Disable warning as error

[FB Internal] Point to the latest tool chain.
An odd fix for GCC 7
2026-07-07 14:47:40 +08:00 · 2019-11-01 18:01:19 -07:00 · 2019-11-01 18:01:19 -07:00 · 2019-11-01 18:01:19 -07:00 · 2019-11-01 18:01:19 -07:00 · 2019-11-01 18:01:19 -07:00
159 changed files with 11351 additions and 3594 deletions
@@ -32,3 +32,4 @@ coverage/COVERAGE_REPORT
 tags
 java/*.log
 java/include/org_rocksdb_*.h
+unity.cc
@@ -1,5 +1,25 @@
 # Rocksdb Change Log

+### Unreleased
+### New Features
+
+### Public API changes
+
+
+## 3.4.0 (8/18/2014)
+### New Features
+* Support Multiple DB paths in universal style compactions
+* Add feature of storing plain table index and bloom filter in SST file.
+* CompactRange() will never output compacted files to level 0. This used to be the case when all the compaction input files were at level 0.
+
+### Public API changes
+* DBOptions.db_paths now is a vector of a DBPath structure which indicates both of path and target size
+* NewPlainTableFactory instead of bunch of parameters now accepts PlainTableOptions, which is defined in include/rocksdb/table.h
+* Moved include/utilities/*.h to include/rocksdb/utilities/*.h
+* Statistics APIs now take uint32_t as type instead of Tickers. Also make two access functions getTickerCount and histogramData const
+* Add DB property rocksdb.estimate-num-keys, estimated number of live keys in DB.
+* Add DB::GetIntProperty(), which returns DB properties that are integer as uint64_t.
+
 ## 3.3.0 (7/10/2014)
 ### New Features
 * Added JSON API prototype.
@@ -49,7 +49,6 @@ else
 	PLATFORM_CCFLAGS += $(JEMALLOC_INCLUDE) -DHAVE_JEMALLOC
 endif

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

@@ -69,6 +68,7 @@ VALGRIND_OPTS = --error-exitcode=$(VALGRIND_ERROR) --leak-check=full

 TESTS = \
 	db_test \
+	db_iter_test \
 	block_hash_index_test \
 	autovector_test \
 	column_family_test \
@@ -106,6 +106,7 @@ TESTS = \
 	backupable_db_test \
 	document_db_test \
 	json_document_test \
+	spatial_db_test \
 	version_edit_test \
 	version_set_test \
 	file_indexer_test \
@@ -113,8 +114,11 @@ TESTS = \
 	deletefile_test \
 	table_test \
 	thread_local_test \
-        geodb_test \
-        rate_limiter_test
+	geodb_test \
+ 	rate_limiter_test \
+	cuckoo_table_builder_test \
+	options_test \
+	cuckoo_table_reader_test

 TOOLS = \
        sst_dump \
@@ -122,6 +126,7 @@ TOOLS = \
        db_stress \
        ldb \
 	db_repl_stress \
+  options_test \
 	blob_store_bench

 PROGRAMS = db_bench signal_test table_reader_bench log_and_apply_bench $(TOOLS)
@@ -149,7 +154,7 @@ SHARED = $(SHARED1)
 else
 # Update db.h if you change these.
 SHARED_MAJOR = 3
-SHARED_MINOR = 3
+SHARED_MINOR = 4
 SHARED1 = ${LIBNAME}.$(PLATFORM_SHARED_EXT)
 SHARED2 = $(SHARED1).$(SHARED_MAJOR)
 SHARED3 = $(SHARED1).$(SHARED_MAJOR).$(SHARED_MINOR)
@@ -228,8 +233,14 @@ valgrind_check: all $(PROGRAMS) $(TESTS)
 		echo $$t $$((etime - stime)) >> $(VALGRIND_DIR)/valgrind_tests_times; \
 	done

+unity.cc:	
+	$(shell (export ROCKSDB_ROOT="$(CURDIR)"; "$(CURDIR)/build_tools/unity" "$(CURDIR)/unity.cc"))
+
+unity: unity.cc unity.o
+	$(CXX) unity.o $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 clean:
-	-rm -f $(PROGRAMS) $(TESTS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) build_config.mk
+	-rm -f $(PROGRAMS) $(TESTS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) build_config.mk unity.cc
 	-rm -rf ios-x86/* ios-arm/*
 	-find . -name "*.[od]" -exec rm {} \;
 	-find . -type f -regex ".*\.\(\(gcda\)\|\(gcno\)\)" -exec rm {} \;
@@ -322,6 +333,9 @@ 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)

+db_iter_test: db/db_iter_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) db/db_iter_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

@@ -352,6 +366,9 @@ document_db_test: utilities/document/document_db_test.o $(LIBOBJECTS) $(TESTHARN
 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)

+spatial_db_test: utilities/spatialdb/spatial_db_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) utilities/spatialdb/spatial_db_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)

@@ -406,6 +423,15 @@ deletefile_test: db/deletefile_test.o $(LIBOBJECTS) $(TESTHARNESS)
 geodb_test: utilities/geodb/geodb_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) utilities/geodb/geodb_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)

+cuckoo_table_builder_test: table/cuckoo_table_builder_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) table/cuckoo_table_builder_test.o  $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
+cuckoo_table_reader_test: table/cuckoo_table_reader_test.o $(LIBOBJECTS) $(TESTHARNESS) $(BENCHHARNESS)
+	$(CXX) table/cuckoo_table_reader_test.o  $(LIBOBJECTS) $(TESTHARNESS) $(BENCHHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
+options_test: util/options_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) util/options_test.o $(LIBOBJECTS) $(TESTHARNESS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+
 $(MEMENVLIBRARY) : $(MEMENVOBJECTS)
 	rm -f $@
 	$(AR) -rs $@ $(MEMENVOBJECTS)
@@ -440,18 +466,20 @@ ldb: tools/ldb.o $(LIBOBJECTS)

 JNI_NATIVE_SOURCES = ./java/rocksjni/*.cc
 JAVA_INCLUDE = -I$(JAVA_HOME)/include/ -I$(JAVA_HOME)/include/linux
-ROCKSDBJNILIB = ./java/librocksdbjni.so
+ROCKSDBJNILIB = librocksdbjni.so
+ROCKSDB_JAR = rocksdbjni.jar

 ifeq ($(PLATFORM), OS_MACOSX)
-ROCKSDBJNILIB = ./java/librocksdbjni.jnilib
+ROCKSDBJNILIB = 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) $(COVERAGEFLAGS)
+	rm -f ./java/$(ROCKSDBJNILIB)
+	$(CXX) $(CXXFLAGS) -I./java/. $(JAVA_INCLUDE) -shared -fPIC -o ./java/$(ROCKSDBJNILIB) $(JNI_NATIVE_SOURCES) $(LIBOBJECTS) $(JAVA_LDFLAGS) $(COVERAGEFLAGS)
+	cd java;jar -cf $(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class HISTORY*.md $(ROCKSDBJNILIB)

 jclean:
 	cd java;$(MAKE) clean;
@@ -7,6 +7,7 @@
 #   CC                          C Compiler path
 #   CXX                         C++ Compiler path
 #   PLATFORM_LDFLAGS            Linker flags
+#   JAVA_LDFLAGS                Linker flags for RocksDBJava
 #   PLATFORM_SHARED_EXT         Extension for shared libraries
 #   PLATFORM_SHARED_LDFLAGS     Flags for building shared library
 #   PLATFORM_SHARED_CFLAGS      Flags for compiling objects for shared library
@@ -48,13 +49,7 @@ COMMON_FLAGS="-DROCKSDB_PLATFORM_POSIX"
 if [ -d /mnt/gvfs/third-party -a -z "$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"
    fi
@@ -157,6 +152,8 @@ case "$TARGET_OS" in
        exit 1
 esac

+JAVA_LDFLAGS="$PLATFORM_LDFLAGS"
+
 if test -z "$DO_NOT_RUN_BUILD_DETECT_VERSION"; then
  "$PWD/build_tools/build_detect_version"
 fi
@@ -215,6 +212,7 @@ EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DSNAPPY"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lsnappy"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -lsnappy"
    fi


@@ -238,7 +236,7 @@ EOF
      int main() {}
 EOF
    if [ "$?" = 0 ]; then
-        COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS=google"
+        COMMON_FLAGS="$COMMON_FLAGS -DGFLAGS=gflags"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lgflags"
    fi

@@ -250,6 +248,7 @@ EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DZLIB"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lz"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -lz"
    fi

    # Test whether bzip library is installed
@@ -260,6 +259,7 @@ EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DBZIP2"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lbz2"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -lbz2"
    fi

    # Test whether lz4 library is installed
@@ -271,6 +271,7 @@ EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DLZ4"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -llz4"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -llz4"
    fi

    # Test whether numa is available
@@ -282,6 +283,7 @@ EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DNUMA"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lnuma"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -lnuma"
    fi

    # Test whether tcmalloc is available
@@ -290,6 +292,7 @@ EOF
 EOF
    if [ "$?" = 0 ]; then
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -ltcmalloc"
+        JAVA_LDFLAGS="$JAVA_LDFLAGS -ltcmalloc"
    fi
 fi

@@ -306,6 +309,7 @@ if test "$USE_HDFS"; then
  HDFS_LDFLAGS="$HDFS_LDFLAGS -ldl -lverify -ljava -ljvm"
  COMMON_FLAGS="$COMMON_FLAGS $HDFS_CCFLAGS"
  PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS $HDFS_LDFLAGS"
+  JAVA_LDFLAGS="$JAVA_LDFLAGS $HDFS_LDFLAGS"
 fi

 # if Intel SSE instruction set is supported, set USE_SSE=" -msse -msse4.2 "
@@ -320,6 +324,7 @@ echo "CC=$CC" >> "$OUTPUT"
 echo "CXX=$CXX" >> "$OUTPUT"
 echo "PLATFORM=$PLATFORM" >> "$OUTPUT"
 echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> "$OUTPUT"
+echo "JAVA_LDFLAGS=$JAVA_LDFLAGS" >> "$OUTPUT"
 echo "VALGRIND_VER=$VALGRIND_VER" >> "$OUTPUT"
 echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> "$OUTPUT"
 echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> "$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
@@ -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 
@@ -0,0 +1,78 @@
+#!/bin/sh
+#
+# Create the unity file
+#
+
+OUTPUT=$1
+if test -z "$OUTPUT"; then
+  echo "usage: $0 <output-filename>" >&2
+  exit 1
+fi
+
+# Delete existing file, if it exists
+rm -f "$OUTPUT"
+touch "$OUTPUT"
+
+# Detect OS
+if test -z "$TARGET_OS"; then
+    TARGET_OS=`uname -s`
+fi
+
+# generic port files (working on all platform by #ifdef) go directly in /port
+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
+    Darwin)
+        # PORT_FILES=port/darwin/darwin_specific.cc
+        ;;
+    IOS)
+        ;;
+    Linux)
+        # PORT_FILES=port/linux/linux_specific.cc
+        ;;
+    SunOS)
+        # PORT_FILES=port/sunos/sunos_specific.cc
+        ;;
+    FreeBSD)
+        # PORT_FILES=port/freebsd/freebsd_specific.cc
+        ;;
+    NetBSD)
+        # PORT_FILES=port/netbsd/netbsd_specific.cc
+        ;;
+    OpenBSD)
+        # PORT_FILES=port/openbsd/openbsd_specific.cc
+        ;;
+    DragonFly)
+        # PORT_FILES=port/dragonfly/dragonfly_specific.cc
+        ;;
+    OS_ANDROID_CROSSCOMPILE)
+        # PORT_FILES=port/android/android.cc
+        ;;
+    *)
+        echo "Unknown platform!" >&2
+        exit 1
+esac
+
+# 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
+# of all files matching either rule, so we need to append -print to make the
+# prune take effect.
+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 $PRUNE_BENCH -o -name '*.cc' -print | sort`
+PORTABLE_CPP=`cd "$ROCKSDB_ROOT"; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cpp' -print | sort`
+set +f # re-enable globbing
+
+# The sources consist of the portable files, plus the platform-specific port
+# file.
+for SOURCE_FILE in $PORTABLE_FILES $GENERIC_PORT_FILES $PORT_FILES $PORTABLE_CPP
+do
+	echo "#include <$SOURCE_FILE>" >> "$OUTPUT"
+done
+
+echo "int main(int argc, char** argv){ return 0; }" >> "$OUTPUT"
+
@@ -113,6 +113,13 @@ Status BuildTable(const std::string& dbname, Env* env, const Options& options,
          is_first_key = false;

          if (this_ikey.type == kTypeMerge) {
+            // TODO(tbd): Add a check here to prevent RocksDB from crash when
+            // reopening a DB w/o properly specifying the merge operator.  But
+            // currently we observed a memory leak on failing in RocksDB
+            // recovery, so we decide to let it crash instead of causing
+            // memory leak for now before we have identified the real cause
+            // of the memory leak.
+
            // Handle merge-type keys using the MergeHelper
            // TODO: pass statistics to MergeUntil
            merge.MergeUntil(iter, 0 /* don't worry about snapshot */);
@@ -36,6 +36,9 @@ using rocksdb::ColumnFamilyHandle;
 using rocksdb::ColumnFamilyOptions;
 using rocksdb::CompactionFilter;
 using rocksdb::CompactionFilterFactory;
+using rocksdb::CompactionFilterV2;
+using rocksdb::CompactionFilterFactoryV2;
+using rocksdb::CompactionFilterContext;
 using rocksdb::CompactionOptionsFIFO;
 using rocksdb::Comparator;
 using rocksdb::CompressionType;
@@ -154,6 +157,104 @@ struct rocksdb_compactionfilterfactory_t : public CompactionFilterFactory {
  virtual const char* Name() const { return (*name_)(state_); }
 };

+struct rocksdb_compactionfilterv2_t : public CompactionFilterV2 {
+  void* state_;
+  void (*destructor_)(void*);
+  const char* (*name_)(void*);
+  void (*filter_)(void*, int level, size_t num_keys,
+                  const char* const* keys_list, const size_t* keys_list_sizes,
+                  const char* const* existing_values_list, const size_t* existing_values_list_sizes,
+                  char** new_values_list, size_t* new_values_list_sizes,
+                  unsigned char* to_delete_list);
+
+  virtual ~rocksdb_compactionfilterv2_t() {
+    (*destructor_)(state_);
+  }
+
+  virtual const char* Name() const {
+    return (*name_)(state_);
+  }
+
+  virtual std::vector<bool> Filter(int level,
+                                   const SliceVector& keys,
+                                   const SliceVector& existing_values,
+                                   std::vector<std::string>* new_values,
+                                   std::vector<bool>* values_changed) const {
+    // Make a vector pointing to the underlying key data.
+    size_t num_keys = keys.size();
+    std::vector<const char*> keys_list(num_keys);
+    std::vector<size_t> keys_list_sizes(num_keys);
+    for (size_t i = 0; i < num_keys; ++i) {
+      keys_list[i] = keys[i].data();
+      keys_list_sizes[i] = keys[i].size();
+    }
+    // Make a vector pointing to the underlying value data.
+    std::vector<const char*> existing_values_list(num_keys);
+    std::vector<size_t> existing_values_list_sizes(num_keys);
+    for (size_t i = 0; i < num_keys; ++i) {
+      existing_values_list[i] = existing_values[i].data();
+      existing_values_list_sizes[i] = existing_values[i].size();
+    }
+    // Make a vector which will accept newly-allocated char* arrays
+    // which we will take ownership of and assign to strings in new_values.
+    new_values->clear();
+    std::vector<char*> new_values_list(num_keys);
+    std::vector<size_t> new_values_list_sizes(num_keys);
+    // Resize values_changed to hold all keys.
+    values_changed->resize(num_keys);
+    // Make a vector for bools indicating a value should be deleted
+    // on compaction (true) or maintained (false).
+    std::vector<unsigned char> to_delete_list(num_keys);
+
+    (*filter_)(
+        state_, level, num_keys, &keys_list[0], &keys_list_sizes[0],
+        &existing_values_list[0], &existing_values_list_sizes[0],
+        &new_values_list[0], &new_values_list_sizes[0], &to_delete_list[0]);
+
+    // Now, we transfer any changed values, setting values_changed and
+    // initializing new_values in the event a value changed.
+    std::vector<bool> to_delete(num_keys);
+    for (size_t i = 0; i < num_keys; ++i) {
+      to_delete[i] = to_delete_list[i];
+      (*values_changed)[i] = new_values_list[i] != nullptr;
+      if ((*values_changed)[i]) {
+        new_values->push_back(std::string(new_values_list[i], new_values_list_sizes[i]));
+        free(new_values_list[i]);
+      }
+    }
+    return to_delete;
+  }
+};
+
+struct rocksdb_compactionfilterfactoryv2_t : public CompactionFilterFactoryV2 {
+  void* state_;
+  void (*destructor_)(void*);
+  const char* (*name_)(void*);
+  rocksdb_compactionfilterv2_t* (*create_compaction_filter_v2_)(
+      void* state, const rocksdb_compactionfiltercontext_t* context);
+
+  rocksdb_compactionfilterfactoryv2_t(const SliceTransform* prefix_extractor)
+      : CompactionFilterFactoryV2(prefix_extractor) {
+  }
+
+  virtual ~rocksdb_compactionfilterfactoryv2_t() {
+    (*destructor_)(state_);
+  }
+
+  virtual const char* Name() const {
+    return (*name_)(state_);
+  }
+
+  virtual std::unique_ptr<CompactionFilterV2> CreateCompactionFilterV2(
+      const CompactionFilterContext& context) {
+    struct rocksdb_compactionfiltercontext_t c_context;
+    c_context.rep.is_full_compaction = context.is_full_compaction;
+    c_context.rep.is_manual_compaction = context.is_manual_compaction;
+    return std::unique_ptr<CompactionFilterV2>(
+        (*create_compaction_filter_v2_)(state_, &c_context));
+  }
+};
+
 struct rocksdb_comparator_t : public Comparator {
  void* state_;
  void (*destructor_)(void*);
@@ -1004,6 +1105,12 @@ void rocksdb_options_set_merge_operator(
  opt->rep.merge_operator = std::shared_ptr<MergeOperator>(merge_operator);
 }

+void rocksdb_options_set_compaction_filter_factory_v2(
+    rocksdb_options_t* opt,
+    rocksdb_compactionfilterfactoryv2_t* compaction_filter_factory_v2) {
+  opt->rep.compaction_filter_factory_v2 = std::shared_ptr<CompactionFilterFactoryV2>(compaction_filter_factory_v2);
+}
+
 void rocksdb_options_set_filter_policy(
    rocksdb_options_t* opt,
    rocksdb_filterpolicy_t* policy) {
@@ -1428,9 +1535,13 @@ void rocksdb_options_set_plain_table_factory(
    double hash_table_ratio, size_t index_sparseness) {
  static rocksdb::TableFactory* factory = 0;
  if (!factory) {
-    factory = rocksdb::NewPlainTableFactory(
-        user_key_len, bloom_bits_per_key,
-        hash_table_ratio, index_sparseness);
+    rocksdb::PlainTableOptions options;
+    options.user_key_len = user_key_len;
+    options.bloom_bits_per_key = bloom_bits_per_key;
+    options.hash_table_ratio = hash_table_ratio;
+    options.index_sparseness = index_sparseness;
+
+    factory = rocksdb::NewPlainTableFactory(options);
  }
  opt->rep.table_factory.reset(factory);
 }
@@ -1546,6 +1657,46 @@ void rocksdb_compactionfilterfactory_destroy(
  delete factory;
 }

+rocksdb_compactionfilterv2_t* rocksdb_compactionfilterv2_create(
+    void* state,
+    void (*destructor)(void*),
+    void (*filter)(void*, int level, size_t num_keys,
+                   const char* const* keys_list, const size_t* keys_list_sizes,
+                   const char* const* existing_values_list, const size_t* existing_values_list_sizes,
+                   char** new_values_list, size_t* new_values_list_sizes,
+                   unsigned char* to_delete_list),
+    const char* (*name)(void*)) {
+  rocksdb_compactionfilterv2_t* result = new rocksdb_compactionfilterv2_t;
+  result->state_ = state;
+  result->destructor_ = destructor;
+  result->filter_ = filter;
+  result->name_ = name;
+  return result;
+}
+
+void rocksdb_compactionfilterv2_destroy(rocksdb_compactionfilterv2_t* filter) {
+  delete filter;
+}
+
+rocksdb_compactionfilterfactoryv2_t* rocksdb_compactionfilterfactoryv2_create(
+    void* state,
+    rocksdb_slicetransform_t* prefix_extractor,
+    void (*destructor)(void*),
+    rocksdb_compactionfilterv2_t* (*create_compaction_filter_v2)(
+        void* state, const rocksdb_compactionfiltercontext_t* context),
+    const char* (*name)(void*)) {
+  rocksdb_compactionfilterfactoryv2_t* result = new rocksdb_compactionfilterfactoryv2_t(prefix_extractor);
+  result->state_ = state;
+  result->destructor_ = destructor;
+  result->create_compaction_filter_v2_ = create_compaction_filter_v2;
+  result->name_ = name;
+  return result;
+}
+
+void rocksdb_compactionfilterfactoryv2_destroy(rocksdb_compactionfilterfactoryv2_t* factory) {
+  delete factory;
+}
+
 rocksdb_comparator_t* rocksdb_comparator_create(
    void* state,
    void (*destructor)(void*),
@@ -225,6 +225,56 @@ static rocksdb_t* CheckCompaction(rocksdb_t* db, rocksdb_options_t* options,
  return db;
 }

+// Custom compaction filter V2.
+static void CompactionFilterV2Destroy(void* arg) { }
+static const char* CompactionFilterV2Name(void* arg) {
+  return "TestCompactionFilterV2";
+}
+static void CompactionFilterV2Filter(
+    void* arg, int level, size_t num_keys,
+    const char* const* keys_list, const size_t* keys_list_sizes,
+    const char* const* existing_values_list, const size_t* existing_values_list_sizes,
+    char** new_values_list, size_t* new_values_list_sizes,
+    unsigned char* to_delete_list) {
+  size_t i;
+  for (i = 0; i < num_keys; i++) {
+    // If any value is "gc", it's removed.
+    if (existing_values_list_sizes[i] == 2 && memcmp(existing_values_list[i], "gc", 2) == 0) {
+      to_delete_list[i] = 1;
+    } else if (existing_values_list_sizes[i] == 6 && memcmp(existing_values_list[i], "gc all", 6) == 0) {
+      // If any value is "gc all", all keys are removed.
+      size_t j;
+      for (j = 0; j < num_keys; j++) {
+        to_delete_list[j] = 1;
+      }
+      return;
+    } else if (existing_values_list_sizes[i] == 6 && memcmp(existing_values_list[i], "change", 6) == 0) {
+      // If value is "change", set changed value to "changed".
+      size_t len;
+      len = strlen("changed");
+      new_values_list[i] = malloc(len);
+      memcpy(new_values_list[i], "changed", len);
+      new_values_list_sizes[i] = len;
+    } else {
+      // Otherwise, no keys are removed.
+    }
+  }
+}
+
+// Custom compaction filter factory V2.
+static void CompactionFilterFactoryV2Destroy(void* arg) {
+  rocksdb_slicetransform_destroy((rocksdb_slicetransform_t*)arg);
+}
+static const char* CompactionFilterFactoryV2Name(void* arg) {
+  return "TestCompactionFilterFactoryV2";
+}
+static rocksdb_compactionfilterv2_t* CompactionFilterFactoryV2Create(
+    void* state, const rocksdb_compactionfiltercontext_t* context) {
+  return rocksdb_compactionfilterv2_create(state, CompactionFilterV2Destroy,
+                                           CompactionFilterV2Filter,
+                                           CompactionFilterV2Name);
+}
+
 // Custom merge operator
 static void MergeOperatorDestroy(void* arg) { }
 static const char* MergeOperatorName(void* arg) {
@@ -531,6 +581,47 @@ int main(int argc, char** argv) {
    rocksdb_options_destroy(options);
  }

+  StartPhase("compaction_filter_v2");
+  {
+    rocksdb_compactionfilterfactoryv2_t* factory;
+    rocksdb_slicetransform_t* prefix_extractor;
+    prefix_extractor = rocksdb_slicetransform_create_fixed_prefix(3);
+    factory = rocksdb_compactionfilterfactoryv2_create(
+        prefix_extractor, prefix_extractor, CompactionFilterFactoryV2Destroy,
+        CompactionFilterFactoryV2Create, CompactionFilterFactoryV2Name);
+    // Create new database
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    rocksdb_options_set_compaction_filter_factory_v2(options, factory);
+    db = rocksdb_open(options, dbname, &err);
+    CheckNoError(err);
+    // Only foo2 is GC'd, foo3 is changed.
+    rocksdb_put(db, woptions, "foo1", 4, "no gc", 5, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "foo2", 4, "gc", 2, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "foo3", 4, "change", 6, &err);
+    CheckNoError(err);
+    // All bars are GC'd.
+    rocksdb_put(db, woptions, "bar1", 4, "no gc", 5, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "bar2", 4, "gc all", 6, &err);
+    CheckNoError(err);
+    rocksdb_put(db, woptions, "bar3", 4, "no gc", 5, &err);
+    CheckNoError(err);
+    // Compact the DB to garbage collect.
+    rocksdb_compact_range(db, NULL, 0, NULL, 0);
+
+    // Verify foo entries.
+    CheckGet(db, roptions, "foo1", "no gc");
+    CheckGet(db, roptions, "foo2", NULL);
+    CheckGet(db, roptions, "foo3", "changed");
+    // Verify bar entries were all deleted.
+    CheckGet(db, roptions, "bar1", NULL);
+    CheckGet(db, roptions, "bar2", NULL);
+    CheckGet(db, roptions, "bar3", NULL);
+  }
+
  StartPhase("merge_operator");
  {
    rocksdb_mergeoperator_t* merge_operator;
@@ -49,15 +49,6 @@ ColumnFamilyHandleImpl::~ColumnFamilyHandleImpl() {

 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) {
@@ -191,8 +182,7 @@ void SuperVersionUnrefHandle(void* ptr) {
 }
 }  // anonymous namespace

-ColumnFamilyData::ColumnFamilyData(const std::string& dbname, uint32_t id,
-                                   const std::string& name,
+ColumnFamilyData::ColumnFamilyData(uint32_t id, const std::string& name,
                                   Version* dummy_versions, Cache* table_cache,
                                   const ColumnFamilyOptions& options,
                                   const DBOptions* db_options,
@@ -222,8 +212,8 @@ ColumnFamilyData::ColumnFamilyData(const std::string& dbname, uint32_t id,

  // 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()));
+    internal_stats_.reset(
+        new InternalStats(options_.num_levels, db_options->env, this));
    table_cache_.reset(new TableCache(&options_, storage_options, table_cache));
    if (options_.compaction_style == kCompactionStyleUniversal) {
      compaction_picker_.reset(
@@ -352,11 +342,13 @@ Compaction* ColumnFamilyData::PickCompaction(LogBuffer* log_buffer) {
 }

 Compaction* ColumnFamilyData::CompactRange(int input_level, int output_level,
+                                           uint32_t output_path_id,
                                           const InternalKey* begin,
                                           const InternalKey* end,
                                           InternalKey** compaction_end) {
  return compaction_picker_->CompactRange(current_, input_level, output_level,
-                                          begin, end, compaction_end);
+                                          output_path_id, begin, end,
+                                          compaction_end);
 }

 SuperVersion* ColumnFamilyData::GetReferencedSuperVersion(
@@ -483,7 +475,7 @@ ColumnFamilySet::ColumnFamilySet(const std::string& dbname,
                                 const EnvOptions& storage_options,
                                 Cache* table_cache)
    : max_column_family_(0),
-      dummy_cfd_(new ColumnFamilyData(dbname, 0, "", nullptr, nullptr,
+      dummy_cfd_(new ColumnFamilyData(0, "", nullptr, nullptr,
                                      ColumnFamilyOptions(), db_options,
                                      storage_options_, nullptr)),
      default_cfd_cache_(nullptr),
@@ -554,8 +546,8 @@ ColumnFamilyData* ColumnFamilySet::CreateColumnFamily(
    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);
+      new ColumnFamilyData(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});
@@ -185,7 +185,8 @@ class ColumnFamilyData {
  // 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,
+                           uint32_t output_path_id, const InternalKey* begin,
+                           const InternalKey* end,
                           InternalKey** compaction_end);

  CompactionPicker* compaction_picker() { return compaction_picker_.get(); }
@@ -247,9 +248,9 @@ class ColumnFamilyData {

 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,
+  ColumnFamilyData(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);
@@ -857,6 +857,7 @@ TEST(ColumnFamilyTest, NewIteratorsTest) {
 TEST(ColumnFamilyTest, ReadOnlyDBTest) {
  Open();
  CreateColumnFamiliesAndReopen({"one", "two", "three", "four"});
+  ASSERT_OK(Put(0, "a", "b"));
  ASSERT_OK(Put(1, "foo", "bla"));
  ASSERT_OK(Put(2, "foo", "blabla"));
  ASSERT_OK(Put(3, "foo", "blablabla"));
@@ -870,6 +871,29 @@ TEST(ColumnFamilyTest, ReadOnlyDBTest) {
  ASSERT_EQ("bla", Get(1, "foo"));
  ASSERT_EQ("blablablabla", Get(2, "foo"));

+
+  // test newiterators
+  {
+    std::vector<Iterator*> iterators;
+    ASSERT_OK(db_->NewIterators(ReadOptions(), handles_, &iterators));
+    for (auto it : iterators) {
+      it->SeekToFirst();
+    }
+    ASSERT_EQ(IterStatus(iterators[0]), "a->b");
+    ASSERT_EQ(IterStatus(iterators[1]), "foo->bla");
+    ASSERT_EQ(IterStatus(iterators[2]), "foo->blablablabla");
+    for (auto it : iterators) {
+      it->Next();
+    }
+    ASSERT_EQ(IterStatus(iterators[0]), "(invalid)");
+    ASSERT_EQ(IterStatus(iterators[1]), "(invalid)");
+    ASSERT_EQ(IterStatus(iterators[2]), "(invalid)");
+
+    for (auto it : iterators) {
+      delete it;
+    }
+  }
+
  Close();
  // can't open dropped column family
  Status s = OpenReadOnly({"default", "one", "two"});
@@ -18,7 +18,7 @@

 namespace rocksdb {

-static uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
+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]->fd.GetFileSize();
@@ -26,14 +26,14 @@ static uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
  return sum;
 }

-Compaction::Compaction(Version* input_version, int level, int out_level,
+Compaction::Compaction(Version* input_version, int start_level, int out_level,
                       uint64_t target_file_size,
                       uint64_t max_grandparent_overlap_bytes,
                       uint32_t output_path_id,
                       CompressionType output_compression, bool seek_compaction,
                       bool deletion_compaction)
-    : level_(level),
-      out_level_(out_level),
+    : start_level_(start_level),
+      output_level_(out_level),
      max_output_file_size_(target_file_size),
      max_grandparent_overlap_bytes_(max_grandparent_overlap_bytes),
      input_version_(input_version),
@@ -61,6 +61,12 @@ Compaction::Compaction(Version* input_version, int level, int out_level,
  for (int i = 0; i < number_levels_; i++) {
    level_ptrs_[i] = 0;
  }
+  int num_levels = output_level_ - start_level_ + 1;
+  input_levels_.resize(num_levels);
+  inputs_.resize(num_levels);
+  for (int i = 0; i < num_levels; ++i) {
+    inputs_[i].level = start_level_ + i;
+  }
 }

