unsigned)encoded_len);
-  table_->Insert(buf);
+  assert((unsigned)(p + val_size - buf) == (unsigned)encoded_len);
+  table_->Insert(handle);
+  num_entries_++;
+
+  if (prefix_bloom_) {
+    assert(prefix_extractor_);
+    prefix_bloom_->Add(prefix_extractor_->Transform(key));
+  }

  // The first sequence number inserted into the memtable
  assert(first_seqno_ == 0 || s > first_seqno_);
  if (first_seqno_ == 0) {
    first_seqno_ = s;
  }
+
+  should_flush_ = ShouldFlushNow();
+}
+
+// Callback from MemTable::Get()
+namespace {
+
+struct Saver {
+  Status* status;
+  const LookupKey* key;
+  bool* found_final_value;  // Is value set correctly? Used by KeyMayExist
+  bool* merge_in_progress;
+  std::string* value;
+  const MergeOperator* merge_operator;
+  // the merge operations encountered;
+  MergeContext* merge_context;
+  MemTable* mem;
+  Logger* logger;
+  Statistics* statistics;
+  bool inplace_update_support;
+};
+}  // namespace
+
+static bool SaveValue(void* arg, const char* entry) {
+  Saver* s = reinterpret_cast<Saver*>(arg);
+  MergeContext* merge_context = s->merge_context;
+  const MergeOperator* merge_operator = s->merge_operator;
+
+  assert(s != nullptr && merge_context != nullptr);
+
+  // entry format is:
+  //    klength  varint32
+  //    userkey  char[klength-8]
+  //    tag      uint64
+  //    vlength  varint32
+  //    value    char[vlength]
+  // Check that it belongs to same user key.  We do not check the
+  // sequence number since the Seek() call above should have skipped
+  // all entries with overly large sequence numbers.
+  uint32_t key_length;
+  const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
+  if (s->mem->GetInternalKeyComparator().user_comparator()->Compare(
+          Slice(key_ptr, key_length - 8), s->key->user_key()) == 0) {
+    // Correct user key
+    const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
+    switch (static_cast<ValueType>(tag & 0xff)) {
+      case kTypeValue: {
+        if (s->inplace_update_support) {
+          s->mem->GetLock(s->key->user_key())->ReadLock();
+        }
+        Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
+        *(s->status) = Status::OK();
+        if (*(s->merge_in_progress)) {
+          assert(merge_operator);
+          if (!merge_operator->FullMerge(s->key->user_key(), &v,
+                                         merge_context->GetOperands(), s->value,
+                                         s->logger)) {
+            RecordTick(s->statistics, NUMBER_MERGE_FAILURES);
+            *(s->status) =
+                Status::Corruption("Error: Could not perform merge.");
+          }
+        } else {
+          s->value->assign(v.data(), v.size());
+        }
+        if (s->inplace_update_support) {
+          s->mem->GetLock(s->key->user_key())->ReadUnlock();
+        }
+        *(s->found_final_value) = true;
+        return false;
+      }
+      case kTypeDeletion: {
+        if (*(s->merge_in_progress)) {
+          assert(merge_operator);
+          *(s->status) = Status::OK();
+          if (!merge_operator->FullMerge(s->key->user_key(), nullptr,
+                                         merge_context->GetOperands(), s->value,
+                                         s->logger)) {
+            RecordTick(s->statistics, NUMBER_MERGE_FAILURES);
+            *(s->status) =
+                Status::Corruption("Error: Could not perform merge.");
+          }
+        } else {
+          *(s->status) = Status::NotFound();
+        }
+        *(s->found_final_value) = true;
+        return false;
+      }
+      case kTypeMerge: {
+        std::string merge_result;  // temporary area for merge results later
+        Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
+        *(s->merge_in_progress) = true;
+        merge_context->PushOperand(v);
+        return true;
+      }
+      default:
+        assert(false);
+        return true;
+    }
+  }
+
+  // s->state could be Corrupt, merge or notfound
+  return false;
 }

 bool MemTable::Get(const LookupKey& key, std::string* value, Status* s,
                   MergeContext& merge_context, const Options& options) {
-  Slice memkey = key.memtable_key();
-  std::unique_ptr<MemTableRep::Iterator> iter(
-      table_->GetIterator(key.user_key()));
-  iter->Seek(memkey.data());
+  PERF_TIMER_AUTO(get_from_memtable_time);

+  Slice user_key = key.user_key();
+  bool found_final_value = false;
  bool merge_in_progress = s->IsMergeInProgress();
-  auto merge_operator = options.merge_operator.get();
-  auto logger = options.info_log;
-  std::string merge_result;

-  for (; iter->Valid(); iter->Next()) {
-    // entry format is:
-    //    klength  varint32
-    //    userkey  char[klength-8]
-    //    tag      uint64
-    //    vlength  varint32
-    //    value    char[vlength]
-    // Check that it belongs to same user key.  We do not check the
-    // sequence number since the Seek() call above should have skipped
-    // all entries with overly large sequence numbers.
-    const char* entry = iter->key();
-    uint32_t key_length;
-    const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
-    if (comparator_.comparator.user_comparator()->Compare(
-        Slice(key_ptr, key_length - 8), key.user_key()) == 0) {
-      // Correct user key
-      const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
-      switch (static_cast<ValueType>(tag & 0xff)) {
-        case kTypeValue: {
-          if (options.inplace_update_support) {
-            GetLock(key.user_key())->ReadLock();
-          }
-          Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
-          *s = Status::OK();
-          if (merge_in_progress) {
-            assert(merge_operator);
-          if (!merge_operator->FullMerge(key.user_key(), &v,
-                                         merge_context.GetOperands(), value,
-                                         logger.get())) {
-              RecordTick(options.statistics.get(), NUMBER_MERGE_FAILURES);
-              *s = Status::Corruption("Error: Could not perform merge.");
-            }
-          } else {
-            value->assign(v.data(), v.size());
-          }
-          if (options.inplace_update_support) {
-            GetLock(key.user_key())->Unlock();
-          }
-          return true;
-        }
-        case kTypeDeletion: {
-          if (merge_in_progress) {
-            assert(merge_operator);
-            *s = Status::OK();
-          if (!merge_operator->FullMerge(key.user_key(), nullptr,
-                                         merge_context.GetOperands(), value,
-                                         logger.get())) {
-              RecordTick(options.statistics.get(), NUMBER_MERGE_FAILURES);
-              *s = Status::Corruption("Error: Could not perform merge.");
-            }
-          } else {
-            *s = Status::NotFound();
-          }
-          return true;
-        }
-        case kTypeMerge: {
-          Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
-          merge_in_progress = true;
-          merge_context.PushOperand(v);
-          while(merge_context.GetNumOperands() >= 2) {
-            // Attempt to associative merge. (Returns true if successful)
-          if (merge_operator->PartialMerge(key.user_key(),
-                                           merge_context.GetOperand(0),
-                                           merge_context.GetOperand(1),
-                                           &merge_result, logger.get())) {
-              merge_context.PushPartialMergeResult(merge_result);
-            } else {
-              // Stack them because user can't associative merge
-              break;
-            }
-          }
-          break;
-        }
-        case kTypeLogData:
-          assert(false);
-          break;
-      }
-    } else {
-      // exit loop if user key does not match
-      break;
-    }
+  if (prefix_bloom_ &&
+      !prefix_bloom_->MayContain(prefix_extractor_->Transform(user_key))) {
+    // iter is null if prefix bloom says the key does not exist
+  } else {
+    Saver saver;
+    saver.status = s;
+    saver.found_final_value = &found_final_value;
+    saver.merge_in_progress = &merge_in_progress;
+    saver.key = &key;
+    saver.value = value;
+    saver.status = s;
+    saver.mem = this;
+    saver.merge_context = &merge_context;
+    saver.merge_operator = options.merge_operator.get();
+    saver.logger = options.info_log.get();
+    saver.inplace_update_support = options.inplace_update_support;
+    saver.statistics = options.statistics.get();
+    table_->Get(key, &saver, SaveValue);
  }

  // No change to value, since we have not yet found a Put/Delete
-
-  if (merge_in_progress) {
+  if (!found_final_value && merge_in_progress) {
    *s = Status::MergeInProgress("");
  }
-  return false;
+  PERF_TIMER_STOP(get_from_memtable_time);
+  PERF_COUNTER_ADD(get_from_memtable_count, 1);
+  return found_final_value;
 }

-bool MemTable::Update(SequenceNumber seq, ValueType type,
+void MemTable::Update(SequenceNumber seq,
                      const Slice& key,
                      const Slice& value) {
  LookupKey lkey(key, seq);
-  Slice memkey = lkey.memtable_key();
+  Slice mem_key = lkey.memtable_key();

  std::unique_ptr<MemTableRep::Iterator> iter(
-      table_->GetIterator(lkey.user_key()));
-  iter->Seek(memkey.data());
+      table_->GetDynamicPrefixIterator());
+  iter->Seek(lkey.internal_key(), mem_key.data());

  if (iter->Valid()) {
    // entry format is:
-    //    klength  varint32
+    //    key_length  varint32
    //    userkey  char[klength-8]
    //    tag      uint64
    //    vlength  varint32
@@ -282,7 +464,7 @@ bool MemTable::Update(SequenceNumber seq, ValueType type,
    // sequence number since the Seek() call above should have skipped
    // all entries with overly large sequence numbers.
    const char* entry = iter->key();
-    uint32_t key_length;
+    uint32_t key_length = 0;
    const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
    if (comparator_.comparator.user_comparator()->Compare(
        Slice(key_ptr, key_length - 8), lkey.user_key()) == 0) {
@@ -290,36 +472,108 @@ bool MemTable::Update(SequenceNumber seq, ValueType type,
      const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
      switch (static_cast<ValueType>(tag & 0xff)) {
        case kTypeValue: {
-          uint32_t vlength;
-          GetVarint32Ptr(key_ptr + key_length,
-                         key_ptr + key_length+5, &vlength);
-          // Update value, if newValue size  <= curValue size
-          if (value.size() <= vlength) {
+          Slice prev_value = GetLengthPrefixedSlice(key_ptr + key_length);
+          uint32_t prev_size = prev_value.size();
+          uint32_t new_size = value.size();
+
+          // Update value, if new value size  <= previous value size
+          if (new_size <= prev_size ) {
            char* p = EncodeVarint32(const_cast<char*>(key_ptr) + key_length,
-                                     value.size());
+                                     new_size);
            WriteLock wl(GetLock(lkey.user_key()));
            memcpy(p, value.data(), value.size());
-            assert(
-              (p + value.size()) - entry ==
-              (unsigned) (VarintLength(key_length) +
-                          key_length +
-                          VarintLength(value.size()) +
-                          value.size())
-            );
-            return true;
+            assert((unsigned)((p + value.size()) - entry) ==
+                   (unsigned)(VarintLength(key_length) + key_length +
+                              VarintLength(value.size()) + value.size()));
+            return;
          }
        }
        default:
          // If the latest value is kTypeDeletion, kTypeMerge or kTypeLogData
-          // then we probably don't have enough space to update in-place
-          // Maybe do something later
-          // Return false, and do normal Add()
-          return false;
+          // we don't have enough space for update inplace
+            Add(seq, kTypeValue, key, value);
+            return;
      }
    }
  }

-  // Key doesn't exist
+  // key doesn't exist
+  Add(seq, kTypeValue, key, value);
+}
+
+bool MemTable::UpdateCallback(SequenceNumber seq,
+                              const Slice& key,
+                              const Slice& delta,
+                              const Options& options) {
+  LookupKey lkey(key, seq);
+  Slice memkey = lkey.memtable_key();
+
+  std::unique_ptr<MemTableRep::Iterator> iter(
+      table_->GetDynamicPrefixIterator());
+  iter->Seek(lkey.internal_key(), memkey.data());
+
+  if (iter->Valid()) {
+    // entry format is:
+    //    key_length  varint32
+    //    userkey  char[klength-8]
+    //    tag      uint64
+    //    vlength  varint32
+    //    value    char[vlength]
+    // Check that it belongs to same user key.  We do not check the
+    // sequence number since the Seek() call above should have skipped
+    // all entries with overly large sequence numbers.
+    const char* entry = iter->key();
+    uint32_t key_length = 0;
+    const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
+    if (comparator_.comparator.user_comparator()->Compare(
+        Slice(key_ptr, key_length - 8), lkey.user_key()) == 0) {
+      // Correct user key
+      const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
+      switch (static_cast<ValueType>(tag & 0xff)) {
+        case kTypeValue: {
+          Slice prev_value = GetLengthPrefixedSlice(key_ptr + key_length);
+          uint32_t  prev_size = prev_value.size();
+
+          char* prev_buffer = const_cast<char*>(prev_value.data());
+          uint32_t  new_prev_size = prev_size;
+
+          std::string str_value;
+          WriteLock wl(GetLock(lkey.user_key()));
+          auto status = options.inplace_callback(prev_buffer, &new_prev_size,
+                                                    delta, &str_value);
+          if (status == UpdateStatus::UPDATED_INPLACE) {
+            // Value already updated by callback.
+            assert(new_prev_size <= prev_size);
+            if (new_prev_size < prev_size) {
+              // overwrite the new prev_size
+              char* p = EncodeVarint32(const_cast<char*>(key_ptr) + key_length,
+                                       new_prev_size);
+              if (VarintLength(new_prev_size) < VarintLength(prev_size)) {
+                // shift the value buffer as well.
+                memcpy(p, prev_buffer, new_prev_size);
+              }
+            }
+            RecordTick(options.statistics.get(), NUMBER_KEYS_UPDATED);
+            should_flush_ = ShouldFlushNow();
+            return true;
+          } else if (status == UpdateStatus::UPDATED) {
+            Add(seq, kTypeValue, key, Slice(str_value));
+            RecordTick(options.statistics.get(), NUMBER_KEYS_WRITTEN);
+            should_flush_ = ShouldFlushNow();
+            return true;
+          } else if (status == UpdateStatus::UPDATE_FAILED) {
+            // No action required. Return.
+            should_flush_ = ShouldFlushNow();
+            return true;
+          }
+        }
+        default:
+          break;
+      }
+    }
+  }
+  // If the latest value is not kTypeValue
+  // or key doesn't exist
  return false;
 }

@@ -330,17 +584,17 @@ size_t MemTable::CountSuccessiveMergeEntries(const LookupKey& key) {
  // reps). By passing in the user key, we allow efficient iterator creation.
  // The iterator only needs to be ordered within the same user key.
  std::unique_ptr<MemTableRep::Iterator> iter(
-      table_->GetIterator(key.user_key()));
-  iter->Seek(memkey.data());
+      table_->GetDynamicPrefixIterator());
+  iter->Seek(key.internal_key(), memkey.data());

  size_t num_successive_merges = 0;

  for (; iter->Valid(); iter->Next()) {
    const char* entry = iter->key();
-    uint32_t key_length;
+    uint32_t key_length = 0;
    const char* iter_key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
-    if (!comparator_.comparator.user_comparator()->Compare(
-        Slice(iter_key_ptr, key_length - 8), key.user_key()) == 0) {
+    if (comparator_.comparator.user_comparator()->Compare(
+            Slice(iter_key_ptr, key_length - 8), key.user_key()) != 0) {
      break;
    }

@@ -355,4 +609,13 @@ size_t MemTable::CountSuccessiveMergeEntries(const LookupKey& key) {
  return num_successive_merges;
 }

+void MemTableRep::Get(const LookupKey& k, void* callback_args,
+                      bool (*callback_func)(void* arg, const char* entry)) {
+  auto iter = GetDynamicPrefixIterator();
+  for (iter->Seek(k.internal_key(), k.memtable_key().data());
+       iter->Valid() && callback_func(callback_args, iter->key());
+       iter->Next()) {
+  }
+}
+
 }  // namespace rocksdb
@@ -13,13 +13,15 @@
 #include <deque>
 #include "db/dbformat.h"
 #include "db/skiplist.h"
-#include "db/version_set.h"
+#include "db/version_edit.h"
 #include "rocksdb/db.h"
 #include "rocksdb/memtablerep.h"
-#include "util/arena_impl.h"
+#include "util/arena.h"
+#include "util/dynamic_bloom.h"

 namespace rocksdb {

+class Arena;
 class Mutex;
 class MemTableIterator;
 class MergeContext;
@@ -29,13 +31,16 @@ class MemTable {
  struct KeyComparator : public MemTableRep::KeyComparator {
    const InternalKeyComparator comparator;
    explicit KeyComparator(const InternalKeyComparator& c) : comparator(c) { }
-    virtual int operator()(const char* a, const char* b) const;
+    virtual int operator()(const char* prefix_len_key1,
+                           const char* prefix_len_key2) const;
+    virtual int operator()(const char* prefix_len_key,
+                           const Slice& key) const override;
  };

  // MemTables are reference counted.  The initial reference count
  // is zero and the caller must call Ref() at least once.
  explicit MemTable(const InternalKeyComparator& comparator,
-                    const Options& options = Options());
+                    const Options& options);

  ~MemTable();

@@ -60,6 +65,10 @@ class MemTable {
  // operations on the same MemTable.
  size_t ApproximateMemoryUsage();

+  // This method heuristically determines if the memtable should continue to
+  // host more data.
+  bool ShouldFlush() const { return should_flush_; }
+
  // Return an iterator that yields the contents of the memtable.
  //
  // The caller must ensure that the underlying MemTable remains live
@@ -67,14 +76,14 @@ class MemTable {
  // iterator are internal keys encoded by AppendInternalKey in the
  // db/dbformat.{h,cc} module.
  //
-  // If options.prefix is supplied, it is passed to the underlying MemTableRep
-  // as a hint that the iterator only need to support access to keys with that
-  // specific prefix.
-  // If options.prefix is not supplied and options.prefix_seek is set, the
-  // iterator is not bound to a specific prefix. However, the semantics of
-  // Seek is changed - the result might only include keys with the same prefix
-  // as the seek-key.
-  Iterator* NewIterator(const ReadOptions& options = ReadOptions());
+  // By default, it returns an iterator for prefix seek if prefix_extractor
+  // is configured in Options.
+  // arena: If not null, the arena needs to be used to allocate the Iterator.
+  //        Calling ~Iterator of the iterator will destroy all the states but
+  //        those allocated in arena.
+  Iterator* NewIterator(const ReadOptions& options,
+                        bool enforce_total_order = false,
+                        Arena* arena = nullptr);

  // Add an entry into memtable that maps key to value at the
  // specified sequence number and with the specified type.
@@ -94,21 +103,39 @@ class MemTable {
  bool Get(const LookupKey& key, std::string* value, Status* s,
           MergeContext& merge_context, const Options& options);

-  // Update the value and return status ok,
-  //   if key exists in current memtable
-  //     if new sizeof(new_value) <= sizeof(old_value) &&
-  //       old_value for that key is a put i.e. kTypeValue
-  //     else return false, and status - NotUpdatable()
-  //   else return false, and status - NotFound()
-  bool Update(SequenceNumber seq, ValueType type,
+  // Attempts to update the new_value inplace, else does normal Add
+  // Pseudocode
+  //   if key exists in current memtable && prev_value is of type kTypeValue
+  //     if new sizeof(new_value) <= sizeof(prev_value)
+  //       update inplace
+  //     else add(key, new_value)
+  //   else add(key, new_value)
+  void Update(SequenceNumber seq,
              const Slice& key,
              const Slice& value);

+  // If prev_value for key exits, attempts to update it inplace.
+  // else returns false
+  // Pseudocode
+  //   if key exists in current memtable && prev_value is of type kTypeValue
+  //     new_value = delta(prev_value)
+  //     if sizeof(new_value) <= sizeof(prev_value)
+  //       update inplace
+  //     else add(key, new_value)
+  //   else return false
+  bool UpdateCallback(SequenceNumber seq,
+                      const Slice& key,
+                      const Slice& delta,
+                      const Options& options);
+
  // Returns the number of successive merge entries starting from the newest
  // entry for the key up to the last non-merge entry or last entry for the
  // key in the memtable.
  size_t CountSuccessiveMergeEntries(const LookupKey& key);

+  // Get total number of entries in the mem table.
+  uint64_t GetNumEntries() const { return num_entries_; }
+
  // Returns the edits area that is needed for flushing the memtable
  VersionEdit* GetEdits() { return &edit_; }

@@ -124,33 +151,49 @@ class MemTable {
  // be flushed to storage
  void SetNextLogNumber(uint64_t num) { mem_next_logfile_number_ = num; }

-  // Returns the logfile number that can be safely deleted when this
-  // memstore is flushed to storage
-  uint64_t GetLogNumber() { return mem_logfile_number_; }
-
-  // Sets the logfile number that can be safely deleted when this
-  // memstore is flushed to storage
-  void SetLogNumber(uint64_t num) { mem_logfile_number_ = num; }
-
  // Notify the underlying storage that no more items will be added
  void MarkImmutable() { table_->MarkReadOnly(); }

+  // return true if the current MemTableRep supports merge operator.
+  bool IsMergeOperatorSupported() const {
+    return table_->IsMergeOperatorSupported();
+  }
+
+  // return true if the current MemTableRep supports snapshots.
+  bool IsSnapshotSupported() const { return table_->IsSnapshotSupported(); }
+
+  // Get the lock associated for the key
+  port::RWMutex* GetLock(const Slice& key);
+
+  const InternalKeyComparator& GetInternalKeyComparator() const {
+    return comparator_.comparator;
+  }
+
+  const Arena& TEST_GetArena() const { return arena_; }
+
 private:
+  // Dynamically check if we can add more incoming entries.
+  bool ShouldFlushNow() const;
+
  friend class MemTableIterator;
  friend class MemTableBackwardIterator;
  friend class MemTableList;

  KeyComparator comparator_;
  int refs_;
-  ArenaImpl arena_impl_;
+  const size_t kArenaBlockSize;
+  const size_t kWriteBufferSize;
+  Arena arena_;
  unique_ptr<MemTableRep> table_;

+  uint64_t num_entries_;
+
  // These are used to manage memtable flushes to storage
  bool flush_in_progress_; // started the flush
  bool flush_completed_;   // finished the flush
  uint64_t file_number_;    // filled up after flush is complete

-  // The udpates to be applied to the transaction log when this
+  // The updates to be applied to the transaction log when this
  // memtable is flushed to storage.
  VersionEdit edit_;

@@ -160,10 +203,6 @@ class MemTable {
  // The log files earlier than this number can be deleted.
  uint64_t mem_next_logfile_number_;

-  // The log file that backs this memtable (to be deleted when
-  // memtable flush is done)
-  uint64_t mem_logfile_number_;
-
  // rw locks for inplace updates
  std::vector<port::RWMutex> locks_;

@@ -171,8 +210,13 @@ class MemTable {
  MemTable(const MemTable&);
  void operator=(const MemTable&);

-  // Get the lock associated for the key
-  port::RWMutex* GetLock(const Slice& key);
+  const SliceTransform* const prefix_extractor_;
+  std::unique_ptr<DynamicBloom> prefix_bloom_;
+
+  // a flag indicating if a memtable has met the criteria to flush
+  bool should_flush_;
 };

+extern const char* EncodeKey(std::string* scratch, const Slice& target);
+
 }  // namespace rocksdb
@@ -3,14 +3,17 @@
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.
 //
-#include "db/memtablelist.h"
+#include "db/memtable_list.h"

 #include <string>
 #include "rocksdb/db.h"
 #include "db/memtable.h"
+#include "db/version_set.h"
 #include "rocksdb/env.h"
 #include "rocksdb/iterator.h"
+#include "table/merger.h"
 #include "util/coding.h"
+#include "util/log_buffer.h"

 namespace rocksdb {

@@ -30,7 +33,7 @@ MemTableListVersion::MemTableListVersion(MemTableListVersion* old) {

 void MemTableListVersion::Ref() { ++refs_; }

-void MemTableListVersion::Unref(std::vector<MemTable*>* to_delete) {
+void MemTableListVersion::Unref(autovector<MemTable*>* to_delete) {
  assert(refs_ >= 1);
  --refs_;
  if (refs_ == 0) {
@@ -76,6 +79,22 @@ void MemTableListVersion::AddIterators(const ReadOptions& options,
  }
 }

+void MemTableListVersion::AddIterators(
+    const ReadOptions& options, MergeIteratorBuilder* merge_iter_builder) {
+  for (auto& m : memlist_) {
+    merge_iter_builder->AddIterator(
+        m->NewIterator(options, merge_iter_builder->GetArena()));
+  }
+}
+
+uint64_t MemTableListVersion::GetTotalNumEntries() const {
+  uint64_t total_num = 0;
+  for (auto& m : memlist_) {
+    total_num += m->GetNumEntries();
+  }
+  return total_num;
+}
+
 // caller is responsible for referencing m
 void MemTableListVersion::Add(MemTable* m) {
  assert(refs_ == 1);  // only when refs_ == 1 is MemTableListVersion mutable
@@ -92,7 +111,7 @@ void MemTableListVersion::Remove(MemTable* m) {

 // Returns true if there is at least one memtable on which flush has
 // not yet started.
-bool MemTableList::IsFlushPending() {
+bool MemTableList::IsFlushPending() const {
  if ((flush_requested_ && num_flush_not_started_ >= 1) ||
      (num_flush_not_started_ >= min_write_buffer_number_to_merge_)) {
    assert(imm_flush_needed.NoBarrier_Load() != nullptr);
@@ -102,7 +121,7 @@ bool MemTableList::IsFlushPending() {
 }

 // Returns the memtables that need to be flushed.
-void MemTableList::PickMemtablesToFlush(std::vector<MemTable*>* ret) {
+void MemTableList::PickMemtablesToFlush(autovector<MemTable*>* ret) {
  const auto& memlist = current_->memlist_;
  for (auto it = memlist.rbegin(); it != memlist.rend(); ++it) {
    MemTable* m = *it;
@@ -112,38 +131,41 @@ void MemTableList::PickMemtablesToFlush(std::vector<MemTable*>* ret) {
      if (num_flush_not_started_ == 0) {
        imm_flush_needed.Release_Store(nullptr);
      }
-      m->flush_in_progress_ = true; // flushing will start very soon
+      m->flush_in_progress_ = true;  // flushing will start very soon
      ret->push_back(m);
    }
  }
-  flush_requested_ = false; // start-flush request is complete
+  flush_requested_ = false;  // start-flush request is complete
+}
+
+void MemTableList::RollbackMemtableFlush(const autovector<MemTable*>& mems,
+                                         uint64_t file_number,
+                                         FileNumToPathIdMap* pending_outputs) {
+  assert(!mems.empty());
+
+  // If the flush was not successful, then just reset state.
+  // Maybe a suceeding attempt to flush will be successful.
+  for (MemTable* m : mems) {
+    assert(m->flush_in_progress_);
+    assert(m->file_number_ == 0);
+
+    m->flush_in_progress_ = false;
+    m->flush_completed_ = false;
+    m->edit_.Clear();
+    num_flush_not_started_++;
+  }
+  pending_outputs->erase(file_number);
+  imm_flush_needed.Release_Store(reinterpret_cast<void *>(1));
 }

 // Record a successful flush in the manifest file
 Status MemTableList::InstallMemtableFlushResults(
-    const std::vector<MemTable*>& mems, VersionSet* vset, Status flushStatus,
+    ColumnFamilyData* cfd, const autovector<MemTable*>& mems, VersionSet* vset,
    port::Mutex* mu, Logger* info_log, uint64_t file_number,
-    std::set<uint64_t>& pending_outputs, std::vector<MemTable*>* to_delete,
-    Directory* db_directory) {
+    FileNumToPathIdMap* pending_outputs, autovector<MemTable*>* to_delete,
+    Directory* db_directory, LogBuffer* log_buffer) {
  mu->AssertHeld();

-  // If the flush was not successful, then just reset state.
-  // Maybe a suceeding attempt to flush will be successful.
-  if (!flushStatus.ok()) {
-    for (MemTable* m : mems) {
-      assert(m->flush_in_progress_);
-      assert(m->file_number_ == 0);
-
-      m->flush_in_progress_ = false;
-      m->flush_completed_ = false;
-      m->edit_.Clear();
-      num_flush_not_started_++;
-      imm_flush_needed.Release_Store((void *)1);
-      pending_outputs.erase(file_number);
-    }
-    return flushStatus;
-  }
-
  // flush was sucessful
  for (size_t i = 0; i < mems.size(); ++i) {
    // All the edits are associated with the first memtable of this batch.
@@ -171,12 +193,11 @@ Status MemTableList::InstallMemtableFlushResults(
      break;
    }

-    Log(info_log,
-        "Level-0 commit table #%lu started",
-        (unsigned long)m->file_number_);
+    LogToBuffer(log_buffer, "[%s] Level-0 commit table #%lu started",
+                cfd->GetName().c_str(), (unsigned long)m->file_number_);

    // this can release and reacquire the mutex.
-    s = vset->LogAndApply(&m->edit_, mu, db_directory);
+    s = vset->LogAndApply(cfd, &m->edit_, mu, db_directory);

    // we will be changing the version in the next code path,
    // so we better create a new one, since versions are immutable
@@ -187,10 +208,10 @@ Status MemTableList::InstallMemtableFlushResults(
    uint64_t mem_id = 1;  // how many memtables has been flushed.
    do {
      if (s.ok()) { // commit new state
-        Log(info_log,
-            "Level-0 commit table #%lu: memtable #%lu done",
-            (unsigned long)m->file_number_,
-            (unsigned long)mem_id);
+        LogToBuffer(log_buffer,
+                    "[%s] Level-0 commit table #%lu: memtable #%lu done",
+                    cfd->GetName().c_str(), (unsigned long)m->file_number_,
+                    (unsigned long)mem_id);
        current_->Remove(m);
        assert(m->file_number_ > 0);

@@ -198,7 +219,7 @@ Status MemTableList::InstallMemtableFlushResults(
        // has been written to a committed version so that other concurrently
        // executing compaction threads do not mistakenly assume that this
        // file is not live.
-        pending_outputs.erase(m->file_number_);
+        pending_outputs->erase(m->file_number_);
        if (m->Unref() != nullptr) {
          to_delete->push_back(m);
        }
@@ -212,10 +233,9 @@ Status MemTableList::InstallMemtableFlushResults(
        m->flush_in_progress_ = false;
        m->edit_.Clear();
        num_flush_not_started_++;
-        pending_outputs.erase(m->file_number_);
+        pending_outputs->erase(m->file_number_);
        m->file_number_ = 0;
        imm_flush_needed.Release_Store((void *)1);
-        s = Status::IOError("Unable to commit flushed memtable");
      }
      ++mem_id;
    } while (!current_->memlist_.empty() && (m = current_->memlist_.back()) &&
@@ -3,22 +3,33 @@
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.
 //
-
 #pragma once
+
 #include <string>
 #include <list>
 #include <vector>
+#include <set>
+#include <deque>
 #include "rocksdb/db.h"
 #include "rocksdb/options.h"
 #include "rocksdb/iterator.h"
+
 #include "db/dbformat.h"
+#include "db/filename.h"
 #include "db/skiplist.h"
-#include "memtable.h"
+#include "db/memtable.h"
+#include "rocksdb/db.h"
+#include "rocksdb/iterator.h"
+#include "rocksdb/options.h"
+#include "util/autovector.h"
+#include "util/log_buffer.h"

 namespace rocksdb {

+class ColumnFamilyData;
 class InternalKeyComparator;
 class Mutex;
+class MergeIteratorBuilder;

 // keeps a list of immutable memtables in a vector. the list is immutable
 // if refcount is bigger than one. It is used as a state for Get() and
@@ -28,7 +39,7 @@ class MemTableListVersion {
  explicit MemTableListVersion(MemTableListVersion* old = nullptr);

  void Ref();
-  void Unref(std::vector<MemTable*>* to_delete = nullptr);
+  void Unref(autovector<MemTable*>* to_delete = nullptr);

  int size() const;

@@ -40,6 +51,11 @@ class MemTableListVersion {
  void AddIterators(const ReadOptions& options,
                    std::vector<Iterator*>* iterator_list);

+  void AddIterators(const ReadOptions& options,
+                    MergeIteratorBuilder* merge_iter_builder);
+
+  uint64_t GetTotalNumEntries() const;
+
 private:
  // REQUIRE: m is mutable memtable
  void Add(MemTable* m);
@@ -74,8 +90,8 @@ class MemTableList {

  MemTableListVersion* current() { return current_; }

-  // so that backgrund threads can detect non-nullptr pointer to
-  // determine whether this is anything more to start flushing.
+  // so that background threads can detect non-nullptr pointer to
+  // determine whether there is anything more to start flushing.
  port::AtomicPointer imm_flush_needed;

  // Returns the total number of memtables in the list
@@ -83,20 +99,24 @@ class MemTableList {

  // Returns true if there is at least one memtable on which flush has
  // not yet started.
-  bool IsFlushPending();
+  bool IsFlushPending() const;

  // Returns the earliest memtables that needs to be flushed. The returned
  // memtables are guaranteed to be in the ascending order of created time.
-  void PickMemtablesToFlush(std::vector<MemTable*>* mems);
+  void PickMemtablesToFlush(autovector<MemTable*>* mems);
+
+  // Reset status of the given memtable list back to pending state so that
+  // they can get picked up again on the next round of flush.
+  void RollbackMemtableFlush(const autovector<MemTable*>& mems,
+                             uint64_t file_number,
+                             FileNumToPathIdMap* pending_outputs);