 Compaction::~Compaction() {
@@ -75,43 +81,50 @@ Compaction::~Compaction() {
  }
 }

+void Compaction::GenerateFileLevels() {
+  input_levels_.resize(num_input_levels());
+  for (int which = 0; which < num_input_levels(); which++) {
+    DoGenerateFileLevel(&input_levels_[which], inputs_[which].files, &arena_);
+  }
+}
+
 bool Compaction::IsTrivialMove() const {
  // Avoid a move if there is lots of overlapping grandparent data.
  // Otherwise, the move could create a parent file that will require
  // a very expensive merge later on.
-  // If level_== out_level_, the purpose is to force compaction filter to be
-  // applied to that level, and thus cannot be a trivia move.
-  return (level_ != out_level_ &&
+  // If start_level_== output_level_, the purpose is to force compaction
+  // filter to be applied to that level, and thus cannot be a trivia move.
+  return (start_level_ != output_level_ &&
+          num_input_levels() == 2 &&
          num_input_files(0) == 1 &&
          num_input_files(1) == 0 &&
          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 (int which = 0; which < num_input_levels(); which++) {
    for (size_t i = 0; i < inputs_[which].size(); i++) {
-      edit->DeleteFile(level_ + which, inputs_[which][i]->fd.GetNumber());
+      edit->DeleteFile(level(which), inputs_[which][i]->fd.GetNumber());
    }
  }
 }

-bool Compaction::IsBaseLevelForKey(const Slice& user_key) {
+bool Compaction::KeyNotExistsBeyondOutputLevel(const Slice& user_key) {
  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 = cfd_->user_comparator();
-  for (int lvl = level_ + 2; lvl < number_levels_; lvl++) {
+  for (int lvl = output_level_ + 1; lvl < number_levels_; lvl++) {
    const std::vector<FileMetaData*>& files = input_version_->files_[lvl];
    for (; level_ptrs_[lvl] < files.size(); ) {
      FileMetaData* f = files[level_ptrs_[lvl]];
      if (user_cmp->Compare(user_key, f->largest.user_key()) <= 0) {
        // We've advanced far enough
        if (user_cmp->Compare(user_key, f->smallest.user_key()) >= 0) {
-          // Key falls in this file's range, so definitely not base level
+          // Key falls in this file's range, so definitely
+          // exists beyond output level
          return false;
        }
        break;
@@ -149,19 +162,18 @@ bool Compaction::ShouldStopBefore(const Slice& internal_key) {
 }

 // Mark (or clear) each file that is being compacted
-void Compaction::MarkFilesBeingCompacted(bool value) {
-  for (int i = 0; i < 2; i++) {
-    std::vector<FileMetaData*> v = inputs_[i];
+void Compaction::MarkFilesBeingCompacted(bool mark_as_compacted) {
+  for (int i = 0; i < num_input_levels(); i++) {
    for (unsigned int j = 0; j < inputs_[i].size(); j++) {
-      assert(value ? !inputs_[i][j]->being_compacted :
-                      inputs_[i][j]->being_compacted);
-      inputs_[i][j]->being_compacted = value;
+      assert(mark_as_compacted ? !inputs_[i][j]->being_compacted :
+                                  inputs_[i][j]->being_compacted);
+      inputs_[i][j]->being_compacted = mark_as_compacted;
    }
  }
 }

 // Is this compaction producing files at the bottommost level?
-void Compaction::SetupBottomMostLevel(bool isManual) {
+void Compaction::SetupBottomMostLevel(bool is_manual) {
  assert(cfd_->options()->compaction_style != kCompactionStyleFIFO);
  if (cfd_->options()->compaction_style == kCompactionStyleUniversal) {
    // If universal compaction style is used and manual
@@ -170,13 +182,14 @@ void Compaction::SetupBottomMostLevel(bool isManual) {
    // run. We can safely set bottommost_level_ = true.
    // If it is not manual compaction, then bottommost_level_
    // is already set when the Compaction was created.
-    if (isManual) {
+    if (is_manual) {
      bottommost_level_ = true;
    }
    return;
  }
  bottommost_level_ = true;
-  for (int i = output_level() + 1; i < number_levels_; i++) {
+  // checks whether there are files living beyond the output_level.
+  for (int i = output_level_ + 1; i < number_levels_; i++) {
    if (input_version_->NumLevelFiles(i) > 0) {
      bottommost_level_ = false;
      break;
@@ -202,7 +215,7 @@ void Compaction::ReleaseCompactionFiles(Status status) {
 }

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

 namespace {
@@ -229,24 +242,23 @@ void Compaction::Summary(char* output, int len) {
  int write =
      snprintf(output, len, "Base version %" PRIu64
                            " Base level %d, seek compaction:%d, inputs: [",
-               input_version_->GetVersionNumber(), level_, seek_compaction_);
+               input_version_->GetVersionNumber(),
+               start_level_, seek_compaction_);
  if (write < 0 || write >= len) {
    return;
  }

-  write += InputSummary(inputs_[0], output + write, len - write);
-  if (write < 0 || write >= len) {
-    return;
-  }
-
-  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;
+  for (int level = 0; level < num_input_levels(); ++level) {
+    if (level > 0) {
+      write += snprintf(output + write, len - write, "], [");
+      if (write < 0 || write >= len) {
+        return;
+      }
+    }
+    write += InputSummary(inputs_[level].files, output + write, len - write);
+    if (write < 0 || write >= len) {
+      return;
+    }
  }

  snprintf(output + write, len - write, "]");
@@ -259,8 +271,10 @@ uint64_t Compaction::OutputFilePreallocationSize() {
    preallocation_size =
        cfd_->compaction_picker()->MaxFileSizeForLevel(output_level());
  } else {
-    for (const auto& f : inputs_[0]) {
-      preallocation_size += f->fd.GetFileSize();
+    for (int level = 0; level < num_input_levels(); ++level) {
+      for (const auto& f : inputs_[level].files) {
+        preallocation_size += f->fd.GetFileSize();
+      }
    }
  }
  // Over-estimate slightly so we don't end up just barely crossing
@@ -8,41 +8,90 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #pragma once
+#include "util/arena.h"
+#include "util/autovector.h"
 #include "db/version_set.h"

 namespace rocksdb {

+// The structure that manages compaction input files associated
+// with the same physical level.
+struct CompactionInputFiles {
+  int level;
+  std::vector<FileMetaData*> files;
+  inline bool empty() const { return files.empty(); }
+  inline size_t size() const { return files.size(); }
+  inline void clear() { files.clear(); }
+  inline FileMetaData* operator[](int i) const { return files[i]; }
+};
+
 class Version;
 class ColumnFamilyData;

 // A Compaction encapsulates information about a compaction.
 class Compaction {
 public:
+  // No copying allowed
+  Compaction(const Compaction&) = delete;
+  void operator=(const Compaction&) = delete;
+
  ~Compaction();

-  // Return the level that is being compacted.  Inputs from "level"
-  // will be merged.
-  int level() const { return level_; }
+  // Returns the level associated to the specified compaction input level.
+  // If compaction_input_level is not specified, then input_level is set to 0.
+  int level(int compaction_input_level = 0) const {
+    return inputs_[compaction_input_level].level;
+  }

  // Outputs will go to this level
-  int output_level() const { return out_level_; }
+  int output_level() const { return output_level_; }
+
+  // Returns the number of input levels in this compaction.
+  int num_input_levels() const { return inputs_.size(); }

  // Return the object that holds the edits to the descriptor done
  // by this compaction.
-  VersionEdit* edit() { return edit_; }
+  VersionEdit* edit() const { return edit_; }

-  // "which" must be either 0 or 1
-  int num_input_files(int which) const { return inputs_[which].size(); }
+  // Returns the number of input files associated to the specified
+  // compaction input level.
+  // The function will return 0 if when "compaction_input_level" < 0
+  // or "compaction_input_level" >= "num_input_levels()".
+  int num_input_files(size_t compaction_input_level) const {
+    if (compaction_input_level < inputs_.size()) {
+      return inputs_[compaction_input_level].size();
+    }
+    return 0;
+  }

  // Returns input version of the compaction
  Version* input_version() const { return input_version_; }

+  // Returns the ColumnFamilyData associated with the compaction.
  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]; }
+  // Returns the file meta data of the 'i'th input file at the
+  // specified compaction input level.
+  // REQUIREMENT: "compaction_input_level" must be >= 0 and
+  //              < "input_levels()"
+  FileMetaData* input(size_t compaction_input_level, int i) const {
+    assert(compaction_input_level < inputs_.size());
+    return inputs_[compaction_input_level][i];
+  }

-  std::vector<FileMetaData*>* inputs(int which) { return &inputs_[which]; }
+  // Returns the list of file meta data of the specified compaction
+  // input level.
+  // REQUIREMENT: "compaction_input_level" must be >= 0 and
+  //              < "input_levels()"
+  std::vector<FileMetaData*>* const inputs(size_t compaction_input_level) {
+    assert(compaction_input_level < inputs_.size());
+    return &inputs_[compaction_input_level].files;
+  }
+
+  // Returns the FileLevel of the specified compaction input level.
+  FileLevel* input_levels(int compaction_input_level) {
+    return &input_levels_[compaction_input_level];
+  }

  // Maximum size of files to build during this compaction.
  uint64_t MaxOutputFileSize() const { return max_output_file_size_; }
@@ -53,20 +102,25 @@ class Compaction {
  // 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
+  // Generate input_levels_ from inputs_
+  // Should be called when inputs_ is stable
+  void GenerateFileLevels();
+
+  // 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;
+  // If true, then the comaction can be done by simply deleting input files.
+  bool IsDeletionCompaction() const {
+    return deletion_compaction_;
+  }

  // Add all inputs to this compaction as delete operations to *edit.
  void AddInputDeletions(VersionEdit* edit);

-  // Returns true if the information we have available guarantees that
-  // the compaction is producing data in "level+1" for which no data exists
-  // in levels greater than "level+1".
-  bool IsBaseLevelForKey(const Slice& user_key);
+  // Returns true if the available information we have guarantees that
+  // the input "user_key" does not exist in any level beyond "output_level()".
+  bool KeyNotExistsBeyondOutputLevel(const Slice& user_key);

  // Returns true iff we should stop building the current output
  // before processing "internal_key".
@@ -80,6 +134,9 @@ class Compaction {
  // Delete this compaction from the list of running compactions.
  void ReleaseCompactionFiles(Status status);

+  // Returns the summary of the compaction in "output" with maximum "len"
+  // in bytes.  The caller is responsible for the memory management of
+  // "output".
  void Summary(char* output, int len);

  // Return the score that was used to pick this compaction run.
@@ -94,9 +151,9 @@ class 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
+  // Returns the size in bytes 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
+  // is the sum of all input file sizes.
  uint64_t OutputFilePreallocationSize();

 private:
@@ -105,39 +162,45 @@ class Compaction {
  friend class FIFOCompactionPicker;
  friend class LevelCompactionPicker;

-  Compaction(Version* input_version, int level, int out_level,
+  Compaction(Version* input_version, int start_level, int out_level,
             uint64_t target_file_size, uint64_t max_grandparent_overlap_bytes,
             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
+  const int start_level_;    // the lowest level to be compacted
+  const int output_level_;  // levels to which output files are stored
  uint64_t max_output_file_size_;
  uint64_t max_grandparent_overlap_bytes_;
  Version* input_version_;
  VersionEdit* edit_;
  int number_levels_;
  ColumnFamilyData* cfd_;
+  Arena arena_;          // Arena used to allocate space for file_levels_

  uint32_t output_path_id_;
  CompressionType output_compression_;
  bool seek_compaction_;
-  // if true, just delete files in inputs_[0]
+  // If true, then the comaction can be done by simply deleting input files.
  bool deletion_compaction_;

-  // Each compaction reads inputs from "level_" and "level_+1"
-  std::vector<FileMetaData*> inputs_[2];      // The two sets of inputs
+  // Compaction input files organized by level.
+  autovector<CompactionInputFiles> inputs_;
+
+  // A copy of inputs_, organized more closely in memory
+  autovector<FileLevel, 2> input_levels_;

  // State used to check for number of of overlapping grandparent files
-  // (parent == level_ + 1, grandparent == level_ + 2)
+  // (grandparent == "output_level_ + 1")
+  // This vector is updated by Version::GetOverlappingInputs().
  std::vector<FileMetaData*> grandparents_;
-  size_t grandparent_index_;  // Index in grandparent_starts_
-  bool seen_key_;             // Some output key has been seen
+  size_t grandparent_index_;   // Index in grandparent_starts_
+  bool seen_key_;              // Some output key has been seen
  uint64_t overlapped_bytes_;  // Bytes of overlap between current output
-                              // and grandparent files
-  int base_index_;   // index of the file in files_[level_]
-  int parent_index_; // index of some file with same range in files_[level_+1]
-  double score_;     // score that was used to pick this compaction.
+                               // and grandparent files
+  int base_index_;    // index of the file in files_[start_level_]
+  int parent_index_;  // index of some file with same range in
+                      // files_[start_level_+1]
+  double score_;      // score that was used to pick this compaction.

  // Is this compaction creating a file in the bottom most level?
  bool bottommost_level_;
@@ -147,21 +210,28 @@ class 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
-  // all L >= level_ + 2).
+  // "level_ptrs_" holds indices into "input_version_->levels_", where each
+  // index remembers which file of an associated level we are currently used
+  // to check KeyNotExistsBeyondOutputLevel() for deletion operation.
+  // As it is for checking KeyNotExistsBeyondOutputLevel(), it only
+  // records indices for all levels beyond "output_level_".
  std::vector<size_t> level_ptrs_;

  // mark (or clear) all files that are being compacted
-  void MarkFilesBeingCompacted(bool);
+  void MarkFilesBeingCompacted(bool mark_as_compacted);

-  // Initialize whether compaction producing files at the bottommost level
-  void SetupBottomMostLevel(bool isManual);
+  // Initialize whether the compaction is producing files at the
+  // bottommost level.
+  //
+  // @see BottomMostLevel()
+  void SetupBottomMostLevel(bool is_manual);

  // In case of compaction error, reset the nextIndex that is used
  // to pick up the next file to be compacted from files_by_size_
  void ResetNextCompactionIndex();
 };

+// Utility function
+extern uint64_t TotalFileSize(const std::vector<FileMetaData*>& files);
+
 }  // namespace rocksdb
@@ -18,6 +18,14 @@

 namespace rocksdb {

+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]->compensated_file_size;
+  }
+  return sum;
+}
+
 namespace {
 // Determine compression type, based on user options, level of the output
 // file and whether compression is disabled.
@@ -45,14 +53,6 @@ CompressionType GetCompressionType(const Options& options, int level,
  }
 }

-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]->compensated_file_size;
-  }
-  return sum;
-}
-
 // Multiple two operands. If they overflow, return op1.
 uint64_t MultiplyCheckOverflow(uint64_t op1, int op2) {
  if (op1 == 0) {
@@ -194,14 +194,15 @@ bool CompactionPicker::ExpandWhileOverlapping(Compaction* c) {
  size_t old_size;
  do {
    old_size = c->inputs_[0].size();
-    GetRange(c->inputs_[0], &smallest, &largest);
+    GetRange(c->inputs_[0].files, &smallest, &largest);
    c->inputs_[0].clear();
    c->input_version_->GetOverlappingInputs(
-        level, &smallest, &largest, &c->inputs_[0], hint_index, &hint_index);
+        level, &smallest, &largest, &c->inputs_[0].files,
+        hint_index, &hint_index);
  } while(c->inputs_[0].size() > old_size);

  // Get the new range
-  GetRange(c->inputs_[0], &smallest, &largest);
+  GetRange(c->inputs_[0].files, &smallest, &largest);

  // If, after the expansion, there are files that are already under
  // compaction, then we must drop/cancel this compaction.
@@ -211,7 +212,7 @@ bool CompactionPicker::ExpandWhileOverlapping(Compaction* c) {
        "[%s] ExpandWhileOverlapping() failure because zero input files",
        c->column_family_data()->GetName().c_str());
  }
-  if (c->inputs_[0].empty() || FilesInCompaction(c->inputs_[0]) ||
+  if (c->inputs_[0].empty() || FilesInCompaction(c->inputs_[0].files) ||
      (c->level() != c->output_level() &&
       ParentRangeInCompaction(c->input_version_, &smallest, &largest, level,
                               &parent_index))) {
@@ -267,16 +268,17 @@ void CompactionPicker::SetupOtherInputs(Compaction* c) {
  InternalKey smallest, largest;

  // Get the range one last time.
-  GetRange(c->inputs_[0], &smallest, &largest);
+  GetRange(c->inputs_[0].files, &smallest, &largest);

  // Populate the set of next-level files (inputs_[1]) to include in compaction
-  c->input_version_->GetOverlappingInputs(level + 1, &smallest, &largest,
-                                          &c->inputs_[1], c->parent_index_,
-                                          &c->parent_index_);
+  c->input_version_->GetOverlappingInputs(
+      level + 1, &smallest, &largest,
+      &c->inputs_[1].files, c->parent_index_,
+      &c->parent_index_);

  // Get entire range covered by compaction
  InternalKey all_start, all_limit;
-  GetRange(c->inputs_[0], c->inputs_[1], &all_start, &all_limit);
+  GetRange(c->inputs_[0].files, c->inputs_[1].files, &all_start, &all_limit);

  // See if we can further grow the number of inputs in "level" without
  // changing the number of "level+1" files we pick up. We also choose NOT
@@ -287,8 +289,8 @@ 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 = TotalCompensatedFileSize(c->inputs_[0]);
-    const uint64_t inputs1_size = TotalCompensatedFileSize(c->inputs_[1]);
+    const uint64_t inputs0_size = TotalCompensatedFileSize(c->inputs_[0].files);
+    const uint64_t inputs1_size = TotalCompensatedFileSize(c->inputs_[1].files);
    const uint64_t expanded0_size = TotalCompensatedFileSize(expanded0);
    uint64_t limit = ExpandedCompactionByteSizeLimit(level);
    if (expanded0.size() > c->inputs_[0].size() &&
@@ -312,9 +314,10 @@ void CompactionPicker::SetupOtherInputs(Compaction* c) {
            inputs1_size);
        smallest = new_start;
        largest = new_limit;
-        c->inputs_[0] = expanded0;
-        c->inputs_[1] = expanded1;
-        GetRange(c->inputs_[0], c->inputs_[1], &all_start, &all_limit);
+        c->inputs_[0].files = expanded0;
+        c->inputs_[1].files = expanded1;
+        GetRange(c->inputs_[0].files, c->inputs_[1].files,
+                 &all_start, &all_limit);
      }
    }
  }
@@ -327,9 +330,9 @@ void CompactionPicker::SetupOtherInputs(Compaction* c) {
  }
 }

-
 Compaction* CompactionPicker::CompactRange(Version* version, int input_level,
                                           int output_level,
+                                           uint32_t output_path_id,
                                           const InternalKey* begin,
                                           const InternalKey* end,
                                           InternalKey** compaction_end) {
@@ -369,12 +372,13 @@ Compaction* CompactionPicker::CompactRange(Version* version, int input_level,
      }
    }
  }
-  Compaction* c = new Compaction(version, input_level, output_level,
-                                 MaxFileSizeForLevel(output_level),
-                                 MaxGrandParentOverlapBytes(input_level), 0,
-                                 GetCompressionType(*options_, output_level));
+  assert(output_path_id < static_cast<uint32_t>(options_->db_paths.size()));
+  Compaction* c = new Compaction(
+      version, input_level, output_level, MaxFileSizeForLevel(output_level),
+      MaxGrandParentOverlapBytes(input_level), output_path_id,
+      GetCompressionType(*options_, output_level));

-  c->inputs_[0] = inputs;
+  c->inputs_[0].files = inputs;
  if (ExpandWhileOverlapping(c) == false) {
    delete c;
    Log(options_->info_log,
@@ -441,18 +445,18 @@ Compaction* LevelCompactionPicker::PickCompaction(Version* version,
  if (level == 0) {
    assert(compactions_in_progress_[0].empty());
    InternalKey smallest, largest;
-    GetRange(c->inputs_[0], &smallest, &largest);
+    GetRange(c->inputs_[0].files, &smallest, &largest);
    // Note that the next call will discard the file we placed in
    // c->inputs_[0] earlier and replace it with an overlapping set
    // which will include the picked file.
    c->inputs_[0].clear();
    c->input_version_->GetOverlappingInputs(0, &smallest, &largest,
-                                            &c->inputs_[0]);
+                                            &c->inputs_[0].files);

    // If we include more L0 files in the same compaction run it can
    // cause the 'smallest' and 'largest' key to get extended to a
    // larger range. So, re-invoke GetRange to get the new key range
-    GetRange(c->inputs_[0], &smallest, &largest);
+    GetRange(c->inputs_[0].files, &smallest, &largest);
    if (ParentRangeInCompaction(c->input_version_, &smallest, &largest, level,
                                &c->parent_index_)) {
      delete c;
@@ -533,7 +537,7 @@ Compaction* LevelCompactionPicker::PickCompactionBySize(Version* version,
                                level, &parent_index)) {
      continue;
    }
-    c->inputs_[0].push_back(f);
+    c->inputs_[0].files.push_back(f);
    c->base_index_ = index;
    c->parent_index_ = parent_index;
    break;
@@ -615,11 +619,11 @@ Compaction* UniversalCompactionPicker::PickCompaction(Version* version,

  // Is the earliest file part of this compaction?
  FileMetaData* last_file = c->input_version_->files_[level].back();
-  c->bottommost_level_ = c->inputs_[0].back() == last_file;
+  c->bottommost_level_ = c->inputs_[0].files.back() == last_file;

  // update statistics
-  MeasureTime(options_->statistics.get(), NUM_FILES_IN_SINGLE_COMPACTION,
-              c->inputs_[0].size());
+  MeasureTime(options_->statistics.get(),
+              NUM_FILES_IN_SINGLE_COMPACTION, c->inputs_[0].size());

  // mark all the files that are being compacted
  c->MarkFilesBeingCompacted(true);
@@ -635,6 +639,37 @@ Compaction* UniversalCompactionPicker::PickCompaction(Version* version,
  return c;
 }

+uint32_t UniversalCompactionPicker::GetPathId(const Options& options,
+                                              uint64_t file_size) {
+  // Two conditions need to be satisfied:
+  // (1) the target path needs to be able to hold the file's size
+  // (2) Total size left in this and previous paths need to be not
+  //     smaller than expected future file size before this new file is
+  //     compacted, which is estimated based on size_ratio.
+  // For example, if now we are compacting files of size (1, 1, 2, 4, 8),
+  // we will make sure the target file, probably with size of 16, will be
+  // placed in a path so that eventually when new files are generated and
+  // compacted to (1, 1, 2, 4, 8, 16), all those files can be stored in or
+  // before the path we chose.
+  //
+  // TODO(sdong): now the case of multiple column families is not
+  // considered in this algorithm. So the target size can be violated in
+  // that case. We need to improve it.
+  uint64_t accumulated_size = 0;
+  uint64_t future_size =
+      file_size * (100 - options.compaction_options_universal.size_ratio) / 100;
+  uint32_t p = 0;
+  for (; p < options.db_paths.size() - 1; p++) {
+    uint64_t target_size = options.db_paths[p].target_size;
+    if (target_size > file_size &&
+        accumulated_size + (target_size - file_size) > future_size) {
+      return p;
+    }
+    accumulated_size += target_size;
+  }
+  return p;
+}
+
 //
 // Consider compaction files based on their size differences with
 // the next file in time order.
@@ -765,14 +800,21 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalReadAmp(
      }
    }
  }
+
+  uint64_t estimated_total_size = 0;
+  for (unsigned int i = 0; i < first_index_after; i++) {
+    estimated_total_size += files[i]->fd.GetFileSize();
+  }
+  uint32_t path_id = GetPathId(*options_, estimated_total_size);
+
  Compaction* c = new Compaction(
-      version, level, level, MaxFileSizeForLevel(level), LLONG_MAX, 0,
+      version, level, level, MaxFileSizeForLevel(level), LLONG_MAX, path_id,
      GetCompressionType(*options_, level, enable_compression));
  c->score_ = score;

  for (unsigned int i = start_index; i < first_index_after; i++) {
    FileMetaData* f = c->input_version_->files_[level][i];
-    c->inputs_[0].push_back(f);
+    c->inputs_[0].files.push_back(f);
    LogToBuffer(log_buffer,
                "[%s] Universal: Picking file %s[%d] "
                "with size %" PRIu64 " (compensated size %" PRIu64 ")\n",
@@ -865,15 +907,22 @@ Compaction* UniversalCompactionPicker::PickCompactionUniversalSizeAmp(
  }
  assert(start_index >= 0 && start_index < files.size() - 1);

+  // Estimate total file size
+  uint64_t estimated_total_size = 0;
+  for (unsigned int loop = start_index; loop < files.size(); loop++) {
+    estimated_total_size += files[loop]->fd.GetFileSize();
+  }
+  uint32_t path_id = GetPathId(*options_, estimated_total_size);
+
  // create a compaction request
  // We always compact all the files, so always compress.
  Compaction* c =
      new Compaction(version, level, level, MaxFileSizeForLevel(level),
-                     LLONG_MAX, 0, GetCompressionType(*options_, level));
+                     LLONG_MAX, path_id, GetCompressionType(*options_, level));
  c->score_ = score;
  for (unsigned int loop = start_index; loop < files.size(); loop++) {
    f = c->input_version_->files_[level][loop];
-    c->inputs_[0].push_back(f);
+    c->inputs_[0].files.push_back(f);
    LogToBuffer(log_buffer,
        "[%s] Universal: size amp picking file %" PRIu64 "[%d] "
        "with size %" PRIu64 " (compensated size %" PRIu64 ")",
@@ -918,7 +967,7 @@ Compaction* FIFOCompactionPicker::PickCompaction(Version* version,
       ritr != version->files_[0].rend(); ++ritr) {
    auto f = *ritr;
    total_size -= f->compensated_file_size;
-    c->inputs_[0].push_back(f);
+    c->inputs_[0].files.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
@@ -935,17 +984,19 @@ Compaction* FIFOCompactionPicker::PickCompaction(Version* version,
  return c;
 }

-Compaction* FIFOCompactionPicker::CompactRange(Version* version,
-                                               int input_level,
-                                               int output_level,
-                                               const InternalKey* begin,
-                                               const InternalKey* end,
-                                               InternalKey** compaction_end) {
+Compaction* FIFOCompactionPicker::CompactRange(
+    Version* version, int input_level, int output_level,
+    uint32_t output_path_id, 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);
+  Compaction* c = PickCompaction(version, &log_buffer);
+  if (c != nullptr) {
+    assert(output_path_id < static_cast<uint32_t>(options_->db_paths.size()));
+    c->output_path_id_ = output_path_id;
+  }
  log_buffer.FlushBufferToLog();
  return c;
 }
@@ -48,10 +48,15 @@ class CompactionPicker {
  // Client is responsible for compaction_end storage -- when called,
  // *compaction_end should point to valid InternalKey!
  virtual Compaction* CompactRange(Version* version, int input_level,
-                                   int output_level, const InternalKey* begin,
+                                   int output_level, uint32_t output_path_id,
+                                   const InternalKey* begin,
                                   const InternalKey* end,
                                   InternalKey** compaction_end);

+  // Given the current number of levels, returns the lowest allowed level
+  // for compaction input.
+  virtual int MaxInputLevel(int current_num_levels) const = 0;
+
  // Free up the files that participated in a compaction
  void ReleaseCompactionFiles(Compaction* c, Status status);

@@ -135,6 +140,11 @@ class UniversalCompactionPicker : public CompactionPicker {
  virtual Compaction* PickCompaction(Version* version,
                                     LogBuffer* log_buffer) override;

+  // The maxinum allowed input level.  Always return 0.
+  virtual int MaxInputLevel(int current_num_levels) const override {
+    return 0;
+  }
+
 private:
  // Pick Universal compaction to limit read amplification
  Compaction* PickCompactionUniversalReadAmp(Version* version, double score,
@@ -145,6 +155,10 @@ class UniversalCompactionPicker : public CompactionPicker {
  // Pick Universal compaction to limit space amplification.
  Compaction* PickCompactionUniversalSizeAmp(Version* version, double score,
                                             LogBuffer* log_buffer);
+
+  // Pick a path ID to place a newly generated file, with its estimated file
+  // size.
+  static uint32_t GetPathId(const Options& options, uint64_t file_size);
 };

 class LevelCompactionPicker : public CompactionPicker {
@@ -155,6 +169,12 @@ class LevelCompactionPicker : public CompactionPicker {
  virtual Compaction* PickCompaction(Version* version,
                                     LogBuffer* log_buffer) override;

+  // Returns current_num_levels - 2, meaning the last level cannot be
+  // compaction input level.
+  virtual int MaxInputLevel(int current_num_levels) const override {
+    return current_num_levels - 2;
+  }
+
 private:
  // For the specfied level, pick a compaction.
  // Returns nullptr if there is no compaction to be done.
@@ -173,9 +193,18 @@ class FIFOCompactionPicker : public CompactionPicker {
                                     LogBuffer* log_buffer) override;

  virtual Compaction* CompactRange(Version* version, int input_level,
-                                   int output_level, const InternalKey* begin,
+                                   int output_level, uint32_t output_path_id,
+                                   const InternalKey* begin,
                                   const InternalKey* end,
                                   InternalKey** compaction_end) override;
+
+  // The maxinum allowed input level.  Always return 0.
+  virtual int MaxInputLevel(int current_num_levels) const override {
+    return 0;
+  }
 };

+// Utility function
+extern uint64_t TotalCompensatedFileSize(const std::vector<FileMetaData*>& files);
+
 }  // namespace rocksdb
@@ -30,7 +30,6 @@ int main() {
 #include <gflags/gflags.h>
 #include "db/db_impl.h"
 #include "db/version_set.h"
-#include "rocksdb/statistics.h"
 #include "rocksdb/options.h"
 #include "rocksdb/cache.h"
 #include "rocksdb/db.h"
@@ -242,6 +241,10 @@ DEFINE_int64(cache_size, -1, "Number of bytes to use as a cache of uncompressed"
 DEFINE_int32(block_size, rocksdb::Options().block_size,
             "Number of bytes in a block.");

+DEFINE_int32(block_restart_interval, rocksdb::Options().block_restart_interval,
+             "Number of keys between restart points "
+             "for delta encoding of keys.");
+
 DEFINE_int64(compressed_cache_size, -1,
             "Number of bytes to use as a cache of compressed data.");