  // Commit a successful flush in the manifest file
-  Status InstallMemtableFlushResults(const std::vector<MemTable*>& m,
-                                     VersionSet* vset, Status flushStatus,
-                                     port::Mutex* mu, Logger* info_log,
-                                     uint64_t file_number,
-                                     std::set<uint64_t>& pending_outputs,
-                                     std::vector<MemTable*>* to_delete,
-                                     Directory* db_directory);
+  Status InstallMemtableFlushResults(
+      ColumnFamilyData* cfd, const autovector<MemTable*>& m, VersionSet* vset,
+      port::Mutex* mu, Logger* info_log, uint64_t file_number,
+      FileNumToPathIdMap* pending_outputs, autovector<MemTable*>* to_delete,
+      Directory* db_directory, LogBuffer* log_buffer);

  // New memtables are inserted at the front of the list.
  // Takes ownership of the referenced held on *m by the caller of Add().
@@ -25,12 +25,12 @@ public:
      operand_list->clear();
    }
  }
-  // Replace the first two operands of merge_result, which are expected be the
-  // merge results of them.
+  // Replace all operands with merge_result, which are expected to be the
+  // merge result of them.
  void PushPartialMergeResult(std::string& merge_result) {
    assert (operand_list);
-    operand_list->pop_front();
-    swap(operand_list->front(), merge_result);
+    operand_list->clear();
+    operand_list->push_front(std::move(merge_result));
  }
  // Push a merge operand
  void PushOperand(const Slice& operand_slice) {
@@ -21,7 +21,7 @@ namespace rocksdb {
 //       operands_ stores the list of merge operands encountered while merging.
 //       keys_[i] corresponds to operands_[i] for each i.
 void MergeHelper::MergeUntil(Iterator* iter, SequenceNumber stop_before,
-                             bool at_bottom, Statistics* stats) {
+                             bool at_bottom, Statistics* stats, int* steps) {
  // Get a copy of the internal key, before it's invalidated by iter->Next()
  // Also maintain the list of merge operands seen.
  keys_.clear();
@@ -40,9 +40,12 @@ void MergeHelper::MergeUntil(Iterator* iter, SequenceNumber stop_before,
  ParseInternalKey(keys_.back(), &orig_ikey);

  bool hit_the_next_user_key = false;
-  ParsedInternalKey ikey;
  std::string merge_result;  // Temporary value for merge results
+  if (steps) {
+    ++(*steps);
+  }
  for (iter->Next(); iter->Valid(); iter->Next()) {
+    ParsedInternalKey ikey;
    assert(operands_.size() >= 1);        // Should be invariants!
    assert(keys_.size() == operands_.size());

@@ -91,6 +94,9 @@ void MergeHelper::MergeUntil(Iterator* iter, SequenceNumber stop_before,

      // move iter to the next entry (before doing anything else)
      iter->Next();
+      if (steps) {
+        ++(*steps);
+      }
      return;
    }

@@ -119,6 +125,9 @@ void MergeHelper::MergeUntil(Iterator* iter, SequenceNumber stop_before,

      // move iter to the next entry
      iter->Next();
+      if (steps) {
+        ++(*steps);
+      }
      return;
    }

@@ -129,28 +138,13 @@ void MergeHelper::MergeUntil(Iterator* iter, SequenceNumber stop_before,
      //   => then continue because we haven't yet seen a Put/Delete.
      assert(!operands_.empty()); // Should have at least one element in it

+      // keep queuing keys and operands until we either meet a put / delete
+      // request or later did a partial merge.
      keys_.push_front(iter->key().ToString());
      operands_.push_front(iter->value().ToString());
-      while (operands_.size() >= 2) {
-        // Returns false when the merge_operator can no longer process it
-        if (user_merge_operator_->PartialMerge(ikey.user_key,
-                                               Slice(operands_[0]),
-                                               Slice(operands_[1]),
-                                               &merge_result,
-                                               logger_)) {
-          // Merging of operands (associative merge) was successful.
-          // Replace these frontmost two operands with the merge result
-          keys_.pop_front();
-          operands_.pop_front();
-          swap(operands_.front(), merge_result);
-        } else {
-          // Merging of operands (associative merge) returned false.
-          // The user merge_operator does not know how to merge these operands.
-          // So we just stack them up until we find a Put/Delete or end of key.
-          break;
-        }
+      if (steps) {
+        ++(*steps);
      }
-      continue;
    }
  }

@@ -192,6 +186,23 @@ void MergeHelper::MergeUntil(Iterator* iter, SequenceNumber stop_before,
      RecordTick(stats, NUMBER_MERGE_FAILURES);
      // Do nothing if not success_. Leave keys() and operands() as they are.
    }
+  } else {
+    // We haven't seen the beginning of the key nor a Put/Delete.
+    // Attempt to use the user's associative merge function to
+    // merge the stacked merge operands into a single operand.
+
+    if (operands_.size() >= 2 &&
+        operands_.size() >= min_partial_merge_operands_ &&
+        user_merge_operator_->PartialMergeMulti(
+            orig_ikey.user_key,
+            std::deque<Slice>(operands_.begin(), operands_.end()),
+            &merge_result, logger_)) {
+      // Merging of operands (associative merge) was successful.
+      // Replace operands with the merge result
+      operands_.clear();
+      operands_.push_front(std::move(merge_result));
+      keys_.erase(keys_.begin(), keys_.end() - 1);
+    }
  }
 }

@@ -22,12 +22,13 @@ class Statistics;
 class MergeHelper {
 public:
  MergeHelper(const Comparator* user_comparator,
-              const MergeOperator* user_merge_operator,
-              Logger* logger,
+              const MergeOperator* user_merge_operator, Logger* logger,
+              unsigned min_partial_merge_operands,
              bool assert_valid_internal_key)
      : user_comparator_(user_comparator),
        user_merge_operator_(user_merge_operator),
        logger_(logger),
+        min_partial_merge_operands_(min_partial_merge_operands),
        assert_valid_internal_key_(assert_valid_internal_key),
        keys_(),
        operands_(),
@@ -46,7 +47,8 @@ class MergeHelper {
  // at_bottom:   (IN) true if the iterator covers the bottem level, which means
  //                   we could reach the start of the history of this user key.
  void MergeUntil(Iterator* iter, SequenceNumber stop_before = 0,
-                  bool at_bottom = false, Statistics* stats = nullptr);
+                  bool at_bottom = false, Statistics* stats = nullptr,
+                  int* steps = nullptr);

  // Query the merge result
  // These are valid until the next MergeUntil call
@@ -88,6 +90,7 @@ class MergeHelper {
  const Comparator* user_comparator_;
  const MergeOperator* user_merge_operator_;
  Logger* logger_;
+  unsigned min_partial_merge_operands_;
  bool assert_valid_internal_key_; // enforce no internal key corruption?

  // the scratch area that holds the result of MergeUntil
@@ -11,6 +11,31 @@

 namespace rocksdb {

+// The default implementation of PartialMergeMulti, which invokes
+// PartialMerge multiple times internally and merges two operands at
+// a time.
+bool MergeOperator::PartialMergeMulti(const Slice& key,
+                                      const std::deque<Slice>& operand_list,
+                                      std::string* new_value,
+                                      Logger* logger) const {
+  assert(operand_list.size() >= 2);
+  // Simply loop through the operands
+  std::string temp_value;
+  Slice temp_slice(operand_list[0]);
+
+  for (size_t i = 1; i < operand_list.size(); ++i) {
+    auto& operand = operand_list[i];
+    if (!PartialMerge(key, temp_slice, operand, &temp_value, logger)) {
+      return false;
+    }
+    swap(temp_value, *new_value);
+    temp_slice = Slice(*new_value);
+  }
+
+  // The result will be in *new_value. All merges succeeded.
+  return true;
+}
+
 // Given a "real" merge from the library, call the user's
 // associative merge function one-by-one on each of the operands.
 // NOTE: It is assumed that the client's merge-operator will handle any errors.
@@ -46,7 +71,6 @@ bool AssociativeMergeOperator::PartialMerge(
    const Slice& right_operand,
    std::string* new_value,
    Logger* logger) const {
-
  return Merge(key, &left_operand, right_operand, new_value, logger);
 }

@@ -17,17 +17,21 @@
 #include "db/write_batch_internal.h"
 #include "utilities/merge_operators.h"
 #include "util/testharness.h"
-#include "utilities/utility_db.h"
+#include "utilities/db_ttl.h"

 using namespace std;
 using namespace rocksdb;

 namespace {
  int numMergeOperatorCalls;
-
  void resetNumMergeOperatorCalls() {
    numMergeOperatorCalls = 0;
  }
+
+  int num_partial_merge_calls;
+  void resetNumPartialMergeCalls() {
+    num_partial_merge_calls = 0;
+  }
 }

 class CountMergeOperator : public AssociativeMergeOperator {
@@ -42,6 +46,11 @@ class CountMergeOperator : public AssociativeMergeOperator {
                     std::string* new_value,
                     Logger* logger) const override {
    ++numMergeOperatorCalls;
+    if (existing_value == nullptr) {
+      new_value->assign(value.data(), value.size());
+      return true;
+    }
+
    return mergeOperator_->PartialMerge(
        key,
        *existing_value,
@@ -50,6 +59,14 @@ class CountMergeOperator : public AssociativeMergeOperator {
        logger);
  }

+  virtual bool PartialMergeMulti(const Slice& key,
+                                 const std::deque<Slice>& operand_list,
+                                 std::string* new_value, Logger* logger) const {
+    ++num_partial_merge_calls;
+    return mergeOperator_->PartialMergeMulti(key, operand_list, new_value,
+                                             logger);
+  }
+
  virtual const char* Name() const override {
    return "UInt64AddOperator";
  }
@@ -58,22 +75,23 @@ class CountMergeOperator : public AssociativeMergeOperator {
  std::shared_ptr<MergeOperator> mergeOperator_;
 };

-std::shared_ptr<DB> OpenDb(
-    const string& dbname,
-    const bool ttl = false,
-    const unsigned max_successive_merges = 0) {
+namespace {
+std::shared_ptr<DB> OpenDb(const string& dbname, const bool ttl = false,
+                           const size_t max_successive_merges = 0,
+                           const uint32_t min_partial_merge_operands = 2) {
  DB* db;
-  StackableDB* sdb;
  Options options;
  options.create_if_missing = true;
  options.merge_operator = std::make_shared<CountMergeOperator>();
  options.max_successive_merges = max_successive_merges;
+  options.min_partial_merge_operands = min_partial_merge_operands;
  Status s;
  DestroyDB(dbname, Options());
  if (ttl) {
    cout << "Opening database with TTL\n";
-    s = UtilityDB::OpenTtlDB(options, dbname, &sdb);
-    db = sdb;
+    DBWithTTL* db_with_ttl;
+    s = DBWithTTL::Open(options, dbname, &db_with_ttl);
+    db = db_with_ttl;
  } else {
    s = DB::Open(options, dbname, &db);
  }
@@ -83,6 +101,7 @@ std::shared_ptr<DB> OpenDb(
  }
  return std::shared_ptr<DB>(db);
 }
+}  // namespace

 // Imagine we are maintaining a set of uint64 counters.
 // Each counter has a distinct name. And we would like
@@ -184,12 +203,16 @@ class Counters {

  uint64_t assert_get(const string& key) {
    uint64_t value = default_;
-    assert(get(key, &value));
+    int result = get(key, &value);
+    assert(result);
+    if (result == 0) exit(1); // Disable unused variable warning.
    return value;
  }

  void assert_add(const string& key, uint64_t value) {
-    assert(add(key, value));
+    int result = add(key, value);
+    assert(result);
+    if (result == 0) exit(1); // Disable unused variable warning. 
  }
 };

@@ -220,6 +243,7 @@ class MergeBasedCounters : public Counters {
  }
 };

+namespace {
 void dumpDb(DB* db) {
  auto it = unique_ptr<Iterator>(db->NewIterator(ReadOptions()));
  for (it->SeekToFirst(); it->Valid(); it->Next()) {
@@ -306,6 +330,44 @@ void testSuccessiveMerge(
  }
 }

+void testPartialMerge(Counters* counters, DB* db, int max_merge, int min_merge,
+                      int count) {
+  FlushOptions o;
+  o.wait = true;
+
+  // Test case 1: partial merge should be called when the number of merge
+  //              operands exceeds the threshold.
+  uint64_t tmp_sum = 0;
+  resetNumPartialMergeCalls();
+  for (int i = 1; i <= count; i++) {
+    counters->assert_add("b", i);
+    tmp_sum += i;
+  }
+  db->Flush(o);
+  db->CompactRange(nullptr, nullptr);
+  ASSERT_EQ(tmp_sum, counters->assert_get("b"));
+  if (count > max_merge) {
+    // in this case, FullMerge should be called instead.
+    ASSERT_EQ(num_partial_merge_calls, 0);
+  } else {
+    // if count >= min_merge, then partial merge should be called once.
+    ASSERT_EQ((count >= min_merge), (num_partial_merge_calls == 1));
+  }
+
+  // Test case 2: partial merge should not be called when a put is found.
+  resetNumPartialMergeCalls();
+  tmp_sum = 0;
+  db->Put(rocksdb::WriteOptions(), "c", "10");
+  for (int i = 1; i <= count; i++) {
+    counters->assert_add("c", i);
+    tmp_sum += i;
+  }
+  db->Flush(o);
+  db->CompactRange(nullptr, nullptr);
+  ASSERT_EQ(tmp_sum, counters->assert_get("c"));
+  ASSERT_EQ(num_partial_merge_calls, 0);
+}
+
 void testSingleBatchSuccessiveMerge(
    DB* db,
    int max_num_merges,
@@ -370,20 +432,41 @@ void runTest(int argc, const string& dbname, const bool use_ttl = false) {

  {
    cout << "Test merge in memtable... \n";
-    unsigned maxMerge = 5;
-    auto db = OpenDb(dbname, use_ttl, maxMerge);
+    size_t max_merge = 5;
+    auto db = OpenDb(dbname, use_ttl, max_merge);
    MergeBasedCounters counters(db, 0);
    testCounters(counters, db.get(), compact);
-    testSuccessiveMerge(counters, maxMerge, maxMerge * 2);
+    testSuccessiveMerge(counters, max_merge, max_merge * 2);
    testSingleBatchSuccessiveMerge(db.get(), 5, 7);
    DestroyDB(dbname, Options());
  }

+  {
+    cout << "Test Partial-Merge\n";
+    size_t max_merge = 100;
+    for (uint32_t min_merge = 5; min_merge < 25; min_merge += 5) {
+      for (uint32_t count = min_merge - 1; count <= min_merge + 1; count++) {
+        auto db = OpenDb(dbname, use_ttl, max_merge, min_merge);
+        MergeBasedCounters counters(db, 0);
+        testPartialMerge(&counters, db.get(), max_merge, min_merge, count);
+        DestroyDB(dbname, Options());
+      }
+      {
+        auto db = OpenDb(dbname, use_ttl, max_merge, min_merge);
+        MergeBasedCounters counters(db, 0);
+        testPartialMerge(&counters, db.get(), max_merge, min_merge,
+                         min_merge * 10);
+        DestroyDB(dbname, Options());
+      }
+    }
+  }
 }
+}  // namespace

 int main(int argc, char *argv[]) {
  //TODO: Make this test like a general rocksdb unit-test
  runTest(argc, test::TmpDir() + "/merge_testdb");
  runTest(argc, test::TmpDir() + "/merge_testdbttl", true); // Run test on TTL database
+  printf("Passed all tests!\n");
  return 0;
 }
@@ -10,6 +10,8 @@

 #include "rocksdb/db.h"
 #include "rocksdb/perf_context.h"
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/memtablerep.h"
 #include "util/histogram.h"
 #include "util/stop_watch.h"
 #include "util/testharness.h"
@@ -174,6 +176,13 @@ void ProfileKeyComparison() {

  HistogramImpl hist_put;
  HistogramImpl hist_get;
+  HistogramImpl hist_get_snapshot;
+  HistogramImpl hist_get_memtable;
+  HistogramImpl hist_get_post_process;
+  HistogramImpl hist_num_memtable_checked;
+  HistogramImpl hist_write_pre_post;
+  HistogramImpl hist_write_wal_time;
+  HistogramImpl hist_write_memtable_time;

  std::cout << "Inserting " << FLAGS_total_keys << " key/value pairs\n...\n";

@@ -192,16 +201,37 @@ void ProfileKeyComparison() {

    perf_context.Reset();
    db->Put(write_options, key, value);
+    hist_write_pre_post.Add(perf_context.write_pre_and_post_process_time);
+    hist_write_wal_time.Add(perf_context.write_wal_time);
+    hist_write_memtable_time.Add(perf_context.write_memtable_time);
    hist_put.Add(perf_context.user_key_comparison_count);

    perf_context.Reset();
    db->Get(read_options, key, &value);
+    hist_get_snapshot.Add(perf_context.get_snapshot_time);
+    hist_get_memtable.Add(perf_context.get_from_memtable_time);
+    hist_num_memtable_checked.Add(perf_context.get_from_memtable_count);
+    hist_get_post_process.Add(perf_context.get_post_process_time);
    hist_get.Add(perf_context.user_key_comparison_count);
  }

  std::cout << "Put uesr key comparison: \n" << hist_put.ToString()
            << "Get uesr key comparison: \n" << hist_get.ToString();
+  std::cout << "Put(): Pre and Post Process Time: \n"
+            << hist_write_pre_post.ToString()
+            << " Writing WAL time: \n"
+            << hist_write_wal_time.ToString() << "\n"
+            << " Writing Mem Table time: \n"
+            << hist_write_memtable_time.ToString() << "\n";

+  std::cout << "Get(): Time to get snapshot: \n"
+            << hist_get_snapshot.ToString()
+            << " Time to get value from memtables: \n"
+            << hist_get_memtable.ToString() << "\n"
+            << " Number of memtables checked: \n"
+            << hist_num_memtable_checked.ToString() << "\n"
+            << " Time to post process: \n"
+            << hist_get_post_process.ToString() << "\n";
 }

 TEST(PerfContextTest, KeyComparisonCount) {
@@ -259,8 +289,8 @@ TEST(PerfContextTest, SeekKeyComparison) {
    db->Put(write_options, key, value);
    auto put_time = timer.ElapsedNanos();
    hist_put_time.Add(put_time);
-    hist_wal_time.Add(perf_context.wal_write_time);
-    hist_time_diff.Add(put_time - perf_context.wal_write_time);
+    hist_wal_time.Add(perf_context.write_wal_time);
+    hist_time_diff.Add(put_time - perf_context.write_wal_time);
  }

  std::cout << "Put time:\n" << hist_put_time.ToString()
@@ -0,0 +1,962 @@
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+#include <algorithm>
+#include <set>
+
+#include "db/db_impl.h"
+#include "db/filename.h"
+#include "db/version_set.h"
+#include "db/write_batch_internal.h"
+#include "rocksdb/cache.h"
+#include "rocksdb/compaction_filter.h"
+#include "rocksdb/db.h"
+#include "rocksdb/env.h"
+#include "rocksdb/filter_policy.h"
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/table.h"
+#include "table/meta_blocks.h"
+#include "table/plain_table_factory.h"
+#include "table/plain_table_reader.h"
+#include "util/hash.h"
+#include "util/logging.h"
+#include "util/mutexlock.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+#include "utilities/merge_operators.h"
+
+using std::unique_ptr;
+
+namespace rocksdb {
+
+class PlainTableDBTest {
+ protected:
+ private:
+  std::string dbname_;
+  Env* env_;
+  DB* db_;
+
+  Options last_options_;
+
+ public:
+  PlainTableDBTest() : env_(Env::Default()) {
+    dbname_ = test::TmpDir() + "/plain_table_db_test";
+    ASSERT_OK(DestroyDB(dbname_, Options()));
+    db_ = nullptr;
+    Reopen();
+  }
+
+  ~PlainTableDBTest() {
+    delete db_;
+    ASSERT_OK(DestroyDB(dbname_, Options()));
+  }
+
+  // Return the current option configuration.
+  Options CurrentOptions() {
+    Options options;
+    options.table_factory.reset(NewPlainTableFactory(0, 2, 0.8, 3, 0, kPrefix));
+    options.memtable_factory.reset(NewHashLinkListRepFactory(4, 0, 3, true, 3));
+    options.prefix_extractor.reset(NewFixedPrefixTransform(8));
+    options.allow_mmap_reads = true;
+    return options;
+  }
+
+  DBImpl* dbfull() {
+    return reinterpret_cast<DBImpl*>(db_);
+  }
+
+  void Reopen(Options* options = nullptr) {
+    ASSERT_OK(TryReopen(options));
+  }
+
+  void Close() {
+    delete db_;
+    db_ = nullptr;
+  }
+
+  void DestroyAndReopen(Options* options = nullptr) {
+    //Destroy using last options
+    Destroy(&last_options_);
+    ASSERT_OK(TryReopen(options));
+  }
+
+  void Destroy(Options* options) {
+    delete db_;
+    db_ = nullptr;
+    ASSERT_OK(DestroyDB(dbname_, *options));
+  }
+
+  Status PureReopen(Options* options, DB** db) {
+    return DB::Open(*options, dbname_, db);
+  }
+
+  Status TryReopen(Options* options = nullptr) {
+    delete db_;
+    db_ = nullptr;
+    Options opts;
+    if (options != nullptr) {
+      opts = *options;
+    } else {
+      opts = CurrentOptions();
+      opts.create_if_missing = true;
+    }
+    last_options_ = opts;
+
+    return DB::Open(opts, dbname_, &db_);
+  }
+
+  Status Put(const Slice& k, const Slice& v) {
+    return db_->Put(WriteOptions(), k, v);
+  }
+
+  Status Delete(const std::string& k) {
+    return db_->Delete(WriteOptions(), k);
+  }
+
+  std::string Get(const std::string& k, const Snapshot* snapshot = nullptr) {
+    ReadOptions options;
+    options.snapshot = snapshot;
+    std::string result;
+    Status s = db_->Get(options, k, &result);
+    if (s.IsNotFound()) {
+      result = "NOT_FOUND";
+    } else if (!s.ok()) {
+      result = s.ToString();
+    }
+    return result;
+  }
+
+
+  int NumTableFilesAtLevel(int level) {
+    std::string property;
+    ASSERT_TRUE(
+        db_->GetProperty("rocksdb.num-files-at-level" + NumberToString(level),
+                         &property));
+    return atoi(property.c_str());
+  }
+
+  // Return spread of files per level
+  std::string FilesPerLevel() {
+    std::string result;
+    int last_non_zero_offset = 0;
+    for (int level = 0; level < db_->NumberLevels(); level++) {
+      int f = NumTableFilesAtLevel(level);
+      char buf[100];
+      snprintf(buf, sizeof(buf), "%s%d", (level ? "," : ""), f);
+      result += buf;
+      if (f > 0) {
+        last_non_zero_offset = result.size();
+      }
+    }
+    result.resize(last_non_zero_offset);
+    return result;
+  }
+
+  std::string IterStatus(Iterator* iter) {
+    std::string result;
+    if (iter->Valid()) {
+      result = iter->key().ToString() + "->" + iter->value().ToString();
+    } else {
+      result = "(invalid)";
+    }
+    return result;
+  }
+};
+
+TEST(PlainTableDBTest, Empty) {
+  ASSERT_TRUE(dbfull() != nullptr);
+  ASSERT_EQ("NOT_FOUND", Get("0000000000000foo"));
+}
+
+class TestPlainTableReader : public PlainTableReader {
+ public:
+  TestPlainTableReader(const EnvOptions& storage_options,
+                       const InternalKeyComparator& icomparator,
+                       EncodingType encoding_type, uint64_t file_size,
+                       int bloom_bits_per_key, double hash_table_ratio,
+                       size_t index_sparseness,
+                       const TableProperties* table_properties,
+                       unique_ptr<RandomAccessFile>&& file,
+                       const Options& options, bool* expect_bloom_not_match)
+      : PlainTableReader(options, std::move(file), storage_options, icomparator,
+                         encoding_type, file_size, table_properties),
+        expect_bloom_not_match_(expect_bloom_not_match) {
+    Status s = MmapDataFile();
+    ASSERT_TRUE(s.ok());
+
+    s = PopulateIndex(const_cast<TableProperties*>(table_properties),
+                      bloom_bits_per_key, hash_table_ratio, index_sparseness,
+                      2 * 1024 * 1024);
+    ASSERT_TRUE(s.ok());
+  }
+
+  virtual ~TestPlainTableReader() {}
+
+ private:
+  virtual bool MatchBloom(uint32_t hash) const override {
+    bool ret = PlainTableReader::MatchBloom(hash);
+    ASSERT_TRUE(!*expect_bloom_not_match_ || !ret);
+    return ret;
+  }
+  bool* expect_bloom_not_match_;
+};
+
+extern const uint64_t kPlainTableMagicNumber;
+class TestPlainTableFactory : public PlainTableFactory {
+ public:
+  explicit TestPlainTableFactory(bool* expect_bloom_not_match,
+                                 uint32_t user_key_len, int bloom_bits_per_key,
+                                 double hash_table_ratio,
+                                 size_t index_sparseness,
+                                 size_t huge_page_tlb_size,
+                                 EncodingType encoding_type)
+      : PlainTableFactory(user_key_len, bloom_bits_per_key, hash_table_ratio,
+                          index_sparseness, huge_page_tlb_size, encoding_type),
+        bloom_bits_per_key_(bloom_bits_per_key),
+        hash_table_ratio_(hash_table_ratio),
+        index_sparseness_(index_sparseness),
+        expect_bloom_not_match_(expect_bloom_not_match) {}
+
+  Status NewTableReader(const Options& options, const EnvOptions& soptions,
+                        const InternalKeyComparator& internal_comparator,
+                        unique_ptr<RandomAccessFile>&& file, uint64_t file_size,
+                        unique_ptr<TableReader>* table) const override {
+    TableProperties* props = nullptr;
+    auto s = ReadTableProperties(file.get(), file_size, kPlainTableMagicNumber,
+                                 options.env, options.info_log.get(), &props);
+    ASSERT_TRUE(s.ok());
+
+    auto& user_props = props->user_collected_properties;
+    auto encoding_type_prop =
+        user_props.find(PlainTablePropertyNames::kEncodingType);
+    assert(encoding_type_prop != user_props.end());
+    EncodingType encoding_type = static_cast<EncodingType>(
+        DecodeFixed32(encoding_type_prop->second.c_str()));
+
+    std::unique_ptr<PlainTableReader> new_reader(new TestPlainTableReader(
+        soptions, internal_comparator, encoding_type, file_size,
+        bloom_bits_per_key_, hash_table_ratio_, index_sparseness_, props,
+        std::move(file), options, expect_bloom_not_match_));
+
+    *table = std::move(new_reader);
+    return s;
+  }
+
+ private:
+  int bloom_bits_per_key_;
+  double hash_table_ratio_;
+  size_t index_sparseness_;
+  bool* expect_bloom_not_match_;
+};
+
+TEST(PlainTableDBTest, Flush) {
+  for (size_t huge_page_tlb_size = 0; huge_page_tlb_size <= 2 * 1024 * 1024;
+       huge_page_tlb_size += 2 * 1024 * 1024) {
+    for (EncodingType encoding_type : {kPlain, kPrefix}) {
+    for (int bloom_bits = 0; bloom_bits <= 117; bloom_bits += 117) {
+      for (int total_order = 0; total_order <= 1; total_order++) {
+        Options options = CurrentOptions();
+        options.create_if_missing = true;
+        // Set only one bucket to force bucket conflict.
+        // Test index interval for the same prefix to be 1, 2 and 4
+        if (total_order) {
+          options.prefix_extractor.reset();
+          options.table_factory.reset(NewPlainTableFactory(
+              0, bloom_bits, 0, 2, huge_page_tlb_size, encoding_type));
+        } else {
+          options.table_factory.reset(NewPlainTableFactory(
+              0, bloom_bits, 0.75, 16, huge_page_tlb_size, encoding_type));
+        }
+        DestroyAndReopen(&options);
+
+        ASSERT_OK(Put("1000000000000foo", "v1"));
+        ASSERT_OK(Put("0000000000000bar", "v2"));
+        ASSERT_OK(Put("1000000000000foo", "v3"));
+        dbfull()->TEST_FlushMemTable();
+
+        TablePropertiesCollection ptc;
+        reinterpret_cast<DB*>(dbfull())->GetPropertiesOfAllTables(&ptc);
+        ASSERT_EQ(1U, ptc.size());
+        auto row = ptc.begin();
+        auto tp = row->second;
+        ASSERT_EQ(total_order ? "4" : "12", (tp->user_collected_properties).at(
+                                                "plain_table_hash_table_size"));
+        ASSERT_EQ("0", (tp->user_collected_properties)
+                           .at("plain_table_sub_index_size"));
+
+        ASSERT_EQ("v3", Get("1000000000000foo"));
+        ASSERT_EQ("v2", Get("0000000000000bar"));
+      }
+    }
+    }
+  }
+}
+
+TEST(PlainTableDBTest, Flush2) {
+  for (size_t huge_page_tlb_size = 0; huge_page_tlb_size <= 2 * 1024 * 1024;
+       huge_page_tlb_size += 2 * 1024 * 1024) {
+    for (EncodingType encoding_type : {kPlain, kPrefix}) {
+    for (int bloom_bits = 0; bloom_bits <= 117; bloom_bits += 117) {
+      for (int total_order = 0; total_order <= 1; total_order++) {
+        if (encoding_type == kPrefix && total_order == 1) {
+          continue;
+        }
+        bool expect_bloom_not_match = false;
+        Options options = CurrentOptions();
+        options.create_if_missing = true;
+        // Set only one bucket to force bucket conflict.
+        // Test index interval for the same prefix to be 1, 2 and 4
+        if (total_order) {
+          options.prefix_extractor = nullptr;
+          options.table_factory.reset(new TestPlainTableFactory(
+              &expect_bloom_not_match, 0, bloom_bits, 0, 2, huge_page_tlb_size,
+              encoding_type));
+        } else {
+          options.table_factory.reset(new TestPlainTableFactory(
+              &expect_bloom_not_match, 0, bloom_bits, 0.75, 16,
+              huge_page_tlb_size, encoding_type));
+        }
+        DestroyAndReopen(&options);
+        ASSERT_OK(Put("0000000000000bar", "b"));
+        ASSERT_OK(Put("1000000000000foo", "v1"));
+        dbfull()->TEST_FlushMemTable();
+
+        ASSERT_OK(Put("1000000000000foo", "v2"));
+        dbfull()->TEST_FlushMemTable();
+        ASSERT_EQ("v2", Get("1000000000000foo"));
+
+        ASSERT_OK(Put("0000000000000eee", "v3"));
+        dbfull()->TEST_FlushMemTable();
+        ASSERT_EQ("v3", Get("0000000000000eee"));
+
+        ASSERT_OK(Delete("0000000000000bar"));
+        dbfull()->TEST_FlushMemTable();
+        ASSERT_EQ("NOT_FOUND", Get("0000000000000bar"));
+
+        ASSERT_OK(Put("0000000000000eee", "v5"));
+        ASSERT_OK(Put("9000000000000eee", "v5"));
+        dbfull()->TEST_FlushMemTable();
+        ASSERT_EQ("v5", Get("0000000000000eee"));
+
+        // Test Bloom Filter
+        if (bloom_bits > 0) {
+          // Neither key nor value should exist.
+          expect_bloom_not_match = true;
+          ASSERT_EQ("NOT_FOUND", Get("5_not00000000bar"));
+
+          // Key doesn't exist any more but prefix exists.
+          if (total_order) {
+            ASSERT_EQ("NOT_FOUND", Get("1000000000000not"));
+            ASSERT_EQ("NOT_FOUND", Get("0000000000000not"));
+          }
+          expect_bloom_not_match = false;
+        }
+      }
+    }
+    }
+  }
+}
+
+TEST(PlainTableDBTest, Iterator) {
+  for (size_t huge_page_tlb_size = 0; huge_page_tlb_size <= 2 * 1024 * 1024;
+       huge_page_tlb_size += 2 * 1024 * 1024) {
+    for (EncodingType encoding_type : {kPlain, kPrefix}) {
+    for (int bloom_bits = 0; bloom_bits <= 117; bloom_bits += 117) {
+      for (int total_order = 0; total_order <= 1; total_order++) {
+        if (encoding_type == kPrefix && total_order == 1) {
+          continue;
+        }
+        bool expect_bloom_not_match = false;
+        Options options = CurrentOptions();
+        options.create_if_missing = true;
+        // Set only one bucket to force bucket conflict.
+        // Test index interval for the same prefix to be 1, 2 and 4
+        if (total_order) {
+          options.prefix_extractor = nullptr;
+          options.table_factory.reset(new TestPlainTableFactory(
+              &expect_bloom_not_match, 16, bloom_bits, 0, 2, huge_page_tlb_size,
+              encoding_type));
+        } else {
+          options.table_factory.reset(new TestPlainTableFactory(
+              &expect_bloom_not_match, 16, bloom_bits, 0.75, 16,
+              huge_page_tlb_size, encoding_type));
+        }
+        DestroyAndReopen(&options);
+
+        ASSERT_OK(Put("1000000000foo002", "v_2"));
+        ASSERT_OK(Put("0000000000000bar", "random"));
+        ASSERT_OK(Put("1000000000foo001", "v1"));
+        ASSERT_OK(Put("3000000000000bar", "bar_v"));
+        ASSERT_OK(Put("1000000000foo003", "v__3"));
+        ASSERT_OK(Put("1000000000foo004", "v__4"));
+        ASSERT_OK(Put("1000000000foo005", "v__5"));
+        ASSERT_OK(Put("1000000000foo007", "v__7"));
+        ASSERT_OK(Put("1000000000foo008", "v__8"));
+        dbfull()->TEST_FlushMemTable();
+        ASSERT_EQ("v1", Get("1000000000foo001"));
+        ASSERT_EQ("v__3", Get("1000000000foo003"));
+        Iterator* iter = dbfull()->NewIterator(ReadOptions());
+        iter->Seek("1000000000foo000");
+        ASSERT_TRUE(iter->Valid());
+        ASSERT_EQ("1000000000foo001", iter->key().ToString());
+        ASSERT_EQ("v1", iter->value().ToString());
+
+        iter->Next();
+        ASSERT_TRUE(iter->Valid());
+        ASSERT_EQ("1000000000foo002", iter->key().ToString());
+        ASSERT_EQ("v_2", iter->value().ToString());
+
+        iter->Next();
+        ASSERT_TRUE(iter->Valid());
+        ASSERT_EQ("1000000000foo003", iter->key().ToString());
+        ASSERT_EQ("v__3", iter->value().ToString());
+
+        iter->Next();
+        ASSERT_TRUE(iter->Valid());
+        ASSERT_EQ("1000000000foo004", iter->key().ToString());
+        ASSERT_EQ("v__4", iter->value().ToString());
+
+        iter->Seek("3000000000000bar");
+        ASSERT_TRUE(iter->Valid());
+        ASSERT_EQ("3000000000000bar", iter->key().ToString());
+        ASSERT_EQ("bar_v", iter->value().ToString());
+
+        iter->Seek("1000000000foo000");
+        ASSERT_TRUE(iter->Valid());
+        ASSERT_EQ("1000000000foo001", iter->key().ToString());
+        ASSERT_EQ("v1", iter->value().ToString());
+
+        iter->Seek("1000000000foo005");
+        ASSERT_TRUE(iter->Valid());
+        ASSERT_EQ("1000000000foo005", iter->key().ToString());
+        ASSERT_EQ("v__5", iter->value().ToString());
+
+        iter->Seek("1000000000foo006");
+        ASSERT_TRUE(iter->Valid());
+        ASSERT_EQ("1000000000foo007", iter->key().ToString());
+        ASSERT_EQ("v__7", iter->value().ToString());
+
+        iter->Seek("1000000000foo008");
+        ASSERT_TRUE(iter->Valid());
+        ASSERT_EQ("1000000000foo008", iter->key().ToString());
+        ASSERT_EQ("v__8", iter->value().ToString());
+
+        if (total_order == 0) {
+          iter->Seek("1000000000foo009");
+          ASSERT_TRUE(iter->Valid());
+          ASSERT_EQ("3000000000000bar", iter->key().ToString());
+        }
+
+        // Test Bloom Filter
+        if (bloom_bits > 0) {
+          if (!total_order) {
+            // Neither key nor value should exist.
+            expect_bloom_not_match = true;
+            iter->Seek("2not000000000bar");
+            ASSERT_TRUE(!iter->Valid());
+            ASSERT_EQ("NOT_FOUND", Get("2not000000000bar"));
+            expect_bloom_not_match = false;
+          } else {
+            expect_bloom_not_match = true;
+            ASSERT_EQ("NOT_FOUND", Get("2not000000000bar"));
+            expect_bloom_not_match = false;
+          }
+        }
+
+        delete iter;
+      }
+    }
+    }
+  }
+}
+
+namespace {
+std::string MakeLongKey(size_t length, char c) {
+  return std::string(length, c);
+}
+}  // namespace
+
+TEST(PlainTableDBTest, IteratorLargeKeys) {
+  Options options = CurrentOptions();
+  options.table_factory.reset(NewPlainTableFactory(0, 0, 0));
+  options.create_if_missing = true;
+  options.prefix_extractor.reset();
+  DestroyAndReopen(&options);
+
+  std::string key_list[] = {
+      MakeLongKey(30, '0'),
+      MakeLongKey(16, '1'),
+      MakeLongKey(32, '2'),
+      MakeLongKey(60, '3'),
+      MakeLongKey(90, '4'),
+      MakeLongKey(50, '5'),
+      MakeLongKey(26, '6')
+  };
+
+  for (size_t i = 0; i < 7; i++) {
+    ASSERT_OK(Put(key_list[i], std::to_string(i)));
+  }
+
+  dbfull()->TEST_FlushMemTable();
+
+  Iterator* iter = dbfull()->NewIterator(ReadOptions());
+  iter->Seek(key_list[0]);
+
+  for (size_t i = 0; i < 7; i++) {
+    ASSERT_TRUE(iter->Valid());
+    ASSERT_EQ(key_list[i], iter->key().ToString());
+    ASSERT_EQ(std::to_string(i), iter->value().ToString());
+    iter->Next();
+  }
+
+  ASSERT_TRUE(!iter->Valid());
+
+  delete iter;
+}
+
+namespace {
+std::string MakeLongKeyWithPrefix(size_t length, char c) {
+  return "00000000" + std::string(length - 8, c);
+}
+}  // namespace
+
+TEST(PlainTableDBTest, IteratorLargeKeysWithPrefix) {
+  Options options = CurrentOptions();
+  options.table_factory.reset(NewPlainTableFactory(16, 0, 0.8, 3, 0, kPrefix));
+  options.create_if_missing = true;
+  DestroyAndReopen(&options);
+
+  std::string key_list[] = {
+      MakeLongKeyWithPrefix(30, '0'), MakeLongKeyWithPrefix(16, '1'),
+      MakeLongKeyWithPrefix(32, '2'), MakeLongKeyWithPrefix(60, '3'),
+      MakeLongKeyWithPrefix(90, '4'), MakeLongKeyWithPrefix(50, '5'),
+      MakeLongKeyWithPrefix(26, '6')};
+
+  for (size_t i = 0; i < 7; i++) {
+    ASSERT_OK(Put(key_list[i], std::to_string(i)));
+  }
+
+  dbfull()->TEST_FlushMemTable();
+
+  Iterator* iter = dbfull()->NewIterator(ReadOptions());
+  iter->Seek(key_list[0]);
+
+  for (size_t i = 0; i < 7; i++) {
+    ASSERT_TRUE(iter->Valid());
+    ASSERT_EQ(key_list[i], iter->key().ToString());
+    ASSERT_EQ(std::to_string(i), iter->value().ToString());
+    iter->Next();
+  }
+
+  ASSERT_TRUE(!iter->Valid());
+
+  delete iter;
+}
+
+// A test comparator which compare two strings in this way:
+// (1) first compare prefix of 8 bytes in alphabet order,
+// (2) if two strings share the same prefix, sort the other part of the string
+//     in the reverse alphabet order.
+class SimpleSuffixReverseComparator : public Comparator {
+ public:
+  SimpleSuffixReverseComparator() {}
+
+  virtual const char* Name() const { return "SimpleSuffixReverseComparator"; }
+
+  virtual int Compare(const Slice& a, const Slice& b) const {
+    Slice prefix_a = Slice(a.data(), 8);
+    Slice prefix_b = Slice(b.data(), 8);
+    int prefix_comp = prefix_a.compare(prefix_b);
+    if (prefix_comp != 0) {
+      return prefix_comp;
+    } else {
+      Slice suffix_a = Slice(a.data() + 8, a.size() - 8);
+      Slice suffix_b = Slice(b.data() + 8, b.size() - 8);
+      return -(suffix_a.compare(suffix_b));
+    }
+  }
+  virtual void FindShortestSeparator(std::string* start,
+                                     const Slice& limit) const {}
+
+  virtual void FindShortSuccessor(std::string* key) const {}
+};
+
+TEST(PlainTableDBTest, IteratorReverseSuffixComparator) {
+  Options options = CurrentOptions();
+  options.create_if_missing = true;
+  // Set only one bucket to force bucket conflict.
+  // Test index interval for the same prefix to be 1, 2 and 4
+  SimpleSuffixReverseComparator comp;
+  options.comparator = &comp;
+  DestroyAndReopen(&options);
+
+  ASSERT_OK(Put("1000000000foo002", "v_2"));
+  ASSERT_OK(Put("0000000000000bar", "random"));
+  ASSERT_OK(Put("1000000000foo001", "v1"));
+  ASSERT_OK(Put("3000000000000bar", "bar_v"));
+  ASSERT_OK(Put("1000000000foo003", "v__3"));
+  ASSERT_OK(Put("1000000000foo004", "v__4"));
+  ASSERT_OK(Put("1000000000foo005", "v__5"));
+  ASSERT_OK(Put("1000000000foo007", "v__7"));
+  ASSERT_OK(Put("1000000000foo008", "v__8"));
+  dbfull()->TEST_FlushMemTable();
+  ASSERT_EQ("v1", Get("1000000000foo001"));
+  ASSERT_EQ("v__3", Get("1000000000foo003"));
+  Iterator* iter = dbfull()->NewIterator(ReadOptions());
+  iter->Seek("1000000000foo009");
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("1000000000foo008", iter->key().ToString());
+  ASSERT_EQ("v__8", iter->value().ToString());
+
+  iter->Next();
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("1000000000foo007", iter->key().ToString());
+  ASSERT_EQ("v__7", iter->value().ToString());
+
+  iter->Next();
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("1000000000foo005", iter->key().ToString());
+  ASSERT_EQ("v__5", iter->value().ToString());
+
+  iter->Next();
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("1000000000foo004", iter->key().ToString());
+  ASSERT_EQ("v__4", iter->value().ToString());
+
+  iter->Seek("3000000000000bar");
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("3000000000000bar", iter->key().ToString());
+  ASSERT_EQ("bar_v", iter->value().ToString());
+
+  iter->Seek("1000000000foo005");
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("1000000000foo005", iter->key().ToString());
+  ASSERT_EQ("v__5", iter->value().ToString());
+
+  iter->Seek("1000000000foo006");
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("1000000000foo005", iter->key().ToString());
+  ASSERT_EQ("v__5", iter->value().ToString());
+
+  iter->Seek("1000000000foo008");
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("1000000000foo008", iter->key().ToString());
+  ASSERT_EQ("v__8", iter->value().ToString());
+
+  iter->Seek("1000000000foo000");
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("3000000000000bar", iter->key().ToString());
+
+  delete iter;
+}
+
+TEST(PlainTableDBTest, HashBucketConflict) {
+  for (size_t huge_page_tlb_size = 0; huge_page_tlb_size <= 2 * 1024 * 1024;
+       huge_page_tlb_size += 2 * 1024 * 1024) {
+    for (unsigned char i = 1; i <= 3; i++) {
+      Options options = CurrentOptions();
+      options.create_if_missing = true;
+      // Set only one bucket to force bucket conflict.
+      // Test index interval for the same prefix to be 1, 2 and 4
+      options.table_factory.reset(
+          NewPlainTableFactory(16, 0, 0, 2 ^ i, huge_page_tlb_size));
+      DestroyAndReopen(&options);
+      ASSERT_OK(Put("5000000000000fo0", "v1"));
+      ASSERT_OK(Put("5000000000000fo1", "v2"));
+      ASSERT_OK(Put("5000000000000fo2", "v"));
+      ASSERT_OK(Put("2000000000000fo0", "v3"));
+      ASSERT_OK(Put("2000000000000fo1", "v4"));
+      ASSERT_OK(Put("2000000000000fo2", "v"));
+      ASSERT_OK(Put("2000000000000fo3", "v"));
+
+      dbfull()->TEST_FlushMemTable();
+
+      ASSERT_EQ("v1", Get("5000000000000fo0"));
+      ASSERT_EQ("v2", Get("5000000000000fo1"));
+      ASSERT_EQ("v3", Get("2000000000000fo0"));
+      ASSERT_EQ("v4", Get("2000000000000fo1"));
+
+      ASSERT_EQ("NOT_FOUND", Get("5000000000000bar"));
+      ASSERT_EQ("NOT_FOUND", Get("2000000000000bar"));
+      ASSERT_EQ("NOT_FOUND", Get("5000000000000fo8"));
+      ASSERT_EQ("NOT_FOUND", Get("2000000000000fo8"));
+
+      ReadOptions ro;
+      Iterator* iter = dbfull()->NewIterator(ro);
+
+      iter->Seek("5000000000000fo0");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("5000000000000fo0", iter->key().ToString());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("5000000000000fo1", iter->key().ToString());
+
+      iter->Seek("5000000000000fo1");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("5000000000000fo1", iter->key().ToString());
+
+      iter->Seek("2000000000000fo0");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("2000000000000fo0", iter->key().ToString());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("2000000000000fo1", iter->key().ToString());
+
+      iter->Seek("2000000000000fo1");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("2000000000000fo1", iter->key().ToString());
+
+      iter->Seek("2000000000000bar");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("2000000000000fo0", iter->key().ToString());
+
+      iter->Seek("5000000000000bar");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("5000000000000fo0", iter->key().ToString());
+
+      iter->Seek("2000000000000fo8");
+      ASSERT_TRUE(!iter->Valid() ||
+                  options.comparator->Compare(iter->key(), "20000001") > 0);
+
+      iter->Seek("5000000000000fo8");
+      ASSERT_TRUE(!iter->Valid());
+
+      iter->Seek("1000000000000fo2");
+      ASSERT_TRUE(!iter->Valid());
+
+      iter->Seek("3000000000000fo2");
+      ASSERT_TRUE(!iter->Valid());
+
+      iter->Seek("8000000000000fo2");
+      ASSERT_TRUE(!iter->Valid());
+
+      delete iter;
+    }
+  }
+}
+
+TEST(PlainTableDBTest, HashBucketConflictReverseSuffixComparator) {
+  for (size_t huge_page_tlb_size = 0; huge_page_tlb_size <= 2 * 1024 * 1024;
+       huge_page_tlb_size += 2 * 1024 * 1024) {
+    for (unsigned char i = 1; i <= 3; i++) {
+      Options options = CurrentOptions();
+      options.create_if_missing = true;
+      SimpleSuffixReverseComparator comp;
+      options.comparator = &comp;
+      // Set only one bucket to force bucket conflict.
+      // Test index interval for the same prefix to be 1, 2 and 4
+      options.table_factory.reset(
+          NewPlainTableFactory(16, 0, 0, 2 ^ i, huge_page_tlb_size));
+      DestroyAndReopen(&options);
+      ASSERT_OK(Put("5000000000000fo0", "v1"));
+      ASSERT_OK(Put("5000000000000fo1", "v2"));
+      ASSERT_OK(Put("5000000000000fo2", "v"));
+      ASSERT_OK(Put("2000000000000fo0", "v3"));
+      ASSERT_OK(Put("2000000000000fo1", "v4"));
+      ASSERT_OK(Put("2000000000000fo2", "v"));
+      ASSERT_OK(Put("2000000000000fo3", "v"));
+
+      dbfull()->TEST_FlushMemTable();
+
+      ASSERT_EQ("v1", Get("5000000000000fo0"));
+      ASSERT_EQ("v2", Get("5000000000000fo1"));
+      ASSERT_EQ("v3", Get("2000000000000fo0"));
+      ASSERT_EQ("v4", Get("2000000000000fo1"));
+
+      ASSERT_EQ("NOT_FOUND", Get("5000000000000bar"));
+      ASSERT_EQ("NOT_FOUND", Get("2000000000000bar"));
+      ASSERT_EQ("NOT_FOUND", Get("5000000000000fo8"));
+      ASSERT_EQ("NOT_FOUND", Get("2000000000000fo8"));
+
+      ReadOptions ro;
+      Iterator* iter = dbfull()->NewIterator(ro);
+
+      iter->Seek("5000000000000fo1");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("5000000000000fo1", iter->key().ToString());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("5000000000000fo0", iter->key().ToString());
+
+      iter->Seek("5000000000000fo1");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("5000000000000fo1", iter->key().ToString());
+
+      iter->Seek("2000000000000fo1");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("2000000000000fo1", iter->key().ToString());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("2000000000000fo0", iter->key().ToString());
+
+      iter->Seek("2000000000000fo1");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("2000000000000fo1", iter->key().ToString());
+
+      iter->Seek("2000000000000var");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("2000000000000fo3", iter->key().ToString());
+
+      iter->Seek("5000000000000var");
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_EQ("5000000000000fo2", iter->key().ToString());
+
+      std::string seek_key = "2000000000000bar";
+      iter->Seek(seek_key);
+      ASSERT_TRUE(!iter->Valid() ||
+                  options.prefix_extractor->Transform(iter->key()) !=
+                      options.prefix_extractor->Transform(seek_key));
+
+      iter->Seek("1000000000000fo2");
+      ASSERT_TRUE(!iter->Valid());
+
+      iter->Seek("3000000000000fo2");
+      ASSERT_TRUE(!iter->Valid());
+
+      iter->Seek("8000000000000fo2");
+      ASSERT_TRUE(!iter->Valid());
+
+      delete iter;
+    }
+  }
+}
+
+TEST(PlainTableDBTest, NonExistingKeyToNonEmptyBucket) {
+  Options options = CurrentOptions();
+  options.create_if_missing = true;
+  // Set only one bucket to force bucket conflict.
+  // Test index interval for the same prefix to be 1, 2 and 4
+  options.table_factory.reset(NewPlainTableFactory(16, 0, 0, 5));
+  DestroyAndReopen(&options);
+  ASSERT_OK(Put("5000000000000fo0", "v1"));
+  ASSERT_OK(Put("5000000000000fo1", "v2"));
+  ASSERT_OK(Put("5000000000000fo2", "v3"));
+
+  dbfull()->TEST_FlushMemTable();
+
+  ASSERT_EQ("v1", Get("5000000000000fo0"));
+  ASSERT_EQ("v2", Get("5000000000000fo1"));
+  ASSERT_EQ("v3", Get("5000000000000fo2"));
+
+  ASSERT_EQ("NOT_FOUND", Get("8000000000000bar"));
+  ASSERT_EQ("NOT_FOUND", Get("1000000000000bar"));
+
+  Iterator* iter = dbfull()->NewIterator(ReadOptions());
+
+  iter->Seek("5000000000000bar");
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ("5000000000000fo0", iter->key().ToString());
+
+  iter->Seek("5000000000000fo8");
+  ASSERT_TRUE(!iter->Valid());
+
+  iter->Seek("1000000000000fo2");
+  ASSERT_TRUE(!iter->Valid());
+
+  iter->Seek("8000000000000fo2");
+  ASSERT_TRUE(!iter->Valid());
+
+  delete iter;
+}
+
+static std::string Key(int i) {
+  char buf[100];
+  snprintf(buf, sizeof(buf), "key_______%06d", i);
+  return std::string(buf);
+}
+
+static std::string RandomString(Random* rnd, int len) {
+  std::string r;
+  test::RandomString(rnd, len, &r);
+  return r;
+}
+
+TEST(PlainTableDBTest, CompactionTrigger) {
+  Options options = CurrentOptions();
+  options.write_buffer_size = 100 << 10; //100KB
+  options.num_levels = 3;
+  options.max_mem_compaction_level = 0;
+  options.level0_file_num_compaction_trigger = 3;
+  Reopen(&options);
+
+  Random rnd(301);
+
+  for (int num = 0; num < options.level0_file_num_compaction_trigger - 1;
+      num++) {
+    std::vector<std::string> values;
+    // Write 120KB (12 values, each 10K)
+    for (int i = 0; i < 12; i++) {
+      values.push_back(RandomString(&rnd, 10000));
+      ASSERT_OK(Put(Key(i), values[i]));
+    }
+    dbfull()->TEST_WaitForFlushMemTable();
+    ASSERT_EQ(NumTableFilesAtLevel(0), num + 1);
+  }
+
+  //generate one more file in level-0, and should trigger level-0 compaction
+  std::vector<std::string> values;
+  for (int i = 0; i < 12; i++) {
+    values.push_back(RandomString(&rnd, 10000));
+    ASSERT_OK(Put(Key(i), values[i]));
+  }
+  dbfull()->TEST_WaitForCompact();
+
+  ASSERT_EQ(NumTableFilesAtLevel(0), 0);
+  ASSERT_EQ(NumTableFilesAtLevel(1), 1);
+}
+
+TEST(PlainTableDBTest, AdaptiveTable) {
+  Options options = CurrentOptions();
+  options.create_if_missing = true;
+
+  options.table_factory.reset(NewPlainTableFactory());
+  DestroyAndReopen(&options);
+
+  ASSERT_OK(Put("1000000000000foo", "v1"));
+  ASSERT_OK(Put("0000000000000bar", "v2"));
+  ASSERT_OK(Put("1000000000000foo", "v3"));
+  dbfull()->TEST_FlushMemTable();
+
+  options.create_if_missing = false;
+  std::shared_ptr<TableFactory> dummy_factory;
+  std::shared_ptr<TableFactory> block_based_factory(
+      NewBlockBasedTableFactory());
+  options.table_factory.reset(NewAdaptiveTableFactory(
+      block_based_factory, dummy_factory, dummy_factory));
+  Reopen(&options);
+  ASSERT_EQ("v3", Get("1000000000000foo"));
+  ASSERT_EQ("v2", Get("0000000000000bar"));
+
+  ASSERT_OK(Put("2000000000000foo", "v4"));
+  ASSERT_OK(Put("3000000000000bar", "v5"));
+  dbfull()->TEST_FlushMemTable();
+  ASSERT_EQ("v4", Get("2000000000000foo"));
+  ASSERT_EQ("v5", Get("3000000000000bar"));
+
+  Reopen(&options);
+  ASSERT_EQ("v3", Get("1000000000000foo"));
+  ASSERT_EQ("v2", Get("0000000000000bar"));
+  ASSERT_EQ("v4", Get("2000000000000foo"));
+  ASSERT_EQ("v5", Get("3000000000000bar"));
+
+  options.table_factory.reset(NewBlockBasedTableFactory());
+  Reopen(&options);
+  ASSERT_NE("v3", Get("1000000000000foo"));
+
+  options.table_factory.reset(NewPlainTableFactory());
+  Reopen(&options);
+  ASSERT_NE("v5", Get("3000000000000bar"));
+}
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  return rocksdb::test::RunAllTests();
+}
@@ -1,75 +0,0 @@
-//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
-//  This source code is licensed under the BSD-style license found in the
-//  LICENSE file in the root directory of this source tree. An additional grant
-//  of patent rights can be found in the PATENTS file in the same directory.
-//
-// Wrap an underlying iterator, but exclude any results not starting
-// with a given prefix.  Seeking to keys not beginning with the prefix
-// is invalid, and SeekToLast is not implemented (that would be
-// non-trivial), but otherwise this iterator will behave just like the
-// underlying iterator would if there happened to be no non-matching
-// keys in the dataset.
-
-#pragma once
-#include "rocksdb/iterator.h"
-#include "rocksdb/slice.h"
-#include "rocksdb/slice_transform.h"
-
-namespace rocksdb {
-
-class PrefixFilterIterator : public Iterator {
- private:
-  Iterator* iter_;
-  const Slice &prefix_;
-  const SliceTransform *prefix_extractor_;
-  Status status_;
-
- public:
-  PrefixFilterIterator(Iterator* iter,
-                       const Slice &prefix,
-                       const SliceTransform* prefix_extractor)
-                             : iter_(iter), prefix_(prefix),
-                               prefix_extractor_(prefix_extractor),
-                               status_(Status::OK()) {
-    if (prefix_extractor == nullptr) {
-      status_ = Status::InvalidArgument("A prefix filter may not be used "
-                                        "unless a function is also defined "
-                                        "for extracting prefixes");
-    } else if (!prefix_extractor_->InRange(prefix)) {
-      status_ = Status::InvalidArgument("Must provide a slice for prefix which"
-                                        "is a prefix for some key");
-    }
-  }
-  ~PrefixFilterIterator() {
-    delete iter_;
-  }
-  Slice key() const { return iter_->key(); }
-  Slice value() const { return iter_->value(); }
-  Status status() const {
-    if (!status_.ok()) {
-      return status_;
-    }
-    return iter_->status();
-  }
-  void Next() { iter_->Next(); }
-  void Prev() { iter_->Prev(); }
-  void Seek(const Slice& k) {
-    if (prefix_extractor_->Transform(k) == prefix_) {
-      iter_->Seek(k);
-    } else {
-      status_ = Status::InvalidArgument("Seek must begin with target prefix");
-    }
-  }
-  void SeekToFirst() {
-    Seek(prefix_);
-  }
-  void SeekToLast() {
-    status_ = Status::NotSupported("SeekToLast is incompatible with prefixes");
-  }
-  bool Valid() const {
-    return (status_.ok() && iter_->Valid() &&
-            prefix_extractor_->Transform(iter_->key()) == prefix_);
-  }
-};
-
-}  // namespace rocksdb
@@ -1,3 +1,16 @@
+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+
+#ifndef GFLAGS
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#else
+
 #include <algorithm>
 #include <iostream>
 #include <vector>
@@ -6,21 +19,29 @@
 #include "rocksdb/comparator.h"
 #include "rocksdb/db.h"
 #include "rocksdb/perf_context.h"
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/memtablerep.h"
 #include "util/histogram.h"
 #include "util/stop_watch.h"
 #include "util/testharness.h"

-DEFINE_bool(use_prefix_hash_memtable, true, "");
+using GFLAGS::ParseCommandLineFlags;
+
 DEFINE_bool(trigger_deadlock, false,
            "issue delete in range scan to trigger PrefixHashMap deadlock");
 DEFINE_uint64(bucket_count, 100000, "number of buckets");
 DEFINE_uint64(num_locks, 10001, "number of locks");
 DEFINE_bool(random_prefix, false, "randomize prefix");
-DEFINE_uint64(total_prefixes, 1000, "total number of prefixes");
-DEFINE_uint64(items_per_prefix, 10, "total number of values per prefix");
-DEFINE_int64(write_buffer_size, 1000000000, "");
-DEFINE_int64(max_write_buffer_number, 8, "");
-DEFINE_int64(min_write_buffer_number_to_merge, 7, "");
+DEFINE_uint64(total_prefixes, 100000, "total number of prefixes");
+DEFINE_uint64(items_per_prefix, 1, "total number of values per prefix");
+DEFINE_int64(write_buffer_size, 33554432, "");
+DEFINE_int64(max_write_buffer_number, 2, "");
+DEFINE_int64(min_write_buffer_number_to_merge, 1, "");
+DEFINE_int32(skiplist_height, 4, "");
+DEFINE_int32(memtable_prefix_bloom_bits, 10000000, "");
+DEFINE_int32(memtable_prefix_bloom_probes, 10, "");
+DEFINE_int32(memtable_prefix_bloom_huge_page_tlb_size, 2 * 1024 * 1024, "");
+DEFINE_int32(value_size, 40, "");

 // Path to the database on file system
 const std::string kDbName = rocksdb::test::TmpDir() + "/prefix_test";
@@ -93,6 +114,38 @@ class TestKeyComparator : public Comparator {

 };

+namespace {
+void PutKey(DB* db, WriteOptions write_options, uint64_t prefix,
+            uint64_t suffix, const Slice& value) {
+  TestKey test_key(prefix, suffix);
+  Slice key = TestKeyToSlice(test_key);
+  ASSERT_OK(db->Put(write_options, key, value));
+}
+
+void SeekIterator(Iterator* iter, uint64_t prefix, uint64_t suffix) {
+  TestKey test_key(prefix, suffix);
+  Slice key = TestKeyToSlice(test_key);
+  iter->Seek(key);
+}
+
+const std::string kNotFoundResult = "NOT_FOUND";
+
+std::string Get(DB* db, const ReadOptions& read_options, uint64_t prefix,
+                uint64_t suffix) {
+  TestKey test_key(prefix, suffix);
+  Slice key = TestKeyToSlice(test_key);
+
+  std::string result;
+  Status s = db->Get(read_options, key, &result);
+  if (s.IsNotFound()) {
+    result = kNotFoundResult;
+  } else if (!s.ok()) {
+    result = s.ToString();
+  }
+  return result;
+}
+}  // namespace
+
 class PrefixTest {
 public:
  std::shared_ptr<DB> OpenDb() {
@@ -104,226 +157,348 @@ class PrefixTest {
    options.min_write_buffer_number_to_merge =
      FLAGS_min_write_buffer_number_to_merge;

-    options.comparator = new TestKeyComparator();
-    if (FLAGS_use_prefix_hash_memtable) {
-      auto prefix_extractor = NewFixedPrefixTransform(8);
-      options.prefix_extractor = prefix_extractor;
-      options.memtable_factory.reset(NewHashSkipListRepFactory(
-          prefix_extractor, FLAGS_bucket_count));
-    }
+    options.memtable_prefix_bloom_bits = FLAGS_memtable_prefix_bloom_bits;
+    options.memtable_prefix_bloom_probes = FLAGS_memtable_prefix_bloom_probes;
+    options.memtable_prefix_bloom_huge_page_tlb_size =
+        FLAGS_memtable_prefix_bloom_huge_page_tlb_size;

    Status s = DB::Open(options, kDbName,  &db);
    ASSERT_OK(s);
    return std::shared_ptr<DB>(db);
  }
+
+  void FirstOption() {
+    option_config_ = kBegin;
+  }
+
+  bool NextOptions(int bucket_count) {
+    // skip some options
+    option_config_++;
+    if (option_config_ < kEnd) {
+      options.prefix_extractor.reset(NewFixedPrefixTransform(8));
+      switch(option_config_) {
+        case kHashSkipList:
+          options.memtable_factory.reset(
+              NewHashSkipListRepFactory(bucket_count, FLAGS_skiplist_height));
+          return true;
+        case kHashLinkList:
+          options.memtable_factory.reset(
+              NewHashLinkListRepFactory(bucket_count));
+          return true;
+        case kHashLinkListHugePageTlb:
+          options.memtable_factory.reset(
+              NewHashLinkListRepFactory(bucket_count, 2 * 1024 * 1024));
+          return true;
+        case kHashLinkListTriggerSkipList:
+          options.memtable_factory.reset(
+              NewHashLinkListRepFactory(bucket_count, 0, 3));
+          return true;
+        default:
+          return false;
+      }
+    }
+    return false;
+  }
+
+  PrefixTest() : option_config_(kBegin) {
+    options.comparator = new TestKeyComparator();
+  }
  ~PrefixTest() {
    delete options.comparator;
  }
 protected:
+  enum OptionConfig {
+    kBegin,
+    kHashSkipList,
+    kHashLinkList,
+    kHashLinkListHugePageTlb,
+    kHashLinkListTriggerSkipList,
+    kEnd
+  };
+  int option_config_;
  Options options;
 };

-TEST(PrefixTest, DynamicPrefixIterator) {
+TEST(PrefixTest, TestResult) {
+  for (int num_buckets = 1; num_buckets <= 2; num_buckets++) {
+    FirstOption();
+    while (NextOptions(num_buckets)) {
+      std::cout << "*** Mem table: " << options.memtable_factory->Name()
+                << " number of buckets: " << num_buckets
+                << std::endl;
+      DestroyDB(kDbName, Options());
+      auto db = OpenDb();
+      WriteOptions write_options;
+      ReadOptions read_options;

-  DestroyDB(kDbName, Options());
-  auto db = OpenDb();
-  WriteOptions write_options;
-  ReadOptions read_options;
+      // 1. Insert one row.
+      Slice v16("v16");
+      PutKey(db.get(), write_options, 1, 6, v16);
+      std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
+      SeekIterator(iter.get(), 1, 6);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v16 == iter->value());
+      SeekIterator(iter.get(), 1, 5);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v16 == iter->value());
+      SeekIterator(iter.get(), 1, 5);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v16 == iter->value());
+      iter->Next();
+      ASSERT_TRUE(!iter->Valid());

-  std::vector<uint64_t> prefixes;
-  for (uint64_t i = 0; i < FLAGS_total_prefixes; ++i) {
-    prefixes.push_back(i);
-  }
+      SeekIterator(iter.get(), 2, 0);
+      ASSERT_TRUE(!iter->Valid());

-  if (FLAGS_random_prefix) {
-    std::random_shuffle(prefixes.begin(), prefixes.end());
-  }
+      ASSERT_EQ(v16.ToString(), Get(db.get(), read_options, 1, 6));
+      ASSERT_EQ(kNotFoundResult, Get(db.get(), read_options, 1, 5));
+      ASSERT_EQ(kNotFoundResult, Get(db.get(), read_options, 1, 7));
+      ASSERT_EQ(kNotFoundResult, Get(db.get(), read_options, 0, 6));
+      ASSERT_EQ(kNotFoundResult, Get(db.get(), read_options, 2, 6));

-  // insert x random prefix, each with y continuous element.
-  for (auto prefix : prefixes) {
-     for (uint64_t sorted = 0; sorted < FLAGS_items_per_prefix; sorted++) {
-      TestKey test_key(prefix, sorted);
+      // 2. Insert an entry for the same prefix as the last entry in the bucket.
+      Slice v17("v17");
+      PutKey(db.get(), write_options, 1, 7, v17);
+      iter.reset(db->NewIterator(read_options));
+      SeekIterator(iter.get(), 1, 7);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v17 == iter->value());

-      Slice key = TestKeyToSlice(test_key);
-      std::string value = "v" + std::to_string(sorted);
+      SeekIterator(iter.get(), 1, 6);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v16 == iter->value());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v17 == iter->value());
+      iter->Next();
+      ASSERT_TRUE(!iter->Valid());