@@ -538,6 +541,9 @@ DEFINE_string(memtablerep, "skip_list", "");
 DEFINE_int64(hash_bucket_count, 1024 * 1024, "hash bucket count");
 DEFINE_bool(use_plain_table, false, "if use plain table "
            "instead of block-based table format");
+DEFINE_bool(use_hash_search, false, "if use kHashSearch "
+            "instead of kBinarySearch. "
+            "This is valid if only we use BlockTable");

 DEFINE_string(merge_operator, "", "The merge operator to use with the database."
              "If a new merge operator is specified, be sure to use fresh"
@@ -1623,8 +1629,9 @@ class Benchmark {
    options.max_background_flushes = FLAGS_max_background_flushes;
    options.compaction_style = FLAGS_compaction_style_e;
    options.block_size = FLAGS_block_size;
+    options.block_restart_interval = FLAGS_block_restart_interval;
    options.filter_policy = filter_policy_;
-    if (FLAGS_use_plain_table) {
+    if (FLAGS_prefix_size != 0) {
      options.prefix_extractor.reset(
          NewFixedPrefixTransform(FLAGS_prefix_size));
    }
@@ -1685,8 +1692,27 @@ class Benchmark {
      if (bloom_bits_per_key < 0) {
        bloom_bits_per_key = 0;
      }
+
+      PlainTableOptions plain_table_options;
+      plain_table_options.user_key_len = FLAGS_key_size;
+      plain_table_options.bloom_bits_per_key = bloom_bits_per_key;
+      plain_table_options.hash_table_ratio = 0.75;
      options.table_factory = std::shared_ptr<TableFactory>(
-          NewPlainTableFactory(FLAGS_key_size, bloom_bits_per_key, 0.75));
+          NewPlainTableFactory(plain_table_options));
+    } else {
+      BlockBasedTableOptions block_based_options;
+      if (FLAGS_use_hash_search) {
+        if (FLAGS_prefix_size == 0) {
+          fprintf(stderr,
+              "prefix_size not assigned when enable use_hash_search \n");
+          exit(1);
+        }
+        block_based_options.index_type = BlockBasedTableOptions::kHashSearch;
+      } else {
+        block_based_options.index_type = BlockBasedTableOptions::kBinarySearch;
+      }
+      options.table_factory.reset(
+          NewBlockBasedTableFactory(block_based_options));
    }
    if (FLAGS_max_bytes_for_level_multiplier_additional_v.size() > 0) {
      if (FLAGS_max_bytes_for_level_multiplier_additional_v.size() !=
@@ -28,7 +28,6 @@
 #include "rocksdb/memtablerep.h"
 #include "rocksdb/transaction_log.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"
@@ -97,13 +96,17 @@ class DBImpl : public DB {
  using DB::GetProperty;
  virtual bool GetProperty(ColumnFamilyHandle* column_family,
                           const Slice& property, std::string* value);
+  using DB::GetIntProperty;
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) override;
  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);
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0);

  using DB::NumberLevels;
  virtual int NumberLevels(ColumnFamilyHandle* column_family);
@@ -146,8 +149,8 @@ class DBImpl : public DB {
  virtual Status GetDbIdentity(std::string& identity);

  Status RunManualCompaction(ColumnFamilyData* cfd, int input_level,
-                             int output_level, const Slice* begin,
-                             const Slice* end);
+                             int output_level, uint32_t output_path_id,
+                             const Slice* begin, const Slice* end);

 #ifndef ROCKSDB_LITE
  // Extra methods (for testing) that are not in the public DB interface
@@ -290,6 +293,7 @@ class DBImpl : public DB {
  const std::string dbname_;
  unique_ptr<VersionSet> versions_;
  const DBOptions options_;
+  Statistics* stats_;

  Iterator* NewInternalIterator(const ReadOptions&, ColumnFamilyData* cfd,
                                SuperVersion* super_version,
@@ -362,13 +366,6 @@ class DBImpl : public DB {
  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);
@@ -478,12 +475,12 @@ class DBImpl : public DB {
  // * 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_;
  bool log_empty_;
  ColumnFamilyHandleImpl* default_cf_handle_;
+  InternalStats* default_cf_internal_stats_;
  unique_ptr<ColumnFamilyMemTablesImpl> column_family_memtables_;
  struct LogFileNumberSize {
    explicit LogFileNumberSize(uint64_t _number)
@@ -502,8 +499,6 @@ class DBImpl : public DB {
  // some code-paths
  bool single_column_family_mode_;

-  std::string host_name_;
-
  std::unique_ptr<Directory> db_directory_;

  // Queue of writers.
@@ -536,14 +531,12 @@ class DBImpl : public DB {
  // number of background memtable flush jobs, submitted to the HIGH pool
  int bg_flush_scheduled_;

-  // Has a background stats log thread scheduled?
-  bool bg_logstats_scheduled_;
-
  // Information for a manual compaction
  struct ManualCompaction {
    ColumnFamilyData* cfd;
    int input_level;
    int output_level;
+    uint32_t output_path_id;
    bool done;
    Status status;
    bool in_progress;           // compaction request being processed?
@@ -556,10 +549,6 @@ class DBImpl : public DB {
  // Have we encountered a background error in paranoid mode?
  Status bg_error_;

-  std::unique_ptr<StatsLogger> logger_;
-
-  int64_t volatile last_log_ts;
-
  // shall we disable deletion of obsolete files
  // if 0 the deletion is enabled.
  // if non-zero, files will not be getting deleted
@@ -622,6 +611,16 @@ class DBImpl : public DB {
  void InstallSuperVersion(ColumnFamilyData* cfd,
                           DeletionState& deletion_state);

+  // Find Super version and reference it. Based on options, it might return
+  // the thread local cached one.
+  inline SuperVersion* GetAndRefSuperVersion(ColumnFamilyData* cfd);
+
+  // Un-reference the super version and return it to thread local cache if
+  // needed. If it is the last reference of the super version. Clean it up
+  // after un-referencing it.
+  inline void ReturnAndCleanupSuperVersion(ColumnFamilyData* cfd,
+                                           SuperVersion* sv);
+
 #ifndef ROCKSDB_LITE
  using DB::GetPropertiesOfAllTables;
  virtual Status GetPropertiesOfAllTables(ColumnFamilyHandle* column_family,
@@ -634,6 +633,10 @@ class DBImpl : public DB {
  Status GetImpl(const ReadOptions& options, ColumnFamilyHandle* column_family,
                 const Slice& key, std::string* value,
                 bool* value_found = nullptr);
+
+  bool GetIntPropertyInternal(ColumnFamilyHandle* column_family,
+                              DBPropertyType property_type,
+                              bool need_out_of_mutex, uint64_t* value);
 };

 // Sanitize db options.  The caller should delete result.info_log if
@@ -644,4 +647,11 @@ extern Options SanitizeOptions(const std::string& db,
                               const Options& src);
 extern DBOptions SanitizeOptions(const std::string& db, const DBOptions& src);

+// 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;
+}
+
 }  // namespace rocksdb
@@ -85,7 +85,7 @@ Status DBImpl::TEST_CompactRange(int level, const Slice* begin,
       cfd->options()->compaction_style == kCompactionStyleFIFO)
          ? level
          : level + 1;
-  return RunManualCompaction(cfd, level, output_level, begin, end);
+  return RunManualCompaction(cfd, level, output_level, 0, begin, end);
 }

 Status DBImpl::TEST_FlushMemTable(bool wait) {
@@ -76,12 +76,42 @@ Iterator* DBImplReadOnly::NewIterator(const ReadOptions& options,
  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(
-      env_, *cfd->options(), cfd->user_comparator(), internal_iter,
+  auto db_iter = NewArenaWrappedDbIterator(
+      env_, *cfd->options(), cfd->user_comparator(),
      (options.snapshot != nullptr
           ? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
           : latest_snapshot));
+  auto internal_iter =
+      NewInternalIterator(options, cfd, super_version, db_iter->GetArena());
+  db_iter->SetIterUnderDBIter(internal_iter);
+  return db_iter;
+}
+
+Status DBImplReadOnly::NewIterators(
+    const ReadOptions& options,
+    const std::vector<ColumnFamilyHandle*>& column_families,
+    std::vector<Iterator*>* iterators) {
+  if (iterators == nullptr) {
+    return Status::InvalidArgument("iterators not allowed to be nullptr");
+  }
+  iterators->clear();
+  iterators->reserve(column_families.size());
+  SequenceNumber latest_snapshot = versions_->LastSequence();
+
+  for (auto cfh : column_families) {
+    auto cfd = reinterpret_cast<ColumnFamilyHandleImpl*>(cfh)->cfd();
+    auto db_iter = NewArenaWrappedDbIterator(
+        env_, *cfd->options(), cfd->user_comparator(),
+        options.snapshot != nullptr
+            ? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
+            : latest_snapshot);
+    auto internal_iter = NewInternalIterator(
+        options, cfd, cfd->GetSuperVersion()->Ref(), db_iter->GetArena());
+    db_iter->SetIterUnderDBIter(internal_iter);
+    iterators->push_back(db_iter);
+  }
+
+  return Status::OK();
 }

 Status DB::OpenForReadOnly(const Options& options, const std::string& dbname,
@@ -20,7 +20,6 @@
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "port/port.h"
-#include "util/stats_logger.h"

 namespace rocksdb {

@@ -33,63 +32,62 @@ class DBImplReadOnly : public DBImpl {
  using DB::Get;
  virtual Status Get(const ReadOptions& options,
                     ColumnFamilyHandle* column_family, const Slice& key,
-                     std::string* value);
+                     std::string* value) override;

  // TODO: Implement ReadOnly MultiGet?

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

  virtual Status NewIterators(
      const ReadOptions& options,
-      const std::vector<ColumnFamilyHandle*>& column_family,
-      std::vector<Iterator*>* iterators) {
-   // TODO
-    return Status::NotSupported("Not supported yet.");
-  }
+      const std::vector<ColumnFamilyHandle*>& column_families,
+      std::vector<Iterator*>* iterators) override;

  using DBImpl::Put;
  virtual Status Put(const WriteOptions& options,
                     ColumnFamilyHandle* column_family, const Slice& key,
-                     const Slice& value) {
+                     const Slice& value) override {
    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) {
+                       const Slice& value) override {
    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) {
+                        ColumnFamilyHandle* column_family,
+                        const Slice& key) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
-  virtual Status Write(const WriteOptions& options, WriteBatch* updates) {
+  virtual Status Write(const WriteOptions& options,
+                       WriteBatch* updates) override {
    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) {
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
-  virtual Status DisableFileDeletions() {
+  virtual Status DisableFileDeletions() override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
-  virtual Status EnableFileDeletions(bool force) {
+  virtual Status EnableFileDeletions(bool force) override {
    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) {
+                              bool flush_memtable = true) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }
  using DBImpl::Flush;
  virtual Status Flush(const FlushOptions& options,
-                       ColumnFamilyHandle* column_family) {
+                       ColumnFamilyHandle* column_family) override {
    return Status::NotSupported("Not supported operation in read only mode.");
  }

@@ -10,6 +10,8 @@
 #include "db/db_iter.h"
 #include <stdexcept>
 #include <deque>
+#include <string>
+#include <limits>

 #include "db/filename.h"
 #include "db/dbformat.h"
@@ -69,7 +71,8 @@ class DBIter: public Iterator {
        valid_(false),
        current_entry_is_merged_(false),
        statistics_(options.statistics.get()) {
-    RecordTick(statistics_, NO_ITERATORS, 1);
+    RecordTick(statistics_, NO_ITERATORS);
+    has_prefix_extractor_ = (options.prefix_extractor.get() != nullptr);
    max_skip_ = options.max_sequential_skip_in_iterations;
  }
  virtual ~DBIter() {
@@ -109,9 +112,14 @@ class DBIter: public Iterator {
  virtual void SeekToLast();

 private:
+  void PrevInternal();
+  void FindParseableKey(ParsedInternalKey* ikey, Direction direction);
+  bool FindValueForCurrentKey();
+  bool FindValueForCurrentKeyUsingSeek();
+  void FindPrevUserKey();
+  void FindNextUserKey();
  inline void FindNextUserEntry(bool skipping);
  void FindNextUserEntryInternal(bool skipping);
-  void FindPrevUserEntry();
  bool ParseKey(ParsedInternalKey* key);
  void MergeValuesNewToOld();

@@ -124,6 +132,7 @@ class DBIter: public Iterator {
    }
  }

+  bool has_prefix_extractor_;
  bool arena_mode_;
  Env* const env_;
  Logger* logger_;
@@ -133,8 +142,8 @@ class DBIter: public Iterator {
  SequenceNumber const sequence_;

  Status status_;
-  IterKey saved_key_;   // == current key when direction_==kReverse
-  std::string saved_value_;   // == current raw value when direction_==kReverse
+  IterKey saved_key_;
+  std::string saved_value_;
  Direction direction_;
  bool valid_;
  bool current_entry_is_merged_;
@@ -160,20 +169,11 @@ inline bool DBIter::ParseKey(ParsedInternalKey* ikey) {
 void DBIter::Next() {
  assert(valid_);

-  if (direction_ == kReverse) {  // Switch directions?
+  if (direction_ == kReverse) {
+    FindNextUserKey();
    direction_ = kForward;
-    // iter_ is pointing just before the entries for this->key(),
-    // so advance into the range of entries for this->key() and then
-    // use the normal skipping code below.
    if (!iter_->Valid()) {
      iter_->SeekToFirst();
-    } else {
-      iter_->Next();
-    }
-    if (!iter_->Valid()) {
-      valid_ = false;
-      saved_key_.Clear();
-      return;
    }
  }

@@ -185,7 +185,6 @@ void DBIter::Next() {
  FindNextUserEntry(true /* skipping the current user key */);
 }

-
 // PRE: saved_key_ has the current user key if skipping
 // POST: saved_key_ should have the next user key if valid_,
 //       if the current entry is a result of merge
@@ -327,100 +326,228 @@ void DBIter::MergeValuesNewToOld() {

 void DBIter::Prev() {
  assert(valid_);
-
-  // Throw an exception now if merge_operator is provided
-  // TODO: support backward iteration
-  if (user_merge_operator_) {
-    Log(logger_, "Prev not supported yet if merge_operator is provided");
-    throw std::logic_error("DBIter::Prev backward iteration not supported"
-                           " if merge_operator is provided");
-  }
-
-  if (direction_ == kForward) {  // Switch directions?
-    // 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
-    saved_key_.SetKey(ExtractUserKey(iter_->key()));
-    while (true) {
-      iter_->Prev();
-      if (!iter_->Valid()) {
-        valid_ = false;
-        saved_key_.Clear();
-        ClearSavedValue();
-        return;
-      }
-      if (user_comparator_->Compare(ExtractUserKey(iter_->key()),
-                                    saved_key_.GetKey()) < 0) {
-        break;
-      }
-    }
+  if (direction_ == kForward) {
+    FindPrevUserKey();
    direction_ = kReverse;
  }
-
-  FindPrevUserEntry();
+  PrevInternal();
 }

-void DBIter::FindPrevUserEntry() {
-  assert(direction_ == kReverse);
-  uint64_t num_skipped = 0;
-
-  ValueType value_type = kTypeDeletion;
-  bool saved_key_valid = true;
-  if (iter_->Valid()) {
-    do {
-      ParsedInternalKey ikey;
-      if (ParseKey(&ikey) && ikey.sequence <= sequence_) {
-        if ((value_type != kTypeDeletion) &&
-            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();
-          ClearSavedValue();
-          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_);
-          }
-          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_valid && num_skipped > max_skip_) {
-        num_skipped = 0;
-        std::string last_key;
-        AppendInternalKey(&last_key, ParsedInternalKey(saved_key_.GetKey(),
-                                                       kMaxSequenceNumber,
-                                                       kValueTypeForSeek));
-        iter_->Seek(last_key);
-        RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
-      } else {
-        iter_->Prev();
-      }
-    } while (iter_->Valid());
+void DBIter::PrevInternal() {
+  if (!iter_->Valid()) {
+    valid_ = false;
+    return;
  }

-  if (value_type == kTypeDeletion) {
-    // End
+  ParsedInternalKey ikey;
+
+  while (iter_->Valid()) {
+    saved_key_.SetKey(ExtractUserKey(iter_->key()));
+    if (FindValueForCurrentKey()) {
+      valid_ = true;
+      if (!iter_->Valid()) {
+        return;
+      }
+      FindParseableKey(&ikey, kReverse);
+      if (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0) {
+        FindPrevUserKey();
+      }
+      return;
+    }
+    if (!iter_->Valid()) {
+      break;
+    }
+    FindParseableKey(&ikey, kReverse);
+    if (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0) {
+
+      FindPrevUserKey();
+    }
+  }
+  // We haven't found any key - iterator is not valid
+  assert(!iter_->Valid());
+  valid_ = false;
+}
+
+// This function checks, if the entry with biggest sequence_number <= sequence_
+// is non kTypeDeletion. If it's not, we save value in saved_value_
+bool DBIter::FindValueForCurrentKey() {
+  assert(iter_->Valid());
+  // Contains operands for merge operator.
+  std::deque<std::string> operands;
+  // last entry before merge (could be kTypeDeletion or kTypeValue)
+  ValueType last_not_merge_type = kTypeDeletion;
+  ValueType last_key_entry_type = kTypeDeletion;
+
+  ParsedInternalKey ikey;
+  FindParseableKey(&ikey, kReverse);
+
+  size_t num_skipped = 0;
+  while (iter_->Valid() && ikey.sequence <= sequence_ &&
+         (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0)) {
+    // We iterate too much: let's use Seek() to avoid too much key comparisons
+    if (num_skipped >= max_skip_) {
+      return FindValueForCurrentKeyUsingSeek();
+    }
+
+    last_key_entry_type = ikey.type;
+    switch (last_key_entry_type) {
+      case kTypeValue:
+        operands.clear();
+        saved_value_ = iter_->value().ToString();
+        last_not_merge_type = kTypeValue;
+        break;
+      case kTypeDeletion:
+        operands.clear();
+        last_not_merge_type = kTypeDeletion;
+        break;
+      case kTypeMerge:
+        assert(user_merge_operator_ != nullptr);
+        operands.push_back(iter_->value().ToString());
+        break;
+      default:
+        assert(false);
+    }
+
+    assert(user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0);
+    iter_->Prev();
+    ++num_skipped;
+    FindParseableKey(&ikey, kReverse);
+  }
+
+  switch (last_key_entry_type) {
+    case kTypeDeletion:
+      valid_ = false;
+      return false;
+    case kTypeMerge:
+      if (last_not_merge_type == kTypeDeletion) {
+        user_merge_operator_->FullMerge(saved_key_.GetKey(), nullptr, operands,
+                                        &saved_value_, logger_);
+      } else {
+        assert(last_not_merge_type == kTypeValue);
+        std::string last_put_value = saved_value_;
+        Slice temp_slice(last_put_value);
+        user_merge_operator_->FullMerge(saved_key_.GetKey(), &temp_slice,
+                                        operands, &saved_value_, logger_);
+      }
+      break;
+    case kTypeValue:
+      // do nothing - we've already has value in saved_value_
+      break;
+    default:
+      assert(false);
+      break;
+  }
+  valid_ = true;
+  return true;
+}
+
+// This function is used in FindValueForCurrentKey.
+// We use Seek() function instead of Prev() to find necessary value
+bool DBIter::FindValueForCurrentKeyUsingSeek() {
+  std::string last_key;
+  AppendInternalKey(&last_key, ParsedInternalKey(saved_key_.GetKey(), sequence_,
+                                                 kValueTypeForSeek));
+  iter_->Seek(last_key);
+  RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
+
+  // assume there is at least one parseable key for this user key
+  ParsedInternalKey ikey;
+  FindParseableKey(&ikey, kForward);
+
+  if (ikey.type == kTypeValue || ikey.type == kTypeDeletion) {
+    if (ikey.type == kTypeValue) {
+      saved_value_ = iter_->value().ToString();
+      valid_ = true;
+      return true;
+    }
    valid_ = false;
-    saved_key_.Clear();
-    ClearSavedValue();
-    direction_ = kForward;
-  } else {
+    return false;
+  }
+
+  // kTypeMerge. We need to collect all kTypeMerge values and save them
+  // in operands
+  std::deque<std::string> operands;
+  while (iter_->Valid() &&
+         (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0) &&
+         ikey.type == kTypeMerge) {
+    operands.push_front(iter_->value().ToString());
+    iter_->Next();
+    FindParseableKey(&ikey, kForward);
+  }
+
+  if (!iter_->Valid() ||
+      (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) != 0) ||
+      ikey.type == kTypeDeletion) {
+    user_merge_operator_->FullMerge(saved_key_.GetKey(), nullptr, operands,
+                                    &saved_value_, logger_);
+
+    // Make iter_ valid and point to saved_key_
+    if (!iter_->Valid() ||
+        (user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) != 0)) {
+      iter_->Seek(last_key);
+      RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
+    }
    valid_ = true;
+    return true;
+  }
+
+  const Slice& value = iter_->value();
+  user_merge_operator_->FullMerge(saved_key_.GetKey(), &value, operands,
+                                  &saved_value_, logger_);
+  valid_ = true;
+  return true;
+}
+
+// Used in Next to change directions
+// Go to next user key
+// Don't use Seek(),
+// because next user key will be very close
+void DBIter::FindNextUserKey() {
+  if (!iter_->Valid()) {
+    return;
+  }
+  ParsedInternalKey ikey;
+  FindParseableKey(&ikey, kForward);
+  while (iter_->Valid() &&
+         user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) != 0) {
+    iter_->Next();
+    FindParseableKey(&ikey, kForward);
+  }
+}
+
+// Go to previous user_key
+void DBIter::FindPrevUserKey() {
+  if (!iter_->Valid()) {
+    return;
+  }
+  size_t num_skipped = 0;
+  ParsedInternalKey ikey;
+  FindParseableKey(&ikey, kReverse);
+  while (iter_->Valid() &&
+         user_comparator_->Compare(ikey.user_key, saved_key_.GetKey()) == 0) {
+    if (num_skipped >= max_skip_) {
+      num_skipped = 0;
+      IterKey last_key;
+      last_key.SetInternalKey(ParsedInternalKey(
+          saved_key_.GetKey(), kMaxSequenceNumber, kValueTypeForSeek));
+      iter_->Seek(last_key.GetKey());
+      RecordTick(statistics_, NUMBER_OF_RESEEKS_IN_ITERATION);
+    }
+
+    iter_->Prev();
+    ++num_skipped;
+    FindParseableKey(&ikey, kReverse);
+  }
+}
+
+// Skip all unparseable keys
+void DBIter::FindParseableKey(ParsedInternalKey* ikey, Direction direction) {
+  while (iter_->Valid() && !ParseKey(ikey)) {
+    if (direction == kReverse) {
+      iter_->Prev();
+    } else {
+      iter_->Next();
+    }
  }
 }

@@ -441,6 +568,11 @@ void DBIter::Seek(const Slice& target) {
 }

 void DBIter::SeekToFirst() {
+  // Don't use iter_::Seek() if we set a prefix extractor
+  // because prefix seek wiil be used.
+  if (has_prefix_extractor_) {
+    max_skip_ = std::numeric_limits<uint64_t>::max();
+  }
  direction_ = kForward;
  ClearSavedValue();
  PERF_TIMER_AUTO(seek_internal_seek_time);
@@ -454,20 +586,18 @@ void DBIter::SeekToFirst() {
 }

 void DBIter::SeekToLast() {
-  // Throw an exception for now if merge_operator is provided
-  // TODO: support backward iteration
-  if (user_merge_operator_) {
-    Log(logger_, "SeekToLast not supported yet if merge_operator is provided");
-    throw std::logic_error("DBIter::SeekToLast: backward iteration not"
-                           " supported if merge_operator is provided");
+  // Don't use iter_::Seek() if we set a prefix extractor
+  // because prefix seek wiil be used.
+  if (has_prefix_extractor_) {
+    max_skip_ = std::numeric_limits<uint64_t>::max();
  }
-
  direction_ = kReverse;
  ClearSavedValue();
  PERF_TIMER_AUTO(seek_internal_seek_time);
  iter_->SeekToLast();
  PERF_TIMER_STOP(seek_internal_seek_time);
-  FindPrevUserEntry();
+
+  PrevInternal();
 }

 Iterator* NewDBIterator(Env* env, const Options& options,
@@ -1,95 +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.
-//
-// 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/db_impl.h"
-#include <string>
-#include <stdint.h>
-#include <stdio.h>
-#include "db/version_set.h"
-#include "rocksdb/db.h"
-#include "rocksdb/env.h"
-#include "port/port.h"
-#include "util/mutexlock.h"
-
-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()) {
-    return;
-  }
-
-  if(bg_logstats_scheduled_ || shutting_down_.Acquire_Load()) {
-    // Already scheduled
-  } else {
-    int64_t current_ts = 0;
-    Status st = env_->GetCurrentTime(&current_ts);
-    if (!st.ok()) {
-      return;
-    }
-    if ((current_ts - last_log_ts) < options_.db_stats_log_interval) {
-      return;
-    }
-    last_log_ts = current_ts;
-    bg_logstats_scheduled_ = true;
-    env_->Schedule(&DBImpl::BGLogDBDeployStats, this);
-  }
-}
-
-void DBImpl::BGLogDBDeployStats(void* db) {
-  DBImpl* db_inst = reinterpret_cast<DBImpl*>(db);
-  db_inst->LogDBDeployStats();
-}
-
-void DBImpl::LogDBDeployStats() {
-  mutex_.Lock();
-
-  if (shutting_down_.Acquire_Load()) {
-    bg_logstats_scheduled_ = false;
-    bg_cv_.SignalAll();
-    mutex_.Unlock();
-    return;
-  }
-
-  char tmp_ver[100];
-  sprintf(tmp_ver, "%d.%d", kMajorVersion, kMinorVersion);
-  std::string version_info(tmp_ver);
-
-  uint64_t file_total_size = 0;
-  uint32_t file_total_num = 0;
-  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);
-  }
-
-  Version::LevelSummaryStorage scratch;
-  const char* file_num_summary = current->LevelSummary(&scratch);
-  std::string file_num_per_level(file_num_summary);
-  std::string data_size_per_level(file_num_summary);
-
-  mutex_.Unlock();
-
-  int64_t unix_ts;
-  env_->GetCurrentTime(&unix_ts);
-
-  logger_->Log_Deploy_Stats(version_info, host_name_,
-      db_absolute_path_, file_total_size, file_total_num, file_num_per_level,
-      data_size_per_level, unix_ts);
-
-  mutex_.Lock();
-  bg_logstats_scheduled_ = false;
-  bg_cv_.SignalAll();
-  mutex_.Unlock();
-#endif
-}
-}
@@ -12,6 +12,7 @@
 #include <set>
 #include <unistd.h>
 #include <unordered_set>
+#include <utility>

 #include "db/dbformat.h"
 #include "db/db_impl.h"
@@ -308,31 +309,31 @@ class DBTest {
 protected:
  // Sequence of option configurations to try
  enum OptionConfig {
-    kBlockBasedTableWithWholeKeyHashIndex,
-    kDefault,
-    kBlockBasedTableWithPrefixHashIndex,
-    kPlainTableFirstBytePrefix,
-    kPlainTableAllBytesPrefix,
-    kVectorRep,
-    kHashLinkList,
-    kHashCuckoo,
-    kMergePut,
-    kFilter,
-    kUncompressed,
-    kNumLevel_3,
-    kDBLogDir,
-    kWalDir,
-    kManifestFileSize,
-    kCompactOnFlush,
-    kPerfOptions,
-    kDeletesFilterFirst,
-    kHashSkipList,
-    kUniversalCompaction,
-    kCompressedBlockCache,
-    kInfiniteMaxOpenFiles,
-    kxxHashChecksum,
-    kFIFOCompaction,
-    kEnd
+    kDefault = 0,
+    kBlockBasedTableWithPrefixHashIndex = 1,
+    kBlockBasedTableWithWholeKeyHashIndex = 2,
+    kPlainTableFirstBytePrefix = 3,
+    kPlainTableAllBytesPrefix = 4,
+    kVectorRep = 5,
+    kHashLinkList = 6,
+    kHashCuckoo = 7,
+    kMergePut = 8,
+    kFilter = 9,
+    kUncompressed = 10,
+    kNumLevel_3 = 11,
+    kDBLogDir = 12,
+    kWalDir = 13,
+    kManifestFileSize = 14,
+    kCompactOnFlush = 15,
+    kPerfOptions = 16,
+    kDeletesFilterFirst = 17,
+    kHashSkipList = 18,
+    kUniversalCompaction = 19,
+    kCompressedBlockCache = 20,
+    kInfiniteMaxOpenFiles = 21,
+    kxxHashChecksum = 22,
+    kFIFOCompaction = 23,
+    kEnd = 24
  };
  int option_config_;

@@ -370,8 +371,10 @@ class DBTest {
  ~DBTest() {
    Close();
    Options options;
-    options.db_paths.push_back(dbname_);
-    options.db_paths.push_back(dbname_ + "_2");
+    options.db_paths.emplace_back(dbname_, 0);
+    options.db_paths.emplace_back(dbname_ + "_2", 0);
+    options.db_paths.emplace_back(dbname_ + "_3", 0);
+    options.db_paths.emplace_back(dbname_ + "_4", 0);
    ASSERT_OK(DestroyDB(dbname_, options));
    delete env_;
    delete filter_policy_;
@@ -402,7 +405,7 @@ class DBTest {
              || option_config_ == kPlainTableFirstBytePrefix)) {
        continue;
      }
-      if ((skip_mask & kSkipPlainTable) &&
+      if ((skip_mask & kSkipHashIndex) &&
          (option_config_ == kBlockBasedTableWithPrefixHashIndex ||
           option_config_ == kBlockBasedTableWithWholeKeyHashIndex)) {
        continue;
@@ -1183,6 +1186,10 @@ TEST(DBTest, IndexAndFilterBlocksOfNewTableAddedToCache) {
  ASSERT_EQ(2, /* only index/filter were added */
            TestGetTickerCount(options, BLOCK_CACHE_ADD));
  ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_DATA_MISS));
+  uint64_t int_num;
+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.estimate-table-readers-mem", &int_num));
+  ASSERT_EQ(int_num, 0U);

  // Make sure filter block is in cache.
  std::string value;
@@ -2483,8 +2490,13 @@ TEST(DBTest, GetProperty) {

  std::string big_value(1000000 * 2, 'x');
  std::string num;
+  uint64_t int_num;
  SetPerfLevel(kEnableTime);

+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.estimate-table-readers-mem", &int_num));
+  ASSERT_EQ(int_num, 0U);
+
  ASSERT_OK(dbfull()->Put(writeOpt, "k1", big_value));
  ASSERT_TRUE(dbfull()->GetProperty("rocksdb.num-immutable-mem-table", &num));
  ASSERT_EQ(num, "0");
@@ -2492,11 +2504,14 @@ TEST(DBTest, GetProperty) {
  ASSERT_EQ(num, "0");
  ASSERT_TRUE(dbfull()->GetProperty("rocksdb.compaction-pending", &num));
  ASSERT_EQ(num, "0");
+  ASSERT_TRUE(dbfull()->GetProperty("rocksdb.estimate-num-keys", &num));
+  ASSERT_EQ(num, "1");
  perf_context.Reset();