-      ASSERT_OK(db->Put(write_options, key, value));
+      SeekIterator(iter.get(), 2, 0);
+      ASSERT_TRUE(!iter->Valid());
+
+      // 3. Insert an entry for the same prefix as the head of the bucket.
+      Slice v15("v15");
+      PutKey(db.get(), write_options, 1, 5, v15);
+      iter.reset(db->NewIterator(read_options));
+
+      SeekIterator(iter.get(), 1, 7);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v17 == iter->value());
+
+      SeekIterator(iter.get(), 1, 5);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v15 == iter->value());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v16 == iter->value());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v17 == iter->value());
+
+      SeekIterator(iter.get(), 1, 5);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v15 == iter->value());
+
+      ASSERT_EQ(v15.ToString(), Get(db.get(), read_options, 1, 5));
+      ASSERT_EQ(v16.ToString(), Get(db.get(), read_options, 1, 6));
+      ASSERT_EQ(v17.ToString(), Get(db.get(), read_options, 1, 7));
+
+      // 4. Insert an entry with a larger prefix
+      Slice v22("v22");
+      PutKey(db.get(), write_options, 2, 2, v22);
+      iter.reset(db->NewIterator(read_options));
+
+      SeekIterator(iter.get(), 2, 2);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v22 == iter->value());
+      SeekIterator(iter.get(), 2, 0);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v22 == iter->value());
+
+      SeekIterator(iter.get(), 1, 5);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v15 == iter->value());
+
+      SeekIterator(iter.get(), 1, 7);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v17 == iter->value());
+
+      // 5. Insert an entry with a smaller prefix
+      Slice v02("v02");
+      PutKey(db.get(), write_options, 0, 2, v02);
+      iter.reset(db->NewIterator(read_options));
+
+      SeekIterator(iter.get(), 0, 2);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v02 == iter->value());
+      SeekIterator(iter.get(), 0, 0);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v02 == iter->value());
+
+      SeekIterator(iter.get(), 2, 0);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v22 == iter->value());
+
+      SeekIterator(iter.get(), 1, 5);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v15 == iter->value());
+
+      SeekIterator(iter.get(), 1, 7);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v17 == iter->value());
+
+      // 6. Insert to the beginning and the end of the first prefix
+      Slice v13("v13");
+      Slice v18("v18");
+      PutKey(db.get(), write_options, 1, 3, v13);
+      PutKey(db.get(), write_options, 1, 8, v18);
+      iter.reset(db->NewIterator(read_options));
+      SeekIterator(iter.get(), 1, 7);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v17 == iter->value());
+
+      SeekIterator(iter.get(), 1, 3);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v13 == iter->value());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v15 == iter->value());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v16 == iter->value());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v17 == iter->value());
+      iter->Next();
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v18 == iter->value());
+
+      SeekIterator(iter.get(), 0, 0);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v02 == iter->value());
+
+      SeekIterator(iter.get(), 2, 0);
+      ASSERT_TRUE(iter->Valid());
+      ASSERT_TRUE(v22 == iter->value());
+
+      ASSERT_EQ(v22.ToString(), Get(db.get(), read_options, 2, 2));
+      ASSERT_EQ(v02.ToString(), Get(db.get(), read_options, 0, 2));
+      ASSERT_EQ(v13.ToString(), Get(db.get(), read_options, 1, 3));
+      ASSERT_EQ(v15.ToString(), Get(db.get(), read_options, 1, 5));
+      ASSERT_EQ(v16.ToString(), Get(db.get(), read_options, 1, 6));
+      ASSERT_EQ(v17.ToString(), Get(db.get(), read_options, 1, 7));
+      ASSERT_EQ(v18.ToString(), Get(db.get(), read_options, 1, 8));
    }
  }
-
-  // test seek existing keys
-  HistogramImpl hist_seek_time;
-  HistogramImpl hist_seek_comparison;
-
-  if (FLAGS_use_prefix_hash_memtable) {
-    read_options.prefix_seek = true;
-  }
-  std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
-
-  for (auto prefix : prefixes) {
-    TestKey test_key(prefix, FLAGS_items_per_prefix / 2);
-    Slice key = TestKeyToSlice(test_key);
-    std::string value = "v" + std::to_string(0);
-
-    perf_context.Reset();
-    StopWatchNano timer(Env::Default(), true);
-    uint64_t total_keys = 0;
-    for (iter->Seek(key); iter->Valid(); iter->Next()) {
-      if (FLAGS_trigger_deadlock) {
-        std::cout << "Behold the deadlock!\n";
-        db->Delete(write_options, iter->key());
-      }
-      auto test_key = SliceToTestKey(iter->key());
-      if (test_key->prefix != prefix) break;
-      total_keys++;
-    }
-    hist_seek_time.Add(timer.ElapsedNanos());
-    hist_seek_comparison.Add(perf_context.user_key_comparison_count);
-    ASSERT_EQ(total_keys, FLAGS_items_per_prefix - FLAGS_items_per_prefix/2);
-  }
-
-  std::cout << "Seek key comparison: \n"
-            << hist_seek_comparison.ToString()
-            << "Seek time: \n"
-            << hist_seek_time.ToString();
-
-  // test non-existing keys
-  HistogramImpl hist_no_seek_time;
-  HistogramImpl hist_no_seek_comparison;
-
-  for (auto prefix = FLAGS_total_prefixes;
-       prefix < FLAGS_total_prefixes + 100;
-       prefix++) {
-    TestKey test_key(prefix, 0);
-    Slice key = TestKeyToSlice(test_key);
-
-    perf_context.Reset();
-    StopWatchNano timer(Env::Default(), true);
-    iter->Seek(key);
-    hist_no_seek_time.Add(timer.ElapsedNanos());
-    hist_no_seek_comparison.Add(perf_context.user_key_comparison_count);
-    ASSERT_TRUE(!iter->Valid());
-  }
-
-  std::cout << "non-existing Seek key comparison: \n"
-            << hist_no_seek_comparison.ToString()
-            << "non-existing Seek time: \n"
-            << hist_no_seek_time.ToString();
 }

-TEST(PrefixTest, PrefixHash) {
+TEST(PrefixTest, DynamicPrefixIterator) {
+  while (NextOptions(FLAGS_bucket_count)) {
+    std::cout << "*** Mem table: " << options.memtable_factory->Name()
+        << std::endl;
+    DestroyDB(kDbName, Options());
+    auto db = OpenDb();
+    WriteOptions write_options;
+    ReadOptions read_options;

-  DestroyDB(kDbName, Options());
-  auto db = OpenDb();
-  WriteOptions write_options;
-  ReadOptions read_options;
+    std::vector<uint64_t> prefixes;
+    for (uint64_t i = 0; i < FLAGS_total_prefixes; ++i) {
+      prefixes.push_back(i);
+    }

-  std::vector<uint64_t> prefixes;
-  for (uint64_t i = 0; i < FLAGS_total_prefixes; ++i) {
-    prefixes.push_back(i);
-  }
+    if (FLAGS_random_prefix) {
+      std::random_shuffle(prefixes.begin(), prefixes.end());
+    }

-  if (FLAGS_random_prefix) {
-    std::random_shuffle(prefixes.begin(), prefixes.end());
-  }
+    HistogramImpl hist_put_time;
+    HistogramImpl hist_put_comparison;

-  // insert x random prefix, each with y continuous element.
-  HistogramImpl hist_put_time;
-  HistogramImpl hist_put_comparison;
+    // insert x random prefix, each with y continuous element.
+    for (auto prefix : prefixes) {
+       for (uint64_t sorted = 0; sorted < FLAGS_items_per_prefix; sorted++) {
+        TestKey test_key(prefix, sorted);

-  for (auto prefix : prefixes) {
-     for (uint64_t sorted = 0; sorted < FLAGS_items_per_prefix; sorted++) {
-      TestKey test_key(prefix, sorted);
+        Slice key = TestKeyToSlice(test_key);
+        std::string value(FLAGS_value_size, 0);

+        perf_context.Reset();
+        StopWatchNano timer(Env::Default(), true);
+        ASSERT_OK(db->Put(write_options, key, value));
+        hist_put_time.Add(timer.ElapsedNanos());
+        hist_put_comparison.Add(perf_context.user_key_comparison_count);
+      }
+    }
+
+    std::cout << "Put key comparison: \n" << hist_put_comparison.ToString()
+              << "Put time: \n" << hist_put_time.ToString();
+
+    // test seek existing keys
+    HistogramImpl hist_seek_time;
+    HistogramImpl hist_seek_comparison;
+
+    std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
+
+    for (auto prefix : prefixes) {
+      TestKey test_key(prefix, FLAGS_items_per_prefix / 2);
      Slice key = TestKeyToSlice(test_key);
-      std::string value = "v" + std::to_string(sorted);
+      std::string value = "v" + std::to_string(0);

      perf_context.Reset();
      StopWatchNano timer(Env::Default(), true);
-      ASSERT_OK(db->Put(write_options, key, value));
-      hist_put_time.Add(timer.ElapsedNanos());
-      hist_put_comparison.Add(perf_context.user_key_comparison_count);
-    }
-  }
-
-  std::cout << "Put key comparison: \n" << hist_put_comparison.ToString()
-            << "Put time: \n" << hist_put_time.ToString();
-
-
-  // test seek existing keys
-  HistogramImpl hist_seek_time;
-  HistogramImpl hist_seek_comparison;
-
-  for (auto prefix : prefixes) {
-    TestKey test_key(prefix, 0);
-    Slice key = TestKeyToSlice(test_key);
-    std::string value = "v" + std::to_string(0);
-
-    Slice key_prefix;
-    if (FLAGS_use_prefix_hash_memtable) {
-      key_prefix = options.prefix_extractor->Transform(key);
-      read_options.prefix = &key_prefix;
-    }
-    std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
-
-    perf_context.Reset();
-    StopWatchNano timer(Env::Default(), true);
-    uint64_t total_keys = 0;
-    for (iter->Seek(key); iter->Valid(); iter->Next()) {
-      if (FLAGS_trigger_deadlock) {
-        std::cout << "Behold the deadlock!\n";
-        db->Delete(write_options, iter->key());
+      auto key_prefix = options.prefix_extractor->Transform(key);
+      uint64_t total_keys = 0;
+      for (iter->Seek(key);
+           iter->Valid() && iter->key().starts_with(key_prefix);
+           iter->Next()) {
+        if (FLAGS_trigger_deadlock) {
+          std::cout << "Behold the deadlock!\n";
+          db->Delete(write_options, iter->key());
+        }
+        total_keys++;
      }
-      auto test_key = SliceToTestKey(iter->key());
-      if (test_key->prefix != prefix) break;
-      total_keys++;
+      hist_seek_time.Add(timer.ElapsedNanos());
+      hist_seek_comparison.Add(perf_context.user_key_comparison_count);
+      ASSERT_EQ(total_keys, FLAGS_items_per_prefix - FLAGS_items_per_prefix/2);
    }
-    hist_seek_time.Add(timer.ElapsedNanos());
-    hist_seek_comparison.Add(perf_context.user_key_comparison_count);
-    ASSERT_EQ(total_keys, FLAGS_items_per_prefix);
-  }

-  std::cout << "Seek key comparison: \n"
-            << hist_seek_comparison.ToString()
-            << "Seek time: \n"
-            << hist_seek_time.ToString();
+    std::cout << "Seek key comparison: \n"
+              << hist_seek_comparison.ToString()
+              << "Seek time: \n"
+              << hist_seek_time.ToString();

-  // test non-existing keys
-  HistogramImpl hist_no_seek_time;
-  HistogramImpl hist_no_seek_comparison;
+    // test non-existing keys
+    HistogramImpl hist_no_seek_time;
+    HistogramImpl hist_no_seek_comparison;

-  for (auto prefix = FLAGS_total_prefixes;
-       prefix < FLAGS_total_prefixes + 100;
-       prefix++) {
-    TestKey test_key(prefix, 0);
-    Slice key = TestKeyToSlice(test_key);
+    for (auto prefix = FLAGS_total_prefixes;
+         prefix < FLAGS_total_prefixes + 10000;
+         prefix++) {
+      TestKey test_key(prefix, 0);
+      Slice key = TestKeyToSlice(test_key);

-    if (FLAGS_use_prefix_hash_memtable) {
-      Slice key_prefix = options.prefix_extractor->Transform(key);
-      read_options.prefix = &key_prefix;
+      perf_context.Reset();
+      StopWatchNano timer(Env::Default(), true);
+      iter->Seek(key);
+      hist_no_seek_time.Add(timer.ElapsedNanos());
+      hist_no_seek_comparison.Add(perf_context.user_key_comparison_count);
+      ASSERT_TRUE(!iter->Valid());
    }
-    std::unique_ptr<Iterator> iter(db->NewIterator(read_options));

-    perf_context.Reset();
-    StopWatchNano timer(Env::Default(), true);
-    iter->Seek(key);
-    hist_no_seek_time.Add(timer.ElapsedNanos());
-    hist_no_seek_comparison.Add(perf_context.user_key_comparison_count);
-    ASSERT_TRUE(!iter->Valid());
+    std::cout << "non-existing Seek key comparison: \n"
+              << hist_no_seek_comparison.ToString()
+              << "non-existing Seek time: \n"
+              << hist_no_seek_time.ToString();
  }
-
-  std::cout << "non-existing Seek key comparison: \n"
-            << hist_no_seek_comparison.ToString()
-            << "non-existing Seek time: \n"
-            << hist_no_seek_time.ToString();
 }

 }

 int main(int argc, char** argv) {
-  google::ParseCommandLineFlags(&argc, &argv, true);
+  ParseCommandLineFlags(&argc, &argv, true);
  std::cout << kDbName << "\n";

  rocksdb::test::RunAllTests();
  return 0;
 }
+
+#endif  // GFLAGS
@@ -29,6 +29,10 @@
 //   Store per-table metadata (smallest, largest, largest-seq#, ...)
 //   in the table's meta section to speed up ScanTable.

+#ifndef ROCKSDB_LITE
+
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include "db/builder.h"
 #include "db/db_impl.h"
 #include "db/dbformat.h"
@@ -55,14 +59,20 @@ class Repairer {
        icmp_(options.comparator),
        ipolicy_(options.filter_policy),
        options_(SanitizeOptions(dbname, &icmp_, &ipolicy_, options)),
+        raw_table_cache_(
+            // TableCache can be small since we expect each table to be opened
+            // once.
+            NewLRUCache(10, options_.table_cache_numshardbits,
+                        options_.table_cache_remove_scan_count_limit)),
        next_file_number_(1) {
-    // TableCache can be small since we expect each table to be opened once.
-    table_cache_ = new TableCache(dbname_, &options_, storage_options_, 10);
+    table_cache_ =
+        new TableCache(&options_, storage_options_, raw_table_cache_.get());
    edit_ = new VersionEdit();
  }

  ~Repairer() {
    delete table_cache_;
+    raw_table_cache_.reset();
    delete edit_;
  }

@@ -74,18 +84,17 @@ class Repairer {
      status = WriteDescriptor();
    }
    if (status.ok()) {
-      unsigned long long bytes = 0;
+      uint64_t bytes = 0;
      for (size_t i = 0; i < tables_.size(); i++) {
-        bytes += tables_[i].meta.file_size;
+        bytes += tables_[i].meta.fd.GetFileSize();
      }
      Log(options_.info_log,
          "**** Repaired rocksdb %s; "
-          "recovered %d files; %llu bytes. "
+          "recovered %zu files; %" PRIu64
+          "bytes. "
          "Some data may have been lost. "
          "****",
-          dbname_.c_str(),
-          static_cast<int>(tables_.size()),
-          bytes);
+          dbname_.c_str(), tables_.size(), bytes);
    }
    return status;
  }
@@ -102,11 +111,12 @@ class Repairer {
  InternalKeyComparator const icmp_;
  InternalFilterPolicy const ipolicy_;
  Options const options_;
+  std::shared_ptr<Cache> raw_table_cache_;
  TableCache* table_cache_;
  VersionEdit* edit_;

  std::vector<std::string> manifests_;
-  std::vector<uint64_t> table_numbers_;
+  std::vector<FileDescriptor> table_fds_;
  std::vector<uint64_t> logs_;
  std::vector<TableInfo> tables_;
  uint64_t next_file_number_;
@@ -114,35 +124,43 @@ class Repairer {

  Status FindFiles() {
    std::vector<std::string> filenames;
-    Status status = env_->GetChildren(dbname_, &filenames);
-    if (!status.ok()) {
-      return status;
-    }
-    if (filenames.empty()) {
-      return Status::IOError(dbname_, "repair found no files");
-    }
+    bool found_file = false;
+    for (uint32_t path_id = 0; path_id < options_.db_paths.size(); path_id++) {
+      Status status = env_->GetChildren(options_.db_paths[path_id], &filenames);
+      if (!status.ok()) {
+        return status;
+      }
+      if (!filenames.empty()) {
+        found_file = true;
+      }

-    uint64_t number;
-    FileType type;
-    for (size_t i = 0; i < filenames.size(); i++) {
-      if (ParseFileName(filenames[i], &number, &type)) {
-        if (type == kDescriptorFile) {
-          manifests_.push_back(filenames[i]);
-        } else {
-          if (number + 1 > next_file_number_) {
-            next_file_number_ = number + 1;
-          }
-          if (type == kLogFile) {
-            logs_.push_back(number);
-          } else if (type == kTableFile) {
-            table_numbers_.push_back(number);
+      uint64_t number;
+      FileType type;
+      for (size_t i = 0; i < filenames.size(); i++) {
+        if (ParseFileName(filenames[i], &number, &type)) {
+          if (type == kDescriptorFile) {
+            assert(path_id == 0);
+            manifests_.push_back(filenames[i]);
          } else {
-            // Ignore other files
+            if (number + 1 > next_file_number_) {
+              next_file_number_ = number + 1;
+            }
+            if (type == kLogFile) {
+              assert(path_id == 0);
+              logs_.push_back(number);
+            } else if (type == kTableFile) {
+              table_fds_.emplace_back(number, path_id, 0);
+            } else {
+              // Ignore other files
+            }
          }
        }
      }
    }
-    return status;
+    if (!found_file) {
+      return Status::Corruption(dbname_, "repair found no files");
+    }
+    return Status::OK();
  }

  void ConvertLogFilesToTables() {
@@ -150,8 +168,8 @@ class Repairer {
      std::string logname = LogFileName(dbname_, logs_[i]);
      Status status = ConvertLogToTable(logs_[i]);
      if (!status.ok()) {
-        Log(options_.info_log, "Log #%llu: ignoring conversion error: %s",
-            (unsigned long long) logs_[i],
+        Log(options_.info_log,
+            "Log #%" PRIu64 ": ignoring conversion error: %s", logs_[i],
            status.ToString().c_str());
      }
      ArchiveFile(logname);
@@ -165,10 +183,8 @@ class Repairer {
      uint64_t lognum;
      virtual void Corruption(size_t bytes, const Status& s) {
        // We print error messages for corruption, but continue repairing.
-        Log(info_log, "Log #%llu: dropping %d bytes; %s",
-            (unsigned long long) lognum,
-            static_cast<int>(bytes),
-            s.ToString().c_str());
+        Log(info_log, "Log #%" PRIu64 ": dropping %d bytes; %s", lognum,
+            static_cast<int>(bytes), s.ToString().c_str());
      }
    };

@@ -197,6 +213,7 @@ class Repairer {
    Slice record;
    WriteBatch batch;
    MemTable* mem = new MemTable(icmp_, options_);
+    auto cf_mems_default = new ColumnFamilyMemTablesDefault(mem, &options_);
    mem->Ref();
    int counter = 0;
    while (reader.ReadRecord(&record, &scratch)) {
@@ -206,12 +223,11 @@ class Repairer {
        continue;
      }
      WriteBatchInternal::SetContents(&batch, record);
-      status = WriteBatchInternal::InsertInto(&batch, mem, &options_);
+      status = WriteBatchInternal::InsertInto(&batch, cf_mems_default);
      if (status.ok()) {
        counter += WriteBatchInternal::Count(&batch);
      } else {
-        Log(options_.info_log, "Log #%llu: ignoring %s",
-            (unsigned long long) log,
+        Log(options_.info_log, "Log #%" PRIu64 ": ignoring %s", log,
            status.ToString().c_str());
        status = Status::OK();  // Keep going with rest of file
      }
@@ -220,38 +236,37 @@ class Repairer {
    // Do not record a version edit for this conversion to a Table
    // since ExtractMetaData() will also generate edits.
    FileMetaData meta;
-    meta.number = next_file_number_++;
-    Iterator* iter = mem->NewIterator();
-    status = BuildTable(dbname_, env_, options_, storage_options_,
-                        table_cache_, iter, &meta,
-                        icmp_.user_comparator(), 0, 0,
-                        kNoCompression);
+    meta.fd = FileDescriptor(next_file_number_++, 0, 0);
+    ReadOptions ro;
+    Iterator* iter = mem->NewIterator(ro, true /* enforce_total_order */);
+    status = BuildTable(dbname_, env_, options_, storage_options_, table_cache_,
+                        iter, &meta, icmp_, 0, 0, kNoCompression);
    delete iter;
    delete mem->Unref();
+    delete cf_mems_default;
    mem = nullptr;
    if (status.ok()) {
-      if (meta.file_size > 0) {
-        table_numbers_.push_back(meta.number);
+      if (meta.fd.GetFileSize() > 0) {
+        table_fds_.push_back(meta.fd);
      }
    }
-    Log(options_.info_log, "Log #%llu: %d ops saved to Table #%llu %s",
-        (unsigned long long) log,
-        counter,
-        (unsigned long long) meta.number,
-        status.ToString().c_str());
+    Log(options_.info_log,
+        "Log #%" PRIu64 ": %d ops saved to Table #%" PRIu64 " %s", log, counter,
+        meta.fd.GetNumber(), status.ToString().c_str());
    return status;
  }

  void ExtractMetaData() {
-    std::vector<TableInfo> kept;
-    for (size_t i = 0; i < table_numbers_.size(); i++) {
+    for (size_t i = 0; i < table_fds_.size(); i++) {
      TableInfo t;
-      t.meta.number = table_numbers_[i];
+      t.meta.fd = table_fds_[i];
      Status status = ScanTable(&t);
      if (!status.ok()) {
-        std::string fname = TableFileName(dbname_, table_numbers_[i]);
-        Log(options_.info_log, "Table #%llu: ignoring %s",
-            (unsigned long long) table_numbers_[i],
+        std::string fname = TableFileName(
+            options_.db_paths, t.meta.fd.GetNumber(), t.meta.fd.GetPathId());
+        Log(options_.info_log, "Table #%s: ignoring %s",
+            FormatFileNumber(t.meta.fd.GetNumber(), t.meta.fd.GetPathId())
+                .c_str(),
            status.ToString().c_str());
        ArchiveFile(fname);
      } else {
@@ -261,12 +276,16 @@ class Repairer {
  }

  Status ScanTable(TableInfo* t) {
-    std::string fname = TableFileName(dbname_, t->meta.number);
+    std::string fname = TableFileName(options_.db_paths, t->meta.fd.GetNumber(),
+                                      t->meta.fd.GetPathId());
    int counter = 0;
-    Status status = env_->GetFileSize(fname, &t->meta.file_size);
+    uint64_t file_size;
+    Status status = env_->GetFileSize(fname, &file_size);
+    t->meta.fd = FileDescriptor(t->meta.fd.GetNumber(), t->meta.fd.GetPathId(),
+                                file_size);
    if (status.ok()) {
      Iterator* iter = table_cache_->NewIterator(
-          ReadOptions(), storage_options_, t->meta.number, t->meta.file_size);
+          ReadOptions(), storage_options_, icmp_, t->meta.fd);
      bool empty = true;
      ParsedInternalKey parsed;
      t->min_sequence = 0;
@@ -274,9 +293,8 @@ class Repairer {
      for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
        Slice key = iter->key();
        if (!ParseInternalKey(key, &parsed)) {
-          Log(options_.info_log, "Table #%llu: unparsable key %s",
-              (unsigned long long) t->meta.number,
-              EscapeString(key).c_str());
+          Log(options_.info_log, "Table #%" PRIu64 ": unparsable key %s",
+              t->meta.fd.GetNumber(), EscapeString(key).c_str());
          continue;
        }

@@ -298,17 +316,16 @@ class Repairer {
      }
      delete iter;
    }
-    Log(options_.info_log, "Table #%llu: %d entries %s",
-        (unsigned long long) t->meta.number,
-        counter,
-        status.ToString().c_str());
+    Log(options_.info_log, "Table #%" PRIu64 ": %d entries %s",
+        t->meta.fd.GetNumber(), counter, status.ToString().c_str());
    return status;
  }

  Status WriteDescriptor() {
    std::string tmp = TempFileName(dbname_, 1);
    unique_ptr<WritableFile> file;
-    Status status = env_->NewWritableFile(tmp, &file, storage_options_);
+    Status status = env_->NewWritableFile(
+        tmp, &file, env_->OptimizeForManifestWrite(storage_options_));
    if (!status.ok()) {
      return status;
    }
@@ -328,9 +345,9 @@ class Repairer {
    for (size_t i = 0; i < tables_.size(); i++) {
      // TODO(opt): separate out into multiple levels
      const TableInfo& t = tables_[i];
-      edit_->AddFile(0, t.meta.number, t.meta.file_size,
-                    t.meta.smallest, t.meta.largest,
-                    t.min_sequence, t.max_sequence);
+      edit_->AddFile(0, t.meta.fd.GetNumber(), t.meta.fd.GetPathId(),
+                     t.meta.fd.GetFileSize(), t.meta.smallest, t.meta.largest,
+                     t.min_sequence, t.max_sequence);
    }

    //fprintf(stderr, "NewDescriptor:\n%s\n", edit_.DebugString().c_str());
@@ -352,7 +369,7 @@ class Repairer {
      // Install new manifest
      status = env_->RenameFile(tmp, DescriptorFileName(dbname_, 1));
      if (status.ok()) {
-        status = SetCurrentFile(env_, dbname_, 1);
+        status = SetCurrentFile(env_, dbname_, 1, nullptr);
      } else {
        env_->DeleteFile(tmp);
      }
@@ -388,3 +405,5 @@ Status RepairDB(const std::string& dbname, const Options& options) {
 }

 }  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE
@@ -22,6 +22,8 @@
 #include "rocksdb/compaction_filter.h"
 #include "rocksdb/env.h"
 #include "rocksdb/table.h"
+#include "rocksdb/table_properties.h"
+#include "table/table_builder.h"
 #include "util/hash.h"
 #include "util/logging.h"
 #include "util/mutexlock.h"
@@ -31,6 +33,7 @@

 using std::unique_ptr;

+// IS THIS FILE STILL NEEDED?
 namespace rocksdb {

 // SimpleTable is a simple table format for UNIT TEST ONLY. It is not built
@@ -80,22 +83,18 @@ public:
                     unique_ptr<RandomAccessFile> && file, uint64_t file_size,
                     unique_ptr<TableReader>* table_reader);

-  bool PrefixMayMatch(const Slice& internal_prefix) override;
+  Iterator* NewIterator(const ReadOptions&, Arena* arena) override;

-  Iterator* NewIterator(const ReadOptions&) override;
-
-  Status Get(
-      const ReadOptions&, const Slice& key, void* arg,
-      bool (*handle_result)(void* arg, const Slice& k, const Slice& v, bool),
-      void (*mark_key_may_exist)(void*) = nullptr) override;
+  Status Get(const ReadOptions&, const Slice& key, void* arg,
+             bool (*handle_result)(void* arg, const ParsedInternalKey& k,
+                                   const Slice& v),
+             void (*mark_key_may_exist)(void*) = nullptr) override;

  uint64_t ApproximateOffsetOf(const Slice& key) override;

-  bool TEST_KeyInCache(const ReadOptions& options, const Slice& key) override;
-
  void SetupForCompaction() override;

-  TableProperties& GetTableProperties() override;
+  std::shared_ptr<const TableProperties> GetTableProperties() const override;

  ~SimpleTableReader();

@@ -171,7 +170,7 @@ struct SimpleTableReader::Rep {
  unique_ptr<RandomAccessFile> file;
  uint64_t index_start_offset;
  int num_entries;
-  TableProperties table_properties;
+  std::shared_ptr<TableProperties> table_properties;

  const static int user_key_size = 16;
  const static int offset_length = 8;
@@ -214,16 +213,19 @@ Status SimpleTableReader::Open(const Options& options,
 void SimpleTableReader::SetupForCompaction() {
 }

-TableProperties& SimpleTableReader::GetTableProperties() {
+std::shared_ptr<const TableProperties> SimpleTableReader::GetTableProperties()
+    const {
  return rep_->table_properties;
 }

-bool SimpleTableReader::PrefixMayMatch(const Slice& internal_prefix) {
-  return true;
-}
-
-Iterator* SimpleTableReader::NewIterator(const ReadOptions& options) {
-  return new SimpleTableIterator(this);
+Iterator* SimpleTableReader::NewIterator(const ReadOptions& options,
+                                         Arena* arena) {
+  if (arena == nullptr) {
+    return new SimpleTableIterator(this);
+  } else {
+    auto mem = arena->AllocateAligned(sizeof(SimpleTableIterator));
+    return new (mem) SimpleTableIterator(this);
+  }
 }

 Status SimpleTableReader::GetOffset(const Slice& target, uint64_t* offset) {
@@ -244,7 +246,8 @@ Status SimpleTableReader::GetOffset(const Slice& target, uint64_t* offset) {
      return s;
    }

-    int compare_result = rep_->options.comparator->Compare(tmp_slice, target);
+    InternalKeyComparator ikc(rep_->options.comparator);
+    int compare_result = ikc.Compare(tmp_slice, target);

    if (compare_result < 0) {
      if (left == right) {
@@ -279,14 +282,20 @@ Status SimpleTableReader::GetOffset(const Slice& target, uint64_t* offset) {
  return s;
 }

-Status SimpleTableReader::Get(
-    const ReadOptions& options, const Slice& k, void* arg,
-    bool (*saver)(void*, const Slice&, const Slice&, bool),
-    void (*mark_key_may_exist)(void*)) {
+Status SimpleTableReader::Get(const ReadOptions& options, const Slice& k,
+                              void* arg,
+                              bool (*saver)(void*, const ParsedInternalKey&,
+                                            const Slice&),
+                              void (*mark_key_may_exist)(void*)) {
  Status s;
  SimpleTableIterator* iter = new SimpleTableIterator(this);
  for (iter->Seek(k); iter->Valid(); iter->Next()) {
-    if (!(*saver)(arg, iter->key(), iter->value(), true)) {
+    ParsedInternalKey parsed_key;
+    if (!ParseInternalKey(iter->key(), &parsed_key)) {
+      return Status::Corruption(Slice());
+    }
+
+    if (!(*saver)(arg, parsed_key, iter->value())) {
      break;
    }
  }
@@ -295,11 +304,6 @@ Status SimpleTableReader::Get(
  return s;
 }

-bool SimpleTableReader::TEST_KeyInCache(const ReadOptions& options,
-                                        const Slice& key) {
-  return false;
-}
-
 uint64_t SimpleTableReader::ApproximateOffsetOf(const Slice& key) {
  return 0;
 }
@@ -540,27 +544,30 @@ public:
  const char* Name() const override {
    return "SimpleTable";
  }
-  Status GetTableReader(const Options& options, const EnvOptions& soptions,
-                        unique_ptr<RandomAccessFile> && file,
-                        uint64_t file_size,
+  Status NewTableReader(const Options& options, const EnvOptions& soptions,
+                        const InternalKeyComparator& internal_key,
+                        unique_ptr<RandomAccessFile>&& file, uint64_t file_size,
                        unique_ptr<TableReader>* table_reader) const;

-  TableBuilder* GetTableBuilder(const Options& options, WritableFile* file,
+  TableBuilder* NewTableBuilder(const Options& options,
+                                const InternalKeyComparator& internal_key,
+                                WritableFile* file,
                                CompressionType compression_type) const;
 };

-Status SimpleTableFactory::GetTableReader(
+Status SimpleTableFactory::NewTableReader(
    const Options& options, const EnvOptions& soptions,
-    unique_ptr<RandomAccessFile> && file, uint64_t file_size,
+    const InternalKeyComparator& internal_key,
+    unique_ptr<RandomAccessFile>&& file, uint64_t file_size,
    unique_ptr<TableReader>* table_reader) const {

  return SimpleTableReader::Open(options, soptions, std::move(file), file_size,
                                 table_reader);
 }

-TableBuilder* SimpleTableFactory::GetTableBuilder(
-    const Options& options, WritableFile* file,
-    CompressionType compression_type) const {
+TableBuilder* SimpleTableFactory::NewTableBuilder(
+    const Options& options, const InternalKeyComparator& internal_key,
+    WritableFile* file, CompressionType compression_type) const {
  return new SimpleTableBuilder(options, file, compression_type);
 }

@@ -33,9 +33,10 @@
 #pragma once
 #include <assert.h>
 #include <stdlib.h>
+#include "util/arena.h"
 #include "port/port.h"
+#include "util/arena.h"
 #include "util/random.h"
-#include "rocksdb/arena.h"

 namespace rocksdb {

@@ -48,7 +49,8 @@ class SkipList {
  // Create a new SkipList object that will use "cmp" for comparing keys,
  // and will allocate memory using "*arena".  Objects allocated in the arena
  // must remain allocated for the lifetime of the skiplist object.
-  explicit SkipList(Comparator cmp, Arena* arena);
+  explicit SkipList(Comparator cmp, Arena* arena,
+                    int32_t max_height = 12, int32_t branching_factor = 4);

  // Insert key into the list.
  // REQUIRES: nothing that compares equal to key is currently in the list.
@@ -102,7 +104,8 @@ class SkipList {
  };

 private:
-  enum { kMaxHeight = 12 };
+  const int32_t kMaxHeight_;
+  const int32_t kBranching_;

  // Immutable after construction
  Comparator const compare_;
@@ -115,8 +118,8 @@ class SkipList {
  port::AtomicPointer max_height_;   // Height of the entire list

  // Used for optimizing sequential insert patterns
-  Node* prev_[kMaxHeight];
-  int   prev_height_;
+  Node** prev_;
+  int32_t prev_height_;

  inline int GetMaxHeight() const {
    return static_cast<int>(
@@ -155,7 +158,7 @@ class SkipList {

 // Implementation details follow
 template<typename Key, class Comparator>
-struct SkipList<Key,Comparator>::Node {
+struct SkipList<Key, Comparator>::Node {
  explicit Node(const Key& k) : key(k) { }

  Key const key;
@@ -191,43 +194,43 @@ struct SkipList<Key,Comparator>::Node {
 };

 template<typename Key, class Comparator>
-typename SkipList<Key,Comparator>::Node*
-SkipList<Key,Comparator>::NewNode(const Key& key, int height) {
+typename SkipList<Key, Comparator>::Node*
+SkipList<Key, Comparator>::NewNode(const Key& key, int height) {
  char* mem = arena_->AllocateAligned(
      sizeof(Node) + sizeof(port::AtomicPointer) * (height - 1));
  return new (mem) Node(key);
 }

 template<typename Key, class Comparator>
-inline SkipList<Key,Comparator>::Iterator::Iterator(const SkipList* list) {
+inline SkipList<Key, Comparator>::Iterator::Iterator(const SkipList* list) {
  SetList(list);
 }

 template<typename Key, class Comparator>
-inline void SkipList<Key,Comparator>::Iterator::SetList(const SkipList* list) {
+inline void SkipList<Key, Comparator>::Iterator::SetList(const SkipList* list) {
  list_ = list;
  node_ = nullptr;
 }

 template<typename Key, class Comparator>
-inline bool SkipList<Key,Comparator>::Iterator::Valid() const {
+inline bool SkipList<Key, Comparator>::Iterator::Valid() const {
  return node_ != nullptr;
 }

 template<typename Key, class Comparator>
-inline const Key& SkipList<Key,Comparator>::Iterator::key() const {
+inline const Key& SkipList<Key, Comparator>::Iterator::key() const {
  assert(Valid());
  return node_->key;
 }

 template<typename Key, class Comparator>
-inline void SkipList<Key,Comparator>::Iterator::Next() {
+inline void SkipList<Key, Comparator>::Iterator::Next() {
  assert(Valid());
  node_ = node_->Next(0);
 }

 template<typename Key, class Comparator>
-inline void SkipList<Key,Comparator>::Iterator::Prev() {
+inline void SkipList<Key, Comparator>::Iterator::Prev() {
  // Instead of using explicit "prev" links, we just search for the
  // last node that falls before key.
  assert(Valid());
@@ -238,17 +241,17 @@ inline void SkipList<Key,Comparator>::Iterator::Prev() {
 }

 template<typename Key, class Comparator>
-inline void SkipList<Key,Comparator>::Iterator::Seek(const Key& target) {
+inline void SkipList<Key, Comparator>::Iterator::Seek(const Key& target) {
  node_ = list_->FindGreaterOrEqual(target, nullptr);
 }

 template<typename Key, class Comparator>
-inline void SkipList<Key,Comparator>::Iterator::SeekToFirst() {
+inline void SkipList<Key, Comparator>::Iterator::SeekToFirst() {
  node_ = list_->head_->Next(0);
 }

 template<typename Key, class Comparator>
-inline void SkipList<Key,Comparator>::Iterator::SeekToLast() {
+inline void SkipList<Key, Comparator>::Iterator::SeekToLast() {
  node_ = list_->FindLast();
  if (node_ == list_->head_) {
    node_ = nullptr;
@@ -256,27 +259,26 @@ inline void SkipList<Key,Comparator>::Iterator::SeekToLast() {
 }

 template<typename Key, class Comparator>
-int SkipList<Key,Comparator>::RandomHeight() {
+int SkipList<Key, Comparator>::RandomHeight() {
  // Increase height with probability 1 in kBranching
-  static const unsigned int kBranching = 4;
  int height = 1;
-  while (height < kMaxHeight && ((rnd_.Next() % kBranching) == 0)) {
+  while (height < kMaxHeight_ && ((rnd_.Next() % kBranching_) == 0)) {
    height++;
  }
  assert(height > 0);
-  assert(height <= kMaxHeight);
+  assert(height <= kMaxHeight_);
  return height;
 }

 template<typename Key, class Comparator>
-bool SkipList<Key,Comparator>::KeyIsAfterNode(const Key& key, Node* n) const {
+bool SkipList<Key, Comparator>::KeyIsAfterNode(const Key& key, Node* n) const {
  // nullptr n is considered infinite
  return (n != nullptr) && (compare_(n->key, key) < 0);
 }

 template<typename Key, class Comparator>
-typename SkipList<Key,Comparator>::Node* SkipList<Key,Comparator>::FindGreaterOrEqual(const Key& key, Node** prev)
-    const {
+typename SkipList<Key, Comparator>::Node* SkipList<Key, Comparator>::
+  FindGreaterOrEqual(const Key& key, Node** prev) const {
  // Use prev as an optimization hint and fallback to slow path
  if (prev && !KeyIsAfterNode(key, prev[0]->Next(0))) {
    Node* x = prev[0];
@@ -313,8 +315,8 @@ typename SkipList<Key,Comparator>::Node* SkipList<Key,Comparator>::FindGreaterOr
 }

 template<typename Key, class Comparator>
-typename SkipList<Key,Comparator>::Node*
-SkipList<Key,Comparator>::FindLessThan(const Key& key) const {
+typename SkipList<Key, Comparator>::Node*
+SkipList<Key, Comparator>::FindLessThan(const Key& key) const {
  Node* x = head_;
  int level = GetMaxHeight() - 1;
  while (true) {
@@ -334,7 +336,7 @@ SkipList<Key,Comparator>::FindLessThan(const Key& key) const {
 }

 template<typename Key, class Comparator>
-typename SkipList<Key,Comparator>::Node* SkipList<Key,Comparator>::FindLast()
+typename SkipList<Key, Comparator>::Node* SkipList<Key, Comparator>::FindLast()
    const {
  Node* x = head_;
  int level = GetMaxHeight() - 1;
@@ -354,21 +356,31 @@ typename SkipList<Key,Comparator>::Node* SkipList<Key,Comparator>::FindLast()
 }

 template<typename Key, class Comparator>
-SkipList<Key,Comparator>::SkipList(Comparator cmp, Arena* arena)
-    : compare_(cmp),
+SkipList<Key, Comparator>::SkipList(const Comparator cmp, Arena* arena,
+                                   int32_t max_height,
+                                   int32_t branching_factor)
+    : kMaxHeight_(max_height),
+      kBranching_(branching_factor),
+      compare_(cmp),
      arena_(arena),
-      head_(NewNode(0 /* any key will do */, kMaxHeight)),
+      head_(NewNode(0 /* any key will do */, max_height)),
      max_height_(reinterpret_cast<void*>(1)),
      prev_height_(1),
      rnd_(0xdeadbeef) {
-  for (int i = 0; i < kMaxHeight; i++) {
+  assert(kMaxHeight_ > 0);
+  assert(kBranching_ > 0);
+  // Allocate the prev_ Node* array, directly from the passed-in arena.
+  // prev_ does not need to be freed, as its life cycle is tied up with
+  // the arena as a whole.
+  prev_ = (Node**) arena_->AllocateAligned(sizeof(Node*) * kMaxHeight_);
+  for (int i = 0; i < kMaxHeight_; i++) {
    head_->SetNext(i, nullptr);
    prev_[i] = head_;
  }
 }

 template<typename Key, class Comparator>
-void SkipList<Key,Comparator>::Insert(const Key& key) {
+void SkipList<Key, Comparator>::Insert(const Key& key) {
  // TODO(opt): We can use a barrier-free variant of FindGreaterOrEqual()
  // here since Insert() is externally synchronized.
  Node* x = FindGreaterOrEqual(key, prev_);
@@ -405,7 +417,7 @@ void SkipList<Key,Comparator>::Insert(const Key& key) {
 }

 template<typename Key, class Comparator>
-bool SkipList<Key,Comparator>::Contains(const Key& key) const {
+bool SkipList<Key, Comparator>::Contains(const Key& key) const {
  Node* x = FindGreaterOrEqual(key, nullptr);
  if (x != nullptr && Equal(key, x->key)) {
    return true;
@@ -10,7 +10,7 @@
 #include "db/skiplist.h"
 #include <set>
 #include "rocksdb/env.h"
-#include "util/arena_impl.h"
+#include "util/arena.h"
 #include "util/hash.h"
 #include "util/random.h"
 #include "util/testharness.h"
@@ -34,9 +34,9 @@ struct TestComparator {
 class SkipTest { };

 TEST(SkipTest, Empty) {
-  ArenaImpl arena_impl;
+  Arena arena;
  TestComparator cmp;
-  SkipList<Key, TestComparator> list(cmp, &arena_impl);
+  SkipList<Key, TestComparator> list(cmp, &arena);
  ASSERT_TRUE(!list.Contains(10));

  SkipList<Key, TestComparator>::Iterator iter(&list);
@@ -54,9 +54,9 @@ TEST(SkipTest, InsertAndLookup) {
  const int R = 5000;
  Random rnd(1000);
  std::set<Key> keys;
-  ArenaImpl arena_impl;
+  Arena arena;
  TestComparator cmp;
-  SkipList<Key, TestComparator> list(cmp, &arena_impl);
+  SkipList<Key, TestComparator> list(cmp, &arena);
  for (int i = 0; i < N; i++) {
    Key key = rnd.Next() % R;
    if (keys.insert(key).second) {
@@ -209,14 +209,14 @@ class ConcurrentTest {
  // Current state of the test
  State current_;

-  ArenaImpl arena_impl_;
+  Arena arena_;

  // SkipList is not protected by mu_.  We just use a single writer
  // thread to modify it.
  SkipList<Key, TestComparator> list_;

 public:
-  ConcurrentTest() : list_(TestComparator(), &arena_impl_) { }
+  ConcurrentTest() : list_(TestComparator(), &arena_) {}

  // REQUIRES: External synchronization
  void WriteStep(Random* rnd) {
@@ -10,9 +10,11 @@
 #include "db/table_cache.h"

 #include "db/filename.h"
+#include "db/version_edit.h"

 #include "rocksdb/statistics.h"
-#include "rocksdb/table.h"
+#include "table/iterator_wrapper.h"
+#include "table/table_reader.h"
 #include "util/coding.h"
 #include "util/stop_watch.h"

@@ -29,42 +31,44 @@ static void UnrefEntry(void* arg1, void* arg2) {
  cache->Release(h);
 }

-static Slice GetSliceForFileNumber(uint64_t* file_number) {
+static Slice GetSliceForFileNumber(const uint64_t* file_number) {
  return Slice(reinterpret_cast<const char*>(file_number),
               sizeof(*file_number));
 }

-TableCache::TableCache(const std::string& dbname,
-                       const Options* options,
-                       const EnvOptions& storage_options,
-                       int entries)
+TableCache::TableCache(const Options* options,
+                       const EnvOptions& storage_options, Cache* const cache)
    : env_(options->env),
-      dbname_(dbname),
+      db_paths_(options->db_paths),
      options_(options),
      storage_options_(storage_options),
-      cache_(
-        NewLRUCache(entries, options->table_cache_numshardbits,
-                    options->table_cache_remove_scan_count_limit)) {
-}
+      cache_(cache) {}

 TableCache::~TableCache() {
 }

+TableReader* TableCache::GetTableReaderFromHandle(Cache::Handle* handle) {
+  return reinterpret_cast<TableReader*>(cache_->Value(handle));
+}
+
+void TableCache::ReleaseHandle(Cache::Handle* handle) {
+  cache_->Release(handle);
+}
+
 Status TableCache::FindTable(const EnvOptions& toptions,
-                             uint64_t file_number, uint64_t file_size,
-                             Cache::Handle** handle, bool* table_io,
+                             const InternalKeyComparator& internal_comparator,
+                             const FileDescriptor& fd, Cache::Handle** handle,
                             const bool no_io) {
  Status s;
-  Slice key = GetSliceForFileNumber(&file_number);
+  uint64_t number = fd.GetNumber();
+  Slice key = GetSliceForFileNumber(&number);
  *handle = cache_->Lookup(key);
  if (*handle == nullptr) {
    if (no_io) { // Dont do IO and return a not-found status
      return Status::Incomplete("Table not found in table_cache, no_io is set");
    }
-    if (table_io != nullptr) {
-      *table_io = true;    // we had to do IO from storage
-    }
-    std::string fname = TableFileName(dbname_, file_number);
+    std::string fname =
+        TableFileName(db_paths_, fd.GetNumber(), fd.GetPathId());
    unique_ptr<RandomAccessFile> file;
    unique_ptr<TableReader> table_reader;
    s = env_->NewRandomAccessFile(fname, &file, toptions);
@@ -74,9 +78,9 @@ Status TableCache::FindTable(const EnvOptions& toptions,
        file->Hint(RandomAccessFile::RANDOM);
      }
      StopWatch sw(env_, options_->statistics.get(), TABLE_OPEN_IO_MICROS);
-      s = options_->table_factory->GetTableReader(*options_, toptions,
-                                                  std::move(file), file_size,
-                                                  &table_reader);
+      s = options_->table_factory->NewTableReader(
+          *options_, toptions, internal_comparator, std::move(file),
+          fd.GetFileSize(), &table_reader);
    }

    if (!s.ok()) {
@@ -94,25 +98,29 @@ Status TableCache::FindTable(const EnvOptions& toptions,

 Iterator* TableCache::NewIterator(const ReadOptions& options,
                                  const EnvOptions& toptions,
-                                  uint64_t file_number,
-                                  uint64_t file_size,
+                                  const InternalKeyComparator& icomparator,
+                                  const FileDescriptor& fd,
                                  TableReader** table_reader_ptr,
-                                  bool for_compaction) {
+                                  bool for_compaction, Arena* arena) {
  if (table_reader_ptr != nullptr) {
    *table_reader_ptr = nullptr;
  }
-
+  TableReader* table_reader = fd.table_reader;
  Cache::Handle* handle = nullptr;
-  Status s = FindTable(toptions, file_number, file_size, &handle,
-                       nullptr, options.read_tier == kBlockCacheTier);
-  if (!s.ok()) {
-    return NewErrorIterator(s);
+  Status s;
+  if (table_reader == nullptr) {
+    s = FindTable(toptions, icomparator, fd, &handle,
+                  options.read_tier == kBlockCacheTier);
+    if (!s.ok()) {
+      return NewErrorIterator(s, arena);
+    }
+    table_reader = GetTableReaderFromHandle(handle);
  }

-  TableReader* table_reader =
-    reinterpret_cast<TableReader*>(cache_->Value(handle));
-  Iterator* result = table_reader->NewIterator(options);
-  result->RegisterCleanup(&UnrefEntry, cache_.get(), handle);
+  Iterator* result = table_reader->NewIterator(options, arena);
+  if (handle != nullptr) {
+    result->RegisterCleanup(&UnrefEntry, cache_, handle);
+  }
  if (table_reader_ptr != nullptr) {
    *table_reader_ptr = table_reader;
  }
@@ -125,22 +133,26 @@ Iterator* TableCache::NewIterator(const ReadOptions& options,
 }

 Status TableCache::Get(const ReadOptions& options,
-                       uint64_t file_number,
-                       uint64_t file_size,
-                       const Slice& k,
-                       void* arg,
-                       bool (*saver)(void*, const Slice&, const Slice&, bool),
-                       bool* table_io,
+                       const InternalKeyComparator& internal_comparator,
+                       const FileDescriptor& fd, const Slice& k, void* arg,
+                       bool (*saver)(void*, const ParsedInternalKey&,
+                                     const Slice&),
                       void (*mark_key_may_exist)(void*)) {
+  TableReader* t = fd.table_reader;
+  Status s;
  Cache::Handle* handle = nullptr;
-  Status s = FindTable(storage_options_, file_number, file_size,
-                       &handle, table_io,
-                       options.read_tier == kBlockCacheTier);
+  if (!t) {
+    s = FindTable(storage_options_, internal_comparator, fd, &handle,
+                  options.read_tier == kBlockCacheTier);
+    if (s.ok()) {
+      t = GetTableReaderFromHandle(handle);
+    }
+  }
  if (s.ok()) {
-    TableReader* t =
-      reinterpret_cast<TableReader*>(cache_->Value(handle));
    s = t->Get(options, k, arg, saver, mark_key_may_exist);
-    cache_->Release(handle);
+    if (handle != nullptr) {
+      ReleaseHandle(handle);
+    }
  } else if (options.read_tier && s.IsIncomplete()) {
    // Couldnt find Table in cache but treat as kFound if no_io set
    (*mark_key_may_exist)(arg);
@@ -148,27 +160,33 @@ Status TableCache::Get(const ReadOptions& options,
  }
  return s;
 }
+Status TableCache::GetTableProperties(
+    const EnvOptions& toptions,
+    const InternalKeyComparator& internal_comparator, const FileDescriptor& fd,
+    std::shared_ptr<const TableProperties>* properties, bool no_io) {
+  Status s;
+  auto table_reader = fd.table_reader;
+  // table already been pre-loaded?
+  if (table_reader) {
+    *properties = table_reader->GetTableProperties();

-bool TableCache::PrefixMayMatch(const ReadOptions& options,
-                                uint64_t file_number,
-                                uint64_t file_size,
-                                const Slice& internal_prefix,
-                                bool* table_io) {
-  Cache::Handle* handle = nullptr;
-  Status s = FindTable(storage_options_, file_number,
-                       file_size, &handle, table_io);
-  bool may_match = true;
-  if (s.ok()) {
-    TableReader* t =
-      reinterpret_cast<TableReader*>(cache_->Value(handle));
-    may_match = t->PrefixMayMatch(internal_prefix);
-    cache_->Release(handle);
+    return s;
  }
-  return may_match;
+
+  Cache::Handle* table_handle = nullptr;
+  s = FindTable(toptions, internal_comparator, fd, &table_handle, no_io);
+  if (!s.ok()) {
+    return s;
+  }
+  assert(table_handle);
+  auto table = GetTableReaderFromHandle(table_handle);
+  *properties = table->GetTableProperties();
+  ReleaseHandle(table_handle);
+  return s;
 }

-void TableCache::Evict(uint64_t file_number) {
-  cache_->Erase(GetSliceForFileNumber(&file_number));
+void TableCache::Evict(Cache* cache, uint64_t file_number) {
+  cache->Erase(GetSliceForFileNumber(&file_number));
 }

 }  // namespace rocksdb
@@ -11,21 +11,26 @@

 #pragma once
 #include <string>
+#include <vector>
 #include <stdint.h>
+
 #include "db/dbformat.h"
-#include "rocksdb/env.h"
-#include "rocksdb/cache.h"
 #include "port/port.h"
+#include "rocksdb/cache.h"
+#include "rocksdb/env.h"
 #include "rocksdb/table.h"
+#include "table/table_reader.h"

 namespace rocksdb {

 class Env;
+class Arena;
+struct FileDescriptor;

 class TableCache {
 public:
-  TableCache(const std::string& dbname, const Options* options,
-             const EnvOptions& storage_options, int entries);
+  TableCache(const Options* options, const EnvOptions& storage_options,
+             Cache* cache);
  ~TableCache();

  // Return an iterator for the specified file number (the corresponding
@@ -35,44 +40,55 @@ class TableCache {
  // the returned iterator.  The returned "*tableptr" object is owned by
  // the cache and should not be deleted, and is valid for as long as the
  // returned iterator is live.
-  Iterator* NewIterator(const ReadOptions& options,
-                        const EnvOptions& toptions,
-                        uint64_t file_number,
-                        uint64_t file_size,
+  Iterator* NewIterator(const ReadOptions& options, const EnvOptions& toptions,
+                        const InternalKeyComparator& internal_comparator,
+                        const FileDescriptor& file_fd,
                        TableReader** table_reader_ptr = nullptr,
-                        bool for_compaction = false);
+                        bool for_compaction = false, Arena* arena = nullptr);

  // If a seek to internal key "k" in specified file finds an entry,
  // call (*handle_result)(arg, found_key, found_value) repeatedly until
  // it returns false.
  Status Get(const ReadOptions& options,
-             uint64_t file_number,
-             uint64_t file_size,
-             const Slice& k,
-             void* arg,
-             bool (*handle_result)(void*, const Slice&, const Slice&, bool),
-             bool* table_io,
+             const InternalKeyComparator& internal_comparator,
+             const FileDescriptor& file_fd, const Slice& k, void* arg,
+             bool (*handle_result)(void*, const ParsedInternalKey&,
+                                   const Slice&),
             void (*mark_key_may_exist)(void*) = nullptr);

-  // Determine whether the table may contain the specified prefix.  If
-  // the table index of blooms are not in memory, this may cause an I/O
-  bool PrefixMayMatch(const ReadOptions& options, uint64_t file_number,
-                      uint64_t file_size, const Slice& internal_prefix,
-                      bool* table_io);
-
  // Evict any entry for the specified file number
-  void Evict(uint64_t file_number);
+  static void Evict(Cache* cache, uint64_t file_number);
+
+  // Find table reader
+  Status FindTable(const EnvOptions& toptions,
+                   const InternalKeyComparator& internal_comparator,
+                   const FileDescriptor& file_fd, Cache::Handle**,
+                   const bool no_io = false);
+
+  // Get TableReader from a cache handle.
+  TableReader* GetTableReaderFromHandle(Cache::Handle* handle);
+
+  // Get the table properties of a given table.
+  // @no_io: indicates if we should load table to the cache if it is not present
+  //         in table cache yet.
+  // @returns: `properties` will be reset on success. Please note that we will
+  //            return Status::Incomplete() if table is not present in cache and
+  //            we set `no_io` to be true.
+  Status GetTableProperties(const EnvOptions& toptions,
+                            const InternalKeyComparator& internal_comparator,
+                            const FileDescriptor& file_meta,
+                            std::shared_ptr<const TableProperties>* properties,
+                            bool no_io = false);
+
+  // Release the handle from a cache
+  void ReleaseHandle(Cache::Handle* handle);

 private:
  Env* const env_;
-  const std::string dbname_;
+  const std::vector<std::string> db_paths_;
  const Options* options_;
  const EnvOptions& storage_options_;
-  std::shared_ptr<Cache> cache_;
-
-  Status FindTable(const EnvOptions& toptions, uint64_t file_number,
-                   uint64_t file_size, Cache::Handle**, bool* table_io=nullptr,
-                   const bool no_io = false);
+  Cache* const cache_;
 };

 }  // namespace rocksdb
@@ -10,87 +10,6 @@

 namespace rocksdb {

-namespace {
-  void AppendProperty(
-      std::string& props,
-      const std::string& key,
-      const std::string& value,
-      const std::string& prop_delim,
-      const std::string& kv_delim) {
-    props.append(key);
-    props.append(kv_delim);
-    props.append(value);
-    props.append(prop_delim);
-  }
-
-  template <class TValue>
-  void AppendProperty(
-      std::string& props,
-      const std::string& key,
-      const TValue& value,
-      const std::string& prop_delim,
-      const std::string& kv_delim) {
-    AppendProperty(
-        props, key, std::to_string(value), prop_delim, kv_delim
-    );
-  }
-}
-
-std::string TableProperties::ToString(
-    const std::string& prop_delim,
-    const std::string& kv_delim) const {
-  std::string result;
-  result.reserve(1024);
-
-  // Basic Info
-  AppendProperty(
-      result, "# data blocks", num_data_blocks, prop_delim, kv_delim
-  );
-  AppendProperty(result, "# entries", num_entries, prop_delim, kv_delim);
-
-  AppendProperty(result, "raw key size", raw_key_size, prop_delim, kv_delim);
-  AppendProperty(
-      result,
-      "raw average key size",
-      num_entries != 0 ?  1.0 * raw_key_size / num_entries : 0.0,
-      prop_delim,
-      kv_delim
-  );
-  AppendProperty(
-      result, "raw value size", raw_value_size, prop_delim, kv_delim
-  );
-  AppendProperty(
-      result,
-      "raw average value size",
-      num_entries != 0 ?  1.0 * raw_value_size / num_entries : 0.0,
-      prop_delim,
-      kv_delim
-  );
-
-  AppendProperty(result, "data block size", data_size, prop_delim, kv_delim);
-  AppendProperty(result, "index block size", index_size, prop_delim, kv_delim);
-  AppendProperty(
-      result, "filter block size", filter_size, prop_delim, kv_delim
-  );
-  AppendProperty(
-      result,
-      "(estimated) table size",
-      data_size + index_size + filter_size,
-      prop_delim,
-      kv_delim
-  );
-
-  AppendProperty(
-      result,
-      "filter policy name",
-      filter_policy_name.empty() ? std::string("N/A") : filter_policy_name,
-      prop_delim,
-      kv_delim
-  );
-
-  return result;
-}
-
 Status InternalKeyPropertiesCollector::Add(
    const Slice& key, const Slice& value) {
  ParsedInternalKey ikey;
@@ -106,7 +25,7 @@ Status InternalKeyPropertiesCollector::Add(
 }

 Status InternalKeyPropertiesCollector::Finish(
-    TableProperties::UserCollectedProperties* properties) {
+    UserCollectedProperties* properties) {
  assert(properties);
  assert(properties->find(
        InternalKeyTablePropertiesNames::kDeletedKeys) == properties->end());
@@ -118,7 +37,7 @@ Status InternalKeyPropertiesCollector::Finish(
  return Status::OK();
 }

-TableProperties::UserCollectedProperties
+UserCollectedProperties
 InternalKeyPropertiesCollector::GetReadableProperties() const {
  return {
    { "kDeletedKeys", std::to_string(deleted_keys_) }
@@ -137,11 +56,11 @@ Status UserKeyTablePropertiesCollector::Add(
 }

 Status UserKeyTablePropertiesCollector::Finish(
-    TableProperties::UserCollectedProperties* properties) {
+    UserCollectedProperties* properties) {
  return collector_->Finish(properties);
 }

-TableProperties::UserCollectedProperties
+UserCollectedProperties
 UserKeyTablePropertiesCollector::GetReadableProperties() const {
  return collector_->GetReadableProperties();
 }
@@ -151,7 +70,7 @@ const std::string InternalKeyTablePropertiesNames::kDeletedKeys
  = "rocksdb.deleted.keys";

 uint64_t GetDeletedKeys(
-    const TableProperties::UserCollectedProperties& props) {
+    const UserCollectedProperties& props) {
  auto pos = props.find(InternalKeyTablePropertiesNames::kDeletedKeys);
  if (pos == props.end()) {
    return 0;
@@ -24,20 +24,30 @@ class InternalKeyPropertiesCollector : public TablePropertiesCollector {
 public:
  virtual Status Add(const Slice& key, const Slice& value) override;

-  virtual Status Finish(
-      TableProperties::UserCollectedProperties* properties) override;
+  virtual Status Finish(UserCollectedProperties* properties) override;

  virtual const char* Name() const override {
    return "InternalKeyPropertiesCollector";
  }

-  TableProperties::UserCollectedProperties
-    GetReadableProperties() const override;
+  UserCollectedProperties GetReadableProperties() const override;

 private:
  uint64_t deleted_keys_ = 0;
 };

+class InternalKeyPropertiesCollectorFactory
+    : public TablePropertiesCollectorFactory {
+ public:
+  virtual TablePropertiesCollector* CreateTablePropertiesCollector() {
+    return new InternalKeyPropertiesCollector();
+  }
+
+  virtual const char* Name() const override {
+    return "InternalKeyPropertiesCollectorFactory";
+  }
+};
+
 // When rocksdb creates a new table, it will encode all "user keys" into
 // "internal keys", which contains meta information of a given entry.
 //
@@ -45,32 +55,41 @@ class InternalKeyPropertiesCollector : public TablePropertiesCollector {
 // invoked.
 class UserKeyTablePropertiesCollector : public TablePropertiesCollector {
 public:
-  explicit UserKeyTablePropertiesCollector(
-      TablePropertiesCollector* collector) :
-      UserKeyTablePropertiesCollector(
-        std::shared_ptr<TablePropertiesCollector>(collector)
-    ) {
-  }
+  // transfer of ownership
+  explicit UserKeyTablePropertiesCollector(TablePropertiesCollector* collector)
+      : collector_(collector) {}

-  explicit UserKeyTablePropertiesCollector(
-      std::shared_ptr<TablePropertiesCollector> collector) :
-      collector_(collector) {
-  }
-
-  virtual ~UserKeyTablePropertiesCollector() { }
+  virtual ~UserKeyTablePropertiesCollector() {}

  virtual Status Add(const Slice& key, const Slice& value) override;

-  virtual Status Finish(
-      TableProperties::UserCollectedProperties* properties) override;
+  virtual Status Finish(UserCollectedProperties* properties) override;

  virtual const char* Name() const override { return collector_->Name(); }

-  TableProperties::UserCollectedProperties
-    GetReadableProperties() const override;
+  UserCollectedProperties GetReadableProperties() const override;

 protected:
-  std::shared_ptr<TablePropertiesCollector> collector_;
+  std::unique_ptr<TablePropertiesCollector> collector_;
+};
+
+class UserKeyTablePropertiesCollectorFactory
+    : public TablePropertiesCollectorFactory {
+ public:
+  explicit UserKeyTablePropertiesCollectorFactory(
+      std::shared_ptr<TablePropertiesCollectorFactory> user_collector_factory)
+      : user_collector_factory_(user_collector_factory) {}
+  virtual TablePropertiesCollector* CreateTablePropertiesCollector() {
+    return new UserKeyTablePropertiesCollector(
+        user_collector_factory_->CreateTablePropertiesCollector());
+  }
+
+  virtual const char* Name() const override {
+    return user_collector_factory_->Name();
+  }
+
+ private:
+  std::shared_ptr<TablePropertiesCollectorFactory> user_collector_factory_;
 };

 }  // namespace rocksdb
@@ -7,12 +7,14 @@
 #include <memory>
 #include <string>

-#include "db/dbformat.h"
 #include "db/db_impl.h"
+#include "db/dbformat.h"
 #include "db/table_properties_collector.h"
-#include "rocksdb/table_properties.h"
 #include "rocksdb/table.h"
 #include "table/block_based_table_factory.h"
+#include "table/meta_blocks.h"
+#include "table/plain_table_factory.h"
+#include "table/table_builder.h"
 #include "util/coding.h"
 #include "util/testharness.h"
 #include "util/testutil.h"
@@ -20,8 +22,6 @@
 namespace rocksdb {

 class TablePropertiesTest {
- private:
-  unique_ptr<TableReader> table_reader_;
 };

 // TODO(kailiu) the following classes should be moved to some more general
@@ -83,41 +83,26 @@ class DumbLogger : public Logger {
 };

 // Utilities test functions
-void MakeBuilder(
-    const Options& options,
-    std::unique_ptr<FakeWritableFile>* writable,
-    std::unique_ptr<TableBuilder>* builder) {
+namespace {
+void MakeBuilder(const Options& options,
+                 const InternalKeyComparator& internal_comparator,
+                 std::unique_ptr<FakeWritableFile>* writable,
+                 std::unique_ptr<TableBuilder>* builder) {
  writable->reset(new FakeWritableFile);
-  builder->reset(
-      options.table_factory->GetTableBuilder(options, writable->get(),
-                                             options.compression));
-}
-
-void OpenTable(
-    const Options& options,
-    const std::string& contents,
-    std::unique_ptr<TableReader>* table_reader) {
-
-  std::unique_ptr<RandomAccessFile> file(new FakeRandomeAccessFile(contents));
-  auto s = options.table_factory->GetTableReader(
-      options,
-      EnvOptions(),
-      std::move(file),
-      contents.size(),
-      table_reader
-  );
-  ASSERT_OK(s);
+  builder->reset(options.table_factory->NewTableBuilder(
+      options, internal_comparator, writable->get(), options.compression));
 }
+}  // namespace

 // Collects keys that starts with "A" in a table.
 class RegularKeysStartWithA: public TablePropertiesCollector {
 public:
   const char* Name() const { return "RegularKeysStartWithA"; }

-   Status Finish(TableProperties::UserCollectedProperties* properties) {
+   Status Finish(UserCollectedProperties* properties) {
     std::string encoded;
     PutVarint32(&encoded, count_);
-     *properties = TableProperties::UserCollectedProperties {
+     *properties = UserCollectedProperties {
       { "TablePropertiesTest", "Rocksdb" },
       { "Count", encoded }
     };
@@ -132,132 +117,194 @@ class RegularKeysStartWithA: public TablePropertiesCollector {
     return Status::OK();
   }

-  virtual TableProperties::UserCollectedProperties
-    GetReadableProperties() const {
-      return {};
+  virtual UserCollectedProperties GetReadableProperties() const {
+    return UserCollectedProperties{};
  }

-
 private:
  uint32_t count_ = 0;
 };

-TEST(TablePropertiesTest, CustomizedTablePropertiesCollector) {
-  Options options;
+class RegularKeysStartWithAFactory : public TablePropertiesCollectorFactory {
+ public:
+  virtual TablePropertiesCollector* CreateTablePropertiesCollector() {
+    return new RegularKeysStartWithA();
+  }
+  const char* Name() const { return "RegularKeysStartWithA"; }
+};