  ASSERT_OK(dbfull()->Put(writeOpt, "k2", big_value));
  ASSERT_TRUE(dbfull()->GetProperty("rocksdb.num-immutable-mem-table", &num));
  ASSERT_EQ(num, "1");
+  ASSERT_OK(dbfull()->Delete(writeOpt, "k-non-existing"));
  ASSERT_OK(dbfull()->Put(writeOpt, "k3", big_value));
  ASSERT_TRUE(dbfull()->GetProperty("rocksdb.num-immutable-mem-table", &num));
  ASSERT_EQ(num, "2");
@@ -2504,6 +2519,23 @@ TEST(DBTest, GetProperty) {
  ASSERT_EQ(num, "1");
  ASSERT_TRUE(dbfull()->GetProperty("rocksdb.compaction-pending", &num));
  ASSERT_EQ(num, "0");
+  ASSERT_TRUE(dbfull()->GetProperty("rocksdb.estimate-num-keys", &num));
+  ASSERT_EQ(num, "4");
+  // Verify the same set of properties through GetIntProperty
+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.num-immutable-mem-table", &int_num));
+  ASSERT_EQ(int_num, 2U);
+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.mem-table-flush-pending", &int_num));
+  ASSERT_EQ(int_num, 1U);
+  ASSERT_TRUE(dbfull()->GetIntProperty("rocksdb.compaction-pending", &int_num));
+  ASSERT_EQ(int_num, 0U);
+  ASSERT_TRUE(dbfull()->GetIntProperty("rocksdb.estimate-num-keys", &int_num));
+  ASSERT_EQ(int_num, 4U);
+
+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.estimate-table-readers-mem", &int_num));
+  ASSERT_EQ(int_num, 0U);

  sleeping_task_high.WakeUp();
  sleeping_task_high.WaitUntilDone();
@@ -2516,8 +2548,31 @@ TEST(DBTest, GetProperty) {
  ASSERT_EQ(num, "0");
  ASSERT_TRUE(dbfull()->GetProperty("rocksdb.compaction-pending", &num));
  ASSERT_EQ(num, "1");
+  ASSERT_TRUE(dbfull()->GetProperty("rocksdb.estimate-num-keys", &num));
+  ASSERT_EQ(num, "4");
+
+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.estimate-table-readers-mem", &int_num));
+  ASSERT_GT(int_num, 0U);
+
  sleeping_task_low.WakeUp();
  sleeping_task_low.WaitUntilDone();
+
+  dbfull()->TEST_WaitForFlushMemTable();
+  options.max_open_files = 10;
+  Reopen(&options);
+  // After reopening, no table reader is loaded, so no memory for table readers
+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.estimate-table-readers-mem", &int_num));
+  ASSERT_EQ(int_num, 0U);
+  ASSERT_TRUE(dbfull()->GetIntProperty("rocksdb.estimate-num-keys", &int_num));
+  ASSERT_GT(int_num, 0U);
+
+  // After reading a key, at least one table reader is loaded.
+  Get("k5");
+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.estimate-table-readers-mem", &int_num));
+  ASSERT_GT(int_num, 0U);
 }

 TEST(DBTest, FLUSH) {
@@ -3474,10 +3529,206 @@ TEST(DBTest, UniversalCompactionCompressRatio2) {

 TEST(DBTest, FailMoreDbPaths) {
  Options options;
-  options.db_paths.push_back(dbname_);
-  options.db_paths.push_back(dbname_ + "_2");
+  options.db_paths.emplace_back(dbname_, 10000000);
+  options.db_paths.emplace_back(dbname_ + "_2", 1000000);
+  options.db_paths.emplace_back(dbname_ + "_3", 1000000);
+  options.db_paths.emplace_back(dbname_ + "_4", 1000000);
+  options.db_paths.emplace_back(dbname_ + "_5", 1000000);
  ASSERT_TRUE(TryReopen(&options).IsNotSupported());
 }
+
+TEST(DBTest, UniversalCompactionSecondPathRatio) {
+  Options options;
+  options.db_paths.emplace_back(dbname_, 500 * 1024);
+  options.db_paths.emplace_back(dbname_ + "_2", 1024 * 1024 * 1024);
+  options.compaction_style = kCompactionStyleUniversal;
+  options.write_buffer_size = 100 << 10;  // 100KB
+  options.level0_file_num_compaction_trigger = 2;
+  options.num_levels = 1;
+  options = CurrentOptions(options);
+
+  std::vector<std::string> filenames;
+  env_->GetChildren(options.db_paths[1].path, &filenames);
+  // Delete archival files.
+  for (size_t i = 0; i < filenames.size(); ++i) {
+    env_->DeleteFile(options.db_paths[1].path + "/" + filenames[i]);
+  }
+  env_->DeleteDir(options.db_paths[1].path);
+  Reopen(&options);
+
+  Random rnd(301);
+  int key_idx = 0;
+
+  // First three 110KB files are not going to second path.
+  // After that, (100K, 200K)
+  for (int num = 0; num < 3; num++) {
+    GenerateNewFile(&rnd, &key_idx);
+  }
+
+  // Another 110KB triggers a compaction to 400K file to second path
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+
+  // (1, 4)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  // (1,1,4) -> (2, 4)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  // (1, 2, 4)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(2, GetSstFileCount(dbname_));
+
+  // (1, 1, 2, 4) -> (8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(0, GetSstFileCount(dbname_));
+
+  // (1, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  // (1, 1, 8) -> (2, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  // (1, 2, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(2, GetSstFileCount(dbname_));
+
+  // (1, 1, 2, 8) -> (4, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(2, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(0, GetSstFileCount(dbname_));
+
+  // (1, 4, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(2, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  for (int i = 0; i < key_idx; i++) {
+    auto v = Get(Key(i));
+    ASSERT_NE(v, "NOT_FOUND");
+    ASSERT_TRUE(v.size() == 1 || v.size() == 10000);
+  }
+
+  Reopen(&options);
+
+  for (int i = 0; i < key_idx; i++) {
+    auto v = Get(Key(i));
+    ASSERT_NE(v, "NOT_FOUND");
+    ASSERT_TRUE(v.size() == 1 || v.size() == 10000);
+  }
+
+  Destroy(&options);
+}
+
+TEST(DBTest, UniversalCompactionFourPaths) {
+  Options options;
+  options.db_paths.emplace_back(dbname_, 300 * 1024);
+  options.db_paths.emplace_back(dbname_ + "_2", 300 * 1024);
+  options.db_paths.emplace_back(dbname_ + "_3", 500 * 1024);
+  options.db_paths.emplace_back(dbname_ + "_4", 1024 * 1024 * 1024);
+  options.compaction_style = kCompactionStyleUniversal;
+  options.write_buffer_size = 100 << 10;  // 100KB
+  options.level0_file_num_compaction_trigger = 2;
+  options.num_levels = 1;
+  options = CurrentOptions(options);
+
+  std::vector<std::string> filenames;
+  env_->GetChildren(options.db_paths[1].path, &filenames);
+  // Delete archival files.
+  for (size_t i = 0; i < filenames.size(); ++i) {
+    env_->DeleteFile(options.db_paths[1].path + "/" + filenames[i]);
+  }
+  env_->DeleteDir(options.db_paths[1].path);
+  Reopen(&options);
+
+  Random rnd(301);
+  int key_idx = 0;
+
+  // First three 110KB files are not going to second path.
+  // After that, (100K, 200K)
+  for (int num = 0; num < 3; num++) {
+    GenerateNewFile(&rnd, &key_idx);
+  }
+
+  // Another 110KB triggers a compaction to 400K file to second path
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[2].path));
+
+  // (1, 4)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[2].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  // (1,1,4) -> (2, 4)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[2].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(0, GetSstFileCount(dbname_));
+
+  // (1, 2, 4)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[2].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  // (1, 1, 2, 4) -> (8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[3].path));
+
+  // (1, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[3].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  // (1, 1, 8) -> (2, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[3].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+
+  // (1, 2, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[3].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  // (1, 1, 2, 8) -> (4, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[2].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[3].path));
+
+  // (1, 4, 8)
+  GenerateNewFile(&rnd, &key_idx);
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[3].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[2].path));
+  ASSERT_EQ(1, GetSstFileCount(dbname_));
+
+  for (int i = 0; i < key_idx; i++) {
+    auto v = Get(Key(i));
+    ASSERT_NE(v, "NOT_FOUND");
+    ASSERT_TRUE(v.size() == 1 || v.size() == 10000);
+  }
+
+  Reopen(&options);
+
+  for (int i = 0; i < key_idx; i++) {
+    auto v = Get(Key(i));
+    ASSERT_NE(v, "NOT_FOUND");
+    ASSERT_TRUE(v.size() == 1 || v.size() == 10000);
+  }
+
+  Destroy(&options);
+}
 #endif

 TEST(DBTest, ConvertCompactionStyle) {
@@ -4558,7 +4809,7 @@ TEST(DBTest, ApproximateSizes) {
    }
    // ApproximateOffsetOf() is not yet implemented in plain table format.
  } while (ChangeOptions(kSkipUniversalCompaction | kSkipFIFOCompaction |
-                         kSkipPlainTable));
+                         kSkipPlainTable | kSkipHashIndex));
 }

 TEST(DBTest, ApproximateSizes_MixOfSmallAndLarge) {
@@ -5053,6 +5304,54 @@ TEST(DBTest, ManualCompaction) {

 }

+TEST(DBTest, ManualCompactionOutputPathId) {
+  Options options = CurrentOptions();
+  options.create_if_missing = true;
+  options.db_paths.emplace_back(dbname_, 1000000000);
+  options.db_paths.emplace_back(dbname_ + "_2", 1000000000);
+  options.compaction_style = kCompactionStyleUniversal;
+  options.level0_file_num_compaction_trigger = 10;
+  Destroy(&options);
+  DestroyAndReopen(&options);
+  CreateAndReopenWithCF({"pikachu"}, &options);
+  MakeTables(3, "p", "q", 1);
+  dbfull()->TEST_WaitForCompact();
+  ASSERT_EQ("3", FilesPerLevel(1));
+  ASSERT_EQ(3, GetSstFileCount(options.db_paths[0].path));
+  ASSERT_EQ(0, GetSstFileCount(options.db_paths[1].path));
+
+  // Full compaction to DB path 0
+  db_->CompactRange(handles_[1], nullptr, nullptr, false, -1, 1);
+  ASSERT_EQ("1", FilesPerLevel(1));
+  ASSERT_EQ(0, GetSstFileCount(options.db_paths[0].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+
+  ReopenWithColumnFamilies({kDefaultColumnFamilyName, "pikachu"}, &options);
+  ASSERT_EQ("1", FilesPerLevel(1));
+  ASSERT_EQ(0, GetSstFileCount(options.db_paths[0].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+
+  MakeTables(1, "p", "q", 1);
+  ASSERT_EQ("2", FilesPerLevel(1));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[0].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+
+  ReopenWithColumnFamilies({kDefaultColumnFamilyName, "pikachu"}, &options);
+  ASSERT_EQ("2", FilesPerLevel(1));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[0].path));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[1].path));
+
+  // Full compaction to DB path 0
+  db_->CompactRange(handles_[1], nullptr, nullptr, false, -1, 0);
+  ASSERT_EQ("1", FilesPerLevel(1));
+  ASSERT_EQ(1, GetSstFileCount(options.db_paths[0].path));
+  ASSERT_EQ(0, GetSstFileCount(options.db_paths[1].path));
+
+  // Fail when compacting to an invalid path ID
+  ASSERT_TRUE(db_->CompactRange(handles_[1], nullptr, nullptr, false, -1, 2)
+                  .IsInvalidArgument());
+}
+
 TEST(DBTest, DBOpen_Options) {
  std::string dbname = test::TmpDir() + "/db_options_test";
  ASSERT_OK(DestroyDB(dbname, Options()));
@@ -6350,6 +6649,11 @@ class ModelDB: public DB {
                           const Slice& property, std::string* value) {
    return false;
  }
+  using DB::GetIntProperty;
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) override {
+    return false;
+  }
  using DB::GetApproximateSizes;
  virtual void GetApproximateSizes(ColumnFamilyHandle* column_family,
                                   const Range* range, int n, uint64_t* sizes) {
@@ -6360,7 +6664,8 @@ class ModelDB: public DB {
  using DB::CompactRange;
  virtual Status CompactRange(ColumnFamilyHandle* column_family,
                              const Slice* start, const Slice* end,
-                              bool reduce_level, int target_level) {
+                              bool reduce_level, int target_level,
+                              uint32_t output_path_id) {
    return Status::NotSupported("Not supported operation.");
  }

@@ -6454,7 +6759,14 @@ class ModelDB: public DB {
      iter_ = map_->lower_bound(k.ToString());
    }
    virtual void Next() { ++iter_; }
-    virtual void Prev() { --iter_; }
+    virtual void Prev() {
+      if (iter_ == map_->begin()) {
+        iter_ = map_->end();
+        return;
+      }
+      --iter_;
+    }
+
    virtual Slice key() const { return iter_->first; }
    virtual Slice value() const { return iter_->second; }
    virtual Status status() const { return Status::OK(); }
@@ -6582,8 +6894,14 @@ TEST(DBTest, Randomized) {
      }

      if ((step % 100) == 0) {
-        ASSERT_TRUE(CompareIterators(step, &model, db_, nullptr, nullptr));
-        ASSERT_TRUE(CompareIterators(step, &model, db_, model_snap, db_snap));
+        // For DB instances that use the hash index + block-based table, the
+        // iterator will be invalid right when seeking a non-existent key, right
+        // than return a key that is close to it.
+        if (option_config_ != kBlockBasedTableWithWholeKeyHashIndex &&
+            option_config_ != kBlockBasedTableWithPrefixHashIndex) {
+          ASSERT_TRUE(CompareIterators(step, &model, db_, nullptr, nullptr));
+          ASSERT_TRUE(CompareIterators(step, &model, db_, model_snap, db_snap));
+        }

        // Save a snapshot from each DB this time that we'll use next
        // time we compare things, to make sure the current state is
@@ -6597,12 +6915,18 @@ TEST(DBTest, Randomized) {
        model_snap = model.GetSnapshot();
        db_snap = db_->GetSnapshot();
      }
+
+      if ((step % 2000) == 0) {
+        fprintf(stdout,
+                "DBTest.Randomized, option ID: %d, step: %d out of %d\n",
+                option_config_, step, N);
+      }
    }
    if (model_snap != nullptr) model.ReleaseSnapshot(model_snap);
    if (db_snap != nullptr) db_->ReleaseSnapshot(db_snap);
    // skip cuckoo hash as it does not support snapshot.
-  } while (ChangeOptions(kSkipDeletesFilterFirst |
-                         kSkipNoSeekToLast | kSkipHashCuckoo));
+  } while (ChangeOptions(kSkipDeletesFilterFirst | kSkipNoSeekToLast |
+                         kSkipHashCuckoo));
 }

 TEST(DBTest, MultiGetSimple) {
@@ -6939,6 +7263,41 @@ TEST(DBTest, TailingIteratorIncomplete) {
  ASSERT_TRUE(iter->Valid() || iter->status().IsIncomplete());
 }

+TEST(DBTest, TailingIteratorSeekToSame) {
+  Options options = CurrentOptions();
+  options.compaction_style = kCompactionStyleUniversal;
+  options.write_buffer_size = 1000;
+  CreateAndReopenWithCF({"pikachu"}, &options);
+
+  ReadOptions read_options;
+  read_options.tailing = true;
+
+  const int NROWS = 10000;
+  // Write rows with keys 00000, 00002, 00004 etc.
+  for (int i = 0; i < NROWS; ++i) {
+    char buf[100];
+    snprintf(buf, sizeof(buf), "%05d", 2*i);
+    std::string key(buf);
+    std::string value("value");
+    ASSERT_OK(db_->Put(WriteOptions(), key, value));
+  }
+
+  std::unique_ptr<Iterator> iter(db_->NewIterator(read_options));
+  // Seek to 00001.  We expect to find 00002.
+  std::string start_key = "00001";
+  iter->Seek(start_key);
+  ASSERT_TRUE(iter->Valid());
+
+  std::string found = iter->key().ToString();
+  ASSERT_EQ("00002", found);
+
+  // Now seek to the same key.  The iterator should remain in the same
+  // position.
+  iter->Seek(found);
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ(found, iter->key().ToString());
+}
+
 TEST(DBTest, BlockBasedTablePrefixIndexTest) {
  // create a DB with block prefix index
  BlockBasedTableOptions table_options;
@@ -7159,7 +7518,7 @@ TEST(DBTest, MTRandomTimeoutTest) {

 /*
 * This test is not reliable enough as it heavily depends on disk behavior.
- *
+ */
 TEST(DBTest, RateLimitingTest) {
  Options options = CurrentOptions();
  options.write_buffer_size = 1 << 20;         // 1MB
@@ -7190,7 +7549,7 @@ TEST(DBTest, RateLimitingTest) {

  // # rate limiting with 0.7 x threshold
  options.rate_limiter.reset(
-      NewRateLimiter(static_cast<int64_t>(0.7 * raw_rate)));
+    NewGenericRateLimiter(static_cast<int64_t>(0.7 * raw_rate)));
  env_->bytes_written_ = 0;
  DestroyAndReopen(&options);

@@ -7206,11 +7565,11 @@ TEST(DBTest, RateLimitingTest) {
              env_->bytes_written_);
  double ratio = env_->bytes_written_ * 1000000 / elapsed / raw_rate;
  fprintf(stderr, "write rate ratio = %.2lf, expected 0.7\n", ratio);
-  ASSERT_TRUE(ratio > 0.6 && ratio < 0.8);
+  ASSERT_TRUE(ratio < 0.8);

  // # rate limiting with half of the raw_rate
  options.rate_limiter.reset(
-      NewRateLimiter(static_cast<int64_t>(raw_rate / 2)));
+    NewGenericRateLimiter(static_cast<int64_t>(raw_rate / 2)));
  env_->bytes_written_ = 0;
  DestroyAndReopen(&options);

@@ -7226,9 +7585,8 @@ TEST(DBTest, RateLimitingTest) {
              env_->bytes_written_);
  ratio = env_->bytes_written_ * 1000000 / elapsed / raw_rate;
  fprintf(stderr, "write rate ratio = %.2lf, expected 0.5\n", ratio);
-  ASSERT_TRUE(ratio > 0.4 && ratio < 0.6);
+  ASSERT_TRUE(ratio < 0.6);
 }
-*/

 }  // namespace rocksdb

@@ -9,6 +9,7 @@

 #pragma once
 #include <stdio.h>
+#include <string>
 #include "rocksdb/comparator.h"
 #include "rocksdb/db.h"
 #include "rocksdb/filter_policy.h"
@@ -254,8 +255,38 @@ class IterKey {

  Slice GetKey() const { return Slice(key_, key_size_); }

+  const size_t Size() { return key_size_; }
+
  void Clear() { key_size_ = 0; }

+  // Append "non_shared_data" to its back, from "shared_len"
+  // This function is used in Block::Iter::ParseNextKey
+  // shared_len: bytes in [0, shard_len-1] would be remained
+  // non_shared_data: data to be append, its length must be >= non_shared_len
+  void TrimAppend(const size_t shared_len, const char* non_shared_data,
+                  const size_t non_shared_len) {
+    assert(shared_len <= key_size_);
+
+    size_t total_size = shared_len + non_shared_len;
+    if (total_size <= buf_size_) {
+      key_size_ = total_size;
+    } else {
+      // Need to allocate space, delete previous space
+      char* p = new char[total_size];
+      memcpy(p, key_, shared_len);
+
+      if (key_ != nullptr && key_ != space_) {
+        delete[] key_;
+      }
+
+      key_ = p;
+      key_size_ = total_size;
+      buf_size_ = total_size;
+    }
+
+    memcpy(key_ + shared_len, non_shared_data, non_shared_len);
+  }
+
  void SetKey(const Slice& key) {
    size_t size = key.size();
    EnlargeBufferIfNeeded(size);
@@ -110,6 +110,45 @@ TEST(FormatTest, InternalKeyShortestSuccessor) {
            ShortSuccessor(IKey("\xff\xff", 100, kTypeValue)));
 }

+TEST(FormatTest, IterKeyOperation) {
+  IterKey k;
+  const char p[] = "abcdefghijklmnopqrstuvwxyz";
+  const char q[] = "0123456789";
+
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string(""));
+
+  k.TrimAppend(0, p, 3);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abc"));
+
+  k.TrimAppend(1, p, 3);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("aabc"));
+
+  k.TrimAppend(0, p, 26);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz"));
+
+  k.TrimAppend(26, q, 10);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz0123456789"));
+
+  k.TrimAppend(36, q, 1);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz01234567890"));
+
+  k.TrimAppend(26, q, 1);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz0"));
+
+  // Size going up, memory allocation is triggered
+  k.TrimAppend(27, p, 26);
+  ASSERT_EQ(std::string(k.GetKey().data(), k.GetKey().size()),
+            std::string("abcdefghijklmnopqrstuvwxyz0"
+              "abcdefghijklmnopqrstuvwxyz"));
+}
+
 }  // namespace rocksdb

 int main(int argc, char** argv) {
@@ -14,21 +14,15 @@

 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) {
-}
-
+FileIndexer::FileIndexer(const Comparator* ucmp)
+    : num_levels_(0), ucmp_(ucmp), level_rb_(nullptr) {}

 uint32_t FileIndexer::NumLevelIndex() {
  return next_level_index_.size();
 }

 uint32_t FileIndexer::LevelIndexSize(uint32_t level) {
-  return next_level_index_[level].size();
+  return next_level_index_[level].num_index;
 }

 void FileIndexer::GetNextLevelIndex(
@@ -46,11 +40,13 @@ void FileIndexer::GetNextLevelIndex(
  assert(level < num_levels_ - 1);
  assert(static_cast<int32_t>(file_index) <= level_rb_[level]);

-  const auto& index = next_level_index_[level][file_index];
+  const IndexUnit* index_units = next_level_index_[level].index_units;
+  const auto& index = index_units[file_index];

  if (cmp_smallest < 0) {
-    *left_bound = (level > 0 && file_index > 0) ?
-      next_level_index_[level][file_index - 1].largest_lb : 0;
+    *left_bound = (level > 0 && file_index > 0)
+                      ? index_units[file_index - 1].largest_lb
+                      : 0;
    *right_bound = index.smallest_rb;
  } else if (cmp_smallest == 0) {
    *left_bound = index.smallest_lb;
@@ -73,16 +69,25 @@ void FileIndexer::GetNextLevelIndex(
  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) {
+void FileIndexer::UpdateIndex(Arena* arena, const uint32_t num_levels,
+                              std::vector<FileMetaData*>* const files) {
  if (files == nullptr) {
    return;
  }
+  if (num_levels == 0) {  // uint_32 0-1 would cause bad behavior
+    num_levels_ = num_levels;
+    return;
+  }
+  assert(level_rb_ == nullptr);  // level_rb_ should be init here
+
+  num_levels_ = num_levels;
+  next_level_index_.resize(num_levels);
+
+  char* mem = arena->AllocateAligned(num_levels_ * sizeof(int32_t));
+  level_rb_ = new (mem) int32_t[num_levels_];
+  for (size_t i = 0; i < num_levels_; i++) {
+    level_rb_[i] = -1;
+  }

  // L1 - Ln-1
  for (uint32_t level = 1; level < num_levels_ - 1; ++level) {
@@ -93,55 +98,56 @@ void FileIndexer::UpdateIndex(std::vector<FileMetaData*>* const files) {
    if (upper_size == 0) {
      continue;
    }
-    auto& index = next_level_index_[level];
-    index.resize(upper_size);
+    IndexLevel& index_level = next_level_index_[level];
+    index_level.num_index = upper_size;
+    char* mem = arena->AllocateAligned(upper_size * sizeof(IndexUnit));
+    index_level.index_units = new (mem) IndexUnit[upper_size];

-    CalculateLB(upper_files, lower_files, &index,
-        [this](const FileMetaData* a, const FileMetaData* b) -> int {
+    CalculateLB(
+        upper_files, lower_files, &index_level,
+        [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 {
+        [](IndexUnit* index, int32_t f_idx) { index->smallest_lb = f_idx; });
+    CalculateLB(
+        upper_files, lower_files, &index_level,
+        [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 {
+        [](IndexUnit* index, int32_t f_idx) { index->largest_lb = f_idx; });
+    CalculateRB(
+        upper_files, lower_files, &index_level,
+        [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 {
+        [](IndexUnit* index, int32_t f_idx) { index->smallest_rb = f_idx; });
+    CalculateRB(
+        upper_files, lower_files, &index_level,
+        [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;
-        });
+        [](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,
+void FileIndexer::CalculateLB(
+    const std::vector<FileMetaData*>& upper_files,
+    const std::vector<FileMetaData*>& lower_files, IndexLevel* index_level,
    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;
+
+  IndexUnit* index = index_level->index_units;
  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);
+      set_index(&index[upper_idx], lower_idx);
      ++upper_idx;
      ++lower_idx;
    } else if (cmp > 0) {
@@ -151,7 +157,7 @@ void FileIndexer::CalculateLB(const std::vector<FileMetaData*>& upper_files,
    } else {
      // Lower level's file becomes larger, update the index, and
      // move to the next upper file
-      set_index(&(*index)[upper_idx], lower_idx);
+      set_index(&index[upper_idx], lower_idx);
      ++upper_idx;
    }
  }
@@ -159,25 +165,27 @@ void FileIndexer::CalculateLB(const std::vector<FileMetaData*>& upper_files,
  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);
+    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,
+void FileIndexer::CalculateRB(
+    const std::vector<FileMetaData*>& upper_files,
+    const std::vector<FileMetaData*>& lower_files, IndexLevel* index_level,
    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;
+
+  IndexUnit* index = index_level->index_units;
  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);
+      set_index(&index[upper_idx], lower_idx);
      --upper_idx;
      --lower_idx;
    } else if (cmp < 0) {
@@ -187,14 +195,14 @@ void FileIndexer::CalculateRB(const std::vector<FileMetaData*>& upper_files,
    } 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);
+      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);
+    set_index(&index[upper_idx], -1);
    --upper_idx;
  }
 }
@@ -12,11 +12,15 @@
 #include <functional>
 #include <limits>
 #include <vector>
+#include "util/arena.h"
+#include "util/autovector.h"

 namespace rocksdb {

 class Comparator;
 struct FileMetaData;
+struct FdWithKeyRange;
+struct FileLevel;

 // 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
@@ -36,7 +40,7 @@ struct FileMetaData;
 // naive approach.
 class FileIndexer {
 public:
-  FileIndexer(const uint32_t num_levels, const Comparator* ucmp);
+  explicit FileIndexer(const Comparator* ucmp);

  uint32_t NumLevelIndex();

@@ -50,16 +54,15 @@ class FileIndexer {
    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);
+  void UpdateIndex(Arena* arena, const uint32_t num_levels,
+                   std::vector<FileMetaData*>* const files);

  enum {
    kLevelMaxIndex = std::numeric_limits<int32_t>::max()
  };

 private:
-  const uint32_t num_levels_;
+  uint32_t num_levels_;
  const Comparator* ucmp_;

  struct IndexUnit {
@@ -110,20 +113,28 @@ class FileIndexer {
    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);
+  // Data structure to store IndexUnits in a whole level
+  struct IndexLevel {
+    size_t num_index;
+    IndexUnit* index_units;

-  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);
+    IndexLevel() : num_index(0), index_units(nullptr) {}
+  };

-  std::vector<std::vector<IndexUnit>> next_level_index_;
-  std::vector<int32_t> level_rb_;
+  void CalculateLB(
+      const std::vector<FileMetaData*>& upper_files,
+      const std::vector<FileMetaData*>& lower_files, IndexLevel* index_level,
+      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, IndexLevel* index_level,
+      std::function<int(const FileMetaData*, const FileMetaData*)> cmp_op,
+      std::function<void(IndexUnit*, int32_t)> set_index);
+
+  autovector<IndexLevel> next_level_index_;
+  int32_t* level_rb_;
 };

 }  // namespace rocksdb
@@ -35,16 +35,13 @@ class IntComparator : public Comparator {
  void FindShortSuccessor(std::string* key) const {}
 };

-
 struct FileIndexerTest {
 public:
-  FileIndexerTest() :
-    kNumLevels(4), indexer(kNumLevels, &ucmp),
-    files(new std::vector<FileMetaData*>[kNumLevels]) {
-  }
+  FileIndexerTest()
+      : kNumLevels(4), files(new std::vector<FileMetaData*>[kNumLevels]) {}

  ~FileIndexerTest() {
-    Reset();
+    ClearFiles();
    delete[] files;
  }

@@ -59,14 +56,13 @@ struct FileIndexerTest {
    return InternalKey(Slice(reinterpret_cast<char*>(&v), 8), 0, kTypeValue);
  }

-  void Reset() {
+  void ClearFiles() {
    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,
@@ -74,23 +70,32 @@ struct FileIndexerTest {
      int32_t* right_index) {
    *left_index = 100;
    *right_index = 100;
-    indexer.GetNextLevelIndex(level, file_index, cmp_smallest, cmp_largest,
-        left_index, right_index);
+    indexer->GetNextLevelIndex(level, file_index, cmp_smallest, cmp_largest,
+                               left_index, right_index);
  }

+  int32_t left = 100;
+  int32_t right = 100;
  const uint32_t kNumLevels;
  IntComparator ucmp;
-  FileIndexer indexer;
+  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 0: Empty
+TEST(FileIndexerTest, Empty) {
+  Arena arena;
+  indexer = new FileIndexer(&ucmp);
+  indexer->UpdateIndex(&arena, 0, files);
+  delete indexer;
+}

-  // Case 1: no overlap, files are on the left of next level files
+// Case 1: no overlap, files are on the left of next level files
+TEST(FileIndexerTest, no_overlap_left) {
+  Arena arena;
+  uint32_t kNumLevels = 4;
+  indexer = new FileIndexer(&ucmp);
  // level 1
  AddFile(1, 100, 200);
  AddFile(1, 300, 400);
@@ -103,9 +108,7 @@ TEST(FileIndexerTest, next_level_hint) {
  AddFile(3, 2500, 2600);
  AddFile(3, 2601, 2699);
  AddFile(3, 2700, 2800);
-  indexer.UpdateIndex(files);
-  int32_t left = 100;
-  int32_t right = 100;
+  indexer->UpdateIndex(&arena, kNumLevels, files);
  for (uint32_t level = 1; level < 3; ++level) {
    for (uint32_t f = 0; f < 3; ++f) {
      GetNextLevelIndex(level, f, -1, -1, &left, &right);
@@ -125,12 +128,15 @@ TEST(FileIndexerTest, next_level_hint) {
      ASSERT_EQ(2, right);
    }
  }
+  delete indexer;
+  ClearFiles();
+}