+extern uint64_t kBlockBasedTableMagicNumber;
+extern uint64_t kPlainTableMagicNumber;
+namespace {
+void TestCustomizedTablePropertiesCollector(
+    uint64_t magic_number, bool encode_as_internal, const Options& options,
+    const InternalKeyComparator& internal_comparator) {
  // make sure the entries will be inserted with order.
  std::map<std::string, std::string> kvs = {
-    {"About",     "val5"},  // starts with 'A'
-    {"Abstract",  "val2"},  // starts with 'A'
-    {"Around",    "val7"},  // starts with 'A'
-    {"Beyond",    "val3"},
-    {"Builder",   "val1"},
-    {"Cancel",    "val4"},
-    {"Find",      "val6"},
+    {"About   ", "val5"},  // starts with 'A'
+    {"Abstract", "val2"},  // starts with 'A'
+    {"Around  ", "val7"},  // starts with 'A'
+    {"Beyond  ", "val3"},
+    {"Builder ", "val1"},
+    {"Cancel  ", "val4"},
+    {"Find    ", "val6"},
  };

-  // Test properties collectors with internal keys or regular keys
-  for (bool encode_as_internal : { true, false }) {
-    // -- Step 1: build table
-    auto collector = new RegularKeysStartWithA();
+  // -- Step 1: build table
+  std::unique_ptr<TableBuilder> builder;
+  std::unique_ptr<FakeWritableFile> writable;
+  MakeBuilder(options, internal_comparator, &writable, &builder);
+
+  for (const auto& kv : kvs) {
    if (encode_as_internal) {
-      options.table_properties_collectors = {
-        std::make_shared<UserKeyTablePropertiesCollector>(collector)
-      };
+      InternalKey ikey(kv.first, 0, ValueType::kTypeValue);
+      builder->Add(ikey.Encode(), kv.second);
    } else {
-      options.table_properties_collectors.resize(1);
-      options.table_properties_collectors[0].reset(collector);
+      builder->Add(kv.first, kv.second);
    }
-    std::unique_ptr<TableBuilder> builder;
-    std::unique_ptr<FakeWritableFile> writable;
-    MakeBuilder(options, &writable, &builder);
-
-    for (const auto& kv : kvs) {
-      if (encode_as_internal) {
-        InternalKey ikey(kv.first, 0, ValueType::kTypeValue);
-        builder->Add(ikey.Encode(), kv.second);
-      } else {
-        builder->Add(kv.first, kv.second);
-      }
-    }
-    ASSERT_OK(builder->Finish());
-
-    // -- Step 2: Open table
-    std::unique_ptr<TableReader> table_reader;
-    OpenTable(options, writable->contents(), &table_reader);
-    const auto& properties =
-      table_reader->GetTableProperties().user_collected_properties;
-
-    ASSERT_EQ("Rocksdb", properties.at("TablePropertiesTest"));
-
-    uint32_t starts_with_A = 0;
-    Slice key(properties.at("Count"));
-    ASSERT_TRUE(GetVarint32(&key, &starts_with_A));
-    ASSERT_EQ(3u, starts_with_A);
  }
+  ASSERT_OK(builder->Finish());
+
+  // -- Step 2: Read properties
+  FakeRandomeAccessFile readable(writable->contents());
+  TableProperties* props;
+  Status s = ReadTableProperties(
+      &readable,
+      writable->contents().size(),
+      magic_number,
+      Env::Default(),
+      nullptr,
+      &props
+  );
+  std::unique_ptr<TableProperties> props_guard(props);
+  ASSERT_OK(s);
+
+  auto user_collected = props->user_collected_properties;
+
+  ASSERT_EQ("Rocksdb", user_collected.at("TablePropertiesTest"));
+
+  uint32_t starts_with_A = 0;
+  Slice key(user_collected.at("Count"));
+  ASSERT_TRUE(GetVarint32(&key, &starts_with_A));
+  ASSERT_EQ(3u, starts_with_A);
+}
+}  // namespace
+
+TEST(TablePropertiesTest, CustomizedTablePropertiesCollector) {
+  // Test properties collectors with internal keys or regular keys
+  // for block based table
+  for (bool encode_as_internal : { true, false }) {
+    Options options;
+    std::shared_ptr<TablePropertiesCollectorFactory> collector_factory(
+        new RegularKeysStartWithAFactory());
+    if (encode_as_internal) {
+      options.table_properties_collector_factories.emplace_back(
+          new UserKeyTablePropertiesCollectorFactory(collector_factory));
+    } else {
+      options.table_properties_collector_factories.resize(1);
+      options.table_properties_collector_factories[0] = collector_factory;
+    }
+    test::PlainInternalKeyComparator ikc(options.comparator);
+    TestCustomizedTablePropertiesCollector(kBlockBasedTableMagicNumber,
+                                           encode_as_internal, options, ikc);
+  }
+
+  // test plain table
+  Options options;
+  options.table_properties_collector_factories.emplace_back(
+      new RegularKeysStartWithAFactory());
+  options.table_factory = std::make_shared<PlainTableFactory>(8, 8, 0);
+  test::PlainInternalKeyComparator ikc(options.comparator);
+  TestCustomizedTablePropertiesCollector(kPlainTableMagicNumber, true, options,
+                                         ikc);
 }

-TEST(TablePropertiesTest, InternalKeyPropertiesCollector) {
+namespace {
+void TestInternalKeyPropertiesCollector(
+    uint64_t magic_number,
+    bool sanitized,
+    std::shared_ptr<TableFactory> table_factory) {
  InternalKey keys[] = {
-    InternalKey("A", 0, ValueType::kTypeValue),
-    InternalKey("B", 0, ValueType::kTypeValue),
-    InternalKey("C", 0, ValueType::kTypeValue),
-    InternalKey("W", 0, ValueType::kTypeDeletion),
-    InternalKey("X", 0, ValueType::kTypeDeletion),
-    InternalKey("Y", 0, ValueType::kTypeDeletion),
-    InternalKey("Z", 0, ValueType::kTypeDeletion),
+    InternalKey("A       ", 0, ValueType::kTypeValue),
+    InternalKey("B       ", 0, ValueType::kTypeValue),
+    InternalKey("C       ", 0, ValueType::kTypeValue),
+    InternalKey("W       ", 0, ValueType::kTypeDeletion),
+    InternalKey("X       ", 0, ValueType::kTypeDeletion),
+    InternalKey("Y       ", 0, ValueType::kTypeDeletion),
+    InternalKey("Z       ", 0, ValueType::kTypeDeletion),
  };

-  for (bool sanitized : { false, true }) {
-    std::unique_ptr<TableBuilder> builder;
-    std::unique_ptr<FakeWritableFile> writable;
-    Options options;
-    if (sanitized) {
-      options.table_properties_collectors = {
-        std::make_shared<RegularKeysStartWithA>()
-      };
-      // with sanitization, even regular properties collector will be able to
-      // handle internal keys.
-      auto comparator = options.comparator;
-      // HACK: Set options.info_log to avoid writing log in
-      // SanitizeOptions().
-      options.info_log = std::make_shared<DumbLogger>();
-      options = SanitizeOptions(
-          "db",  // just a place holder
-          nullptr,  // with skip internal key comparator
-          nullptr,  // don't care filter policy
-          options
-      );
-      options.comparator = comparator;
-    } else {
-      options.table_properties_collectors = {
-        std::make_shared<InternalKeyPropertiesCollector>()
-      };
-    }
+  std::unique_ptr<TableBuilder> builder;
+  std::unique_ptr<FakeWritableFile> writable;
+  Options options;
+  test::PlainInternalKeyComparator pikc(options.comparator);

-    MakeBuilder(options, &writable, &builder);
+  options.table_factory = table_factory;
+  if (sanitized) {
+    options.table_properties_collector_factories.emplace_back(
+        new RegularKeysStartWithAFactory());
+    // with sanitization, even regular properties collector will be able to
+    // handle internal keys.
+    auto comparator = options.comparator;
+    // HACK: Set options.info_log to avoid writing log in
+    // SanitizeOptions().
+    options.info_log = std::make_shared<DumbLogger>();
+    options = SanitizeOptions("db",            // just a place holder
+                              &pikc, nullptr,  // don't care filter policy
+                              options);
+    options.comparator = comparator;
+  } else {
+    options.table_properties_collector_factories = {
+        std::make_shared<InternalKeyPropertiesCollectorFactory>()};
+  }
+
+  for (int iter = 0; iter < 2; ++iter) {
+    MakeBuilder(options, pikc, &writable, &builder);
    for (const auto& k : keys) {
      builder->Add(k.Encode(), "val");
    }

    ASSERT_OK(builder->Finish());

-    std::unique_ptr<TableReader> table_reader;
-    OpenTable(options, writable->contents(), &table_reader);
-    const auto& properties =
-      table_reader->GetTableProperties().user_collected_properties;
+    FakeRandomeAccessFile readable(writable->contents());
+    TableProperties* props;
+    Status s =
+        ReadTableProperties(&readable, writable->contents().size(),
+                            magic_number, Env::Default(), nullptr, &props);
+    ASSERT_OK(s);

-    uint64_t deleted = GetDeletedKeys(properties);
+    std::unique_ptr<TableProperties> props_guard(props);
+    auto user_collected = props->user_collected_properties;
+    uint64_t deleted = GetDeletedKeys(user_collected);
    ASSERT_EQ(4u, deleted);

    if (sanitized) {
      uint32_t starts_with_A = 0;
-      Slice key(properties.at("Count"));
+      Slice key(user_collected.at("Count"));
      ASSERT_TRUE(GetVarint32(&key, &starts_with_A));
      ASSERT_EQ(1u, starts_with_A);
    }
  }
 }
+}  // namespace
+
+TEST(TablePropertiesTest, InternalKeyPropertiesCollector) {
+  TestInternalKeyPropertiesCollector(
+      kBlockBasedTableMagicNumber,
+      true /* sanitize */,
+      std::make_shared<BlockBasedTableFactory>()
+  );
+  TestInternalKeyPropertiesCollector(
+      kBlockBasedTableMagicNumber,
+      true /* not sanitize */,
+      std::make_shared<BlockBasedTableFactory>()
+  );
+  TestInternalKeyPropertiesCollector(
+      kPlainTableMagicNumber,
+      false /* not sanitize */,
+      std::make_shared<PlainTableFactory>(8, 8, 0)
+  );
+}

 }  // namespace rocksdb

@@ -3,22 +3,36 @@
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.

+#ifndef ROCKSDB_LITE
 #include "db/tailing_iter.h"

 #include <string>
 #include <utility>
+#include <vector>
 #include "db/db_impl.h"
+#include "db/db_iter.h"
+#include "db/column_family.h"
+#include "rocksdb/env.h"
 #include "rocksdb/slice.h"
 #include "rocksdb/slice_transform.h"
+#include "table/merger.h"

 namespace rocksdb {

-TailingIterator::TailingIterator(DBImpl* db, const ReadOptions& options,
-                                 const Comparator* comparator)
-    : db_(db), options_(options), comparator_(comparator),
-      version_number_(0), current_(nullptr),
+TailingIterator::TailingIterator(Env* const env, DBImpl* db,
+    const ReadOptions& read_options, ColumnFamilyData* cfd)
+    : env_(env),
+      db_(db),
+      read_options_(read_options),
+      cfd_(cfd),
+      super_version_(nullptr),
+      current_(nullptr),
      status_(Status::InvalidArgument("Seek() not called on this iterator")) {}

+TailingIterator::~TailingIterator() {
+  Cleanup();
+}
+
 bool TailingIterator::Valid() const {
  return current_ != nullptr;
 }
@@ -46,18 +60,17 @@ void TailingIterator::Seek(const Slice& target) {
  // need to do a seek if 'target' belongs to that interval (i.e. immutable_ is
  // already at the correct position)!
  //
-  // If options.prefix_seek is used and immutable_ is not valid, seek if target
-  // has a different prefix than prev_key.
+  // If prefix seek is used and immutable_ is not valid, seek if target has a
+  // different prefix than prev_key.
  //
  // prev_key_ is updated by Next(). SeekImmutable() sets prev_key_ to
  // 'target' -- in this case, prev_key_ is included in the interval, so
  // prev_inclusive_ has to be set.

-  if (!is_prev_set_ ||
-      comparator_->Compare(prev_key_, target) >= !is_prev_inclusive_ ||
-      (immutable_->Valid() &&
-       comparator_->Compare(target, immutable_->key()) > 0) ||
-      (options_.prefix_seek && !IsSamePrefix(target))) {
+  const Comparator* cmp = cfd_->user_comparator();
+  if (!is_prev_set_ || cmp->Compare(prev_key_, target) >= !is_prev_inclusive_ ||
+      (immutable_->Valid() && cmp->Compare(target, immutable_->key()) > 0) ||
+      (cfd_->options()->prefix_extractor != nullptr && !IsSamePrefix(target))) {
    SeekImmutable(target);
  }

@@ -119,14 +132,45 @@ void TailingIterator::SeekToLast() {
  status_ = Status::NotSupported("This iterator doesn't support SeekToLast()");
 }

+void TailingIterator::Cleanup() {
+  // Release old super version if necessary
+  mutable_.reset();
+  immutable_.reset();
+  if (super_version_ != nullptr && super_version_->Unref()) {
+    DBImpl::DeletionState deletion_state;
+    db_->mutex_.Lock();
+    super_version_->Cleanup();
+    db_->FindObsoleteFiles(deletion_state, false, true);
+    db_->mutex_.Unlock();
+    delete super_version_;
+    if (deletion_state.HaveSomethingToDelete()) {
+      db_->PurgeObsoleteFiles(deletion_state);
+    }
+  }
+}
+
 void TailingIterator::CreateIterators() {
-  std::pair<Iterator*, Iterator*> iters =
-    db_->GetTailingIteratorPair(options_, &version_number_);
+  Cleanup();
+  super_version_= cfd_->GetReferencedSuperVersion(&(db_->mutex_));

-  assert(iters.first && iters.second);
+  Iterator* mutable_iter = super_version_->mem->NewIterator(read_options_);
+  // create a DBIter that only uses memtable content; see NewIterator()
+  mutable_.reset(
+      NewDBIterator(env_, *cfd_->options(), cfd_->user_comparator(),
+                    mutable_iter, kMaxSequenceNumber));
+
+  std::vector<Iterator*> list;
+  super_version_->imm->AddIterators(read_options_, &list);
+  super_version_->current->AddIterators(
+      read_options_, *cfd_->soptions(), &list);
+  Iterator* immutable_iter =
+      NewMergingIterator(&cfd_->internal_comparator(), &list[0], list.size());
+
+  // create a DBIter that only uses memtable content; see NewIterator()
+  immutable_.reset(
+      NewDBIterator(env_, *cfd_->options(), cfd_->user_comparator(),
+                    immutable_iter, kMaxSequenceNumber));

-  mutable_.reset(iters.first);
-  immutable_.reset(iters.second);
  current_ = nullptr;
  is_prev_set_ = false;
 }
@@ -137,9 +181,10 @@ void TailingIterator::UpdateCurrent() {
  if (mutable_->Valid()) {
    current_ = mutable_.get();
  }
+  const Comparator* cmp = cfd_->user_comparator();
  if (immutable_->Valid() &&
      (current_ == nullptr ||
-       comparator_->Compare(immutable_->key(), current_->key()) < 0)) {
+       cmp->Compare(immutable_->key(), current_->key()) < 0)) {
    current_ = immutable_.get();
  }

@@ -150,12 +195,12 @@ void TailingIterator::UpdateCurrent() {
 }

 bool TailingIterator::IsCurrentVersion() const {
-  return mutable_ != nullptr && immutable_ != nullptr &&
-    version_number_ == db_->CurrentVersionNumber();
+  return super_version_ != nullptr &&
+         super_version_->version_number == cfd_->GetSuperVersionNumber();
 }

 bool TailingIterator::IsSamePrefix(const Slice& target) const {
-  const SliceTransform* extractor = db_->options_.prefix_extractor;
+  const SliceTransform* extractor = cfd_->options()->prefix_extractor.get();

  assert(extractor);
  assert(is_prev_set_);
@@ -173,3 +218,4 @@ void TailingIterator::SeekImmutable(const Slice& target) {
 }

 }  // namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -4,6 +4,8 @@
 //  of patent rights can be found in the PATENTS file in the same directory.
 #pragma once

+#ifndef ROCKSDB_LITE
+
 #include <string>

 #include "rocksdb/db.h"
@@ -13,6 +15,9 @@
 namespace rocksdb {

 class DBImpl;
+class Env;
+struct SuperVersion;
+class ColumnFamilyData;

 /**
 * TailingIterator is a special type of iterator that doesn't use an (implicit)
@@ -24,9 +29,9 @@ class DBImpl;
 */
 class TailingIterator : public Iterator {
 public:
-  TailingIterator(DBImpl* db, const ReadOptions& options,
-                  const Comparator* comparator);
-  virtual ~TailingIterator() {}
+  TailingIterator(Env* const env, DBImpl* db, const ReadOptions& read_options,
+                  ColumnFamilyData* cfd);
+  virtual ~TailingIterator();

  virtual bool Valid() const override;
  virtual void SeekToFirst() override;
@@ -39,10 +44,13 @@ class TailingIterator : public Iterator {
  virtual Status status() const override;

 private:
+  void Cleanup();
+
+  Env* const env_;
  DBImpl* const db_;
-  const ReadOptions options_;
-  const Comparator* const comparator_;
-  uint64_t version_number_;
+  const ReadOptions read_options_;
+  ColumnFamilyData* const cfd_;
+  SuperVersion* super_version_;

  // TailingIterator merges the contents of the two iterators below (one using
  // mutable memtable contents only, other over SSTs and immutable memtables).
@@ -72,7 +80,7 @@ class TailingIterator : public Iterator {
  bool IsCurrentVersion() const;

  // check if SeekImmutable() is needed due to target having a different prefix
-  // than prev_key_ (used when options.prefix_seek is set)
+  // than prev_key_ (used when in prefix seek mode)
  bool IsSamePrefix(const Slice& target) const;

  // creates mutable_ and immutable_ iterators and updates version_number_
@@ -86,3 +94,4 @@ class TailingIterator : public Iterator {
 };

 }  // namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -2,30 +2,30 @@
 //  This source code is licensed under the BSD-style license found in the
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.
-//
+
+#ifndef ROCKSDB_LITE
 #include "db/transaction_log_impl.h"
 #include "db/write_batch_internal.h"

 namespace rocksdb {

 TransactionLogIteratorImpl::TransactionLogIteratorImpl(
-                           const std::string& dir,
-                           const Options* options,
-                           const EnvOptions& soptions,
-                           const SequenceNumber seq,
-                           std::unique_ptr<VectorLogPtr> files,
-                           DBImpl const * const dbimpl) :
-    dir_(dir),
-    options_(options),
-    soptions_(soptions),
-    startingSequenceNumber_(seq),
-    files_(std::move(files)),
-    started_(false),
-    isValid_(false),
-    currentFileIndex_(0),
-    currentBatchSeq_(0),
-    currentLastSeq_(0),
-    dbimpl_(dbimpl) {
+    const std::string& dir, const DBOptions* options,
+    const TransactionLogIterator::ReadOptions& read_options,
+    const EnvOptions& soptions, const SequenceNumber seq,
+    std::unique_ptr<VectorLogPtr> files, DBImpl const* const dbimpl)
+    : dir_(dir),
+      options_(options),
+      read_options_(read_options),
+      soptions_(soptions),
+      startingSequenceNumber_(seq),
+      files_(std::move(files)),
+      started_(false),
+      isValid_(false),
+      currentFileIndex_(0),
+      currentBatchSeq_(0),
+      currentLastSeq_(0),
+      dbimpl_(dbimpl) {
  assert(files_ != nullptr);
  assert(dbimpl_ != nullptr);

@@ -49,9 +49,6 @@ Status TransactionLogIteratorImpl::OpenLogFile(
      //  Try the archive dir, as it could have moved in the meanwhile.
      fname = ArchivedLogFileName(dir_, logFile->LogNumber());
      status = env->NewSequentialFile(fname, file, soptions_);
-      if (!status.ok()) {
-        return Status::IOError("Requested file not present in the dir");
-      }
    }
    return status;
  }
@@ -96,6 +93,7 @@ void TransactionLogIteratorImpl::SeekToStartSequence(
  Status s = OpenLogReader(files_->at(startFileIndex).get());
  if (!s.ok()) {
    currentStatus_ = s;
+    reporter_.Info(currentStatus_.ToString().c_str());
    return;
  }
  while (RestrictedRead(&record, &scratch)) {
@@ -190,7 +188,7 @@ void TransactionLogIteratorImpl::NextImpl(bool internal) {
      if (currentLastSeq_ == dbimpl_->GetLatestSequenceNumber()) {
        currentStatus_ = Status::OK();
      } else {
-        currentStatus_ = Status::IOError("NO MORE DATA LEFT");
+        currentStatus_ = Status::Corruption("NO MORE DATA LEFT");
      }
      return;
    }
@@ -256,9 +254,9 @@ Status TransactionLogIteratorImpl::OpenLogReader(const LogFile* logFile) {
    return status;
  }
  assert(file);
-  currentLogReader_.reset(
-    new log::Reader(std::move(file), &reporter_, true, 0)
-  );
+  currentLogReader_.reset(new log::Reader(std::move(file), &reporter_,
+                                          read_options_.verify_checksums_, 0));
  return Status::OK();
 }
 }  //  namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -2,7 +2,8 @@
 //  This source code is licensed under the BSD-style license found in the
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.
-//
+
+#ifndef ROCKSDB_LITE
 #pragma once
 #include <vector>

@@ -66,12 +67,11 @@ class LogFileImpl : public LogFile {

 class TransactionLogIteratorImpl : public TransactionLogIterator {
 public:
-  TransactionLogIteratorImpl(const std::string& dir,
-                             const Options* options,
-                             const EnvOptions& soptions,
-                             const SequenceNumber seqNum,
-                             std::unique_ptr<VectorLogPtr> files,
-                             DBImpl const * const dbimpl);
+  TransactionLogIteratorImpl(
+      const std::string& dir, const DBOptions* options,
+      const TransactionLogIterator::ReadOptions& read_options,
+      const EnvOptions& soptions, const SequenceNumber seqNum,
+      std::unique_ptr<VectorLogPtr> files, DBImpl const* const dbimpl);

  virtual bool Valid();

@@ -83,7 +83,8 @@ class TransactionLogIteratorImpl : public TransactionLogIterator {

 private:
  const std::string& dir_;
-  const Options* options_;
+  const DBOptions* options_;
+  const TransactionLogIterator::ReadOptions read_options_;
  const EnvOptions& soptions_;
  SequenceNumber startingSequenceNumber_;
  std::unique_ptr<VectorLogPtr> files_;
@@ -116,3 +117,4 @@ class TransactionLogIteratorImpl : public TransactionLogIterator {
  Status OpenLogReader(const LogFile* file);
 };
 }  //  namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -11,26 +11,37 @@

 #include "db/version_set.h"
 #include "util/coding.h"
+#include "rocksdb/slice.h"

 namespace rocksdb {

 // Tag numbers for serialized VersionEdit.  These numbers are written to
 // disk and should not be changed.
 enum Tag {
-  kComparator           = 1,
-  kLogNumber            = 2,
-  kNextFileNumber       = 3,
-  kLastSequence         = 4,
-  kCompactPointer       = 5,
-  kDeletedFile          = 6,
-  kNewFile              = 7,
+  kComparator = 1,
+  kLogNumber = 2,
+  kNextFileNumber = 3,
+  kLastSequence = 4,
+  kCompactPointer = 5,
+  kDeletedFile = 6,
+  kNewFile = 7,
  // 8 was used for large value refs
-  kPrevLogNumber        = 9,
+  kPrevLogNumber = 9,

  // these are new formats divergent from open source leveldb
-  kNewFile2             = 100  // store smallest & largest seqno
+  kNewFile2 = 100,
+  kNewFile3 = 102,
+  kColumnFamily = 200,  // specify column family for version edit
+  kColumnFamilyAdd = 201,
+  kColumnFamilyDrop = 202,
+  kMaxColumnFamily = 203,
 };

+uint64_t PackFileNumberAndPathId(uint64_t number, uint64_t path_id) {
+  assert(number <= kFileNumberMask);
+  return number | (path_id * (kFileNumberMask + 1));
+}
+
 void VersionEdit::Clear() {
  comparator_.clear();
  max_level_ = 0;
@@ -38,13 +49,19 @@ void VersionEdit::Clear() {
  prev_log_number_ = 0;
  last_sequence_ = 0;
  next_file_number_ = 0;
+  max_column_family_ = 0;
  has_comparator_ = false;
  has_log_number_ = false;
  has_prev_log_number_ = false;
  has_next_file_number_ = false;
  has_last_sequence_ = false;
+  has_max_column_family_ = false;
  deleted_files_.clear();
  new_files_.clear();
+  column_family_ = 0;
+  is_column_family_add_ = 0;
+  is_column_family_drop_ = 0;
+  column_family_name_.clear();
 }

 void VersionEdit::EncodeTo(std::string* dst) const {
@@ -68,33 +85,59 @@ void VersionEdit::EncodeTo(std::string* dst) const {
    PutVarint32(dst, kLastSequence);
    PutVarint64(dst, last_sequence_);
  }
+  if (has_max_column_family_) {
+    PutVarint32(dst, kMaxColumnFamily);
+    PutVarint32(dst, max_column_family_);
+  }

-  for (DeletedFileSet::const_iterator iter = deleted_files_.begin();
-       iter != deleted_files_.end();
-       ++iter) {
+  for (const auto& deleted : deleted_files_) {
    PutVarint32(dst, kDeletedFile);
-    PutVarint32(dst, iter->first);   // level
-    PutVarint64(dst, iter->second);  // file number
+    PutVarint32(dst, deleted.first /* level */);
+    PutVarint64(dst, deleted.second /* file number */);
  }

  for (size_t i = 0; i < new_files_.size(); i++) {
    const FileMetaData& f = new_files_[i].second;
-    PutVarint32(dst, kNewFile2);
+    if (f.fd.GetPathId() == 0) {
+      // Use older format to make sure user can roll back the build if they
+      // don't config multiple DB paths.
+      PutVarint32(dst, kNewFile2);
+    } else {
+      PutVarint32(dst, kNewFile3);
+    }
    PutVarint32(dst, new_files_[i].first);  // level
-    PutVarint64(dst, f.number);
-    PutVarint64(dst, f.file_size);
+    PutVarint64(dst, f.fd.GetNumber());
+    if (f.fd.GetPathId() != 0) {
+      PutVarint32(dst, f.fd.GetPathId());
+    }
+    PutVarint64(dst, f.fd.GetFileSize());
    PutLengthPrefixedSlice(dst, f.smallest.Encode());
    PutLengthPrefixedSlice(dst, f.largest.Encode());
    PutVarint64(dst, f.smallest_seqno);
    PutVarint64(dst, f.largest_seqno);
  }
+
+  // 0 is default and does not need to be explicitly written
+  if (column_family_ != 0) {
+    PutVarint32(dst, kColumnFamily);
+    PutVarint32(dst, column_family_);
+  }
+
+  if (is_column_family_add_) {
+    PutVarint32(dst, kColumnFamilyAdd);
+    PutLengthPrefixedSlice(dst, Slice(column_family_name_));
+  }
+
+  if (is_column_family_drop_) {
+    PutVarint32(dst, kColumnFamilyDrop);
+  }
 }

 static bool GetInternalKey(Slice* input, InternalKey* dst) {
  Slice str;
  if (GetLengthPrefixedSlice(input, &str)) {
    dst->DecodeFrom(str);
-    return true;
+    return dst->Valid();
  } else {
    return false;
  }
@@ -169,6 +212,14 @@ Status VersionEdit::DecodeFrom(const Slice& src) {
        }
        break;

+      case kMaxColumnFamily:
+        if (GetVarint32(&input, &max_column_family_)) {
+          has_max_column_family_ = true;
+        } else {
+          msg = "max column family";
+        }
+        break;
+
      case kCompactPointer:
        if (GetLevel(&input, &level, &msg) &&
            GetInternalKey(&input, &key)) {
@@ -193,12 +244,14 @@ Status VersionEdit::DecodeFrom(const Slice& src) {
        }
        break;

-      case kNewFile:
-        if (GetLevel(&input, &level, &msg) &&
-            GetVarint64(&input, &f.number) &&
-            GetVarint64(&input, &f.file_size) &&
+      case kNewFile: {
+        uint64_t number;
+        uint64_t file_size;
+        if (GetLevel(&input, &level, &msg) && GetVarint64(&input, &number) &&
+            GetVarint64(&input, &file_size) &&
            GetInternalKey(&input, &f.smallest) &&
            GetInternalKey(&input, &f.largest)) {
+          f.fd = FileDescriptor(number, 0, file_size);
          new_files_.push_back(std::make_pair(level, f));
        } else {
          if (!msg) {
@@ -206,15 +259,17 @@ Status VersionEdit::DecodeFrom(const Slice& src) {
          }
        }
        break;
-
-      case kNewFile2:
-        if (GetLevel(&input, &level, &msg) &&
-            GetVarint64(&input, &f.number) &&
-            GetVarint64(&input, &f.file_size) &&
+      }
+      case kNewFile2: {
+        uint64_t number;
+        uint64_t file_size;
+        if (GetLevel(&input, &level, &msg) && GetVarint64(&input, &number) &&
+            GetVarint64(&input, &file_size) &&
            GetInternalKey(&input, &f.smallest) &&
            GetInternalKey(&input, &f.largest) &&
            GetVarint64(&input, &f.smallest_seqno) &&
-            GetVarint64(&input, &f.largest_seqno) ) {
+            GetVarint64(&input, &f.largest_seqno)) {
+          f.fd = FileDescriptor(number, 0, file_size);
          new_files_.push_back(std::make_pair(level, f));
        } else {
          if (!msg) {
@@ -222,6 +277,50 @@ Status VersionEdit::DecodeFrom(const Slice& src) {
          }
        }
        break;
+      }
+
+      case kNewFile3: {
+        uint64_t number;
+        uint32_t path_id;
+        uint64_t file_size;
+        if (GetLevel(&input, &level, &msg) && GetVarint64(&input, &number) &&
+            GetVarint32(&input, &path_id) && GetVarint64(&input, &file_size) &&
+            GetInternalKey(&input, &f.smallest) &&
+            GetInternalKey(&input, &f.largest) &&
+            GetVarint64(&input, &f.smallest_seqno) &&
+            GetVarint64(&input, &f.largest_seqno)) {
+          f.fd = FileDescriptor(number, path_id, file_size);
+          new_files_.push_back(std::make_pair(level, f));
+        } else {
+          if (!msg) {
+            msg = "new-file2 entry";
+          }
+        }
+        break;
+      }
+
+      case kColumnFamily:
+        if (!GetVarint32(&input, &column_family_)) {
+          if (!msg) {
+            msg = "set column family id";
+          }
+        }
+        break;
+
+      case kColumnFamilyAdd:
+        if (GetLengthPrefixedSlice(&input, &str)) {
+          is_column_family_add_ = true;
+          column_family_name_ = str.ToString();
+        } else {
+          if (!msg) {
+            msg = "column family add";
+          }
+        }
+        break;
+
+      case kColumnFamilyDrop:
+        is_column_family_drop_ = true;
+        break;

      default:
        msg = "unknown tag";
@@ -276,14 +375,27 @@ std::string VersionEdit::DebugString(bool hex_key) const {
    r.append("\n  AddFile: ");
    AppendNumberTo(&r, new_files_[i].first);
    r.append(" ");
-    AppendNumberTo(&r, f.number);
+    AppendNumberTo(&r, f.fd.GetNumber());
    r.append(" ");
-    AppendNumberTo(&r, f.file_size);
+    AppendNumberTo(&r, f.fd.GetFileSize());
    r.append(" ");
    r.append(f.smallest.DebugString(hex_key));
    r.append(" .. ");
    r.append(f.largest.DebugString(hex_key));
  }
+  r.append("\n  ColumnFamily: ");
+  AppendNumberTo(&r, column_family_);
+  if (is_column_family_add_) {
+    r.append("\n  ColumnFamilyAdd: ");
+    r.append(column_family_name_);
+  }
+  if (is_column_family_drop_) {
+    r.append("\n  ColumnFamilyDrop");
+  }
+  if (has_max_column_family_) {
+    r.append("\n  MaxColumnFamily: ");
+    AppendNumberTo(&r, max_column_family_);
+  }
  r.append("\n}\n");
  return r;
 }
@@ -11,25 +11,116 @@
 #include <set>
 #include <utility>
 #include <vector>
+#include <string>
+#include "rocksdb/cache.h"
 #include "db/dbformat.h"

 namespace rocksdb {

 class VersionSet;