-  // 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));
-  }
+// Case 2: no overlap, files are on the right of next level files
+TEST(FileIndexerTest, no_overlap_right) {
+  Arena arena;
+  uint32_t kNumLevels = 4;
+  indexer = new FileIndexer(&ucmp);
  // level 1
  AddFile(1, 2100, 2200);
  AddFile(1, 2300, 2400);
@@ -143,7 +149,7 @@ TEST(FileIndexerTest, next_level_hint) {
  AddFile(3, 500, 600);
  AddFile(3, 501, 699);
  AddFile(3, 700, 800);
-  indexer.UpdateIndex(files);
+  indexer->UpdateIndex(&arena, kNumLevels, files);
  for (uint32_t level = 1; level < 3; ++level) {
    for (uint32_t f = 0; f < 3; ++f) {
      GetNextLevelIndex(level, f, -1, -1, &left, &right);
@@ -166,11 +172,16 @@ TEST(FileIndexerTest, next_level_hint) {
      ASSERT_EQ(2, right);
    }
  }
+  delete indexer;
+}

-  // Case 3: empty L2
-  Reset();
+// Case 3: empty L2
+TEST(FileIndexerTest, empty_L2) {
+  Arena arena;
+  uint32_t kNumLevels = 4;
+  indexer = new FileIndexer(&ucmp);
  for (uint32_t i = 1; i < kNumLevels; ++i) {
-    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
+    ASSERT_EQ(0U, indexer->LevelIndexSize(i));
  }
  // level 1
  AddFile(1, 2100, 2200);
@@ -180,7 +191,7 @@ TEST(FileIndexerTest, next_level_hint) {
  AddFile(3, 500, 600);
  AddFile(3, 501, 699);
  AddFile(3, 700, 800);
-  indexer.UpdateIndex(files);
+  indexer->UpdateIndex(&arena, kNumLevels, files);
  for (uint32_t f = 0; f < 3; ++f) {
    GetNextLevelIndex(1, f, -1, -1, &left, &right);
    ASSERT_EQ(0, left);
@@ -201,13 +212,14 @@ TEST(FileIndexerTest, next_level_hint) {
    ASSERT_EQ(0, left);
    ASSERT_EQ(-1, right);
  }
+  delete indexer;
+  ClearFiles();
+}

-
-  // Case 4: mixed
-  Reset();
-  for (uint32_t i = 1; i < kNumLevels; ++i) {
-    ASSERT_EQ(0U, indexer.LevelIndexSize(i));
-  }
+// Case 4: mixed
+TEST(FileIndexerTest, mixed) {
+  Arena arena;
+  indexer = new FileIndexer(&ucmp);
  // level 1
  AddFile(1, 100, 200);
  AddFile(1, 250, 400);
@@ -222,7 +234,7 @@ TEST(FileIndexerTest, next_level_hint) {
  AddFile(3, 0, 50);
  AddFile(3, 100, 200);
  AddFile(3, 201, 250);
-  indexer.UpdateIndex(files);
+  indexer->UpdateIndex(&arena, kNumLevels, files);
  // level 1, 0
  GetNextLevelIndex(1, 0, -1, -1, &left, &right);
  ASSERT_EQ(0, left);
@@ -321,6 +333,8 @@ TEST(FileIndexerTest, next_level_hint) {
    ASSERT_EQ(3, left);
    ASSERT_EQ(2, right);
  }
+  delete indexer;
+  ClearFiles();
 }

 }  // namespace rocksdb
@@ -71,14 +71,14 @@ 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) {
+std::string TableFileName(const std::vector<DbPath>& db_paths, uint64_t number,
+                          uint32_t path_id) {
  assert(number > 0);
  std::string path;
  if (path_id >= db_paths.size()) {
-    path = db_paths.back();
+    path = db_paths.back().path;
  } else {
-    path = db_paths[path_id];
+    path = db_paths[path_id].path;
  }
  return MakeTableFileName(path, number);
 }
@@ -58,7 +58,7 @@ 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::vector<std::string> db_paths,
+extern std::string TableFileName(const std::vector<DbPath>& db_paths,
                                 uint64_t number, uint32_t path_id);

 extern std::string FormatFileNumber(uint64_t number, uint32_t path_id);
@@ -108,8 +108,9 @@ TEST(FileNameTest, Construction) {
  ASSERT_EQ(192U, number);
  ASSERT_EQ(kLogFile, type);

-  fname = TableFileName({"bar"}, 200, 0);
-  std::string fname1 = TableFileName({"foo", "bar"}, 200, 1);
+  fname = TableFileName({DbPath("bar", 0)}, 200, 0);
+  std::string fname1 =
+      TableFileName({DbPath("foo", 0), DbPath("bar", 0)}, 200, 1);
  ASSERT_EQ(fname, fname1);
  ASSERT_EQ("bar/", std::string(fname.data(), 4));
  ASSERT_TRUE(ParseFileName(fname.c_str() + 4, &number, &type));
@@ -292,6 +292,9 @@ void ForwardIterator::SeekInternal(const Slice& internal_key,
      prev_key_.SetKey(internal_key);
      is_prev_set_ = true;
    }
+  } else if (current_ && current_ != mutable_iter_) {
+    // current_ is one of immutable iterators, push it back to the heap
+    immutable_min_heap_.push(current_);
  }

  UpdateCurrent();
@@ -7,16 +7,96 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #include "db/internal_stats.h"
-#include "db/column_family.h"
-
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include <vector>
+#include "db/column_family.h"

 namespace rocksdb {

-DBPropertyType GetPropertyType(const Slice& property) {
+namespace {
+const double kMB = 1048576.0;
+const double kGB = kMB * 1024;
+
+void PrintLevelStatsHeader(char* buf, size_t len, const std::string& cf_name) {
+  snprintf(
+      buf, len,
+      "\n** Compaction Stats [%s] **\n"
+      "Level   Files   Size(MB) Score Read(GB)  Rn(GB) Rnp1(GB) "
+      "Write(GB) Wnew(GB) RW-Amp W-Amp Rd(MB/s) Wr(MB/s)  Rn(cnt) "
+      "Rnp1(cnt) Wnp1(cnt) Wnew(cnt)  Comp(sec) Comp(cnt) Avg(sec) "
+      "Stall(sec) Stall(cnt) Avg(ms)\n"
+      "--------------------------------------------------------------------"
+      "--------------------------------------------------------------------"
+      "--------------------------------------------------------------------\n",
+      cf_name.c_str());
+}
+
+void PrintLevelStats(char* buf, size_t len, const std::string& name,
+    int num_files, int being_compacted, double total_file_size, double score,
+    double rw_amp, double w_amp, double stall_us, uint64_t stalls,
+    const InternalStats::CompactionStats& stats) {
+  uint64_t bytes_read = stats.bytes_readn + stats.bytes_readnp1;
+  uint64_t bytes_new = stats.bytes_written - stats.bytes_readnp1;
+  double elapsed = (stats.micros + 1) / 1000000.0;
+
+  snprintf(buf, len,
+    "%4s %5d/%-3d %8.0f %5.1f " /* Level, Files, Size(MB), Score */
+    "%8.1f " /* Read(GB) */
+    "%7.1f " /* Rn(GB) */
+    "%8.1f " /* Rnp1(GB) */
+    "%9.1f " /* Write(GB) */
+    "%8.1f " /* Wnew(GB) */
+    "%6.1f " /* RW-Amp */
+    "%5.1f " /* W-Amp */
+    "%8.1f " /* Rd(MB/s) */
+    "%8.1f " /* Wr(MB/s) */
+    "%8d " /* Rn(cnt) */
+    "%9d " /* Rnp1(cnt) */
+    "%9d " /* Wnp1(cnt) */
+    "%9d " /* Wnew(cnt) */
+    "%10.0f " /* Comp(sec) */
+    "%9d " /* Comp(cnt) */
+    "%8.3f " /* Avg(sec) */
+    "%10.2f " /* Stall(sec) */
+    "%10" PRIu64 " " /* Stall(cnt) */
+    "%7.2f\n" /* Avg(ms) */,
+    name.c_str(), num_files, being_compacted, total_file_size / kMB, score,
+    bytes_read / kGB,
+    stats.bytes_readn / kGB,
+    stats.bytes_readnp1 / kGB,
+    stats.bytes_written / kGB,
+    bytes_new / kGB,
+    rw_amp,
+    w_amp,
+    bytes_read / kMB / elapsed,
+    stats.bytes_written / kMB / elapsed,
+    stats.files_in_leveln,
+    stats.files_in_levelnp1,
+    stats.files_out_levelnp1,
+    stats.files_out_levelnp1 - stats.files_in_levelnp1,
+    stats.micros / 1000000.0,
+    stats.count,
+    stats.count == 0 ? 0 : stats.micros / 1000000.0 / stats.count,
+    stall_us / 1000000.0,
+    stalls,
+    stalls == 0 ? 0 : stall_us / 1000.0 / stalls);
+}
+
+
+}
+
+DBPropertyType GetPropertyType(const Slice& property, bool* is_int_property,
+                               bool* need_out_of_mutex) {
+  assert(is_int_property != nullptr);
+  assert(need_out_of_mutex != nullptr);
  Slice in = property;
  Slice prefix("rocksdb.");
-  if (!in.starts_with(prefix)) return kUnknown;
+  *need_out_of_mutex = false;
+  *is_int_property = false;
+  if (!in.starts_with(prefix)) {
+    return kUnknown;
+  }
  in.remove_prefix(prefix.size());

  if (in.starts_with("num-files-at-level")) {
@@ -25,9 +105,16 @@ DBPropertyType GetPropertyType(const Slice& property) {
    return kLevelStats;
  } else if (in == "stats") {
    return kStats;
+  } else if (in == "cfstats") {
+    return kCFStats;
+  } else if (in == "dbstats") {
+    return kDBStats;
  } else if (in == "sstables") {
    return kSsTables;
-  } else if (in == "num-immutable-mem-table") {
+  }
+
+  *is_int_property = true;
+  if (in == "num-immutable-mem-table") {
    return kNumImmutableMemTable;
  } else if (in == "mem-table-flush-pending") {
    return kMemtableFlushPending;
@@ -41,14 +128,35 @@ DBPropertyType GetPropertyType(const Slice& property) {
    return kNumEntriesInMutableMemtable;
  } else if (in == "num-entries-imm-mem-tables") {
    return kNumEntriesInImmutableMemtable;
+  } else if (in == "estimate-num-keys") {
+    return kEstimatedNumKeys;
+  } else if (in == "estimate-table-readers-mem") {
+    *need_out_of_mutex = true;
+    return kEstimatedUsageByTableReaders;
  }
  return kUnknown;
 }

-bool InternalStats::GetProperty(DBPropertyType property_type,
-                                const Slice& property, std::string* value,
-                                ColumnFamilyData* cfd) {
-  Version* current = cfd->current();
+bool InternalStats::GetIntPropertyOutOfMutex(DBPropertyType property_type,
+                                             Version* version,
+                                             uint64_t* value) const {
+  assert(value != nullptr);
+  if (property_type != kEstimatedUsageByTableReaders) {
+    return false;
+  }
+  if (version == nullptr) {
+    *value = 0;
+  } else {
+    *value = version->GetMemoryUsageByTableReaders();
+  }
+  return true;
+}
+
+bool InternalStats::GetStringProperty(DBPropertyType property_type,
+                                      const Slice& property,
+                                      std::string* value) {
+  assert(value != nullptr);
+  Version* current = cfd_->current();
  Slice in = property;

  switch (property_type) {
@@ -76,294 +184,287 @@ bool InternalStats::GetProperty(DBPropertyType property_type,
      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);
+                 current->NumLevelBytes(level) / kMB);
        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);
+      if (!GetStringProperty(kCFStats, "rocksdb.cfstats", value)) {
+        return false;
      }
-
-      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);
-        }
+      if (!GetStringProperty(kDBStats, "rocksdb.dbstats", value)) {
+        return false;
      }
-
-      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 kCFStats: {
+      DumpCFStats(value);
+      return true;
+    }
+    case kDBStats: {
+      DumpDBStats(value);
      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;
  }
 }

+bool InternalStats::GetIntProperty(DBPropertyType property_type,
+                                   uint64_t* value) const {
+  Version* current = cfd_->current();
+
+  switch (property_type) {
+    case kNumImmutableMemTable:
+      *value = cfd_->imm()->size();
+      return true;
+    case kMemtableFlushPending:
+      // Return number of mem tables that are ready to flush (made immutable)
+      *value = (cfd_->imm()->IsFlushPending() ? 1 : 0);
+      return true;
+    case kCompactionPending:
+      // 1 if the system already determines at least one compacdtion is needed.
+      // 0 otherwise,
+      *value = (current->NeedsCompaction() ? 1 : 0);
+      return true;
+    case kBackgroundErrors:
+      // Accumulated number of  errors in background flushes or compactions.
+      *value = GetBackgroundErrorCount();
+      return true;
+    case kCurSizeActiveMemTable:
+      // Current size of the active memtable
+      *value = cfd_->mem()->ApproximateMemoryUsage();
+      return true;
+    case kNumEntriesInMutableMemtable:
+      // Current size of the active memtable
+      *value = cfd_->mem()->GetNumEntries();
+      return true;
+    case kNumEntriesInImmutableMemtable:
+      // Current size of the active memtable
+      *value = cfd_->imm()->current()->GetTotalNumEntries();
+      return true;
+    case kEstimatedNumKeys:
+      // Estimate number of entries in the column family:
+      // Use estimated entries in tables + total entries in memtables.
+      *value = cfd_->mem()->GetNumEntries() +
+               cfd_->imm()->current()->GetTotalNumEntries() +
+               current->GetEstimatedActiveKeys();
+      return true;
+    default:
+      return false;
+  }
+}
+
+void InternalStats::DumpDBStats(std::string* value) {
+  char buf[1000];
+  // DB-level stats, only available from default column family
+  double seconds_up = (env_->NowMicros() - started_at_ + 1) / 1000000.0;
+  double interval_seconds_up = seconds_up - db_stats_snapshot_.seconds_up;
+  snprintf(buf, sizeof(buf),
+           "\n** DB Stats **\nUptime(secs): %.1f total, %.1f interval\n",
+           seconds_up, interval_seconds_up);
+  value->append(buf);
+  // Cumulative
+  uint64_t user_bytes_written = db_stats_[InternalStats::BYTES_WRITTEN];
+  uint64_t write_other = db_stats_[InternalStats::WRITE_DONE_BY_OTHER];
+  uint64_t write_self = db_stats_[InternalStats::WRITE_DONE_BY_SELF];
+  uint64_t wal_bytes = db_stats_[InternalStats::WAL_FILE_BYTES];
+  uint64_t wal_synced = db_stats_[InternalStats::WAL_FILE_SYNCED];
+  uint64_t write_with_wal = db_stats_[InternalStats::WRITE_WITH_WAL];
+  // Data
+  snprintf(buf, sizeof(buf),
+           "Cumulative writes: %" PRIu64 " writes, %" PRIu64 " batches, "
+           "%.1f writes per batch, %.2f GB user ingest\n",
+           write_other + write_self, write_self,
+           (write_other + write_self) / static_cast<double>(write_self + 1),
+           user_bytes_written / kGB);
+  value->append(buf);
+  // WAL
+  snprintf(buf, sizeof(buf),
+           "Cumulative WAL: %" PRIu64 " writes, %" PRIu64 " syncs, "
+           "%.2f writes per sync, %.2f GB written\n",
+           write_with_wal, wal_synced,
+           write_with_wal / static_cast<double>(wal_synced + 1),
+           wal_bytes / kGB);
+  value->append(buf);
+
+  // Interval
+  uint64_t interval_write_other = write_other - db_stats_snapshot_.write_other;
+  uint64_t interval_write_self = write_self - db_stats_snapshot_.write_self;
+  snprintf(buf, sizeof(buf),
+           "Interval writes: %" PRIu64 " writes, %" PRIu64 " batches, "
+           "%.1f writes per batch, %.1f MB user ingest\n",
+           interval_write_other + interval_write_self,
+           interval_write_self,
+           static_cast<double>(interval_write_other + interval_write_self) /
+               (interval_write_self + 1),
+           (user_bytes_written - db_stats_snapshot_.ingest_bytes) / kMB);
+  value->append(buf);
+
+  uint64_t interval_write_with_wal =
+      write_with_wal - db_stats_snapshot_.write_with_wal;
+  uint64_t interval_wal_synced = wal_synced - db_stats_snapshot_.wal_synced;
+  uint64_t interval_wal_bytes = wal_bytes - db_stats_snapshot_.wal_bytes;
+
+  snprintf(buf, sizeof(buf),
+           "Interval WAL: %" PRIu64 " writes, %" PRIu64 " syncs, "
+           "%.2f writes per sync, %.2f MB written\n",
+           interval_write_with_wal,
+           interval_wal_synced,
+           interval_write_with_wal /
+              static_cast<double>(interval_wal_synced + 1),
+           interval_wal_bytes / kGB);
+  value->append(buf);
+
+  db_stats_snapshot_.seconds_up = seconds_up;
+  db_stats_snapshot_.ingest_bytes = user_bytes_written;
+  db_stats_snapshot_.write_other = write_other;
+  db_stats_snapshot_.write_self = write_self;
+  db_stats_snapshot_.wal_bytes = wal_bytes;
+  db_stats_snapshot_.wal_synced = wal_synced;
+  db_stats_snapshot_.write_with_wal = write_with_wal;
+}
+
+void InternalStats::DumpCFStats(std::string* value) {
+  Version* current = cfd_->current();
+
+  int num_levels_to_check =
+      (cfd_->options()->compaction_style != kCompactionStyleUniversal &&
+       cfd_->options()->compaction_style != kCompactionStyleFIFO)
+          ? current->NumberLevels() - 1
+          : 1;
+  // Compaction scores are sorted base on its value. Restore them to the
+  // level order
+  std::vector<double> compaction_score(number_levels_, 0);
+  for (int i = 0; i < num_levels_to_check; ++i) {
+    compaction_score[current->compaction_level_[i]] =
+      current->compaction_score_[i];
+  }
+  // Count # of files being compacted for each level
+  std::vector<int> files_being_compacted(number_levels_, 0);
+  for (int level = 0; level < num_levels_to_check; ++level) {
+    for (auto* f : current->files_[level]) {
+      if (f->being_compacted) {
+        ++files_being_compacted[level];
+      }
+    }
+  }
+
+  char buf[1000];
+  // Per-ColumnFamily stats
+  PrintLevelStatsHeader(buf, sizeof(buf), cfd_->GetName());
+  value->append(buf);
+
+  CompactionStats stats_sum(0);
+  int total_files = 0;
+  int total_files_being_compacted = 0;
+  double total_file_size = 0;
+  uint64_t total_slowdown_soft = 0;
+  uint64_t total_slowdown_count_soft = 0;
+  uint64_t total_slowdown_hard = 0;
+  uint64_t total_slowdown_count_hard = 0;
+  uint64_t total_stall_count = 0;
+  double total_stall_us = 0;
+  for (int level = 0; level < number_levels_; level++) {
+    int files = current->NumLevelFiles(level);
+    total_files += files;
+    total_files_being_compacted += files_being_compacted[level];
+    if (comp_stats_[level].micros > 0 || files > 0) {
+      uint64_t stalls = level == 0 ?
+        (cf_stats_count_[LEVEL0_SLOWDOWN] +
+         cf_stats_count_[LEVEL0_NUM_FILES] +
+         cf_stats_count_[MEMTABLE_COMPACTION])
+        : (stall_leveln_slowdown_count_soft_[level] +
+           stall_leveln_slowdown_count_hard_[level]);
+
+      double stall_us = level == 0 ?
+         (cf_stats_value_[LEVEL0_SLOWDOWN] +
+          cf_stats_value_[LEVEL0_NUM_FILES] +
+          cf_stats_value_[MEMTABLE_COMPACTION])
+         : (stall_leveln_slowdown_soft_[level] +
+            stall_leveln_slowdown_hard_[level]);
+
+      stats_sum.Add(comp_stats_[level]);
+      total_file_size += current->NumLevelBytes(level);
+      total_stall_us += stall_us;
+      total_stall_count += stalls;
+      total_slowdown_soft += stall_leveln_slowdown_soft_[level];
+      total_slowdown_count_soft += stall_leveln_slowdown_count_soft_[level];
+      total_slowdown_hard += stall_leveln_slowdown_hard_[level];
+      total_slowdown_count_hard += stall_leveln_slowdown_count_hard_[level];
+      int64_t bytes_read = comp_stats_[level].bytes_readn +
+                           comp_stats_[level].bytes_readnp1;
+      double rw_amp = (comp_stats_[level].bytes_readn == 0) ? 0.0
+          : (comp_stats_[level].bytes_written + bytes_read) /
+            static_cast<double>(comp_stats_[level].bytes_readn);
+      double w_amp = (comp_stats_[level].bytes_readn == 0) ? 0.0
+          : comp_stats_[level].bytes_written /
+            static_cast<double>(comp_stats_[level].bytes_readn);
+      PrintLevelStats(buf, sizeof(buf), "L" + std::to_string(level),
+          files, files_being_compacted[level], current->NumLevelBytes(level),
+          compaction_score[level], rw_amp, w_amp, stall_us, stalls,
+          comp_stats_[level]);
+      value->append(buf);
+    }
+  }
+  uint64_t curr_ingest = cf_stats_value_[BYTES_FLUSHED];
+  // Cumulative summary
+  double rw_amp = (stats_sum.bytes_written + stats_sum.bytes_readn +
+      stats_sum.bytes_readnp1) / static_cast<double>(curr_ingest + 1);
+  double w_amp = stats_sum.bytes_written / static_cast<double>(curr_ingest + 1);
+  // Stats summary across levels
+  PrintLevelStats(buf, sizeof(buf), "Sum", total_files,
+      total_files_being_compacted, total_file_size, 0, rw_amp, w_amp,
+      total_stall_us, total_stall_count, stats_sum);
+  value->append(buf);
+  // Interval summary
+  uint64_t interval_ingest =
+      curr_ingest - cf_stats_snapshot_.ingest_bytes + 1;
+  CompactionStats interval_stats(stats_sum);
+  interval_stats.Subtract(cf_stats_snapshot_.comp_stats);
+  rw_amp = (interval_stats.bytes_written +
+      interval_stats.bytes_readn + interval_stats.bytes_readnp1) /
+      static_cast<double>(interval_ingest);
+  w_amp = interval_stats.bytes_written / static_cast<double>(interval_ingest);
+  PrintLevelStats(buf, sizeof(buf), "Int", 0, 0, 0, 0,
+      rw_amp, w_amp, total_stall_us - cf_stats_snapshot_.stall_us,
+      total_stall_count - cf_stats_snapshot_.stall_count, interval_stats);
+  value->append(buf);
+
+  snprintf(buf, sizeof(buf),
+           "Flush(GB): accumulative %.3f, interval %.3f\n",
+           curr_ingest / kGB, interval_ingest / kGB);
+  value->append(buf);
+  snprintf(buf, sizeof(buf),
+           "Stalls(secs): %.3f level0_slowdown, %.3f level0_numfiles, "
+           "%.3f memtable_compaction, %.3f leveln_slowdown_soft, "
+           "%.3f leveln_slowdown_hard\n",
+           cf_stats_value_[LEVEL0_SLOWDOWN] / 1000000.0,
+           cf_stats_value_[LEVEL0_NUM_FILES] / 1000000.0,
+           cf_stats_value_[MEMTABLE_COMPACTION] / 1000000.0,
+           total_slowdown_soft / 1000000.0,
+           total_slowdown_hard / 1000000.0);
+  value->append(buf);
+
+  snprintf(buf, sizeof(buf),
+           "Stalls(count): %" PRIu64 " level0_slowdown, "
+           "%" PRIu64 " level0_numfiles, %" PRIu64 " memtable_compaction, "
+           "%" PRIu64 " leveln_slowdown_soft, "
+           "%" PRIu64 " leveln_slowdown_hard\n",
+           cf_stats_count_[LEVEL0_SLOWDOWN],
+           cf_stats_count_[LEVEL0_NUM_FILES],
+           cf_stats_count_[MEMTABLE_COMPACTION],
+           total_slowdown_count_soft, total_slowdown_count_hard);
+  value->append(buf);
+
+  cf_stats_snapshot_.ingest_bytes = curr_ingest;
+  cf_stats_snapshot_.comp_stats = stats_sum;
+  cf_stats_snapshot_.stall_us = total_stall_us;
+  cf_stats_snapshot_.stall_count = total_stall_count;
+}
+
 }  // namespace rocksdb
@@ -9,8 +9,6 @@
 //

 #pragma once
-#include "rocksdb/statistics.h"
-#include "util/statistics.h"
 #include "db/version_set.h"

 #include <vector>
@@ -23,11 +21,15 @@ namespace rocksdb {
 class MemTableList;
 class DBImpl;

-enum DBPropertyType {
+enum DBPropertyType : uint32_t {
+  kUnknown,
  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
+  kCFStats,          // Return general statitistics of CF
+  kDBStats,          // Return general statitistics of DB
+  kStats,            // Return general statitistics of both DB and CF
  kSsTables,         // Return a human readable string of current SST files
+  kStartIntTypes,    // ---- Dummy value to indicate the start of integer values
  kNumImmutableMemTable,   // Return number of immutable mem tables
  kMemtableFlushPending,   // Return 1 if mem table flushing is pending,
                           // otherwise 0.
@@ -38,45 +40,77 @@ enum DBPropertyType {
                                   // memtable.
  kNumEntriesInImmutableMemtable,  // Return sum of number of entries in all
                                   // the immutable mem tables.
-  kUnknown,
+  kEstimatedNumKeys,  // Estimated total number of keys in the database.
+  kEstimatedUsageByTableReaders,  // Estimated memory by table readers.
 };

-extern DBPropertyType GetPropertyType(const Slice& property);
+extern DBPropertyType GetPropertyType(const Slice& property,
+                                      bool* is_int_property,
+                                      bool* need_out_of_mutex);

 class InternalStats {
 public:
-  enum WriteStallType {
+  enum InternalCFStatsType {
    LEVEL0_SLOWDOWN,
    MEMTABLE_COMPACTION,
    LEVEL0_NUM_FILES,
    WRITE_STALLS_ENUM_MAX,
+    BYTES_FLUSHED,
+    INTERNAL_CF_STATS_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),
+  enum InternalDBStatsType {
+    WAL_FILE_BYTES,
+    WAL_FILE_SYNCED,
+    BYTES_WRITTEN,
+    WRITE_DONE_BY_OTHER,
+    WRITE_DONE_BY_SELF,
+    WRITE_WITH_WAL,
+    INTERNAL_DB_STATS_ENUM_MAX,
+  };
+
+  InternalStats(int num_levels, Env* env, ColumnFamilyData* cfd)
+      : db_stats_(INTERNAL_DB_STATS_ENUM_MAX),
+        cf_stats_value_(INTERNAL_CF_STATS_ENUM_MAX),
+        cf_stats_count_(INTERNAL_CF_STATS_ENUM_MAX),
+        comp_stats_(num_levels),
+        stall_leveln_slowdown_hard_(num_levels),
+        stall_leveln_slowdown_count_hard_(num_levels),
+        stall_leveln_slowdown_soft_(num_levels),
+        stall_leveln_slowdown_count_soft_(num_levels),
        bg_error_count_(0),
        number_levels_(num_levels),
-        statistics_(statistics),
        env_(env),
-        started_at_(env->NowMicros()) {}
+        cfd_(cfd),
+        started_at_(env->NowMicros()) {
+    for (int i = 0; i< INTERNAL_DB_STATS_ENUM_MAX; ++i) {
+      db_stats_[i] = 0;
+    }
+    for (int i = 0; i< INTERNAL_CF_STATS_ENUM_MAX; ++i) {
+      cf_stats_value_[i] = 0;
+      cf_stats_count_[i] = 0;
+    }
+    for (int i = 0; i < num_levels; ++i) {
+      stall_leveln_slowdown_hard_[i] = 0;
+      stall_leveln_slowdown_count_hard_[i] = 0;
+      stall_leveln_slowdown_soft_[i] = 0;
+      stall_leveln_slowdown_count_soft_[i] = 0;
+    }
+  }

-  // Per level compaction stats.  compaction_stats_[level] stores the stats for
+  // Per level compaction stats.  comp_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;
+    uint64_t bytes_readn;

    // Bytes read from level N+1 during compaction between levels N and N+1
-    int64_t bytes_readnp1;
+    uint64_t bytes_readnp1;

    // Total bytes written during compaction between levels N and N+1
-    int64_t bytes_written;
+    uint64_t bytes_written;

    // Files read from level N during compaction between levels N and N+1
    int files_in_leveln;
@@ -90,7 +124,7 @@ class InternalStats {
    // Number of compactions done
    int count;

-    CompactionStats()
+    explicit CompactionStats(int count = 0)
        : micros(0),
          bytes_readn(0),
          bytes_readnp1(0),
@@ -98,7 +132,17 @@ class InternalStats {
          files_in_leveln(0),
          files_in_levelnp1(0),
          files_out_levelnp1(0),
-          count(0) {}
+          count(count) {}
+
+    explicit CompactionStats(const CompactionStats& c)
+        : micros(c.micros),
+          bytes_readn(c.bytes_readn),
+          bytes_readnp1(c.bytes_readnp1),
+          bytes_written(c.bytes_written),
+          files_in_leveln(c.files_in_leveln),
+          files_in_levelnp1(c.files_in_levelnp1),
+          files_out_levelnp1(c.files_out_levelnp1),
+          count(c.count) {}

    void Add(const CompactionStats& c) {
      this->micros += c.micros;
@@ -108,68 +152,109 @@ class InternalStats {
      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;
+      this->count += c.count;
+    }
+
+    void Subtract(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 -= c.count;
    }
  };

  void AddCompactionStats(int level, const CompactionStats& stats) {
-    compaction_stats_[level].Add(stats);
+    comp_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, bool soft) {
+    if (soft) {
+      stall_leveln_slowdown_soft_[level] += micros;
+      ++stall_leveln_slowdown_count_soft_[level];
+    } else {
+      stall_leveln_slowdown_hard_[level] += micros;
+      ++stall_leveln_slowdown_count_hard_[level];
+    }
  }

-  void RecordLevelNSlowdown(int level, uint64_t micros) {
-    stall_leveln_slowdown_[level] += micros;
-    ++stall_leveln_slowdown_count_[level];
+  void AddCFStats(InternalCFStatsType type, uint64_t value) {
+    cf_stats_value_[type] += value;
+    ++cf_stats_count_[type];
+  }
+
+  void AddDBStats(InternalDBStatsType type, uint64_t value) {
+    db_stats_[type] += value;
  }

  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);
+  bool GetStringProperty(DBPropertyType property_type, const Slice& property,
+                         std::string* value);
+
+  bool GetIntProperty(DBPropertyType property_type, uint64_t* value) const;
+
+  bool GetIntPropertyOutOfMutex(DBPropertyType property_type, Version* version,
+                                uint64_t* value) const;

 private:
-  std::vector<CompactionStats> compaction_stats_;
+  void DumpDBStats(std::string* value);
+  void DumpCFStats(std::string* value);
+
+  // Per-DB stats
+  std::vector<uint64_t> db_stats_;
+  // Per-ColumnFamily stats
+  std::vector<uint64_t> cf_stats_value_;
+  std::vector<uint64_t> cf_stats_count_;
+  // Per-ColumnFamily/level compaction stats
+  std::vector<CompactionStats> comp_stats_;
+  // These count the number of microseconds for which MakeRoomForWrite stalls.
+  std::vector<uint64_t> stall_leveln_slowdown_hard_;
+  std::vector<uint64_t> stall_leveln_slowdown_count_hard_;
+  std::vector<uint64_t> stall_leveln_slowdown_soft_;
+  std::vector<uint64_t> stall_leveln_slowdown_count_soft_;

  // 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
+  struct CFStatsSnapshot {
+    // ColumnFamily-level stats
+    CompactionStats comp_stats;
+    uint64_t ingest_bytes;            // Bytes written to L0
+    uint64_t stall_us;                // Stall time in micro-seconds
+    uint64_t stall_count;             // Stall count
+
+    CFStatsSnapshot()
+        : comp_stats(0),
+          ingest_bytes(0),
+          stall_us(0),
+          stall_count(0) {}
+  } cf_stats_snapshot_;
+
+  struct DBStatsSnapshot {
+    // DB-level stats
+    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_;
+    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_;
+    DBStatsSnapshot()
+        : ingest_bytes(0),
+          wal_bytes(0),
+          wal_synced(0),
+          write_with_wal(0),
+          write_other(0),
+          write_self(0),
+          seconds_up(0) {}
+  } db_stats_snapshot_;

  // Total number of background errors encountered. Every time a flush task
  // or compaction task fails, this counter is incremented. The failure can
@@ -178,10 +263,10 @@ class InternalStats {
  // or compaction will cause the counter to increase too.
  uint64_t bg_error_count_;

-  int number_levels_;
-  Statistics* statistics_;
+  const int number_levels_;
  Env* env_;
-  uint64_t started_at_;
+  ColumnFamilyData* cfd_;
+  const uint64_t started_at_;
 };

 }  // namespace rocksdb
@@ -42,6 +42,11 @@ void BM_LogAndApply(int iters, int num_base_files) {

    Options options;
    EnvOptions sopt;
+    // Notice we are using the default options not through SanitizeOptions().
+    // We might want to initialize some options manually if needed.
+    options.db_paths.emplace_back(dbname, 0);
+    // The parameter of table cache is passed in as null, so any file I/O
+    // operation is likely to fail.
    vset = new VersionSet(dbname, &options, sopt, nullptr);
    std::vector<ColumnFamilyDescriptor> dummy;
    dummy.push_back(ColumnFamilyDescriptor());
@@ -390,6 +390,16 @@ static bool SaveValue(void* arg, const char* entry) {
        return false;
      }
      case kTypeMerge: {
+        if (!merge_operator) {
+          *(s->status) = Status::InvalidArgument(
+              "merge_operator is not properly initialized.");
+          // Normally we continue the loop (return true) when we see a merge
+          // operand.  But in case of an error, we should stop the loop
+          // immediately and pretend we have found the value to stop further
+          // seek.  Otherwise, the later call will override this error status.
+          *(s->found_final_value) = true;
+          return false;
+        }
        std::string merge_result;  // temporary area for merge results later
        Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
        *(s->merge_in_progress) = true;
@@ -24,10 +24,12 @@ void MergeHelper::MergeUntil(Iterator* iter, SequenceNumber stop_before,
                             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.
+  assert(HasOperator());
  keys_.clear();
  operands_.clear();
  keys_.push_front(iter->key().ToString());
  operands_.push_front(iter->value().ToString());
+  assert(user_merge_operator_);

  success_ = false;   // Will become true if we hit Put/Delete or bottom

@@ -78,13 +78,16 @@ class MergeHelper {
  //   IMPORTANT 2: The entries were traversed in order from BACK to FRONT.
  //                So keys().back() was the first key seen by iterator.
  // TODO: Re-style this comment to be like the first one
-  bool IsSuccess() { return success_; }
-  Slice key() { assert(success_); return Slice(keys_.back()); }
-  Slice value() { assert(success_); return Slice(operands_.back()); }
-  const std::deque<std::string>& keys() { assert(!success_); return keys_; }
-  const std::deque<std::string>& values() {
+  bool IsSuccess() const { return success_; }
+  Slice key() const { assert(success_); return Slice(keys_.back()); }
+  Slice value() const { assert(success_); return Slice(operands_.back()); }
+  const std::deque<std::string>& keys() const {
+    assert(!success_); return keys_;
+  }
+  const std::deque<std::string>& values() const {
    assert(!success_); return operands_;
  }
+  bool HasOperator() const { return user_merge_operator_ != nullptr; }

 private:
  const Comparator* user_comparator_;
@@ -12,12 +12,12 @@
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "rocksdb/merge_operator.h"
+#include "rocksdb/utilities/db_ttl.h"
 #include "db/dbformat.h"
 #include "db/db_impl.h"
 #include "db/write_batch_internal.h"
 #include "utilities/merge_operators.h"
 #include "util/testharness.h"
-#include "utilities/db_ttl.h"

 using namespace std;
 using namespace rocksdb;
@@ -212,7 +212,7 @@ class Counters {
  void assert_add(const string& key, uint64_t value) {
    int result = add(key, value);
    assert(result);
-    if (result == 0) exit(1); // Disable unused variable warning. 
+    if (result == 0) exit(1); // Disable unused variable warning.
  }
 };

@@ -460,6 +460,41 @@ void runTest(int argc, const string& dbname, const bool use_ttl = false) {
      }
    }
  }
+
+  {
+    cout << "Test merge-operator not set after reopen\n";
+    {
+      auto db = OpenDb(dbname);
+      MergeBasedCounters counters(db, 0);
+      counters.add("test-key", 1);
+      counters.add("test-key", 1);
+      counters.add("test-key", 1);
+      db->CompactRange(nullptr, nullptr);
+    }
+
+    DB* reopen_db;
+    ASSERT_OK(DB::Open(Options(), dbname, &reopen_db));
+    std::string value;
+    ASSERT_TRUE(!(reopen_db->Get(ReadOptions(), "test-key", &value).ok()));
+    delete reopen_db;
+    DestroyDB(dbname, Options());
+  }
+
+  /* Temporary remove this test
+  {
+    cout << "Test merge-operator not set after reopen (recovery case)\n";
+    {
+      auto db = OpenDb(dbname);
+      MergeBasedCounters counters(db, 0);
+      counters.add("test-key", 1);
+      counters.add("test-key", 1);
+      counters.add("test-key", 1);
+    }
+
+    DB* reopen_db;
+    ASSERT_TRUE(DB::Open(Options(), dbname, &reopen_db).IsInvalidArgument());
+  }
+  */
 }
 }  // namespace

@@ -23,6 +23,7 @@
 #include "rocksdb/slice_transform.h"
 #include "rocksdb/table.h"
 #include "table/meta_blocks.h"
+#include "table/bloom_block.h"
 #include "table/plain_table_factory.h"
 #include "table/plain_table_reader.h"
 #include "util/hash.h"
@@ -61,8 +62,20 @@ class PlainTableDBTest {
  // 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));
+
+    PlainTableOptions plain_table_options;
+    plain_table_options.user_key_len = 0;
+    plain_table_options.bloom_bits_per_key = 2;
+    plain_table_options.hash_table_ratio = 0.8;
+    plain_table_options.index_sparseness = 3;
+    plain_table_options.huge_page_tlb_size = 0;
+    plain_table_options.encoding_type = kPrefix;
+    plain_table_options.full_scan_mode = false;
+    plain_table_options.store_index_in_file = false;
+
+    options.table_factory.reset(NewPlainTableFactory(plain_table_options));
+    options.memtable_factory.reset(NewHashLinkListRepFactory(4, 0, 3, true));
+
    options.prefix_extractor.reset(NewFixedPrefixTransform(8));
    options.allow_mmap_reads = true;
    return options;
@@ -175,6 +188,8 @@ TEST(PlainTableDBTest, Empty) {
  ASSERT_EQ("NOT_FOUND", Get("0000000000000foo"));
 }

+extern const uint64_t kPlainTableMagicNumber;
+
 class TestPlainTableReader : public PlainTableReader {
 public:
  TestPlainTableReader(const EnvOptions& storage_options,
@@ -184,7 +199,8 @@ class TestPlainTableReader : public PlainTableReader {
                       size_t index_sparseness,
                       const TableProperties* table_properties,
                       unique_ptr<RandomAccessFile>&& file,
-                       const Options& options, bool* expect_bloom_not_match)
+                       const Options& options, bool* expect_bloom_not_match,
+                       bool store_index_in_file)
      : PlainTableReader(options, std::move(file), storage_options, icomparator,
                         encoding_type, file_size, table_properties),
        expect_bloom_not_match_(expect_bloom_not_match) {
@@ -195,6 +211,19 @@ class TestPlainTableReader : public PlainTableReader {
                      bloom_bits_per_key, hash_table_ratio, index_sparseness,
                      2 * 1024 * 1024);
    ASSERT_TRUE(s.ok());
+
+    TableProperties* props = const_cast<TableProperties*>(table_properties);
+    if (store_index_in_file) {
+      auto bloom_version_ptr = props->user_collected_properties.find(
+          PlainTablePropertyNames::kBloomVersion);
+      ASSERT_TRUE(bloom_version_ptr != props->user_collected_properties.end());
+      ASSERT_EQ(bloom_version_ptr->second, std::string("1"));
+      if (options.bloom_locality > 0) {
+        auto num_blocks_ptr = props->user_collected_properties.find(
+            PlainTablePropertyNames::kNumBloomBlocks);
+        ASSERT_TRUE(num_blocks_ptr != props->user_collected_properties.end());
+      }
+    }
  }

  virtual ~TestPlainTableReader() {}
@@ -202,7 +231,11 @@ class TestPlainTableReader : public PlainTableReader {
 private:
  virtual bool MatchBloom(uint32_t hash) const override {
    bool ret = PlainTableReader::MatchBloom(hash);
-    ASSERT_TRUE(!*expect_bloom_not_match_ || !ret);
+    if (*expect_bloom_not_match_) {
+      ASSERT_TRUE(!ret);
+    } else {
+      ASSERT_TRUE(ret);
+    }
    return ret;
  }
  bool* expect_bloom_not_match_;
@@ -212,16 +245,12 @@ 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),
+                                 const PlainTableOptions& options)
+      : PlainTableFactory(options),
+        bloom_bits_per_key_(options.bloom_bits_per_key),
+        hash_table_ratio_(options.hash_table_ratio),
+        index_sparseness_(options.index_sparseness),
+        store_index_in_file_(options.store_index_in_file),
        expect_bloom_not_match_(expect_bloom_not_match) {}

  Status NewTableReader(const Options& options, const EnvOptions& soptions,
@@ -233,6 +262,20 @@ class TestPlainTableFactory : public PlainTableFactory {
                                 options.env, options.info_log.get(), &props);
    ASSERT_TRUE(s.ok());

+    if (store_index_in_file_) {
+      BlockHandle bloom_block_handle;
+      s = FindMetaBlock(file.get(), file_size, kPlainTableMagicNumber,
+                        options.env, BloomBlockBuilder::kBloomBlock,
+                        &bloom_block_handle);
+      ASSERT_TRUE(s.ok());
+
+      BlockHandle index_block_handle;
+      s = FindMetaBlock(
+          file.get(), file_size, kPlainTableMagicNumber, options.env,
+          PlainTableIndexBuilder::kPlainTableIndexBlock, &index_block_handle);
+      ASSERT_TRUE(s.ok());
+    }
+
    auto& user_props = props->user_collected_properties;
    auto encoding_type_prop =
        user_props.find(PlainTablePropertyNames::kEncodingType);
@@ -243,7 +286,8 @@ class TestPlainTableFactory : public PlainTableFactory {
    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_));
+        std::move(file), options, expect_bloom_not_match_,
+        store_index_in_file_));

    *table = std::move(new_reader);
    return s;
@@ -253,6 +297,7 @@ class TestPlainTableFactory : public PlainTableFactory {
  int bloom_bits_per_key_;
  double hash_table_ratio_;
  size_t index_sparseness_;
+  bool store_index_in_file_;
  bool* expect_bloom_not_match_;
 };

@@ -262,40 +307,84 @@ TEST(PlainTableDBTest, Flush) {
    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));
+        for (int store_index_in_file = 0; store_index_in_file <= 1;
+             ++store_index_in_file) {
+          if (!bloom_bits && store_index_in_file) {
+            continue;
+          }
+
+          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();
+
+            PlainTableOptions plain_table_options;
+            plain_table_options.user_key_len = 0;
+            plain_table_options.bloom_bits_per_key = bloom_bits;
+            plain_table_options.hash_table_ratio = 0;
+            plain_table_options.index_sparseness = 2;
+            plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+            plain_table_options.encoding_type = encoding_type;
+            plain_table_options.full_scan_mode = false;
+            plain_table_options.store_index_in_file = store_index_in_file;
+
+            options.table_factory.reset(
+                NewPlainTableFactory(plain_table_options));
+          } else {
+            PlainTableOptions plain_table_options;
+            plain_table_options.user_key_len = 0;
+            plain_table_options.bloom_bits_per_key = bloom_bits;
+            plain_table_options.hash_table_ratio = 0.75;
+            plain_table_options.index_sparseness = 16;
+            plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+            plain_table_options.encoding_type = encoding_type;
+            plain_table_options.full_scan_mode = false;
+            plain_table_options.store_index_in_file = store_index_in_file;
+
+            options.table_factory.reset(
+                NewPlainTableFactory(plain_table_options));
+          }
+          DestroyAndReopen(&options);
+          uint64_t int_num;
+          ASSERT_TRUE(dbfull()->GetIntProperty(
+              "rocksdb.estimate-table-readers-mem", &int_num));
+          ASSERT_EQ(int_num, 0U);
+
+          ASSERT_OK(Put("1000000000000foo", "v1"));
+          ASSERT_OK(Put("0000000000000bar", "v2"));
+          ASSERT_OK(Put("1000000000000foo", "v3"));
+          dbfull()->TEST_FlushMemTable();
+
+          ASSERT_TRUE(dbfull()->GetIntProperty(
+              "rocksdb.estimate-table-readers-mem", &int_num));
+          ASSERT_GT(int_num, 0U);
+
+          TablePropertiesCollection ptc;
+          reinterpret_cast<DB*>(dbfull())->GetPropertiesOfAllTables(&ptc);
+          ASSERT_EQ(1U, ptc.size());
+          auto row = ptc.begin();
+          auto tp = row->second;
+
+          if (!store_index_in_file) {
+            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"));
+          } else {
+            ASSERT_EQ("0", (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"));
+        }
        }
-        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"));
      }
    }
-    }
  }
 }

@@ -305,7 +394,15 @@ TEST(PlainTableDBTest, Flush2) {
    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) {
+        for (int store_index_in_file = 0; store_index_in_file <= 1;
+             ++store_index_in_file) {
+          if (encoding_type == kPrefix && total_order) {
+            continue;
+          }
+          if (!bloom_bits && store_index_in_file) {
+            continue;
+          }
+          if (total_order && store_index_in_file) {
          continue;
        }
        bool expect_bloom_not_match = false;
@@ -313,16 +410,23 @@ TEST(PlainTableDBTest, Flush2) {
        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
+        PlainTableOptions plain_table_options;
        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));
+          plain_table_options.hash_table_ratio = 0;
+          plain_table_options.index_sparseness = 2;
        } else {
-          options.table_factory.reset(new TestPlainTableFactory(
-              &expect_bloom_not_match, 0, bloom_bits, 0.75, 16,
-              huge_page_tlb_size, encoding_type));
+          plain_table_options.hash_table_ratio = 0.75;
+          plain_table_options.index_sparseness = 16;
        }
+        plain_table_options.user_key_len = kPlainTableVariableLength;
+        plain_table_options.bloom_bits_per_key = bloom_bits;
+        plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+        plain_table_options.encoding_type = encoding_type;
+        plain_table_options.store_index_in_file = store_index_in_file;
+        options.table_factory.reset(new TestPlainTableFactory(
+            &expect_bloom_not_match, plain_table_options));
+
        DestroyAndReopen(&options);
        ASSERT_OK(Put("0000000000000bar", "b"));
        ASSERT_OK(Put("1000000000000foo", "v1"));
@@ -350,7 +454,6 @@ TEST(PlainTableDBTest, Flush2) {
          // 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"));
@@ -359,6 +462,7 @@ TEST(PlainTableDBTest, Flush2) {
          expect_bloom_not_match = false;
        }
      }
+      }
    }
    }
  }
@@ -380,13 +484,28 @@ TEST(PlainTableDBTest, Iterator) {
        // Test index interval for the same prefix to be 1, 2 and 4
        if (total_order) {
          options.prefix_extractor = nullptr;
+
+          PlainTableOptions plain_table_options;
+          plain_table_options.user_key_len = 16;
+          plain_table_options.bloom_bits_per_key = bloom_bits;
+          plain_table_options.hash_table_ratio = 0;
+          plain_table_options.index_sparseness = 2;
+          plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+          plain_table_options.encoding_type = encoding_type;
+
          options.table_factory.reset(new TestPlainTableFactory(
-              &expect_bloom_not_match, 16, bloom_bits, 0, 2, huge_page_tlb_size,
-              encoding_type));
+              &expect_bloom_not_match, plain_table_options));
        } else {
+          PlainTableOptions plain_table_options;
+          plain_table_options.user_key_len = 16;
+          plain_table_options.bloom_bits_per_key = bloom_bits;
+          plain_table_options.hash_table_ratio = 0.75;
+          plain_table_options.index_sparseness = 16;
+          plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+          plain_table_options.encoding_type = encoding_type;
+
          options.table_factory.reset(new TestPlainTableFactory(
-              &expect_bloom_not_match, 16, bloom_bits, 0.75, 16,
-              huge_page_tlb_size, encoding_type));
+              &expect_bloom_not_match, plain_table_options));
        }
        DestroyAndReopen(&options);

@@ -485,7 +604,13 @@ std::string MakeLongKey(size_t length, char c) {

 TEST(PlainTableDBTest, IteratorLargeKeys) {
  Options options = CurrentOptions();
-  options.table_factory.reset(NewPlainTableFactory(0, 0, 0));
+
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 0;
+  plain_table_options.bloom_bits_per_key = 0;
+  plain_table_options.hash_table_ratio = 0;
+
+  options.table_factory.reset(NewPlainTableFactory(plain_table_options));
  options.create_if_missing = true;
  options.prefix_extractor.reset();
  DestroyAndReopen(&options);
@@ -529,7 +654,16 @@ std::string MakeLongKeyWithPrefix(size_t length, char c) {

 TEST(PlainTableDBTest, IteratorLargeKeysWithPrefix) {
  Options options = CurrentOptions();
-  options.table_factory.reset(NewPlainTableFactory(16, 0, 0.8, 3, 0, kPrefix));
+
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 16;
+  plain_table_options.bloom_bits_per_key = 0;
+  plain_table_options.hash_table_ratio = 0.8;
+  plain_table_options.index_sparseness = 3;
+  plain_table_options.huge_page_tlb_size = 0;
+  plain_table_options.encoding_type = kPrefix;
+
+  options.table_factory.reset(NewPlainTableFactory(plain_table_options));
  options.create_if_missing = true;
  DestroyAndReopen(&options);

@@ -665,8 +799,16 @@ TEST(PlainTableDBTest, HashBucketConflict) {
      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));
+
+      PlainTableOptions plain_table_options;
+      plain_table_options.user_key_len = 16;
+      plain_table_options.bloom_bits_per_key = 0;
+      plain_table_options.hash_table_ratio = 0;
+      plain_table_options.index_sparseness = 2 ^ i;
+      plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+
+      options.table_factory.reset(NewPlainTableFactory(plain_table_options));
+
      DestroyAndReopen(&options);
      ASSERT_OK(Put("5000000000000fo0", "v1"));
      ASSERT_OK(Put("5000000000000fo1", "v2"));
@@ -752,8 +894,15 @@ TEST(PlainTableDBTest, HashBucketConflictReverseSuffixComparator) {
      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));
+
+      PlainTableOptions plain_table_options;
+      plain_table_options.user_key_len = 16;
+      plain_table_options.bloom_bits_per_key = 0;
+      plain_table_options.hash_table_ratio = 0;
+      plain_table_options.index_sparseness = 2 ^ i;
+      plain_table_options.huge_page_tlb_size = huge_page_tlb_size;
+
+      options.table_factory.reset(NewPlainTableFactory(plain_table_options));
      DestroyAndReopen(&options);
      ASSERT_OK(Put("5000000000000fo0", "v1"));
      ASSERT_OK(Put("5000000000000fo1", "v2"));
@@ -833,7 +982,13 @@ TEST(PlainTableDBTest, NonExistingKeyToNonEmptyBucket) {
  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));
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 16;
+  plain_table_options.bloom_bits_per_key = 0;
+  plain_table_options.hash_table_ratio = 0;
+  plain_table_options.index_sparseness = 5;
+
+  options.table_factory.reset(NewPlainTableFactory(plain_table_options));
  DestroyAndReopen(&options);
  ASSERT_OK(Put("5000000000000fo0", "v1"));
  ASSERT_OK(Put("5000000000000fo1", "v2"));
@@ -126,7 +126,8 @@ class Repairer {
    std::vector<std::string> filenames;
    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);
+      Status status =
+          env_->GetChildren(options_.db_paths[path_id].path, &filenames);
      if (!status.ok()) {
        return status;
      }
@@ -92,6 +92,8 @@ public:

  uint64_t ApproximateOffsetOf(const Slice& key) override;

+  virtual size_t ApproximateMemoryUsage() const override { return 0; }
+
  void SetupForCompaction() override;

  std::shared_ptr<const TableProperties> GetTableProperties() const override;
@@ -185,6 +185,29 @@ Status TableCache::GetTableProperties(
  return s;
 }

+size_t TableCache::GetMemoryUsageByTableReader(
+    const EnvOptions& toptions,
+    const InternalKeyComparator& internal_comparator,
+    const FileDescriptor& fd) {
+  Status s;
+  auto table_reader = fd.table_reader;
+  // table already been pre-loaded?
+  if (table_reader) {
+    return table_reader->ApproximateMemoryUsage();
+  }
+
+  Cache::Handle* table_handle = nullptr;
+  s = FindTable(toptions, internal_comparator, fd, &table_handle, true);
+  if (!s.ok()) {
+    return 0;
+  }
+  assert(table_handle);
+  auto table = GetTableReaderFromHandle(table_handle);
+  auto ret = table->ApproximateMemoryUsage();
+  ReleaseHandle(table_handle);
+  return ret;
+}
+
 void TableCache::Evict(Cache* cache, uint64_t file_number) {
  cache->Erase(GetSliceForFileNumber(&file_number));
 }
@@ -80,12 +80,19 @@ class TableCache {
                            std::shared_ptr<const TableProperties>* properties,
                            bool no_io = false);

+  // Return total memory usage of the table reader of the file.
+  // 0 of table reader of the file is not loaded.
+  size_t GetMemoryUsageByTableReader(
+      const EnvOptions& toptions,
+      const InternalKeyComparator& internal_comparator,
+      const FileDescriptor& fd);
+
  // Release the handle from a cache
  void ReleaseHandle(Cache::Handle* handle);

 private:
  Env* const env_;
-  const std::vector<std::string> db_paths_;
+  const std::vector<DbPath> db_paths_;
  const Options* options_;
  const EnvOptions& storage_options_;
  Cache* const cache_;
@@ -213,7 +213,14 @@ TEST(TablePropertiesTest, CustomizedTablePropertiesCollector) {
  Options options;
  options.table_properties_collector_factories.emplace_back(
      new RegularKeysStartWithAFactory());
-  options.table_factory = std::make_shared<PlainTableFactory>(8, 8, 0);
+
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 8;
+  plain_table_options.bloom_bits_per_key = 8;
+  plain_table_options.hash_table_ratio = 0;
+
+  options.table_factory =
+      std::make_shared<PlainTableFactory>(plain_table_options);
  test::PlainInternalKeyComparator ikc(options.comparator);
  TestCustomizedTablePropertiesCollector(kPlainTableMagicNumber, true, options,
                                         ikc);
@@ -299,11 +306,15 @@ TEST(TablePropertiesTest, InternalKeyPropertiesCollector) {
      true /* not sanitize */,
      std::make_shared<BlockBasedTableFactory>()
  );
+
+  PlainTableOptions plain_table_options;
+  plain_table_options.user_key_len = 8;
+  plain_table_options.bloom_bits_per_key = 8;
+  plain_table_options.hash_table_ratio = 0;
+
  TestInternalKeyPropertiesCollector(
-      kPlainTableMagicNumber,
-      false /* not sanitize */,
-      std::make_shared<PlainTableFactory>(8, 8, 0)
-  );
+      kPlainTableMagicNumber, false /* not sanitize */,
+      std::make_shared<PlainTableFactory>(plain_table_options));
 }

 }  // namespace rocksdb
@@ -14,6 +14,8 @@
 #include <string>
 #include "rocksdb/cache.h"
 #include "db/dbformat.h"
+#include "util/arena.h"
+#include "util/autovector.h"

 namespace rocksdb {

@@ -40,23 +40,267 @@

 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]->fd.GetFileSize();
+namespace {
+
+// Find File in FileLevel data structure
+// Within an index range defined by left and right
+int FindFileInRange(const InternalKeyComparator& icmp,
+    const FileLevel& file_level,
+    const Slice& key,
+    uint32_t left,
+    uint32_t right) {
+  while (left < right) {
+    uint32_t mid = (left + right) / 2;
+    const FdWithKeyRange& f = file_level.files[mid];
+    if (icmp.InternalKeyComparator::Compare(f.largest_key, 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 sum;
+  return right;
 }

-static 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]->compensated_file_size;
+bool NewestFirstBySeqNo(FileMetaData* a, FileMetaData* b) {
+  if (a->smallest_seqno != b->smallest_seqno) {
+    return a->smallest_seqno > b->smallest_seqno;
  }
-  return sum;
+  if (a->largest_seqno != b->largest_seqno) {
+    return a->largest_seqno > b->largest_seqno;
+  }
+  // Break ties by file number
+  return a->fd.GetNumber() > b->fd.GetNumber();
 }

+bool BySmallestKey(FileMetaData* a, FileMetaData* b,
+                   const InternalKeyComparator* cmp) {
+  int r = cmp->Compare(a->smallest, b->smallest);
+  if (r != 0) {
+    return (r < 0);
+  }
+  // Break ties by file number
+  return (a->fd.GetNumber() < b->fd.GetNumber());
+}
+
+// Class to help choose the next file to search for the particular key.
+// Searches and returns files level by level.
+// We can search level-by-level since entries never hop across
+// levels. Therefore we are guaranteed that if we find data
+// in a smaller level, later levels are irrelevant (unless we
+// are MergeInProgress).
+class FilePicker {
+ public:
+  FilePicker(
+      std::vector<FileMetaData*>* files,
+      const Slice& user_key,
+      const Slice& ikey,
+      autovector<FileLevel>* file_levels,
+      unsigned int num_levels,
+      FileIndexer* file_indexer,
+      const Comparator* user_comparator,
+      const InternalKeyComparator* internal_comparator)
+      : num_levels_(num_levels),
+        curr_level_(-1),
+        search_left_bound_(0),
+        search_right_bound_(FileIndexer::kLevelMaxIndex),
+#ifndef NDEBUG
+        files_(files),
+#endif
+        file_levels_(file_levels),
+        user_key_(user_key),
+        ikey_(ikey),
+        file_indexer_(file_indexer),
+        user_comparator_(user_comparator),
+        internal_comparator_(internal_comparator) {
+    // Setup member variables to search first level.
+    search_ended_ = !PrepareNextLevel();
+    if (!search_ended_) {
+      // Prefetch Level 0 table data to avoid cache miss if possible.
+      for (unsigned int i = 0; i < (*file_levels_)[0].num_files; ++i) {
+        auto* r = (*file_levels_)[0].files[i].fd.table_reader;
+        if (r) {
+          r->Prepare(ikey);
+        }
+      }
+    }
+  }
+
+  FdWithKeyRange* GetNextFile() {
+    while (!search_ended_) {  // Loops over different levels.
+      while (curr_index_in_curr_level_ < curr_file_level_->num_files) {
+        // Loops over all files in current level.
+        FdWithKeyRange* f = &curr_file_level_->files[curr_index_in_curr_level_];
+        int cmp_largest = -1;
+
+        // Do key range filtering of files or/and fractional cascading if:
+        // (1) not all the files are in level 0, or
+        // (2) there are more than 3 Level 0 files
+        // If there are only 3 or less level 0 files in the system, we skip
+        // the key range filtering. In this case, more likely, the system is
+        // highly tuned to minimize number of tables queried by each query,
+        // so it is unlikely that key range filtering is more efficient than
+        // querying the files.
+        if (num_levels_ > 1 || curr_file_level_->num_files > 3) {
+          // Check if key is within a file's range. If search left bound and
+          // right bound point to the same find, we are sure key falls in
+          // range.
+          assert(
+              curr_level_ == 0 ||
+              curr_index_in_curr_level_ == start_index_in_curr_level_ ||
+              user_comparator_->Compare(user_key_,
+                ExtractUserKey(f->smallest_key)) <= 0);
+
+          int cmp_smallest = user_comparator_->Compare(user_key_,
+              ExtractUserKey(f->smallest_key));
+          if (cmp_smallest >= 0) {
+            cmp_largest = user_comparator_->Compare(user_key_,
+                ExtractUserKey(f->largest_key));
+          }
+
+          // Setup file search bound for the next level based on the
+          // comparison results
+          if (curr_level_ > 0) {
+            file_indexer_->GetNextLevelIndex(curr_level_,
+                                            curr_index_in_curr_level_,
+                                            cmp_smallest, cmp_largest,
+                                            &search_left_bound_,
+                                            &search_right_bound_);
+          }
+          // Key falls out of current file's range
+          if (cmp_smallest < 0 || cmp_largest > 0) {
+            if (curr_level_ == 0) {
+              ++curr_index_in_curr_level_;
+              continue;
+            } else {
+              // Search next level.
+              break;
+            }
+          }
+        }
+#ifndef NDEBUG
+        // Sanity check to make sure that the files are correctly sorted
+        if (prev_file_) {
+          if (curr_level_ != 0) {
+            int comp_sign = internal_comparator_->Compare(
+                prev_file_->largest_key, f->smallest_key);
+            assert(comp_sign < 0);
+          } else {
+            // level == 0, the current file cannot be newer than the previous
+            // one. Use compressed data structure, has no attribute seqNo
+            assert(curr_index_in_curr_level_ > 0);
+            assert(!NewestFirstBySeqNo(files_[0][curr_index_in_curr_level_],
+                  files_[0][curr_index_in_curr_level_-1]));
+          }
+        }
+        prev_file_ = f;
+#endif
+        if (curr_level_ > 0 && cmp_largest < 0) {
+          // No more files to search in this level.
+          search_ended_ = !PrepareNextLevel();
+        } else {
+          ++curr_index_in_curr_level_;
+        }
+        return f;
+      }
+      // Start searching next level.
+      search_ended_ = !PrepareNextLevel();
+    }
+    // Search ended.
+    return nullptr;
+  }
+
+ private:
+  unsigned int num_levels_;
+  unsigned int curr_level_;
+  int search_left_bound_;
+  int search_right_bound_;
+#ifndef NDEBUG
+  std::vector<FileMetaData*>* files_;
+#endif
+  autovector<FileLevel>* file_levels_;
+  bool search_ended_;
+  FileLevel* curr_file_level_;
+  unsigned int curr_index_in_curr_level_;
+  unsigned int start_index_in_curr_level_;
+  Slice user_key_;
+  Slice ikey_;
+  FileIndexer* file_indexer_;
+  const Comparator* user_comparator_;
+  const InternalKeyComparator* internal_comparator_;
+#ifndef NDEBUG
+  FdWithKeyRange* prev_file_;
+#endif
+
+  // Setup local variables to search next level.
+  // Returns false if there are no more levels to search.
+  bool PrepareNextLevel() {
+    curr_level_++;
+    while (curr_level_ < num_levels_) {
+      curr_file_level_ = &(*file_levels_)[curr_level_];
+      if (curr_file_level_->num_files == 0) {
+        // When current level is empty, the search bound generated from upper
+        // level must be [0, -1] or [0, FileIndexer::kLevelMaxIndex] if it is
+        // also empty.
+        assert(search_left_bound_ == 0);
+        assert(search_right_bound_ == -1 ||
+               search_right_bound_ == FileIndexer::kLevelMaxIndex);
+        // Since current level is empty, it will need to search all files in
+        // the next level
+        search_left_bound_ = 0;
+        search_right_bound_ = FileIndexer::kLevelMaxIndex;
+        curr_level_++;
+        continue;
+      }
+
+      // Some files may overlap each other. We find
+      // all files that overlap user_key and process them in order from
+      // newest to oldest. In the context of merge-operator, this can occur at
+      // any level. Otherwise, it only occurs at Level-0 (since Put/Deletes
+      // are always compacted into a single entry).
+      int32_t start_index;
+      if (curr_level_ == 0) {
+        // On Level-0, we read through all files to check for overlap.
+        start_index = 0;
+      } else {
+        // On Level-n (n>=1), files are sorted. Binary search to find the
+        // earliest file whose largest key >= ikey. Search left bound and
+        // right bound are used to narrow the range.
+        if (search_left_bound_ == search_right_bound_) {
+          start_index = search_left_bound_;
+        } else if (search_left_bound_ < search_right_bound_) {
+          if (search_right_bound_ == FileIndexer::kLevelMaxIndex) {
+            search_right_bound_ = curr_file_level_->num_files - 1;
+          }
+          start_index = FindFileInRange(*internal_comparator_,
+              *curr_file_level_, ikey_,
+              search_left_bound_, search_right_bound_);
+        } else {
+          // search_left_bound > search_right_bound, key does not exist in
+          // this level. Since no comparision is done in this level, it will
+          // need to search all files in the next level.
+          search_left_bound_ = 0;
+          search_right_bound_ = FileIndexer::kLevelMaxIndex;
+          curr_level_++;
+          continue;
+        }
+      }
+      start_index_in_curr_level_ = start_index;
+      curr_index_in_curr_level_ = start_index;
+#ifndef NDEBUG
+      prev_file_ = nullptr;
+#endif
+      return true;
+    }
+    // curr_level_ = num_levels_. So, no more levels to search.
+    return false;
+  }
+};
+}  // anonymous namespace
+
 Version::~Version() {
  assert(refs_ == 0);