+const uint64_t kFileNumberMask = 0x3FFFFFFFFFFFFFFF;
+
+extern uint64_t PackFileNumberAndPathId(uint64_t number, uint64_t path_id);
+
+// A copyable structure contains information needed to read data from an SST
+// file. It can contains a pointer to a table reader opened for the file, or
+// file number and size, which can be used to create a new table reader for it.
+// The behavior is undefined when a copied of the structure is used when the
+// file is not in any live version any more.
+struct FileDescriptor {
+  // Table reader in table_reader_handle
+  TableReader* table_reader;
+  uint64_t packed_number_and_path_id;
+  uint64_t file_size;  // File size in bytes
+
+  FileDescriptor() : FileDescriptor(0, 0, 0) {}
+
+  FileDescriptor(uint64_t number, uint32_t path_id, uint64_t file_size)
+      : table_reader(nullptr),
+        packed_number_and_path_id(PackFileNumberAndPathId(number, path_id)),
+        file_size(file_size) {}
+
+  FileDescriptor& operator=(const FileDescriptor& fd) {
+    table_reader = fd.table_reader;
+    packed_number_and_path_id = fd.packed_number_and_path_id;
+    file_size = fd.file_size;
+    return *this;
+  }
+
+  uint64_t GetNumber() const {
+    return packed_number_and_path_id & kFileNumberMask;
+  }
+  uint32_t GetPathId() const {
+    return packed_number_and_path_id / (kFileNumberMask + 1);
+  }
+  uint64_t GetFileSize() const { return file_size; }
+};
+
 struct FileMetaData {
  int refs;
-  int allowed_seeks;          // Seeks allowed until compaction
-  uint64_t number;
-  uint64_t file_size;         // File size in bytes
-  InternalKey smallest;       // Smallest internal key served by table
-  InternalKey largest;        // Largest internal key served by table
-  bool being_compacted;       // Is this file undergoing compaction?
-  SequenceNumber smallest_seqno;// The smallest seqno in this file
-  SequenceNumber largest_seqno; // The largest seqno in this file
+  FileDescriptor fd;
+  InternalKey smallest;            // Smallest internal key served by table
+  InternalKey largest;             // Largest internal key served by table
+  bool being_compacted;            // Is this file undergoing compaction?
+  SequenceNumber smallest_seqno;   // The smallest seqno in this file
+  SequenceNumber largest_seqno;    // The largest seqno in this file

-  FileMetaData() : refs(0), allowed_seeks(1 << 30), file_size(0),
-                   being_compacted(false) { }
+  // Needs to be disposed when refs becomes 0.
+  Cache::Handle* table_reader_handle;
+
+  // Stats for compensating deletion entries during compaction
+
+  // File size compensated by deletion entry.
+  // This is updated in Version::UpdateTemporaryStats() first time when the
+  // file is created or loaded.  After it is updated, it is immutable.
+  uint64_t compensated_file_size;
+  uint64_t num_entries;            // the number of entries.
+  uint64_t num_deletions;          // the number of deletion entries.
+  uint64_t raw_key_size;           // total uncompressed key size.
+  uint64_t raw_value_size;         // total uncompressed value size.
+
+  FileMetaData()
+      : refs(0),
+        being_compacted(false),
+        table_reader_handle(nullptr),
+        compensated_file_size(0),
+        num_entries(0),
+        num_deletions(0),
+        raw_key_size(0),
+        raw_value_size(0) {}
+};
+
+// A compressed copy of file meta data that just contain
+// smallest and largest key's slice
+struct FdWithKeyRange {
+  FileDescriptor fd;
+  Slice smallest_key;    // slice that contain smallest key
+  Slice largest_key;     // slice that contain largest key
+
+  FdWithKeyRange()
+      : fd(),
+        smallest_key(),
+        largest_key() {
+  }
+
+  FdWithKeyRange(FileDescriptor fd,
+      Slice smallest_key, Slice largest_key)
+      : fd(fd),
+        smallest_key(smallest_key),
+        largest_key(largest_key) {
+  }
+};
+
+// Data structure to store an array of FdWithKeyRange in one level
+// Actual data is guaranteed to be stored closely
+struct FileLevel {
+  size_t num_files;
+  FdWithKeyRange* files;
+  FileLevel() {
+    num_files = 0;
+    files = nullptr;
+  }
 };

 class VersionEdit {
@@ -59,30 +150,31 @@ class VersionEdit {
    has_last_sequence_ = true;
    last_sequence_ = seq;
  }
+  void SetMaxColumnFamily(uint32_t max_column_family) {
+    has_max_column_family_ = true;
+    max_column_family_ = max_column_family;
+  }

  // Add the specified file at the specified number.
  // REQUIRES: This version has not been saved (see VersionSet::SaveTo)
  // REQUIRES: "smallest" and "largest" are smallest and largest keys in file
-  void AddFile(int level, uint64_t file,
-               uint64_t file_size,
-               const InternalKey& smallest,
-               const InternalKey& largest,
-               const SequenceNumber& smallest_seqno,
+  void AddFile(int level, uint64_t file, uint64_t file_size,
+               uint64_t file_path_id, const InternalKey& smallest,
+               const InternalKey& largest, const SequenceNumber& smallest_seqno,
               const SequenceNumber& largest_seqno) {
+    assert(smallest_seqno <= largest_seqno);
    FileMetaData f;
-    f.number = file;
-    f.file_size = file_size;
+    f.fd = FileDescriptor(file, file_size, file_path_id);
    f.smallest = smallest;
    f.largest = largest;
    f.smallest_seqno = smallest_seqno;
    f.largest_seqno = largest_seqno;
-    assert(smallest_seqno <= largest_seqno);
    new_files_.push_back(std::make_pair(level, f));
  }

  // Delete the specified "file" from the specified "level".
  void DeleteFile(int level, uint64_t file) {
-    deleted_files_.insert(std::make_pair(level, file));
+    deleted_files_.insert({level, file});
  }

  // Number of edits
@@ -90,6 +182,31 @@ class VersionEdit {
    return new_files_.size() + deleted_files_.size();
  }

+  bool IsColumnFamilyManipulation() {
+    return is_column_family_add_ || is_column_family_drop_;
+  }
+
+  void SetColumnFamily(uint32_t column_family_id) {
+    column_family_ = column_family_id;
+  }
+
+  // set column family ID by calling SetColumnFamily()
+  void AddColumnFamily(const std::string& name) {
+    assert(!is_column_family_drop_);
+    assert(!is_column_family_add_);
+    assert(NumEntries() == 0);
+    is_column_family_add_ = true;
+    column_family_name_ = name;
+  }
+
+  // set column family ID by calling SetColumnFamily()
+  void DropColumnFamily() {
+    assert(!is_column_family_drop_);
+    assert(!is_column_family_add_);
+    assert(NumEntries() == 0);
+    is_column_family_drop_ = true;
+  }
+
  void EncodeTo(std::string* dst) const;
  Status DecodeFrom(const Slice& src);

@@ -97,8 +214,9 @@ class VersionEdit {

 private:
  friend class VersionSet;
+  friend class Version;

-  typedef std::set< std::pair<int, uint64_t> > DeletedFileSet;
+  typedef std::set< std::pair<int, uint64_t>> DeletedFileSet;

  bool GetLevel(Slice* input, int* level, const char** msg);

@@ -107,15 +225,27 @@ class VersionEdit {
  uint64_t log_number_;
  uint64_t prev_log_number_;
  uint64_t next_file_number_;
+  uint32_t max_column_family_;
  SequenceNumber last_sequence_;
  bool has_comparator_;
  bool has_log_number_;
  bool has_prev_log_number_;
  bool has_next_file_number_;
  bool has_last_sequence_;
+  bool has_max_column_family_;

  DeletedFileSet deleted_files_;
-  std::vector<std::pair<int, FileMetaData> > new_files_;
+  std::vector<std::pair<int, FileMetaData>> new_files_;
+
+  // Each version edit record should have column_family_id set
+  // If it's not set, it is default (0)
+  uint32_t column_family_;
+  // a version edit can be either column_family add or
+  // column_family drop. If it's column family add,
+  // it also includes column family name.
+  bool is_column_family_drop_;
+  bool is_column_family_add_;
+  std::string column_family_name_;
 };

 }  // namespace rocksdb
@@ -30,11 +30,10 @@ TEST(VersionEditTest, EncodeDecode) {
  VersionEdit edit;
  for (int i = 0; i < 4; i++) {
    TestEncodeDecode(edit);
-    edit.AddFile(3, kBig + 300 + i, kBig + 400 + i,
+    edit.AddFile(3, kBig + 300 + i, kBig + 400 + i, 0,
                 InternalKey("foo", kBig + 500 + i, kTypeValue),
                 InternalKey("zoo", kBig + 600 + i, kTypeDeletion),
-                 kBig + 500 + i,
-                 kBig + 600 + i);
+                 kBig + 500 + i, kBig + 600 + i);
    edit.DeleteFile(4, kBig + 700 + i);
  }

@@ -45,6 +44,19 @@ TEST(VersionEditTest, EncodeDecode) {
  TestEncodeDecode(edit);
 }

+TEST(VersionEditTest, ColumnFamilyTest) {
+  VersionEdit edit;
+  edit.SetColumnFamily(2);
+  edit.AddColumnFamily("column_family");
+  edit.SetMaxColumnFamily(5);
+  TestEncodeDecode(edit);
+
+  edit.Clear();
+  edit.SetColumnFamily(3);
+  edit.DropColumnFamily();
+  TestEncodeDecode(edit);
+}
+
 }  // namespace rocksdb

 int main(int argc, char** argv) {
@@ -23,12 +23,17 @@
 #include <set>
 #include <vector>
 #include <deque>
+#include <atomic>
+#include <limits>
 #include "db/dbformat.h"
 #include "db/version_edit.h"
 #include "port/port.h"
 #include "db/table_cache.h"
 #include "db/compaction.h"
 #include "db/compaction_picker.h"
+#include "db/column_family.h"
+#include "db/log_reader.h"
+#include "db/file_indexer.h"

 namespace rocksdb {

@@ -37,11 +42,17 @@ namespace log { class Writer; }
 class Compaction;
 class CompactionPicker;
 class Iterator;
+class LogBuffer;
+class LookupKey;
 class MemTable;
-class TableCache;
 class Version;
 class VersionSet;
 class MergeContext;
+class ColumnFamilyData;
+class ColumnFamilySet;
+class TableCache;
+class MergeIteratorBuilder;
+

 // Return the smallest index i such that files[i]->largest >= key.
 // Return files.size() if there is no such file.
@@ -50,16 +61,24 @@ extern int FindFile(const InternalKeyComparator& icmp,
                    const std::vector<FileMetaData*>& files,
                    const Slice& key);

+// Return the smallest index i such that file_level.files[i]->largest >= key.
+// Return file_level.num_files if there is no such file.
+// REQUIRES: "file_level.files" contains a sorted list of
+// non-overlapping files.
+extern int FindFile(const InternalKeyComparator& icmp,
+                    const FileLevel& file_level,
+                    const Slice& key);
+
 // Returns true iff some file in "files" overlaps the user key range
 // [*smallest,*largest].
 // smallest==nullptr represents a key smaller than all keys in the DB.
 // largest==nullptr represents a key largest than all keys in the DB.
-// REQUIRES: If disjoint_sorted_files, files[] contains disjoint ranges
-//           in sorted order.
+// REQUIRES: If disjoint_sorted_files, file_level.files[]
+// contains disjoint ranges in sorted order.
 extern bool SomeFileOverlapsRange(
    const InternalKeyComparator& icmp,
    bool disjoint_sorted_files,
-    const std::vector<FileMetaData*>& files,
+    const FileLevel& file_level,
    const Slice* smallest_user_key,
    const Slice* largest_user_key);

@@ -71,33 +90,36 @@ class Version {
  void AddIterators(const ReadOptions&, const EnvOptions& soptions,
                    std::vector<Iterator*>* iters);

+  void AddIterators(const ReadOptions&, const EnvOptions& soptions,
+                    MergeIteratorBuilder* merger_iter_builder);
+
  // Lookup the value for key.  If found, store it in *val and
-  // return OK.  Else return a non-OK status.  Fills *stats.
+  // return OK.  Else return a non-OK status.
  // Uses *operands to store merge_operator operations to apply later
  // REQUIRES: lock is not held
-  struct GetStats {
-    FileMetaData* seek_file;
-    int seek_file_level;
-  };
  void Get(const ReadOptions&, const LookupKey& key, std::string* val,
           Status* status, MergeContext* merge_context,
-           GetStats* stats, const Options& db_option, bool* value_found =
-               nullptr);
-
-  // Adds "stats" into the current state.  Returns true if a new
-  // compaction may need to be triggered, false otherwise.
-  // REQUIRES: lock is held
-  bool UpdateStats(const GetStats& stats);
+           bool* value_found = nullptr);

  // Updates internal structures that keep track of compaction scores
  // We use compaction scores to figure out which compaction to do next
-  // Also pre-sorts level0 files for Get()
-  void Finalize(std::vector<uint64_t>& size_being_compacted);
+  // REQUIRES: If Version is not yet saved to current_, it can be called without
+  // a lock. Once a version is saved to current_, call only with mutex held
+  void ComputeCompactionScore(std::vector<uint64_t>& size_being_compacted);
+
+  // Generate file_levels_ from files_
+  void GenerateFileLevels();
+
+  // Update scores, pre-calculated variables. It needs to be called before
+  // applying the version to the version set.
+  void PrepareApply(std::vector<uint64_t>& size_being_compacted);

  // Reference count management (so Versions do not disappear out from
  // under live iterators)
  void Ref();
-  void Unref();
+  // Decrease reference count. Delete the object if no reference left
+  // and return true. Otherwise, return false.
+  bool Unref();

  // Returns true iff some level needs a compaction.
  bool NeedsCompaction() const;
@@ -178,7 +200,7 @@ class Version {
  int64_t MaxNextLevelOverlappingBytes();

  // Add all files listed in the current version to *live.
-  void AddLiveFiles(std::set<uint64_t>* live);
+  void AddLiveFiles(std::vector<FileDescriptor>* live);

  // Return a human readable string that describes this version's contents.
  std::string DebugString(bool hex = false) const;
@@ -186,6 +208,31 @@ class Version {
  // Returns the version nuber of this version
  uint64_t GetVersionNumber() const { return version_number_; }

+  uint64_t GetAverageValueSize() const {
+    if (num_non_deletions_ == 0) {
+      return 0;
+    }
+    assert(total_raw_key_size_ + total_raw_value_size_ > 0);
+    assert(total_file_size_ > 0);
+    return total_raw_value_size_ / num_non_deletions_ * total_file_size_ /
+           (total_raw_key_size_ + total_raw_value_size_);
+  }
+
+  // REQUIRES: lock is held
+  // On success, "tp" will contains the table properties of the file
+  // specified in "file_meta".  If the file name of "file_meta" is
+  // known ahread, passing it by a non-null "fname" can save a
+  // file-name conversion.
+  Status GetTableProperties(std::shared_ptr<const TableProperties>* tp,
+                            const FileMetaData* file_meta,
+                            const std::string* fname = nullptr);
+
+  // REQUIRES: lock is held
+  // On success, *props will be populated with all SSTables' table properties.
+  // The keys of `props` are the sst file name, the values of `props` are the
+  // tables' propertis, represented as shared_ptr.
+  Status GetPropertiesOfAllTables(TablePropertiesCollection* props);
+
  // used to sort files by size
  struct Fsize {
    int index;
@@ -196,36 +243,63 @@ class Version {
  friend class Compaction;
  friend class VersionSet;
  friend class DBImpl;
+  friend class ColumnFamilyData;
  friend class CompactionPicker;
  friend class LevelCompactionPicker;
  friend class UniversalCompactionPicker;
+  friend class FIFOCompactionPicker;
+  friend class ForwardIterator;

  class LevelFileNumIterator;
-  Iterator* NewConcatenatingIterator(const ReadOptions&,
-                                     const EnvOptions& soptions,
-                                     int level) const;
-  bool PrefixMayMatch(const ReadOptions& options, const EnvOptions& soptions,
-                      const Slice& internal_prefix, Iterator* level_iter) const;
+  class LevelFileIteratorState;
+
+  bool PrefixMayMatch(const ReadOptions& options, Iterator* level_iter,
+                      const Slice& internal_prefix) const;
+
+  // Update num_non_empty_levels_.
+  void UpdateNumNonEmptyLevels();
+
+  // The helper function of UpdateTemporaryStats, which may fill the missing
+  // fields of file_mata from its associated TableProperties.
+  // Returns true if it does initialize FileMetaData.
+  bool MaybeInitializeFileMetaData(FileMetaData* file_meta);
+
+  // Update the temporary stats associated with the current version.
+  // This temporary stats will be used in compaction.
+  void UpdateTemporaryStats();

  // Sort all files for this version based on their file size and
  // record results in files_by_size_. The largest files are listed first.
  void UpdateFilesBySize();

+  ColumnFamilyData* cfd_;  // ColumnFamilyData to which this Version belongs
+  const InternalKeyComparator* internal_comparator_;
+  const Comparator* user_comparator_;
+  TableCache* table_cache_;
+  const MergeOperator* merge_operator_;
+
+  autovector<FileLevel> file_levels_;   // A copy of list of files per level
+  Logger* info_log_;
+  Statistics* db_statistics_;
+  int num_levels_;              // Number of levels
+  int num_non_empty_levels_;    // Number of levels. Any level larger than it
+                                // is guaranteed to be empty.
  VersionSet* vset_;            // VersionSet to which this Version belongs
+  Arena arena_;                 // Used to allocate space for file_levels_
  Version* next_;               // Next version in linked list
  Version* prev_;               // Previous version in linked list
  int refs_;                    // Number of live refs to this version
-  int num_levels_;              // Number of levels

  // List of files per level, files in each level are arranged
  // in increasing order of keys
  std::vector<FileMetaData*>* files_;

+
  // A list for the same set of files that are stored in files_,
  // but files in each level are now sorted based on file
  // size. The file with the largest size is at the front.
  // This vector stores the index of the file from files_.
-  std::vector< std::vector<int> > files_by_size_;
+  std::vector<std::vector<int>> files_by_size_;

  // An index into files_by_size_ that specifies the first
  // file that is not yet compacted
@@ -236,11 +310,7 @@ class Version {
  // that on a running system, we need to look at only the first
  // few largest files because a new version is created every few
  // seconds/minutes (because of concurrent compactions).
-  static const int number_of_files_to_sort_ = 50;
-
-  // Next file to compact based on seek stats.
-  FileMetaData* file_to_compact_;
-  int file_to_compact_level_;
+  static const size_t number_of_files_to_sort_ = 50;

  // Level that should be compacted next and its compaction score.
  // Score < 1 means compaction is not strictly needed.  These fields
@@ -256,7 +326,18 @@ class Version {
  // used for debugging and logging purposes only.
  uint64_t version_number_;

-  explicit Version(VersionSet* vset, uint64_t version_number = 0);
+  Version(ColumnFamilyData* cfd, VersionSet* vset, uint64_t version_number = 0);
+  FileIndexer file_indexer_;
+
+  // total file size
+  uint64_t total_file_size_;
+  // the total size of all raw keys.
+  uint64_t total_raw_key_size_;
+  // the total size of all raw values.
+  uint64_t total_raw_value_size_;
+  // total number of non-deletion entries
+  uint64_t num_non_deletions_;
+

  ~Version();

@@ -273,23 +354,34 @@ class Version {

 class VersionSet {
 public:
-  VersionSet(const std::string& dbname, const Options* options,
-             const EnvOptions& storage_options, TableCache* table_cache,
-             const InternalKeyComparator*);
+  VersionSet(const std::string& dbname, const DBOptions* options,
+             const EnvOptions& storage_options, Cache* table_cache);
  ~VersionSet();

  // Apply *edit to the current version to form a new descriptor that
  // is both saved to persistent state and installed as the new
  // current version.  Will release *mu while actually writing to the file.
+  // column_family_options has to be set if edit is column family add
  // REQUIRES: *mu is held on entry.
  // REQUIRES: no other thread concurrently calls LogAndApply()
-  Status LogAndApply(VersionEdit* edit, port::Mutex* mu,
-                     Directory* db_directory = nullptr,
-                     bool new_descriptor_log = false);
+  Status LogAndApply(ColumnFamilyData* column_family_data, VersionEdit* edit,
+                     port::Mutex* mu, Directory* db_directory = nullptr,
+                     bool new_descriptor_log = false,
+                     const ColumnFamilyOptions* column_family_options =
+                         nullptr);

  // Recover the last saved descriptor from persistent storage.
-  Status Recover();
+  // If read_only == true, Recover() will not complain if some column families
+  // are not opened
+  Status Recover(const std::vector<ColumnFamilyDescriptor>& column_families,
+                 bool read_only = false);

+  // Reads a manifest file and returns a list of column families in
+  // column_families.
+  static Status ListColumnFamilies(std::vector<std::string>* column_families,
+                                   const std::string& dbname, Env* env);
+
+#ifndef ROCKSDB_LITE
  // Try to reduce the number of levels. This call is valid when
  // only one level from the new max level to the old
  // max level containing files.
@@ -304,25 +396,26 @@ class VersionSet {
                                     const EnvOptions& storage_options,
                                     int new_levels);

-  // Return the current version.
-  Version* current() const { return current_; }
+  // printf contents (for debugging)
+  Status DumpManifest(Options& options, std::string& manifestFileName,
+                      bool verbose, bool hex = false);

-  // A Flag indicating whether write needs to slowdown because of there are
-  // too many number of level0 files.
-  bool NeedSlowdownForNumLevel0Files() const {
-    return need_slowdown_for_num_level0_files_;
-  }
+#endif  // ROCKSDB_LITE

  // Return the current manifest file number
  uint64_t ManifestFileNumber() const { return manifest_file_number_; }

+  uint64_t PendingManifestFileNumber() const {
+    return pending_manifest_file_number_;
+  }
+
  // Allocate and return a new file number
  uint64_t NewFileNumber() { return next_file_number_++; }

  // Arrange to reuse "file_number" unless a newer file number has
  // already been allocated.
  // REQUIRES: "file_number" was returned by a call to NewFileNumber().
-  void ReuseFileNumber(uint64_t file_number) {
+  void ReuseLogFileNumber(uint64_t file_number) {
    if (next_file_number_ == file_number + 1) {
      next_file_number_ = file_number;
    }
@@ -342,53 +435,33 @@ class VersionSet {
  // Mark the specified file number as used.
  void MarkFileNumberUsed(uint64_t number);

-  // Return the current log file number.
-  uint64_t LogNumber() const { return log_number_; }
-
  // Return the log file number for the log file that is currently
  // being compacted, or zero if there is no such log file.
  uint64_t PrevLogNumber() const { return prev_log_number_; }

-  int NumberLevels() const { return num_levels_; }
-
-  // Pick level and inputs for a new compaction.
-  // Returns nullptr if there is no compaction to be done.
-  // Otherwise returns a pointer to a heap-allocated object that
-  // describes the compaction.  Caller should delete the result.
-  Compaction* PickCompaction();
-
-  // Return a compaction object for compacting the range [begin,end] in
-  // the specified level.  Returns nullptr if there is nothing in that
-  // level that overlaps the specified range.  Caller should delete
-  // the result.
-  //
-  // The returned Compaction might not include the whole requested range.
-  // In that case, compaction_end will be set to the next key that needs
-  // compacting. In case the compaction will compact the whole range,
-  // compaction_end will be set to nullptr.
-  // Client is responsible for compaction_end storage -- when called,
-  // *compaction_end should point to valid InternalKey!
-  Compaction* CompactRange(int input_level,
-                           int output_level,
-                           const InternalKey* begin,
-                           const InternalKey* end,
-                           InternalKey** compaction_end);
+  // Returns the minimum log number such that all
+  // log numbers less than or equal to it can be deleted
+  uint64_t MinLogNumber() const {
+    uint64_t min_log_num = std::numeric_limits<uint64_t>::max();
+    for (auto cfd : *column_family_set_) {
+      if (min_log_num > cfd->GetLogNumber()) {
+        min_log_num = cfd->GetLogNumber();
+      }
+    }
+    return min_log_num;
+  }

  // Create an iterator that reads over the compaction inputs for "*c".
  // The caller should delete the iterator when no longer needed.
  Iterator* MakeInputIterator(Compaction* c);

  // Add all files listed in any live version to *live.
-  void AddLiveFiles(std::vector<uint64_t>* live_list);
+  void AddLiveFiles(std::vector<FileDescriptor>* live_list);

  // Return the approximate offset in the database of the data for
  // "key" as of version "v".
  uint64_t ApproximateOffsetOf(Version* v, const InternalKey& key);

-  // printf contents (for debugging)
-  Status DumpManifest(Options& options, std::string& manifestFileName,
-                      bool verbose, bool hex = false);
-
  // Return the size of the current manifest file
  uint64_t ManifestFileSize() const { return manifest_file_size_; }

@@ -398,60 +471,53 @@ class VersionSet {
  // pick the same files to compact.
  bool VerifyCompactionFileConsistency(Compaction* c);

-  double MaxBytesForLevel(int level);
-
-  // Get the max file size in a given level.
-  uint64_t MaxFileSizeForLevel(int level);
-
-  void ReleaseCompactionFiles(Compaction* c, Status status);
-
-  Status GetMetadataForFile(
-    uint64_t number, int *filelevel, FileMetaData *metadata);
+  Status GetMetadataForFile(uint64_t number, int* filelevel,
+                            FileMetaData** metadata, ColumnFamilyData** cfd);

  void GetLiveFilesMetaData(
    std::vector<LiveFileMetaData> *metadata);

  void GetObsoleteFiles(std::vector<FileMetaData*>* files);

+  ColumnFamilySet* GetColumnFamilySet() { return column_family_set_.get(); }
+
 private:
  class Builder;
  struct ManifestWriter;

-  friend class Compaction;
  friend class Version;

+  struct LogReporter : public log::Reader::Reporter {
+    Status* status;
+    virtual void Corruption(size_t bytes, const Status& s) {
+      if (this->status->ok()) *this->status = s;
+    }
+  };
+
  // Save current contents to *log
  Status WriteSnapshot(log::Writer* log);

-  void AppendVersion(Version* v);
+  void AppendVersion(ColumnFamilyData* column_family_data, Version* v);

-  bool ManifestContains(const std::string& record) const;
+  bool ManifestContains(uint64_t manifest_file_number,
+                        const std::string& record) const;
+
+  ColumnFamilyData* CreateColumnFamily(const ColumnFamilyOptions& options,
+                                       VersionEdit* edit);
+
+  std::unique_ptr<ColumnFamilySet> column_family_set_;

  Env* const env_;
  const std::string dbname_;
-  const Options* const options_;
-  TableCache* const table_cache_;
-  const InternalKeyComparator icmp_;
+  const DBOptions* const options_;
  uint64_t next_file_number_;
  uint64_t manifest_file_number_;
+  uint64_t pending_manifest_file_number_;
  std::atomic<uint64_t> last_sequence_;
-  uint64_t log_number_;
  uint64_t prev_log_number_;  // 0 or backing store for memtable being compacted

-  int num_levels_;
-
  // Opened lazily
  unique_ptr<log::Writer> descriptor_log_;
-  Version dummy_versions_;  // Head of circular doubly-linked list of versions.
-  Version* current_;        // == dummy_versions_.prev_
-
-  // A flag indicating whether we should delay writes because
-  // we have too many level 0 files
-  bool need_slowdown_for_num_level0_files_;
-
-  // An object that keeps all the compaction stats
-  // and picks the next compaction
-  std::unique_ptr<CompactionPicker> compaction_picker_;

  // generates a increasing version number for every new version
  uint64_t current_version_number_;
@@ -475,8 +541,9 @@ class VersionSet {
  VersionSet(const VersionSet&);
  void operator=(const VersionSet&);

-  void LogAndApplyHelper(Builder*b, Version* v,
-                           VersionEdit* edit, port::Mutex* mu);
+  void LogAndApplyCFHelper(VersionEdit* edit);
+  void LogAndApplyHelper(ColumnFamilyData* cfd, Builder* b, Version* v,
+                         VersionEdit* edit, port::Mutex* mu);
 };

 }  // namespace rocksdb
@@ -31,7 +31,7 @@ class FindFileTest {
           SequenceNumber smallest_seq = 100,
           SequenceNumber largest_seq = 100) {
    FileMetaData* f = new FileMetaData;
-    f->number = files_.size() + 1;
+    f->fd = FileDescriptor(files_.size() + 1, 0, 0);
    f->smallest = InternalKey(smallest, smallest_seq, kTypeValue);
    f->largest = InternalKey(largest, largest_seq, kTypeValue);
    files_.push_back(f);
@@ -42,18 +42,108 @@ class FindFileTest {
    InternalKeyComparator cmp(BytewiseComparator());
    return FindFile(cmp, files_, target.Encode());
  }
+};
+
+TEST(FindFileTest, Empty) {
+  ASSERT_EQ(0, Find("foo"));
+}
+
+TEST(FindFileTest, Single) {
+  Add("p", "q");
+  ASSERT_EQ(0, Find("a"));
+  ASSERT_EQ(0, Find("p"));
+  ASSERT_EQ(0, Find("p1"));
+  ASSERT_EQ(0, Find("q"));
+  ASSERT_EQ(1, Find("q1"));
+  ASSERT_EQ(1, Find("z"));
+}
+
+
+TEST(FindFileTest, Multiple) {
+  Add("150", "200");
+  Add("200", "250");
+  Add("300", "350");
+  Add("400", "450");
+  ASSERT_EQ(0, Find("100"));
+  ASSERT_EQ(0, Find("150"));
+  ASSERT_EQ(0, Find("151"));
+  ASSERT_EQ(0, Find("199"));
+  ASSERT_EQ(0, Find("200"));
+  ASSERT_EQ(1, Find("201"));
+  ASSERT_EQ(1, Find("249"));
+  ASSERT_EQ(1, Find("250"));
+  ASSERT_EQ(2, Find("251"));
+  ASSERT_EQ(2, Find("299"));
+  ASSERT_EQ(2, Find("300"));
+  ASSERT_EQ(2, Find("349"));
+  ASSERT_EQ(2, Find("350"));
+  ASSERT_EQ(3, Find("351"));
+  ASSERT_EQ(3, Find("400"));
+  ASSERT_EQ(3, Find("450"));
+  ASSERT_EQ(4, Find("451"));
+}
+
+class FindLevelFileTest {
+ public:
+  FileLevel level_files_;
+  bool disjoint_sorted_files_;
+  Arena arena_;
+
+  FindLevelFileTest() : disjoint_sorted_files_(true) { }
+
+  ~FindLevelFileTest() {
+  }
+
+  void LevelFileInit(size_t num = 0) {
+    char* mem = arena_.AllocateAligned(num * sizeof(FdWithKeyRange));
+    level_files_.files = new (mem)FdWithKeyRange[num];
+    level_files_.num_files = 0;
+  }
+
+  void Add(const char* smallest, const char* largest,
+           SequenceNumber smallest_seq = 100,
+           SequenceNumber largest_seq = 100) {
+    InternalKey smallest_key = InternalKey(smallest, smallest_seq, kTypeValue);
+    InternalKey largest_key = InternalKey(largest, largest_seq, kTypeValue);
+
+    Slice smallest_slice = smallest_key.Encode();
+    Slice largest_slice = largest_key.Encode();
+
+    char* mem = arena_.AllocateAligned(
+        smallest_slice.size() + largest_slice.size());
+    memcpy(mem, smallest_slice.data(), smallest_slice.size());
+    memcpy(mem + smallest_slice.size(), largest_slice.data(),
+        largest_slice.size());
+
+    // add compressd_level_
+    size_t num = level_files_.num_files;
+    auto& file = level_files_.files[num];
+    file.fd = FileDescriptor(num + 1, 0, 0);
+    file.smallest_key = Slice(mem, smallest_slice.size());
+    file.largest_key = Slice(mem + smallest_slice.size(),
+        largest_slice.size());
+    level_files_.num_files++;
+  }
+
+  int Find(const char* key) {
+    InternalKey target(key, 100, kTypeValue);
+    InternalKeyComparator cmp(BytewiseComparator());
+    return FindFile(cmp, level_files_, target.Encode());
+  }

  bool Overlaps(const char* smallest, const char* largest) {
    InternalKeyComparator cmp(BytewiseComparator());
    Slice s(smallest != nullptr ? smallest : "");
    Slice l(largest != nullptr ? largest : "");
-    return SomeFileOverlapsRange(cmp, disjoint_sorted_files_, files_,
+    return SomeFileOverlapsRange(cmp, disjoint_sorted_files_, level_files_,
                                 (smallest != nullptr ? &s : nullptr),
                                 (largest != nullptr ? &l : nullptr));
  }
 };

-TEST(FindFileTest, Empty) {
+TEST(FindLevelFileTest, LevelEmpty) {
+  LevelFileInit(0);
+
  ASSERT_EQ(0, Find("foo"));
  ASSERT_TRUE(! Overlaps("a", "z"));
  ASSERT_TRUE(! Overlaps(nullptr, "z"));
@@ -61,7 +151,9 @@ TEST(FindFileTest, Empty) {
  ASSERT_TRUE(! Overlaps(nullptr, nullptr));
 }

-TEST(FindFileTest, Single) {
+TEST(FindLevelFileTest, LevelSingle) {
+  LevelFileInit(1);
+
  Add("p", "q");
  ASSERT_EQ(0, Find("a"));
  ASSERT_EQ(0, Find("p"));
@@ -91,8 +183,9 @@ TEST(FindFileTest, Single) {
  ASSERT_TRUE(Overlaps(nullptr, nullptr));
 }

+TEST(FindLevelFileTest, LevelMultiple) {
+  LevelFileInit(4);

-TEST(FindFileTest, Multiple) {
  Add("150", "200");
  Add("200", "250");
  Add("300", "350");
@@ -130,7 +223,9 @@ TEST(FindFileTest, Multiple) {
  ASSERT_TRUE(Overlaps("450", "500"));
 }

-TEST(FindFileTest, MultipleNullBoundaries) {
+TEST(FindLevelFileTest, LevelMultipleNullBoundaries) {
+  LevelFileInit(4);
+
  Add("150", "200");
  Add("200", "250");
  Add("300", "350");
@@ -150,7 +245,9 @@ TEST(FindFileTest, MultipleNullBoundaries) {
  ASSERT_TRUE(Overlaps("450", nullptr));
 }