@@ -82,62 +326,42 @@ Version::~Version() {
  delete[] files_;
 }

-int FindFileInRange(const InternalKeyComparator& icmp,
-    const std::vector<FileMetaData*>& files,
-    const Slice& key,
-    uint32_t left,
-    uint32_t right) {
-  while (left < right) {
-    uint32_t mid = (left + right) / 2;
-    const FileMetaData* f = files[mid];
-    if (icmp.InternalKeyComparator::Compare(f->largest.Encode(), 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;
-}
-
-int FindFile(const InternalKeyComparator& icmp,
-             const std::vector<FileMetaData*>& files,
-             const Slice& key) {
-  return FindFileInRange(icmp, files, key, 0, files.size());
-}
-
-// Find File in FileLevel data structure
-// Within an index range defined by left and right
-int FindFileInRange(const InternalKeyComparator& icmp,
-    const FileLevel& file_level,
-    const Slice& key,
-    uint32_t left,
-    uint32_t right) {
-  while (left < right) {
-    uint32_t mid = (left + right) / 2;
-    const FdWithKeyRange& f = file_level.files[mid];
-    if (icmp.InternalKeyComparator::Compare(f.largest_key, 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;
-}
-
 int FindFile(const InternalKeyComparator& icmp,
             const FileLevel& file_level,
             const Slice& key) {
  return FindFileInRange(icmp, file_level, key, 0, file_level.num_files);
 }

+void DoGenerateFileLevel(FileLevel* file_level,
+        const std::vector<FileMetaData*>& files,
+        Arena* arena) {
+  assert(file_level);
+  assert(files.size() >= 0);
+  assert(arena);
+
+  size_t num = files.size();
+  file_level->num_files = num;
+  char* mem = arena->AllocateAligned(num * sizeof(FdWithKeyRange));
+  file_level->files = new (mem)FdWithKeyRange[num];
+
+  for (size_t i = 0; i < num; i++) {
+    Slice smallest_key = files[i]->smallest.Encode();
+    Slice largest_key = files[i]->largest.Encode();
+
+    // Copy key slice to sequential memory
+    size_t smallest_size = smallest_key.size();
+    size_t largest_size = largest_key.size();
+    mem = arena->AllocateAligned(smallest_size + largest_size);
+    memcpy(mem, smallest_key.data(), smallest_size);
+    memcpy(mem + smallest_size, largest_key.data(), largest_size);
+
+    FdWithKeyRange& f = file_level->files[i];
+    f.fd = files[i]->fd;
+    f.smallest_key = Slice(mem, smallest_size);
+    f.largest_key = Slice(mem + smallest_size, largest_size);
+  }
+}
+
 static bool AfterFile(const Comparator* ucmp,
                      const Slice* user_key, const FdWithKeyRange* f) {
  // nullptr user_key occurs before all keys and is therefore never after *f
@@ -152,7 +376,6 @@ static bool BeforeFile(const Comparator* ucmp,
          ucmp->Compare(*user_key, ExtractUserKey(f->smallest_key)) < 0);
 }

-
 bool SomeFileOverlapsRange(
    const InternalKeyComparator& icmp,
    bool disjoint_sorted_files,
@@ -198,21 +421,21 @@ bool SomeFileOverlapsRange(
 class Version::LevelFileNumIterator : public Iterator {
 public:
  LevelFileNumIterator(const InternalKeyComparator& icmp,
-                       const std::vector<FileMetaData*>* flist)
+                       const FileLevel* flevel)
      : icmp_(icmp),
-        flist_(flist),
-        index_(flist->size()),
+        flevel_(flevel),
+        index_(flevel->num_files),
        current_value_(0, 0, 0) {  // Marks as invalid
  }
  virtual bool Valid() const {
-    return index_ < flist_->size();
+    return index_ < flevel_->num_files;
  }
  virtual void Seek(const Slice& target) {
-    index_ = FindFile(icmp_, *flist_, target);
+    index_ = FindFile(icmp_, *flevel_, target);
  }
  virtual void SeekToFirst() { index_ = 0; }
  virtual void SeekToLast() {
-    index_ = flist_->empty() ? 0 : flist_->size() - 1;
+    index_ = (flevel_->num_files == 0) ? 0 : flevel_->num_files - 1;
  }
  virtual void Next() {
    assert(Valid());
@@ -221,26 +444,27 @@ class Version::LevelFileNumIterator : public Iterator {
  virtual void Prev() {
    assert(Valid());
    if (index_ == 0) {
-      index_ = flist_->size();  // Marks as invalid
+      index_ = flevel_->num_files;  // Marks as invalid
    } else {
      index_--;
    }
  }
  Slice key() const {
    assert(Valid());
-    return (*flist_)[index_]->largest.Encode();
+    return flevel_->files[index_].largest_key;
  }
  Slice value() const {
    assert(Valid());
-    auto* file_meta = (*flist_)[index_];
-    current_value_ = file_meta->fd;
+
+    auto file_meta = flevel_->files[index_];
+    current_value_ = file_meta.fd;
    return Slice(reinterpret_cast<const char*>(&current_value_),
                 sizeof(FileDescriptor));
  }
  virtual Status status() const { return Status::OK(); }
 private:
  const InternalKeyComparator icmp_;
-  const std::vector<FileMetaData*>* const flist_;
+  const FileLevel* flevel_;
  uint32_t index_;
  mutable FileDescriptor current_value_;
 };
@@ -325,8 +549,7 @@ Status Version::GetTableProperties(std::shared_ptr<const TableProperties>* tp,
  if (!s.ok()) {
    return s;
  }
-  RecordTick(options->statistics.get(),
-             NUMBER_DIRECT_LOAD_TABLE_PROPERTIES);
+  RecordTick(options->statistics.get(), NUMBER_DIRECT_LOAD_TABLE_PROPERTIES);

  *tp = std::shared_ptr<const TableProperties>(raw_table_properties);
  return s;
@@ -353,25 +576,47 @@ Status Version::GetPropertiesOfAllTables(TablePropertiesCollection* props) {
  return Status::OK();
 }

+size_t Version::GetMemoryUsageByTableReaders() {
+  size_t total_usage = 0;
+  for (auto& file_level : file_levels_) {
+    for (size_t i = 0; i < file_level.num_files; i++) {
+      total_usage += cfd_->table_cache()->GetMemoryUsageByTableReader(
+          vset_->storage_options_, cfd_->internal_comparator(),
+          file_level.files[i].fd);
+    }
+  }
+  return total_usage;
+}
+
+uint64_t Version::GetEstimatedActiveKeys() {
+  // Estimation will be not accurate when:
+  // (1) there is merge keys
+  // (2) keys are directly overwritten
+  // (3) deletion on non-existing keys
+  return num_non_deletions_ - num_deletions_;
+}
+
 void Version::AddIterators(const ReadOptions& read_options,
                           const EnvOptions& soptions,
                           std::vector<Iterator*>* iters) {
  // Merge all level zero files together since they may overlap
-  for (const FileMetaData* file : files_[0]) {
+  for (size_t i = 0; i < file_levels_[0].num_files; i++) {
+    const auto& file = file_levels_[0].files[i];
    iters->push_back(cfd_->table_cache()->NewIterator(
-        read_options, soptions, cfd_->internal_comparator(), file->fd));
+        read_options, soptions, cfd_->internal_comparator(), file.fd));
  }

  // For levels > 0, we can use a concatenating iterator that sequentially
  // walks through the non-overlapping files in the level, opening them
  // lazily.
  for (int level = 1; level < num_levels_; level++) {
-    if (!files_[level].empty()) {
+    if (file_levels_[level].num_files != 0) {
      iters->push_back(NewTwoLevelIterator(new LevelFileIteratorState(
          cfd_->table_cache(), read_options, soptions,
          cfd_->internal_comparator(), false /* for_compaction */,
          cfd_->options()->prefix_extractor != nullptr),
-        new LevelFileNumIterator(cfd_->internal_comparator(), &files_[level])));
+        new LevelFileNumIterator(cfd_->internal_comparator(),
+            &file_levels_[level])));
    }
  }
 }
@@ -380,9 +625,10 @@ void Version::AddIterators(const ReadOptions& read_options,
                           const EnvOptions& soptions,
                           MergeIteratorBuilder* merge_iter_builder) {
  // Merge all level zero files together since they may overlap
-  for (const FileMetaData* file : files_[0]) {
+  for (size_t i = 0; i < file_levels_[0].num_files; i++) {
+    const auto& file = file_levels_[0].files[i];
    merge_iter_builder->AddIterator(cfd_->table_cache()->NewIterator(
-        read_options, soptions, cfd_->internal_comparator(), file->fd, nullptr,
+        read_options, soptions, cfd_->internal_comparator(), file.fd, nullptr,
        false, merge_iter_builder->GetArena()));
  }

@@ -390,20 +636,19 @@ void Version::AddIterators(const ReadOptions& read_options,
  // walks through the non-overlapping files in the level, opening them
  // lazily.
  for (int level = 1; level < num_levels_; level++) {
-    if (!files_[level].empty()) {
+    if (file_levels_[level].num_files != 0) {
      merge_iter_builder->AddIterator(NewTwoLevelIterator(
          new LevelFileIteratorState(
              cfd_->table_cache(), read_options, soptions,
              cfd_->internal_comparator(), false /* for_compaction */,
              cfd_->options()->prefix_extractor != nullptr),
-          new LevelFileNumIterator(cfd_->internal_comparator(), &files_[level]),
-          merge_iter_builder->GetArena()));
+          new LevelFileNumIterator(cfd_->internal_comparator(),
+              &file_levels_[level]), merge_iter_builder->GetArena()));
    }
  }
 }

 // Callback from TableCache::Get()
-namespace {
 enum SaverState {
  kNotFound,
  kFound,
@@ -411,6 +656,8 @@ enum SaverState {
  kCorrupt,
  kMerge // saver contains the current merge result (the operands)
 };
+
+namespace version_set {
 struct Saver {
  SaverState state;
  const Comparator* ucmp;
@@ -423,7 +670,7 @@ struct Saver {
  Logger* logger;
  Statistics* statistics;
 };
-}
+} // namespace version_set

 // Called from TableCache::Get and Table::Get when file/block in which
 // key may  exist are not there in TableCache/BlockCache respectively. In this
@@ -431,7 +678,7 @@ struct Saver {
 // IO to be  certain.Set the status=kFound and value_found=false to let the
 // caller know that key may exist but is not there in memory
 static void MarkKeyMayExist(void* arg) {
-  Saver* s = reinterpret_cast<Saver*>(arg);
+  version_set::Saver* s = reinterpret_cast<version_set::Saver*>(arg);
  s->state = kFound;
  if (s->value_found != nullptr) {
    *(s->value_found) = false;
@@ -440,7 +687,7 @@ static void MarkKeyMayExist(void* arg) {

 static bool SaveValue(void* arg, const ParsedInternalKey& parsed_key,
                      const Slice& v) {
-  Saver* s = reinterpret_cast<Saver*>(arg);
+  version_set::Saver* s = reinterpret_cast<version_set::Saver*>(arg);
  MergeContext* merge_contex = s->merge_context;
  std::string merge_result;  // temporary area for merge results later

@@ -501,36 +748,13 @@ static bool SaveValue(void* arg, const ParsedInternalKey& parsed_key,
  return false;
 }

-namespace {
-bool NewestFirstBySeqNo(FileMetaData* a, FileMetaData* b) {
-  if (a->smallest_seqno != b->smallest_seqno) {
-    return a->smallest_seqno > b->smallest_seqno;
-  }
-  if (a->largest_seqno != b->largest_seqno) {
-    return a->largest_seqno > b->largest_seqno;
-  }
-  // Break ties by file number
-  return a->fd.GetNumber() > b->fd.GetNumber();
-}
-bool BySmallestKey(FileMetaData* a, FileMetaData* b,
-                   const InternalKeyComparator* cmp) {
-  int r = cmp->Compare(a->smallest, b->smallest);
-  if (r != 0) {
-    return (r < 0);
-  }
-  // Break ties by file number
-  return (a->fd.GetNumber() < b->fd.GetNumber());
-}
-}  // anonymous namespace
-
 Version::Version(ColumnFamilyData* cfd, VersionSet* vset,
                 uint64_t version_number)
    : cfd_(cfd),
      internal_comparator_((cfd == nullptr) ? nullptr
                                            : &cfd->internal_comparator()),
-      user_comparator_((cfd == nullptr)
-                           ? nullptr
-                           : internal_comparator_->user_comparator()),
+      user_comparator_(
+          (cfd == nullptr) ? nullptr : internal_comparator_->user_comparator()),
      table_cache_((cfd == nullptr) ? nullptr : cfd->table_cache()),
      merge_operator_((cfd == nullptr) ? nullptr
                                       : cfd->options()->merge_operator.get()),
@@ -540,6 +764,9 @@ Version::Version(ColumnFamilyData* cfd, VersionSet* vset,
      // cfd is nullptr if Version is dummy
      num_levels_(cfd == nullptr ? 0 : cfd->NumberLevels()),
      num_non_empty_levels_(num_levels_),
+      file_indexer_(cfd == nullptr
+                        ? nullptr
+                        : cfd->internal_comparator().user_comparator()),
      vset_(vset),
      next_(this),
      prev_(this),
@@ -550,17 +777,17 @@ Version::Version(ColumnFamilyData* cfd, VersionSet* vset,
      compaction_score_(num_levels_),
      compaction_level_(num_levels_),
      version_number_(version_number),
-      file_indexer_(num_levels_, cfd == nullptr ?  nullptr
-          : cfd->internal_comparator().user_comparator()),
      total_file_size_(0),
      total_raw_key_size_(0),
      total_raw_value_size_(0),
-      num_non_deletions_(0) {
+      num_non_deletions_(0),
+      num_deletions_(0) {
  if (cfd != nullptr && cfd->current() != nullptr) {
      total_file_size_ = cfd->current()->total_file_size_;
      total_raw_key_size_ = cfd->current()->total_raw_key_size_;
      total_raw_value_size_ = cfd->current()->total_raw_value_size_;
      num_non_deletions_ = cfd->current()->num_non_deletions_;
+      num_deletions_ = cfd->current()->num_deletions_;
  }
 }

@@ -574,7 +801,7 @@ void Version::Get(const ReadOptions& options,
  Slice user_key = k.user_key();

  assert(status->ok() || status->IsMergeInProgress());
-  Saver saver;
+  version_set::Saver saver;
  saver.state = status->ok()? kNotFound : kMerge;
  saver.ucmp = user_comparator_;
  saver.user_key = user_key;
@@ -585,169 +812,40 @@ void Version::Get(const ReadOptions& options,
  saver.logger = info_log_;
  saver.statistics = db_statistics_;

-  // We can search level-by-level since entries never hop across
-  // levels. Therefore we are guaranteed that if we find data
-  // in an smaller level, later levels are irrelevant (unless we
-  // are MergeInProgress).
-
-  int32_t search_left_bound = 0;
-  int32_t search_right_bound = FileIndexer::kLevelMaxIndex;
-  for (int level = 0; level < num_non_empty_levels_; ++level) {
-    int num_files = file_levels_[level].num_files;
-    if (num_files == 0) {
-      // When current level is empty, the search bound generated from upper
-      // level must be [0, -1] or [0, FileIndexer::kLevelMaxIndex] if it is
-      // also empty.
-      assert(search_left_bound == 0);
-      assert(search_right_bound == -1 ||
-             search_right_bound == FileIndexer::kLevelMaxIndex);
-      // Since current level is empty, it will need to search all files in the
-      // next level
-      search_left_bound = 0;
-      search_right_bound = FileIndexer::kLevelMaxIndex;
-      continue;
+  FilePicker fp(files_, user_key, ikey, &file_levels_, num_non_empty_levels_,
+      &file_indexer_, user_comparator_, internal_comparator_);
+  FdWithKeyRange* f = fp.GetNextFile();
+  while (f != nullptr) {
+    *status = table_cache_->Get(options, *internal_comparator_, f->fd, ikey,
+                                &saver, SaveValue, MarkKeyMayExist);
+    // TODO: examine the behavior for corrupted key
+    if (!status->ok()) {
+      return;
    }

-    // Prefetch table data to avoid cache miss if possible
-    if (level == 0) {
-      for (int i = 0; i < num_files; ++i) {
-        auto* r = file_levels_[0].files[i].fd.table_reader;
-        if (r) {
-          r->Prepare(ikey);
-        }
-      }
-    }
-
-    // Get the list of files to search in this level
-    FdWithKeyRange* files = file_levels_[level].files;
-
-    // Some files may overlap each other. We find
-    // all files that overlap user_key and process them in order from
-    // newest to oldest. In the context of merge-operator,
-    // this can occur at any level. Otherwise, it only occurs
-    // at Level-0 (since Put/Deletes are always compacted into a single entry).
-    int32_t start_index;
-    if (level == 0) {
-      // On Level-0, we read through all files to check for overlap.
-      start_index = 0;
-    } else {
-      // On Level-n (n>=1), files are sorted. Binary search to find the earliest
-      // file whose largest key >= ikey. Search left bound and right bound are
-      // used to narrow the range.
-      if (search_left_bound == search_right_bound) {
-        start_index = search_left_bound;
-      } else if (search_left_bound < search_right_bound) {
-        if (search_right_bound == FileIndexer::kLevelMaxIndex) {
-          search_right_bound = num_files - 1;
-        }
-        start_index = FindFileInRange(cfd_->internal_comparator(),
-            file_levels_[level], ikey,
-            search_left_bound, search_right_bound);
-      } else {
-        // search_left_bound > search_right_bound, key does not exist in this
-        // level. Since no comparision is done in this level, it will need to
-        // search all files in the next level.
-        search_left_bound = 0;
-        search_right_bound = FileIndexer::kLevelMaxIndex;
-        continue;
-      }
-    }
-    // Traverse each relevant file to find the desired key
-#ifndef NDEBUG
-    FdWithKeyRange* prev_file = nullptr;
-#endif
-
-    for (int32_t i = start_index; i < num_files;) {
-      FdWithKeyRange* f = &files[i];
-      int cmp_largest = -1;
-
-      // Do key range filtering of files or/and fractional cascading if:
-      // (1) not all the files are in level 0, or
-      // (2) there are more than 3 Level 0 files
-      // If there are only 3 or less level 0 files in the system, we skip the
-      // key range filtering. In this case, more likely, the system is highly
-      // tuned to minimize number of tables queried by each query, so it is
-      // unlikely that key range filtering is more efficient than querying the
-      // files.
-      if (num_non_empty_levels_ > 1 || num_files > 3) {
-        // Check if key is within a file's range. If search left bound and right
-        // bound point to the same find, we are sure key falls in range.
-        assert(
-            level == 0 || i == start_index || user_comparator_->Compare(
-                user_key, ExtractUserKey(f->smallest_key)) <= 0);
-
-        int cmp_smallest = user_comparator_->Compare(user_key,
-                                        ExtractUserKey(f->smallest_key));
-        if (cmp_smallest >= 0) {
-          cmp_largest = user_comparator_->Compare(user_key,
-                                        ExtractUserKey(f->largest_key));
-        }
-
-        // Setup file search bound for the next level based on the comparison
-        // results
-        if (level > 0) {
-          file_indexer_.GetNextLevelIndex(level, i, cmp_smallest, cmp_largest,
-                                          &search_left_bound,
-                                          &search_right_bound);
-        }
-        // Key falls out of current file's range
-        if (cmp_smallest < 0 || cmp_largest > 0) {
-          if (level == 0) {
-            ++i;
-            continue;
-          } else {
-            break;
-          }
-        }
-      }
-
-#ifndef NDEBUG
-      // Sanity check to make sure that the files are correctly sorted
-      if (prev_file) {
-        if (level != 0) {
-          int comp_sign = internal_comparator_->Compare(prev_file->largest_key,
-               f->smallest_key);
-          assert(comp_sign < 0);
-        } else {
-          // level == 0, the current file cannot be newer than the previous one.
-          // Use compressed data structure, has no attribute seqNo
-          assert(i > 0);
-          assert(!NewestFirstBySeqNo(files_[0][i], files_[0][i-1]));
-        }
-      }
-      prev_file = f;
-#endif
-      *status = table_cache_->Get(options, *internal_comparator_, f->fd, ikey,
-                                  &saver, SaveValue, MarkKeyMayExist);
-      // TODO: examine the behavior for corrupted key
-      if (!status->ok()) {
+    switch (saver.state) {
+      case kNotFound:
+        break;      // Keep searching in other files
+      case kFound:
        return;
-      }
-
-      switch (saver.state) {
-        case kNotFound:
-          break;      // Keep searching in other files
-        case kFound:
-          return;
-        case kDeleted:
-          *status = Status::NotFound();  // Use empty error message for speed
-          return;
-        case kCorrupt:
-          *status = Status::Corruption("corrupted key for ", user_key);
-          return;
-        case kMerge:
-          break;
-      }
-      if (level > 0 && cmp_largest < 0) {
+      case kDeleted:
+        *status = Status::NotFound();  // Use empty error message for speed
+        return;
+      case kCorrupt:
+        *status = Status::Corruption("corrupted key for ", user_key);
+        return;
+      case kMerge:
        break;
-      } else {
-        ++i;
-      }
    }
+    f = fp.GetNextFile();
  }

-
  if (kMerge == saver.state) {
+    if (!merge_operator_) {
+      *status =  Status::InvalidArgument(
+          "merge_operator is not properly initialized.");
+      return;
+    }
    // merge_operands are in saver and we hit the beginning of the key history
    // do a final merge of nullptr and operands;
    if (merge_operator_->FullMerge(user_key, nullptr,
@@ -767,29 +865,7 @@ void Version::Get(const ReadOptions& options,
 void Version::GenerateFileLevels() {
  file_levels_.resize(num_non_empty_levels_);
  for (int level = 0; level < num_non_empty_levels_; level++) {
-    const auto& files = files_[level];
-    auto& file_level = file_levels_[level];
-
-    size_t num = files.size();
-    file_level.num_files = num;
-    char* mem = arena_.AllocateAligned(num * sizeof(FdWithKeyRange));
-    file_level.files = new (mem)FdWithKeyRange[num];
-
-    for (size_t i = 0; i < files.size(); i++) {
-      Slice smallest_key = files[i]->smallest.Encode();
-      Slice largest_key = files[i]->largest.Encode();
-
-      // Copy key slice to sequential memory
-      size_t smallest_size = smallest_key.size();
-      size_t largest_size = largest_key.size();
-      mem = arena_.AllocateAligned(smallest_size + largest_size);
-      memcpy(mem, smallest_key.data(), smallest_size);
-      memcpy(mem + smallest_size, largest_key.data(), largest_size);
-
-      file_level.files[i].fd = files[i]->fd;
-      file_level.files[i].smallest_key = Slice(mem, smallest_size);
-      file_level.files[i].largest_key = Slice(mem+smallest_size, largest_size);
-    }
+    DoGenerateFileLevel(&file_levels_[level], files_[level], &arena_);
  }
 }

@@ -798,6 +874,7 @@ void Version::PrepareApply(std::vector<uint64_t>& size_being_compacted) {
  ComputeCompactionScore(size_being_compacted);
  UpdateFilesBySize();
  UpdateNumNonEmptyLevels();
+  file_indexer_.UpdateIndex(&arena_, num_non_empty_levels_, files_);
  GenerateFileLevels();
 }

@@ -835,6 +912,7 @@ void Version::UpdateTemporaryStats() {
        total_raw_value_size_ += file_meta->raw_value_size;
        num_non_deletions_ +=
            file_meta->num_entries - file_meta->num_deletions;
+        num_deletions_ += file_meta->num_deletions;
        init_count++;
      }
      total_count++;
@@ -862,13 +940,10 @@ void Version::ComputeCompactionScore(
  double max_score = 0;
  int max_score_level = 0;

-  int num_levels_to_check =
-      (cfd_->options()->compaction_style != kCompactionStyleUniversal &&
-       cfd_->options()->compaction_style != kCompactionStyleFIFO)
-          ? NumberLevels() - 1
-          : 1;
+  int max_input_level =
+      cfd_->compaction_picker()->MaxInputLevel(NumberLevels());

-  for (int level = 0; level < num_levels_to_check; level++) {
+  for (int level = 0; level <= max_input_level; level++) {
    double score;
    if (level == 0) {
      // We treat level-0 specially by bounding the number of files
@@ -1017,12 +1092,10 @@ bool Version::NeedsCompaction() const {
  // ending up with nothing to do. We can improve it later.
  // TODO(sdong): improve this function to be accurate for universal
  //              compactions.
-  int num_levels_to_check =
-      (cfd_->options()->compaction_style != kCompactionStyleUniversal &&
-       cfd_->options()->compaction_style != kCompactionStyleFIFO)
-          ? NumberLevels() - 1
-          : 1;
-  for (int i = 0; i < num_levels_to_check; i++) {
+  int max_input_level =
+      cfd_->compaction_picker()->MaxInputLevel(NumberLevels());
+
+  for (int i = 0; i <= max_input_level; i++) {
    if (compaction_score_[i] >= 1) {
      return true;
    }
@@ -1181,7 +1254,7 @@ void Version::GetOverlappingInputsBinarySearch(
 // The midIndex specifies the index of at least one file that
 // overlaps the specified range. From that file, iterate backward
 // and forward to find all overlapping files.
-// Use compressed file meda data, make search faster
+// Use FileLevel in searching, make it faster
 void Version::ExtendOverlappingInputs(
    int level,
    const Slice& user_begin,
@@ -1615,8 +1688,6 @@ class VersionSet::Builder {
    }

    CheckConsistency(v);
-
-    v->file_indexer_.UpdateIndex(v->files_);
  }

  void LoadTableHandlers() {
@@ -1806,6 +1877,9 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
    // This is fine because everything inside of this block is serialized --
    // only one thread can be here at the same time
    if (new_descriptor_log) {
+      // create manifest file
+      Log(options_->info_log,
+          "Creating manifest %" PRIu64 "\n", pending_manifest_file_number_);
      unique_ptr<WritableFile> descriptor_file;
      s = env_->NewWritableFile(
          DescriptorFileName(dbname_, pending_manifest_file_number_),
@@ -1927,6 +2001,9 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
        column_family_data->GetName().c_str());
    delete v;
    if (new_descriptor_log) {
+      Log(options_->info_log,
+        "Deleting manifest %" PRIu64 " current manifest %" PRIu64 "\n",
+        manifest_file_number_, pending_manifest_file_number_);
      descriptor_log_.reset();
      env_->DeleteFile(
          DescriptorFileName(dbname_, pending_manifest_file_number_));
@@ -2764,16 +2841,19 @@ Iterator* VersionSet::MakeInputIterator(Compaction* c) {
  // Level-0 files have to be merged together.  For other levels,
  // we will make a concatenating iterator per level.
  // TODO(opt): use concatenating iterator for level-0 if there is no overlap
-  const int space = (c->level() == 0 ? c->inputs(0)->size() + 1 : 2);
+  const int space = (c->level() == 0 ?
+      c->input_levels(0)->num_files + c->num_input_levels() - 1:
+      c->num_input_levels());
  Iterator** list = new Iterator*[space];
  int num = 0;
-  for (int which = 0; which < 2; which++) {
-    if (!c->inputs(which)->empty()) {
-      if (c->level() + which == 0) {
-        for (const auto& file : *c->inputs(which)) {
+  for (int which = 0; which < c->num_input_levels(); which++) {
+    if (c->input_levels(which)->num_files != 0) {
+      if (c->level(which) == 0) {
+        const FileLevel* flevel = c->input_levels(which);
+        for (size_t i = 0; i < flevel->num_files; i++) {
          list[num++] = cfd->table_cache()->NewIterator(
              read_options, storage_options_compactions_,
-              cfd->internal_comparator(), file->fd, nullptr,
+              cfd->internal_comparator(), flevel->files[i].fd, nullptr,
              true /* for compaction */);
        }
      } else {
@@ -2783,7 +2863,7 @@ Iterator* VersionSet::MakeInputIterator(Compaction* c) {
              cfd->internal_comparator(), true /* for_compaction */,
              false /* prefix enabled */),
            new Version::LevelFileNumIterator(cfd->internal_comparator(),
-                                              c->inputs(which)));
+                                              c->input_levels(which)));
      }
    }
  }
@@ -2872,10 +2952,10 @@ void VersionSet::GetLiveFilesMetaData(std::vector<LiveFileMetaData>* metadata) {
        filemetadata.column_family_name = cfd->GetName();
        uint32_t path_id = file->fd.GetPathId();
        if (path_id < options_->db_paths.size()) {
-          filemetadata.db_path = options_->db_paths[path_id];
+          filemetadata.db_path = options_->db_paths[path_id].path;
        } else {
          assert(!options_->db_paths.empty());
-          filemetadata.db_path = options_->db_paths.back();
+          filemetadata.db_path = options_->db_paths.back().path;
        }
        filemetadata.name = MakeTableFileName("", file->fd.GetNumber());
        filemetadata.level = level;
@@ -53,14 +53,6 @@ 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.
-// REQUIRES: "files" contains a sorted list of non-overlapping files.
-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
@@ -82,6 +74,13 @@ extern bool SomeFileOverlapsRange(
    const Slice* smallest_user_key,
    const Slice* largest_user_key);