-TEST(FindFileTest, OverlapSequenceChecks) {
+TEST(FindLevelFileTest, LevelOverlapSequenceChecks) {
+  LevelFileInit(1);
+
  Add("200", "200", 5000, 3000);
  ASSERT_TRUE(! Overlaps("199", "199"));
  ASSERT_TRUE(! Overlaps("201", "300"));
@@ -159,7 +256,9 @@ TEST(FindFileTest, OverlapSequenceChecks) {
  ASSERT_TRUE(Overlaps("200", "210"));
 }

-TEST(FindFileTest, OverlappingFiles) {
+TEST(FindLevelFileTest, LevelOverlappingFiles) {
+  LevelFileInit(2);
+
  Add("150", "600");
  Add("400", "500");
  disjoint_sorted_files_ = false;
@@ -15,6 +15,9 @@
 //    kTypeValue varstring varstring
 //    kTypeMerge varstring varstring
 //    kTypeDeletion varstring
+//    kTypeColumnFamilyValue varint32 varstring varstring
+//    kTypeColumnFamilyMerge varint32 varstring varstring
+//    kTypeColumnFamilyDeletion varint32 varstring varstring
 // varstring :=
 //    len: varint32
 //    data: uint8[len]
@@ -45,10 +48,20 @@ WriteBatch::~WriteBatch() { }

 WriteBatch::Handler::~Handler() { }

+void WriteBatch::Handler::Put(const Slice& key, const Slice& value) {
+  // you need to either implement Put or PutCF
+  throw std::runtime_error("Handler::Put not implemented!");
+}
+
 void WriteBatch::Handler::Merge(const Slice& key, const Slice& value) {
  throw std::runtime_error("Handler::Merge not implemented!");
 }

+void WriteBatch::Handler::Delete(const Slice& key) {
+  // you need to either implement Delete or DeleteCF
+  throw std::runtime_error("Handler::Delete not implemented!");
+}
+
 void WriteBatch::Handler::LogData(const Slice& blob) {
  // If the user has not specified something to do with blobs, then we ignore
  // them.
@@ -76,31 +89,48 @@ Status WriteBatch::Iterate(Handler* handler) const {
  input.remove_prefix(kHeader);
  Slice key, value, blob;
  int found = 0;
-  while (!input.empty() && handler->Continue()) {
+  Status s;
+  while (s.ok() && !input.empty() && handler->Continue()) {
    char tag = input[0];
    input.remove_prefix(1);
+    uint32_t column_family = 0;  // default
    switch (tag) {
+      case kTypeColumnFamilyValue:
+        if (!GetVarint32(&input, &column_family)) {
+          return Status::Corruption("bad WriteBatch Put");
+        }
+      // intentional fallthrough
      case kTypeValue:
        if (GetLengthPrefixedSlice(&input, &key) &&
            GetLengthPrefixedSlice(&input, &value)) {
-          handler->Put(key, value);
+          s = handler->PutCF(column_family, key, value);
          found++;
        } else {
          return Status::Corruption("bad WriteBatch Put");
        }
        break;
+      case kTypeColumnFamilyDeletion:
+        if (!GetVarint32(&input, &column_family)) {
+          return Status::Corruption("bad WriteBatch Delete");
+        }
+      // intentional fallthrough
      case kTypeDeletion:
        if (GetLengthPrefixedSlice(&input, &key)) {
-          handler->Delete(key);
+          s = handler->DeleteCF(column_family, key);
          found++;
        } else {
          return Status::Corruption("bad WriteBatch Delete");
        }
        break;
+      case kTypeColumnFamilyMerge:
+        if (!GetVarint32(&input, &column_family)) {
+          return Status::Corruption("bad WriteBatch Merge");
+        }
+      // intentional fallthrough
      case kTypeMerge:
        if (GetLengthPrefixedSlice(&input, &key) &&
            GetLengthPrefixedSlice(&input, &value)) {
-          handler->Merge(key, value);
+          s = handler->MergeCF(column_family, key, value);
          found++;
        } else {
          return Status::Corruption("bad WriteBatch Merge");
@@ -117,6 +147,9 @@ Status WriteBatch::Iterate(Handler* handler) const {
        return Status::Corruption("unknown WriteBatch tag");
    }
  }
+  if (!s.ok()) {
+    return s;
+  }
  if (found != WriteBatchInternal::Count(this)) {
    return Status::Corruption("WriteBatch has wrong count");
  } else {
@@ -140,31 +173,102 @@ void WriteBatchInternal::SetSequence(WriteBatch* b, SequenceNumber seq) {
  EncodeFixed64(&b->rep_[0], seq);
 }

-void WriteBatch::Put(const Slice& key, const Slice& value) {
-  WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
-  rep_.push_back(static_cast<char>(kTypeValue));
-  PutLengthPrefixedSlice(&rep_, key);
-  PutLengthPrefixedSlice(&rep_, value);
+void WriteBatchInternal::Put(WriteBatch* b, uint32_t column_family_id,
+                             const Slice& key, const Slice& value) {
+  WriteBatchInternal::SetCount(b, WriteBatchInternal::Count(b) + 1);
+  if (column_family_id == 0) {
+    b->rep_.push_back(static_cast<char>(kTypeValue));
+  } else {
+    b->rep_.push_back(static_cast<char>(kTypeColumnFamilyValue));
+    PutVarint32(&b->rep_, column_family_id);
+  }
+  PutLengthPrefixedSlice(&b->rep_, key);
+  PutLengthPrefixedSlice(&b->rep_, value);
 }

-void WriteBatch::Put(const SliceParts& key, const SliceParts& value) {
-  WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
-  rep_.push_back(static_cast<char>(kTypeValue));
-  PutLengthPrefixedSliceParts(&rep_, key);
-  PutLengthPrefixedSliceParts(&rep_, value);
+namespace {
+inline uint32_t GetColumnFamilyID(ColumnFamilyHandle* column_family) {
+  uint32_t column_family_id = 0;
+  if (column_family != nullptr) {
+    auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
+    column_family_id = cfh->GetID();
+  }
+  return column_family_id;
+}
+}  // namespace
+
+void WriteBatch::Put(ColumnFamilyHandle* column_family, const Slice& key,
+                     const Slice& value) {
+  WriteBatchInternal::Put(this, GetColumnFamilyID(column_family), key, value);
 }

-void WriteBatch::Delete(const Slice& key) {
-  WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
-  rep_.push_back(static_cast<char>(kTypeDeletion));
-  PutLengthPrefixedSlice(&rep_, key);
+void WriteBatchInternal::Put(WriteBatch* b, uint32_t column_family_id,
+                             const SliceParts& key, const SliceParts& value) {
+  WriteBatchInternal::SetCount(b, WriteBatchInternal::Count(b) + 1);
+  if (column_family_id == 0) {
+    b->rep_.push_back(static_cast<char>(kTypeValue));
+  } else {
+    b->rep_.push_back(static_cast<char>(kTypeColumnFamilyValue));
+    PutVarint32(&b->rep_, column_family_id);
+  }
+  PutLengthPrefixedSliceParts(&b->rep_, key);
+  PutLengthPrefixedSliceParts(&b->rep_, value);
 }

-void WriteBatch::Merge(const Slice& key, const Slice& value) {
-  WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
-  rep_.push_back(static_cast<char>(kTypeMerge));
-  PutLengthPrefixedSlice(&rep_, key);
-  PutLengthPrefixedSlice(&rep_, value);
+void WriteBatch::Put(ColumnFamilyHandle* column_family, const SliceParts& key,
+                     const SliceParts& value) {
+  WriteBatchInternal::Put(this, GetColumnFamilyID(column_family), key, value);
+}
+
+void WriteBatchInternal::Delete(WriteBatch* b, uint32_t column_family_id,
+                                const Slice& key) {
+  WriteBatchInternal::SetCount(b, WriteBatchInternal::Count(b) + 1);
+  if (column_family_id == 0) {
+    b->rep_.push_back(static_cast<char>(kTypeDeletion));
+  } else {
+    b->rep_.push_back(static_cast<char>(kTypeColumnFamilyDeletion));
+    PutVarint32(&b->rep_, column_family_id);
+  }
+  PutLengthPrefixedSlice(&b->rep_, key);
+}
+
+void WriteBatch::Delete(ColumnFamilyHandle* column_family, const Slice& key) {
+  WriteBatchInternal::Delete(this, GetColumnFamilyID(column_family), key);
+}
+
+void WriteBatchInternal::Delete(WriteBatch* b, uint32_t column_family_id,
+                                const SliceParts& key) {
+  WriteBatchInternal::SetCount(b, WriteBatchInternal::Count(b) + 1);
+  if (column_family_id == 0) {
+    b->rep_.push_back(static_cast<char>(kTypeDeletion));
+  } else {
+    b->rep_.push_back(static_cast<char>(kTypeColumnFamilyDeletion));
+    PutVarint32(&b->rep_, column_family_id);
+  }
+  PutLengthPrefixedSliceParts(&b->rep_, key);
+}
+
+void WriteBatch::Delete(ColumnFamilyHandle* column_family,
+                        const SliceParts& key) {
+  WriteBatchInternal::Delete(this, GetColumnFamilyID(column_family), key);
+}
+
+void WriteBatchInternal::Merge(WriteBatch* b, uint32_t column_family_id,
+                               const Slice& key, const Slice& value) {
+  WriteBatchInternal::SetCount(b, WriteBatchInternal::Count(b) + 1);
+  if (column_family_id == 0) {
+    b->rep_.push_back(static_cast<char>(kTypeMerge));
+  } else {
+    b->rep_.push_back(static_cast<char>(kTypeColumnFamilyMerge));
+    PutVarint32(&b->rep_, column_family_id);
+  }
+  PutLengthPrefixedSlice(&b->rep_, key);
+  PutLengthPrefixedSlice(&b->rep_, value);
+}
+
+void WriteBatch::Merge(ColumnFamilyHandle* column_family, const Slice& key,
+                       const Slice& value) {
+  WriteBatchInternal::Merge(this, GetColumnFamilyID(column_family), key, value);
 }

 void WriteBatch::PutLogData(const Slice& blob) {
@@ -176,45 +280,128 @@ namespace {
 class MemTableInserter : public WriteBatch::Handler {
 public:
  SequenceNumber sequence_;
-  MemTable* mem_;
-  const Options* options_;
+  ColumnFamilyMemTables* cf_mems_;
+  bool recovery_;
+  uint64_t log_number_;
  DBImpl* db_;
-  const bool filter_deletes_;
+  const bool dont_filter_deletes_;

-  MemTableInserter(SequenceNumber sequence, MemTable* mem, const Options* opts,
-                   DB* db, const bool filter_deletes)
-    : sequence_(sequence),
-      mem_(mem),
-      options_(opts),
-      db_(reinterpret_cast<DBImpl*>(db)),
-      filter_deletes_(filter_deletes) {
-    assert(mem_);
-    if (filter_deletes_) {
-      assert(options_);
+  MemTableInserter(SequenceNumber sequence, ColumnFamilyMemTables* cf_mems,
+                   bool recovery, uint64_t log_number, DB* db,
+                   const bool dont_filter_deletes)
+      : sequence_(sequence),
+        cf_mems_(cf_mems),
+        recovery_(recovery),
+        log_number_(log_number),
+        db_(reinterpret_cast<DBImpl*>(db)),
+        dont_filter_deletes_(dont_filter_deletes) {
+    assert(cf_mems);
+    if (!dont_filter_deletes_) {
      assert(db_);
    }
  }

-  virtual void Put(const Slice& key, const Slice& value) {
-    if (options_->inplace_update_support
-        && mem_->Update(sequence_, kTypeValue, key, value)) {
-      RecordTick(options_->statistics.get(), NUMBER_KEYS_UPDATED);
-    } else {
-      mem_->Add(sequence_, kTypeValue, key, value);
+  bool SeekToColumnFamily(uint32_t column_family_id, Status* s) {
+    bool found = cf_mems_->Seek(column_family_id);
+    if (recovery_ && (!found || log_number_ < cf_mems_->GetLogNumber())) {
+      // if in recovery envoronment:
+      // * If column family was not found, it might mean that the WAL write
+      // batch references to the column family that was dropped after the
+      // insert. We don't want to fail the whole write batch in that case -- we
+      // just ignore the update.
+      // * If log_number_ < cf_mems_->GetLogNumber(), this means that column
+      // family already contains updates from this log. We can't apply updates
+      // twice because of update-in-place or merge workloads -- ignore the
+      // update
+      *s = Status::OK();
+      return false;
    }
-    sequence_++;
+    if (!found) {
+      assert(!recovery_);
+      // If the column family was not found in non-recovery enviornment
+      // (client's write code-path), we have to fail the write and return
+      // the failure status to the client.
+      *s = Status::InvalidArgument(
+          "Invalid column family specified in write batch");
+      return false;
+    }
+    return true;
  }
-  virtual void Merge(const Slice& key, const Slice& value) {
+
+  virtual Status PutCF(uint32_t column_family_id, const Slice& key,
+                       const Slice& value) {
+    Status seek_status;
+    if (!SeekToColumnFamily(column_family_id, &seek_status)) {
+      ++sequence_;
+      return seek_status;
+    }
+    MemTable* mem = cf_mems_->GetMemTable();
+    const Options* options = cf_mems_->GetOptions();
+    if (!options->inplace_update_support) {
+      mem->Add(sequence_, kTypeValue, key, value);
+    } else if (options->inplace_callback == nullptr) {
+      mem->Update(sequence_, key, value);
+      RecordTick(options->statistics.get(), NUMBER_KEYS_UPDATED);
+    } else {
+      if (mem->UpdateCallback(sequence_, key, value, *options)) {
+      } else {
+        // key not found in memtable. Do sst get, update, add
+        SnapshotImpl read_from_snapshot;
+        read_from_snapshot.number_ = sequence_;
+        ReadOptions ropts;
+        ropts.snapshot = &read_from_snapshot;
+
+        std::string prev_value;
+        std::string merged_value;
+
+        auto cf_handle = cf_mems_->GetColumnFamilyHandle();
+        if (cf_handle == nullptr) {
+          cf_handle = db_->DefaultColumnFamily();
+        }
+        Status s = db_->Get(ropts, cf_handle, key, &prev_value);
+
+        char* prev_buffer = const_cast<char*>(prev_value.c_str());
+        uint32_t prev_size = prev_value.size();
+        auto status = options->inplace_callback(s.ok() ? prev_buffer : nullptr,
+                                                s.ok() ? &prev_size : nullptr,
+                                                value, &merged_value);
+        if (status == UpdateStatus::UPDATED_INPLACE) {
+          // prev_value is updated in-place with final value.
+          mem->Add(sequence_, kTypeValue, key, Slice(prev_buffer, prev_size));
+          RecordTick(options->statistics.get(), NUMBER_KEYS_WRITTEN);
+        } else if (status == UpdateStatus::UPDATED) {
+          // merged_value contains the final value.
+          mem->Add(sequence_, kTypeValue, key, Slice(merged_value));
+          RecordTick(options->statistics.get(), NUMBER_KEYS_WRITTEN);
+        }
+      }
+    }
+    // Since all Puts are logged in trasaction logs (if enabled), always bump
+    // sequence number. Even if the update eventually fails and does not result
+    // in memtable add/update.
+    sequence_++;
+    return Status::OK();
+  }
+
+  virtual Status MergeCF(uint32_t column_family_id, const Slice& key,
+                         const Slice& value) {
+    Status seek_status;
+    if (!SeekToColumnFamily(column_family_id, &seek_status)) {
+      ++sequence_;
+      return seek_status;
+    }
+    MemTable* mem = cf_mems_->GetMemTable();
+    const Options* options = cf_mems_->GetOptions();
    bool perform_merge = false;

-    if (options_->max_successive_merges > 0 && db_ != nullptr) {
+    if (options->max_successive_merges > 0 && db_ != nullptr) {
      LookupKey lkey(key, sequence_);

      // Count the number of successive merges at the head
      // of the key in the memtable
-      size_t num_merges = mem_->CountSuccessiveMergeEntries(lkey);
+      size_t num_merges = mem->CountSuccessiveMergeEntries(lkey);

-      if (num_merges >= options_->max_successive_merges) {
+      if (num_merges >= options->max_successive_merges) {
        perform_merge = true;
      }
    }
@@ -230,62 +417,78 @@ class MemTableInserter : public WriteBatch::Handler {
      ReadOptions read_options;
      read_options.snapshot = &read_from_snapshot;

-      db_->Get(read_options, key, &get_value);
+      auto cf_handle = cf_mems_->GetColumnFamilyHandle();
+      if (cf_handle == nullptr) {
+        cf_handle = db_->DefaultColumnFamily();
+      }
+      db_->Get(read_options, cf_handle, key, &get_value);
      Slice get_value_slice = Slice(get_value);

      // 2) Apply this merge
-      auto merge_operator = options_->merge_operator.get();
+      auto merge_operator = options->merge_operator.get();
      assert(merge_operator);

      std::deque<std::string> operands;
      operands.push_front(value.ToString());
      std::string new_value;
-      if (!merge_operator->FullMerge(key,
-                                     &get_value_slice,
-                                     operands,
-                                     &new_value,
-                                     options_->info_log.get())) {
+      if (!merge_operator->FullMerge(key, &get_value_slice, operands,
+                                     &new_value, options->info_log.get())) {
          // Failed to merge!
-          RecordTick(options_->statistics.get(), NUMBER_MERGE_FAILURES);
+        RecordTick(options->statistics.get(), NUMBER_MERGE_FAILURES);

          // Store the delta in memtable
          perform_merge = false;
      } else {
        // 3) Add value to memtable
-        mem_->Add(sequence_, kTypeValue, key, new_value);
+        mem->Add(sequence_, kTypeValue, key, new_value);
      }
    }

    if (!perform_merge) {
      // Add merge operator to memtable
-      mem_->Add(sequence_, kTypeMerge, key, value);
+      mem->Add(sequence_, kTypeMerge, key, value);
    }

    sequence_++;
+    return Status::OK();
  }
-  virtual void Delete(const Slice& key) {
-    if (filter_deletes_) {
+
+  virtual Status DeleteCF(uint32_t column_family_id, const Slice& key) {
+    Status seek_status;
+    if (!SeekToColumnFamily(column_family_id, &seek_status)) {
+      ++sequence_;
+      return seek_status;
+    }
+    MemTable* mem = cf_mems_->GetMemTable();
+    const Options* options = cf_mems_->GetOptions();
+    if (!dont_filter_deletes_ && options->filter_deletes) {
      SnapshotImpl read_from_snapshot;
      read_from_snapshot.number_ = sequence_;
      ReadOptions ropts;
      ropts.snapshot = &read_from_snapshot;
      std::string value;
-      if (!db_->KeyMayExist(ropts, key, &value)) {
-        RecordTick(options_->statistics.get(), NUMBER_FILTERED_DELETES);
-        return;
+      auto cf_handle = cf_mems_->GetColumnFamilyHandle();
+      if (cf_handle == nullptr) {
+        cf_handle = db_->DefaultColumnFamily();
+      }
+      if (!db_->KeyMayExist(ropts, cf_handle, key, &value)) {
+        RecordTick(options->statistics.get(), NUMBER_FILTERED_DELETES);
+        return Status::OK();
      }
    }
-    mem_->Add(sequence_, kTypeDeletion, key, Slice());
+    mem->Add(sequence_, kTypeDeletion, key, Slice());
    sequence_++;
+    return Status::OK();
  }
 };
 }  // namespace

-Status WriteBatchInternal::InsertInto(const WriteBatch* b, MemTable* mem,
-                                      const Options* opts, DB* db,
-                                      const bool filter_deletes) {
-  MemTableInserter inserter(WriteBatchInternal::Sequence(b), mem, opts, db,
-                            filter_deletes);
+Status WriteBatchInternal::InsertInto(const WriteBatch* b,
+                                      ColumnFamilyMemTables* memtables,
+                                      bool recovery, uint64_t log_number,
+                                      DB* db, const bool dont_filter_deletes) {
+  MemTableInserter inserter(WriteBatchInternal::Sequence(b), memtables,
+                            recovery, log_number, db, dont_filter_deletes);
  return b->Iterate(&inserter);
 }

@@ -17,10 +17,69 @@ namespace rocksdb {

 class MemTable;

+class ColumnFamilyMemTables {
+ public:
+  virtual ~ColumnFamilyMemTables() {}
+  virtual bool Seek(uint32_t column_family_id) = 0;
+  // returns true if the update to memtable should be ignored
+  // (useful when recovering from log whose updates have already
+  // been processed)
+  virtual uint64_t GetLogNumber() const = 0;
+  virtual MemTable* GetMemTable() const = 0;
+  virtual const Options* GetOptions() const = 0;
+  virtual ColumnFamilyHandle* GetColumnFamilyHandle() = 0;
+};
+
+class ColumnFamilyMemTablesDefault : public ColumnFamilyMemTables {
+ public:
+  ColumnFamilyMemTablesDefault(MemTable* mem, const Options* options)
+      : ok_(false), mem_(mem), options_(options) {}
+
+  bool Seek(uint32_t column_family_id) override {
+    ok_ = (column_family_id == 0);
+    return ok_;
+  }
+
+  uint64_t GetLogNumber() const override { return 0; }
+
+  MemTable* GetMemTable() const override {
+    assert(ok_);
+    return mem_;
+  }
+
+  const Options* GetOptions() const override {
+    assert(ok_);
+    return options_;
+  }
+
+  ColumnFamilyHandle* GetColumnFamilyHandle() override { return nullptr; }
+
+ private:
+  bool ok_;
+  MemTable* mem_;
+  const Options* const options_;
+};
+
 // WriteBatchInternal provides static methods for manipulating a
 // WriteBatch that we don't want in the public WriteBatch interface.
 class WriteBatchInternal {
 public:
+  // WriteBatch methods with column_family_id instead of ColumnFamilyHandle*
+  static void Put(WriteBatch* batch, uint32_t column_family_id,
+                  const Slice& key, const Slice& value);
+
+  static void Put(WriteBatch* batch, uint32_t column_family_id,
+                  const SliceParts& key, const SliceParts& value);
+
+  static void Delete(WriteBatch* batch, uint32_t column_family_id,
+                     const SliceParts& key);
+
+  static void Delete(WriteBatch* batch, uint32_t column_family_id,
+                     const Slice& key);
+
+  static void Merge(WriteBatch* batch, uint32_t column_family_id,
+                    const Slice& key, const Slice& value);
+
  // Return the number of entries in the batch.
  static int Count(const WriteBatch* batch);

@@ -45,11 +104,21 @@ class WriteBatchInternal {
  static void SetContents(WriteBatch* batch, const Slice& contents);

  // Inserts batch entries into memtable
-  // Drops deletes in batch if filter_del is set to true and
-  // db->KeyMayExist returns false
-  static Status InsertInto(const WriteBatch* batch, MemTable* memtable,
-                           const Options* opts, DB* db = nullptr,
-                           const bool filter_del = false);
+  // If dont_filter_deletes is false AND options.filter_deletes is true,
+  // then --> Drops deletes in batch if db->KeyMayExist returns false
+  // If recovery == true, this means InsertInto is executed on a recovery
+  // code-path. WriteBatch referencing a dropped column family can be
+  // found on a recovery code-path and should be ignored (recovery should not
+  // fail). Additionally, the memtable will be updated only if
+  // memtables->GetLogNumber() >= log_number
+  // However, if recovery == false, any WriteBatch referencing
+  // non-existing column family will return a failure. Also, log_number is
+  // ignored in that case
+  static Status InsertInto(const WriteBatch* batch,
+                           ColumnFamilyMemTables* memtables,
+                           bool recovery = false, uint64_t log_number = 0,
+                           DB* db = nullptr,
+                           const bool dont_filter_deletes = true);

  static void Append(WriteBatch* dst, const WriteBatch* src);
 };
@@ -11,6 +11,7 @@

 #include <memory>
 #include "db/memtable.h"
+#include "db/column_family.h"
 #include "db/write_batch_internal.h"
 #include "rocksdb/env.h"
 #include "rocksdb/memtablerep.h"
@@ -27,9 +28,10 @@ static std::string PrintContents(WriteBatch* b) {
  MemTable* mem = new MemTable(cmp, options);
  mem->Ref();
  std::string state;
-  Status s = WriteBatchInternal::InsertInto(b, mem, &options);
+  ColumnFamilyMemTablesDefault cf_mems_default(mem, &options);
+  Status s = WriteBatchInternal::InsertInto(b, &cf_mems_default);
  int count = 0;
-  Iterator* iter = mem->NewIterator();
+  Iterator* iter = mem->NewIterator(ReadOptions());
  for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
    ParsedInternalKey ikey;
    memset((void *)&ikey, 0, sizeof(ikey));
@@ -57,7 +59,7 @@ static std::string PrintContents(WriteBatch* b) {
        state.append(")");
        count++;
        break;
-      case kTypeLogData:
+      default:
        assert(false);
        break;
    }
@@ -144,17 +146,37 @@ TEST(WriteBatchTest, Append) {
 namespace {
  struct TestHandler : public WriteBatch::Handler {
    std::string seen;
-    virtual void Put(const Slice& key, const Slice& value) {
-      seen += "Put(" + key.ToString() + ", " + value.ToString() + ")";
+    virtual Status PutCF(uint32_t column_family_id, const Slice& key,
+                       const Slice& value) {
+      if (column_family_id == 0) {
+        seen += "Put(" + key.ToString() + ", " + value.ToString() + ")";
+      } else {
+        seen += "PutCF(" + std::to_string(column_family_id) + ", " +
+                key.ToString() + ", " + value.ToString() + ")";
+      }
+      return Status::OK();
    }
-    virtual void Merge(const Slice& key, const Slice& value) {
-      seen += "Merge(" + key.ToString() + ", " + value.ToString() + ")";
+    virtual Status MergeCF(uint32_t column_family_id, const Slice& key,
+                         const Slice& value) {
+      if (column_family_id == 0) {
+        seen += "Merge(" + key.ToString() + ", " + value.ToString() + ")";
+      } else {
+        seen += "MergeCF(" + std::to_string(column_family_id) + ", " +
+                key.ToString() + ", " + value.ToString() + ")";
+      }
+      return Status::OK();
    }
    virtual void LogData(const Slice& blob) {
      seen += "LogData(" + blob.ToString() + ")";
    }
-    virtual void Delete(const Slice& key) {
-      seen += "Delete(" + key.ToString() + ")";
+    virtual Status DeleteCF(uint32_t column_family_id, const Slice& key) {
+      if (column_family_id == 0) {
+        seen += "Delete(" + key.ToString() + ")";
+      } else {
+        seen += "DeleteCF(" + std::to_string(column_family_id) + ", " +
+                key.ToString() + ")";
+      }
+      return Status::OK();
    }
  };
 }
@@ -194,21 +216,23 @@ TEST(WriteBatchTest, Continue) {

  struct Handler : public TestHandler {
    int num_seen = 0;
-    virtual void Put(const Slice& key, const Slice& value) {
+    virtual Status PutCF(uint32_t column_family_id, const Slice& key,
+                       const Slice& value) {
      ++num_seen;
-      TestHandler::Put(key, value);
+      return TestHandler::PutCF(column_family_id, key, value);
    }
-    virtual void Merge(const Slice& key, const Slice& value) {
+    virtual Status MergeCF(uint32_t column_family_id, const Slice& key,
+                         const Slice& value) {
      ++num_seen;
-      TestHandler::Merge(key, value);
+      return TestHandler::MergeCF(column_family_id, key, value);
    }
    virtual void LogData(const Slice& blob) {
      ++num_seen;
      TestHandler::LogData(blob);
    }
-    virtual void Delete(const Slice& key) {
+    virtual Status DeleteCF(uint32_t column_family_id, const Slice& key) {
      ++num_seen;
-      TestHandler::Delete(key);
+      return TestHandler::DeleteCF(column_family_id, key);
    }
    virtual bool Continue() override {
      return num_seen < 3;
@@ -256,6 +280,42 @@ TEST(WriteBatchTest, PutGatherSlices) {
  ASSERT_EQ(3, batch.Count());
 }

+namespace {
+class ColumnFamilyHandleImplDummy : public ColumnFamilyHandleImpl {
+ public:
+  explicit ColumnFamilyHandleImplDummy(int id)
+      : ColumnFamilyHandleImpl(nullptr, nullptr, nullptr), id_(id) {}
+  uint32_t GetID() const override { return id_; }
+
+ private:
+  uint32_t id_;
+};
+}  // namespace anonymous
+
+TEST(WriteBatchTest, ColumnFamiliesBatchTest) {
+  WriteBatch batch;
+  ColumnFamilyHandleImplDummy zero(0), two(2), three(3), eight(8);
+  batch.Put(&zero, Slice("foo"), Slice("bar"));
+  batch.Put(&two, Slice("twofoo"), Slice("bar2"));
+  batch.Put(&eight, Slice("eightfoo"), Slice("bar8"));
+  batch.Delete(&eight, Slice("eightfoo"));
+  batch.Merge(&three, Slice("threethree"), Slice("3three"));
+  batch.Put(&zero, Slice("foo"), Slice("bar"));
+  batch.Merge(Slice("omom"), Slice("nom"));
+
+  TestHandler handler;
+  batch.Iterate(&handler);
+  ASSERT_EQ(
+      "Put(foo, bar)"
+      "PutCF(2, twofoo, bar2)"
+      "PutCF(8, eightfoo, bar8)"
+      "DeleteCF(8, eightfoo)"
+      "MergeCF(3, threethree, 3three)"
+      "Put(foo, bar)"
+      "Merge(omom, nom)",
+      handler.seen);
+}
+
 }  // namespace rocksdb

 int main(int argc, char** argv) {
@@ -609,13 +609,13 @@ key-value during background compaction.
 </ul>
 <p>
 Other options impacting performance of compactions and when they get triggered
-are: 
+are:
 <ul>
 <p>
-<li> <code>Options::access_hint_on_compaction_start</code> - Specify the file access 
+<li> <code>Options::access_hint_on_compaction_start</code> - Specify the file access
 pattern once a compaction is started. It will be applied to all input files of a compaction. Default: NORMAL
 <p>
-<li> <code>Options::level0_file_num_compaction_trigger</code> -  Number of files to trigger level-0 compaction. 
+<li> <code>Options::level0_file_num_compaction_trigger</code> -  Number of files to trigger level-0 compaction.
 A negative value means that level-0 compaction will not be triggered by number of files at all.
 <p>
 <li> <code>Options::max_mem_compaction_level</code> -  Maximum level to which a new compacted memtable is pushed if it
@@ -623,7 +623,7 @@ does not create overlap.  We try to push to level 2 to avoid the relatively expe
 expensive manifest file operations.  We do not push all the way to the largest level since that can generate a lot of wasted disk
 space if the same key space is being repeatedly overwritten.
 <p>
-<li> <code>Options::target_file_size_base</code> and <code>Options::target_file_size_multiplier</code> - 
+<li> <code>Options::target_file_size_base</code> and <code>Options::target_file_size_multiplier</code> -
 Target file size for compaction.  target_file_size_base is per-file size for level-1.
 Target file size for level L can be calculated by target_file_size_base * (target_file_size_multiplier ^ (L-1))
 For example, if target_file_size_base is 2MB and target_file_size_multiplier is 10, then each file on level-1 will
@@ -642,10 +642,6 @@ Default:1, i.e. pick maxfilesize amount of data as the source of a compaction.
 <li> <code>Options::max_grandparent_overlap_factor</code> -   Control maximum bytes of overlaps in grandparent (i.e., level+2) before we
 stop building a single file in a level->level+1 compaction.
 <p>
-<li> <code>Options::disable_seek_compaction</code> -  Disable compaction triggered by seek.
-With bloomfilter and fast storage, a miss on one level is very cheap if the file handle is cached in table cache
-(which is true if max_open_files is large).
-<p>
 <li> <code>Options::max_background_compactions</code> - Maximum number of concurrent background jobs, submitted to
 the default LOW priority thread pool
 </ul>
@@ -698,7 +694,7 @@ Default: kCompactionStopStyleTotalSize
 A thread pool is associated with Env environment object. The client has to create a thread pool by setting the number of background
 threads using method <code>Env::SetBackgroundThreads()</code> defined in <code>rocksdb/env.h</code>.
 We use the thread pool for compactions and memtable flushes.
-Since memtable flushes are in critical code path (stalling memtable flush can stall writes, increasing p99), we suggest 
+Since memtable flushes are in critical code path (stalling memtable flush can stall writes, increasing p99), we suggest
 having two thread pools - with priorities HIGH and LOW. Memtable flushes can be set up to be scheduled on HIGH thread pool.
 There are two options available for configuration of background compactions and flushes:
 <ul>
@@ -779,9 +775,9 @@ implementation.  See <code>rocksdb/util/env_posix.h</code> for an example.
 <p>
 To be able to efficiently tune your application, it is always helpful if you
 have access to usage statistics. You can collect those statistics by setting
-<code>Options::table_stats_collectors</code> or
+<code>Options::table_properties_collectors</code> or
 <code>Options::statistics</code>. For more information, refer to
-<code>rocksdb/table_stats.h</code> and <code>rocksdb/statistics.h</code>.
+<code>rocksdb/table_properties.h</code> and <code>rocksdb/statistics.h</code>.
 These should not add significant overhead to your application and we
 recommend exporting them to other monitoring tools.

@@ -0,0 +1,2 @@
+column_families_example
+simple_example
@@ -0,0 +1,9 @@
+include ../build_config.mk
+
+all: simple_example column_families_example
+
+simple_example: simple_example.cc
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+
+column_families_example: column_families_example.cc
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
@@ -0,0 +1 @@
+Compile RocksDB first by executing `make static_lib` in parent dir
--- a/Show More
+++ b/Show More
				`@@ -0,0 +1 @@`
				Compile RocksDB first by executing `make static_lib` in parent dir