+// Generate FileLevel from vector<FdWithKeyRange*>
+// Would copy smallest_key and largest_key data to sequential memory
+// arena: Arena used to allocate the memory
+extern void DoGenerateFileLevel(FileLevel* file_level,
+        const std::vector<FileMetaData*>& files,
+        Arena* arena);
+
 class Version {
 public:
  // Append to *iters a sequence of iterators that will
@@ -233,6 +232,10 @@ class Version {
  // tables' propertis, represented as shared_ptr.
  Status GetPropertiesOfAllTables(TablePropertiesCollection* props);

+  uint64_t GetEstimatedActiveKeys();
+
+  size_t GetMemoryUsageByTableReaders();
+
  // used to sort files by size
  struct Fsize {
    int index;
@@ -249,6 +252,7 @@ class Version {
  friend class UniversalCompactionPicker;
  friend class FIFOCompactionPicker;
  friend class ForwardIterator;
+  friend class InternalStats;

  class LevelFileNumIterator;
  class LevelFileIteratorState;
@@ -284,6 +288,7 @@ class Version {
  int num_levels_;              // Number of levels
  int num_non_empty_levels_;    // Number of levels. Any level larger than it
                                // is guaranteed to be empty.
+  FileIndexer file_indexer_;
  VersionSet* vset_;            // VersionSet to which this Version belongs
  Arena arena_;                 // Used to allocate space for file_levels_
  Version* next_;               // Next version in linked list
@@ -294,7 +299,6 @@ class Version {
  // 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.
@@ -327,7 +331,6 @@ class Version {
  uint64_t version_number_;

  Version(ColumnFamilyData* cfd, VersionSet* vset, uint64_t version_number = 0);
-  FileIndexer file_indexer_;

  // total file size
  uint64_t total_file_size_;
@@ -337,7 +340,8 @@ class Version {
  uint64_t total_raw_value_size_;
  // total number of non-deletion entries
  uint64_t num_non_deletions_;
-
+  // total number of deletion entries
+  uint64_t num_deletions_;

  ~Version();

@@ -14,14 +14,15 @@

 namespace rocksdb {

-class FindFileTest {
+class GenerateFileLevelTest {
 public:
  std::vector<FileMetaData*> files_;
-  bool disjoint_sorted_files_;
+  FileLevel file_level_;
+  Arena arena_;

-  FindFileTest() : disjoint_sorted_files_(true) { }
+  GenerateFileLevelTest() { }

-  ~FindFileTest() {
+  ~GenerateFileLevelTest() {
    for (unsigned int i = 0; i < files_.size(); i++) {
      delete files_[i];
    }
@@ -37,55 +38,44 @@ class FindFileTest {
    files_.push_back(f);
  }

-  int Find(const char* key) {
-    InternalKey target(key, 100, kTypeValue);
-    InternalKeyComparator cmp(BytewiseComparator());
-    return FindFile(cmp, files_, target.Encode());
+  int Compare() {
+    int diff = 0;
+    for (size_t i = 0; i < files_.size(); i++) {
+      if (file_level_.files[i].fd.GetNumber() != files_[i]->fd.GetNumber()) {
+        diff++;
+      }
+    }
+    return diff;
  }
 };

-TEST(FindFileTest, Empty) {
-  ASSERT_EQ(0, Find("foo"));
+TEST(GenerateFileLevelTest, Empty) {
+  DoGenerateFileLevel(&file_level_, files_, &arena_);
+  ASSERT_EQ(0u, file_level_.num_files);
+  ASSERT_EQ(0, Compare());
 }

-TEST(FindFileTest, Single) {
+TEST(GenerateFileLevelTest, 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"));
+  DoGenerateFileLevel(&file_level_, files_, &arena_);
+  ASSERT_EQ(1u, file_level_.num_files);
+  ASSERT_EQ(0, Compare());
 }


-TEST(FindFileTest, Multiple) {
+TEST(GenerateFileLevelTest, 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"));
+  DoGenerateFileLevel(&file_level_, files_, &arena_);
+  ASSERT_EQ(4u, file_level_.num_files);
+  ASSERT_EQ(0, Compare());
 }

 class FindLevelFileTest {
 public:
-  FileLevel level_files_;
+  FileLevel file_level_;
  bool disjoint_sorted_files_;
  Arena arena_;

@@ -96,8 +86,8 @@ class 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;
+    file_level_.files = new (mem)FdWithKeyRange[num];
+    file_level_.num_files = 0;
  }

  void Add(const char* smallest, const char* largest,
@@ -115,27 +105,27 @@ class FindLevelFileTest {
    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];
+    // add to file_level_
+    size_t num = file_level_.num_files;
+    auto& file = file_level_.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++;
+    file_level_.num_files++;
  }

  int Find(const char* key) {
    InternalKey target(key, 100, kTypeValue);
    InternalKeyComparator cmp(BytewiseComparator());
-    return FindFile(cmp, level_files_, target.Encode());
+    return FindFile(cmp, file_level_, 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_, level_files_,
+    return SomeFileOverlapsRange(cmp, disjoint_sorted_files_, file_level_,
                                 (smallest != nullptr ? &s : nullptr),
                                 (largest != nullptr ? &l : nullptr));
  }
@@ -436,8 +436,8 @@ class MemTableInserter : public WriteBatch::Handler {
          // Failed to merge!
        RecordTick(options->statistics.get(), NUMBER_MERGE_FAILURES);

-          // Store the delta in memtable
-          perform_merge = false;
+        // Store the delta in memtable
+        perform_merge = false;
      } else {
        // 3) Add value to memtable
        mem->Add(sequence_, kTypeValue, key, new_value);
@@ -6,8 +6,8 @@
  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.

-  C bindings for leveldb.  May be useful as a stable ABI that can be
-  used by programs that keep leveldb in a shared library, or for
+  C bindings for rocksdb.  May be useful as a stable ABI that can be
+  used by programs that keep rocksdb in a shared library, or for
  a JNI api.

  Does not support:
@@ -61,6 +61,10 @@ typedef struct rocksdb_compactionfiltercontext_t
    rocksdb_compactionfiltercontext_t;
 typedef struct rocksdb_compactionfilterfactory_t
    rocksdb_compactionfilterfactory_t;
+typedef struct rocksdb_compactionfilterv2_t
+    rocksdb_compactionfilterv2_t;
+typedef struct rocksdb_compactionfilterfactoryv2_t
+    rocksdb_compactionfilterfactoryv2_t;
 typedef struct rocksdb_comparator_t      rocksdb_comparator_t;
 typedef struct rocksdb_env_t             rocksdb_env_t;
 typedef struct rocksdb_fifo_compaction_options_t rocksdb_fifo_compaction_options_t;
@@ -359,11 +363,15 @@ extern void rocksdb_options_set_compaction_filter(
    rocksdb_compactionfilter_t*);
 extern void rocksdb_options_set_compaction_filter_factory(
    rocksdb_options_t*, rocksdb_compactionfilterfactory_t*);
+extern void rocksdb_options_set_compaction_filter_factory_v2(
+    rocksdb_options_t*,
+    rocksdb_compactionfilterfactoryv2_t*);
 extern void rocksdb_options_set_comparator(
    rocksdb_options_t*,
    rocksdb_comparator_t*);
-extern void rocksdb_options_set_merge_operator(rocksdb_options_t*,
-                                               rocksdb_mergeoperator_t*);
+extern void rocksdb_options_set_merge_operator(
+    rocksdb_options_t*,
+    rocksdb_mergeoperator_t*);
 extern void rocksdb_options_set_compression_per_level(
  rocksdb_options_t* opt,
  int* level_values,
@@ -571,6 +579,35 @@ extern rocksdb_compactionfilterfactory_t*
 extern void rocksdb_compactionfilterfactory_destroy(
    rocksdb_compactionfilterfactory_t*);

+/* Compaction Filter V2 */
+
+extern rocksdb_compactionfilterv2_t* rocksdb_compactionfilterv2_create(
+    void* state,
+    void (*destructor)(void*),
+    // num_keys specifies the number of array entries in every *list parameter.
+    // New values added to the new_values_list should be malloc'd and will be
+    // freed by the caller. Specify true in the to_delete_list to remove an
+    // entry during compaction; false to keep it.
+    void (*filter)(
+        void*, int level, size_t num_keys,
+        const char* const* keys_list, const size_t* keys_list_sizes,
+        const char* const* existing_values_list, const size_t* existing_values_list_sizes,
+        char** new_values_list, size_t* new_values_list_sizes,
+        unsigned char* to_delete_list),
+    const char* (*name)(void*));
+extern void rocksdb_compactionfilterv2_destroy(rocksdb_compactionfilterv2_t*);
+
+/* Compaction Filter Factory V2 */
+
+extern rocksdb_compactionfilterfactoryv2_t* rocksdb_compactionfilterfactoryv2_create(
+    void* state,
+    rocksdb_slicetransform_t* prefix_extractor,
+    void (*destructor)(void*),
+    rocksdb_compactionfilterv2_t* (*create_compaction_filter_v2)(
+        void*, const rocksdb_compactionfiltercontext_t* context),
+    const char* (*name)(void*));
+extern void rocksdb_compactionfilterfactoryv2_destroy(rocksdb_compactionfilterfactoryv2_t*);
+
 /* Comparator */

 extern rocksdb_comparator_t* rocksdb_comparator_create(
@@ -160,6 +160,7 @@ class DB {
  virtual Status DropColumnFamily(ColumnFamilyHandle* column_family);

  // Set the database entry for "key" to "value".
+  // If "key" already exists, it will be overwritten.
  // Returns OK on success, and a non-OK status on error.
  // Note: consider setting options.sync = true.
  virtual Status Put(const WriteOptions& options,
@@ -306,6 +307,14 @@ class DB {
    return GetProperty(DefaultColumnFamily(), property, value);
  }

+  // Similar to GetProperty(), but only works for a subset of properties whose
+  // return value is an integer. Return the value by integer.
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) = 0;
+  virtual bool GetIntProperty(const Slice& property, uint64_t* value) {
+    return GetIntProperty(DefaultColumnFamily(), property, value);
+  }
+
  // For each i in [0,n-1], store in "sizes[i]", the approximate
  // file system space used by keys in "[range[i].start .. range[i].limit)".
  //
@@ -338,15 +347,17 @@ class DB {
  // hosting all the files. In this case, client could set reduce_level
  // to true, to move the files back to the minimum level capable of holding
  // the data set or a given level (specified by non-negative target_level).
+  // Compaction outputs should be placed in options.db_paths[target_path_id].
+  // Behavior is undefined if target_path_id is out of range.
  virtual Status CompactRange(ColumnFamilyHandle* column_family,
                              const Slice* begin, const Slice* end,
-                              bool reduce_level = false,
-                              int target_level = -1) = 0;
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0) = 0;
  virtual Status CompactRange(const Slice* begin, const Slice* end,
-                              bool reduce_level = false,
-                              int target_level = -1) {
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0) {
    return CompactRange(DefaultColumnFamily(), begin, end, reduce_level,
-                        target_level);
+                        target_level, target_path_id);
  }

  // Number of levels used for this DB.
@@ -39,7 +39,6 @@ class Slice;
 class SliceTransform;
 class Statistics;
 class InternalKeyComparator;
-class RateLimiter;

 // DB contents are stored in a set of blocks, each of which holds a
 // sequence of key,value pairs.  Each block may be compressed before
@@ -83,6 +82,14 @@ enum UpdateStatus {    // Return status For inplace update callback
  UPDATED         = 2, // No inplace update. Merged value set
 };

+struct DbPath {
+  std::string path;
+  uint64_t target_size;  // Target size of total files under the path, in byte.
+
+  DbPath() : target_size(0) {}
+  DbPath(const std::string& p, uint64_t t) : path(p), target_size(t) {}
+};
+
 struct Options;

 struct ColumnFamilyOptions {
@@ -480,7 +487,9 @@ struct ColumnFamilyOptions {
      TablePropertiesCollectorFactories;
  TablePropertiesCollectorFactories table_properties_collector_factories;

-  // Allows thread-safe inplace updates.
+  // Allows thread-safe inplace updates. If this is true, there is no way to
+  // achieve point-in-time consistency using snapshot or iterator (assuming
+  // concurrent updates).
  // If inplace_callback function is not set,
  //   Put(key, new_value) will update inplace the existing_value iff
  //   * key exists in current memtable
@@ -674,18 +683,34 @@ struct DBOptions {
  // Default: false
  bool use_fsync;

-  // This number controls how often a new scribe log about
-  // db deploy stats is written out.
-  // -1 indicates no logging at all.
-  // Default value is 1800 (half an hour).
+  // This options is not used!!
  int db_stats_log_interval;

-  // A list paths where SST files can be put into. A compaction style can
-  // determine which of those paths it will put the file to.
+  // A list of paths where SST files can be put into, with its target size.
+  // Newer data is placed into paths specified earlier in the vector while
+  // older data gradually moves to paths specified later in the vector.
+  //
+  // For example, you have a flash device with 10GB allocated for the DB,
+  // as well as a hard drive of 2TB, you should config it to be:
+  //   [{"/flash_path", 10GB}, {"/hard_drive", 2TB}]
+  //
+  // The system will try to guarantee data under each path is close to but
+  // not larger than the target size. But current and future file sizes used
+  // by determining where to place a file are based on best-effort estimation,
+  // which means there is a chance that the actual size under the directory
+  // is slightly more than target size under some workloads. User should give
+  // some buffer room for those cases.
+  //
+  // If none of the paths has sufficient room to place a file, the file will
+  // be placed to the last path anyway, despite to the target size.
+  //
+  // Placing newer data to ealier paths is also best-efforts. User should
+  // expect user files to be placed in higher levels in some extreme cases.
+  //
  // If left empty, only one path will be used, which is db_name passed when
  // opening the DB.
  // Default: empty
-  std::vector<std::string> db_paths;
+  std::vector<DbPath> db_paths;

  // This specifies the info LOG dir.
  // If it is empty, the log files will be in the same dir as data.
@@ -1003,21 +1028,16 @@ struct FlushOptions {
  FlushOptions() : wait(true) {}
 };

-
-// Create a RateLimiter object, which can be shared among RocksDB instances to
-// control write rate of flush and compaction.
-// @rate_bytes_per_sec: desired total write rate in bytes per second.
-// @refill_period_us: token refill interval in micro-second.
-// @fairness: RateLimiter accepts high-pri requests and low-pri requests.
-// low-pri request is usually blocked in favor of hi-pri request. To prevent
-// low-pri request from being blocked for too long, it can get processed first
-// by 1/fairness chance.
-extern RateLimiter* NewRateLimiter(
-    int64_t rate_bytes_per_sec,
-    int64_t refill_period_us = 100 * 1000,
-    int32_t fairness = 10);
-
-
+// Get options based on some guidelines. Now only tune parameter based on
+// flush/compaction and fill default parameters for other parameters.
+// total_write_buffer_limit: budget for memory spent for mem tables
+// read_amplification_threshold: comfortable value of read amplification
+// write_amplification_threshold: comfortable value of write amplification.
+// target_db_size: estimated total DB size.
+extern Options GetOptions(size_t total_write_buffer_limit,
+                          int read_amplification_threshold = 8,
+                          int write_amplification_threshold = 32,
+                          uint64_t target_db_size = 68719476736 /* 64GB */);
 }  // namespace rocksdb

 #endif  // STORAGE_ROCKSDB_INCLUDE_OPTIONS_H_
@@ -0,0 +1,60 @@
+//  Copyright (c) 2014, 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/env.h"
+
+namespace rocksdb {
+
+class RateLimiter {
+ public:
+  virtual ~RateLimiter() {}
+
+  // Request for token to write bytes. If this request can not be satisfied,
+  // the call is blocked. Caller is responsible to make sure
+  // bytes < GetSingleBurstBytes()
+  virtual void Request(const int64_t bytes, const Env::IOPriority pri) = 0;
+
+  // Max bytes can be granted in a single burst
+  virtual int64_t GetSingleBurstBytes() const = 0;
+
+  // Total bytes that go though rate limiter
+  virtual int64_t GetTotalBytesThrough(
+      const Env::IOPriority pri = Env::IO_TOTAL) const = 0;
+
+  // Total # of requests that go though rate limiter
+  virtual int64_t GetTotalRequests(
+      const Env::IOPriority pri = Env::IO_TOTAL) const = 0;
+};
+
+// Create a RateLimiter object, which can be shared among RocksDB instances to
+// control write rate of flush and compaction.
+// @rate_bytes_per_sec: this is the only parameter you want to set most of the
+// time. It controls the total write rate of compaction and flush in bytes per
+// second. Currently, RocksDB does not enforce rate limit for anything other
+// than flush and compaction, e.g. write to WAL.
+// @refill_period_us: this controls how often tokens are refilled. For example,
+// when rate_bytes_per_sec is set to 10MB/s and refill_period_us is set to
+// 100ms, then 1MB is refilled every 100ms internally. Larger value can lead to
+// burstier writes while smaller value introduces more CPU overhead.
+// The default should work for most cases.
+// @fairness: RateLimiter accepts high-pri requests and low-pri requests.
+// A low-pri request is usually blocked in favor of hi-pri request. Currently,
+// RocksDB assigns low-pri to request from compaciton and high-pri to request
+// from flush. Low-pri requests can get blocked if flush requests come in
+// continuouly. This fairness parameter grants low-pri requests permission by
+// 1/fairness chance even though high-pri requests exist to avoid starvation.
+// You should be good by leaving it at default 10.
+extern RateLimiter* NewGenericRateLimiter(
+    int64_t rate_bytes_per_sec,
+    int64_t refill_period_us = 100 * 1000,
+    int32_t fairness = 10);
+
+}  // namespace rocksdb
@@ -20,12 +20,12 @@ namespace rocksdb {
 *  1. Any ticker should be added before TICKER_ENUM_MAX.
 *  2. Add a readable string in TickersNameMap below for the newly added ticker.
 */
-enum Tickers {
+enum Tickers : uint32_t {
  // total block cache misses
  // REQUIRES: BLOCK_CACHE_MISS == BLOCK_CACHE_INDEX_MISS +
  //                               BLOCK_CACHE_FILTER_MISS +
  //                               BLOCK_CACHE_DATA_MISS;
-  BLOCK_CACHE_MISS,
+  BLOCK_CACHE_MISS = 0,
  // total block cache hit
  // REQUIRES: BLOCK_CACHE_HIT == BLOCK_CACHE_INDEX_HIT +
  //                              BLOCK_CACHE_FILTER_HIT +
@@ -198,8 +198,8 @@ const std::vector<std::pair<Tickers, std::string>> TickersNameMap = {
 * Add a string representation in HistogramsNameMap below
 * And increment HISTOGRAM_ENUM_MAX
 */
-enum Histograms {
-  DB_GET,
+enum Histograms : uint32_t {
+  DB_GET = 0,
  DB_WRITE,
  COMPACTION_TIME,
  TABLE_SYNC_MICROS,
@@ -256,14 +256,24 @@ class Statistics {
 public:
  virtual ~Statistics() {}

-  virtual long getTickerCount(Tickers tickerType) = 0;
-  virtual void recordTick(Tickers tickerType, uint64_t count = 0) = 0;
-  virtual void setTickerCount(Tickers tickerType, uint64_t count) = 0;
-  virtual void measureTime(Histograms histogramType, uint64_t time) = 0;
+  virtual uint64_t getTickerCount(uint32_t tickerType) const = 0;
+  virtual void histogramData(uint32_t type,
+                             HistogramData* const data) const = 0;
+
+  virtual void recordTick(uint32_t tickerType, uint64_t count = 0) = 0;
+  virtual void setTickerCount(uint32_t tickerType, uint64_t count) = 0;
+  virtual void measureTime(uint32_t histogramType, uint64_t time) = 0;

-  virtual void histogramData(Histograms type, HistogramData* const data) = 0;
  // String representation of the statistic object.
-  std::string ToString();
+  virtual std::string ToString() const {
+    // Do nothing by default
+    return std::string("ToString(): not implemented");
+  }
+
+  // Override this function to disable particular histogram collection
+  virtual bool HistEnabledForType(uint32_t type) const {
+    return type < HISTOGRAM_ENUM_MAX;
+  }
 };

 // Create a concrete DBStatistics object
@@ -119,33 +119,43 @@ enum EncodingType : char {
 struct PlainTablePropertyNames {
  static const std::string kPrefixExtractorName;
  static const std::string kEncodingType;
+  static const std::string kBloomVersion;
+  static const std::string kNumBloomBlocks;
 };

-// -- Plain Table with prefix-only seek
-// For this factory, you need to set Options.prefix_extrator properly to make it
-// work. Look-up will starts with prefix hash lookup for key prefix. Inside the
-// hash bucket found, a binary search is executed for hash conflicts. Finally,
-// a linear search is used.
+const uint32_t kPlainTableVariableLength = 0;
+
+struct PlainTableOptions {
 // @user_key_len: plain table has optimization for fix-sized keys, which can be
 //                specified via user_key_len.  Alternatively, you can pass
 //                `kPlainTableVariableLength` if your keys have variable
 //                lengths.
+uint32_t user_key_len = kPlainTableVariableLength;
+
 // @bloom_bits_per_key: the number of bits used for bloom filer per prefix. You
 //                      may disable it by passing a zero.
+int bloom_bits_per_key = 10;
+
 // @hash_table_ratio: the desired utilization of the hash table used for prefix
 //                    hashing. hash_table_ratio = number of prefixes / #buckets
 //                    in the hash table
+double hash_table_ratio = 0.75;
+
 // @index_sparseness: inside each prefix, need to build one index record for how
 //                    many keys for binary search inside each hash bucket.
 //                    For encoding type kPrefix, the value will be used when
 //                    writing to determine an interval to rewrite the full key.
 //                    It will also be used as a suggestion and satisfied when
 //                    possible.
+size_t index_sparseness = 16;
+
 // @huge_page_tlb_size: if <=0, allocate hash indexes and blooms from malloc.
 //                      Otherwise from huge page TLB. The user needs to reserve
 //                      huge pages for it to be allocated, like:
 //                          sysctl -w vm.nr_hugepages=20
 //                      See linux doc Documentation/vm/hugetlbpage.txt
+size_t huge_page_tlb_size = 0;
+
 // @encoding_type: how to encode the keys. See enum EncodingType above for
 //                 the choices. The value will determine how to encode keys
 //                 when writing to a new SST file. This value will be stored
@@ -153,13 +163,34 @@ struct PlainTablePropertyNames {
 //                 file, which makes it possible for users to choose different
 //                 encoding type when reopening a DB. Files with different
 //                 encoding types can co-exist in the same DB and can be read.
+EncodingType encoding_type = kPlain;

-const uint32_t kPlainTableVariableLength = 0;
-extern TableFactory* NewPlainTableFactory(
-    uint32_t user_key_len = kPlainTableVariableLength,
-    int bloom_bits_per_prefix = 10, double hash_table_ratio = 0.75,
-    size_t index_sparseness = 16, size_t huge_page_tlb_size = 0,
-    EncodingType encoding_type = kPlain, bool full_scan_mode = false);
+// @full_scan_mode: mode for reading the whole file one record by one without
+//                  using the index.
+  bool full_scan_mode = false;
+
+  // @store_index_in_file: compute plain table index and bloom filter during
+  //                       file building and store it in file. When reading
+  //                       file, index will be mmaped instead of recomputation.
+  bool store_index_in_file = false;
+};
+
+// -- Plain Table with prefix-only seek
+// For this factory, you need to set Options.prefix_extrator properly to make it
+// work. Look-up will starts with prefix hash lookup for key prefix. Inside the
+// hash bucket found, a binary search is executed for hash conflicts. Finally,
+// a linear search is used.
+
+extern TableFactory* NewPlainTableFactory(const PlainTableOptions& options =
+                                              PlainTableOptions());
+
+struct CuckooTablePropertyNames {
+  static const std::string kEmptyKey;
+  static const std::string kValueLength;
+  static const std::string kNumHashTable;
+  static const std::string kMaxNumBuckets;
+  static const std::string kIsLastLevel;
+};

 #endif  // ROCKSDB_LITE

@@ -0,0 +1,252 @@
+//  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
+#ifndef ROCKSDB_LITE
+
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
+#include <string>
+#include <map>
+#include <vector>
+
+#include "rocksdb/utilities/stackable_db.h"
+
+#include "rocksdb/env.h"
+#include "rocksdb/status.h"
+
+namespace rocksdb {
+
+struct BackupableDBOptions {
+  // Where to keep the backup files. Has to be different than dbname_
+  // Best to set this to dbname_ + "/backups"
+  // Required
+  std::string backup_dir;
+
+  // Backup Env object. It will be used for backup file I/O. If it's
+  // nullptr, backups will be written out using DBs Env. If it's
+  // non-nullptr, backup's I/O will be performed using this object.
+  // If you want to have backups on HDFS, use HDFS Env here!
+  // Default: nullptr
+  Env* backup_env;
+
+  // If share_table_files == true, backup will assume that table files with
+  // same name have the same contents. This enables incremental backups and
+  // avoids unnecessary data copies.
+  // If share_table_files == false, each backup will be on its own and will
+  // not share any data with other backups.
+  // default: true
+  bool share_table_files;
+
+  // Backup info and error messages will be written to info_log
+  // if non-nullptr.
+  // Default: nullptr
+  Logger* info_log;
+
+  // If sync == true, we can guarantee you'll get consistent backup even
+  // on a machine crash/reboot. Backup process is slower with sync enabled.
+  // If sync == false, we don't guarantee anything on machine reboot. However,
+  // chances are some of the backups are consistent.
+  // Default: true
+  bool sync;
+
+  // If true, it will delete whatever backups there are already
+  // Default: false
+  bool destroy_old_data;
+
+  // If false, we won't backup log files. This option can be useful for backing
+  // up in-memory databases where log file are persisted, but table files are in
+  // memory.
+  // Default: true
+  bool backup_log_files;
+
+  // Max bytes that can be transferred in a second during backup.
+  // If 0, go as fast as you can
+  // Default: 0
+  uint64_t backup_rate_limit;
+
+  // Max bytes that can be transferred in a second during restore.
+  // If 0, go as fast as you can
+  // Default: 0
+  uint64_t restore_rate_limit;
+
+  // Only used if share_table_files is set to true. If true, will consider that
+  // backups can come from different databases, hence a sst is not uniquely
+  // identifed by its name, but by the triple (file name, crc32, file length)
+  // Default: false
+  // Note: this is an experimental option, and you'll need to set it manually
+  // *turn it on only if you know what you're doing*
+  bool share_files_with_checksum;
+
+  void Dump(Logger* logger) const;
+
+  explicit BackupableDBOptions(const std::string& _backup_dir,
+                               Env* _backup_env = nullptr,
+                               bool _share_table_files = true,
+                               Logger* _info_log = nullptr, bool _sync = true,
+                               bool _destroy_old_data = false,
+                               bool _backup_log_files = true,
+                               uint64_t _backup_rate_limit = 0,
+                               uint64_t _restore_rate_limit = 0)
+      : backup_dir(_backup_dir),
+        backup_env(_backup_env),
+        share_table_files(_share_table_files),
+        info_log(_info_log),
+        sync(_sync),
+        destroy_old_data(_destroy_old_data),
+        backup_log_files(_backup_log_files),
+        backup_rate_limit(_backup_rate_limit),
+        restore_rate_limit(_restore_rate_limit),
+        share_files_with_checksum(false) {
+    assert(share_table_files || !share_files_with_checksum);
+  }
+};
+
+struct RestoreOptions {
+  // If true, restore won't overwrite the existing log files in wal_dir. It will
+  // also move all log files from archive directory to wal_dir. Use this option
+  // in combination with BackupableDBOptions::backup_log_files = false for
+  // persisting in-memory databases.
+  // Default: false
+  bool keep_log_files;
+
+  explicit RestoreOptions(bool _keep_log_files = false)
+      : keep_log_files(_keep_log_files) {}
+};
+
+typedef uint32_t BackupID;
+
+struct BackupInfo {
+  BackupID backup_id;
+  int64_t timestamp;
+  uint64_t size;
+
+  BackupInfo() {}
+  BackupInfo(BackupID _backup_id, int64_t _timestamp, uint64_t _size)
+      : backup_id(_backup_id), timestamp(_timestamp), size(_size) {}
+};
+
+class BackupEngineReadOnly {
+ public:
+  virtual ~BackupEngineReadOnly() {}
+
+  static BackupEngineReadOnly* NewReadOnlyBackupEngine(
+      Env* db_env, const BackupableDBOptions& options);
+
+  // You can GetBackupInfo safely, even with other BackupEngine performing
+  // backups on the same directory
+  virtual void GetBackupInfo(std::vector<BackupInfo>* backup_info) = 0;
+
+  // Restoring DB from backup is NOT safe when there is another BackupEngine
+  // running that might call DeleteBackup() or PurgeOldBackups(). It is caller's
+  // responsibility to synchronize the operation, i.e. don't delete the backup
+  // when you're restoring from it
+  virtual Status RestoreDBFromBackup(
+      BackupID backup_id, const std::string& db_dir, const std::string& wal_dir,
+      const RestoreOptions& restore_options = RestoreOptions()) = 0;
+  virtual Status RestoreDBFromLatestBackup(
+      const std::string& db_dir, const std::string& wal_dir,
+      const RestoreOptions& restore_options = RestoreOptions()) = 0;
+};
+
+// Please see the documentation in BackupableDB and RestoreBackupableDB
+class BackupEngine {
+ public:
+  virtual ~BackupEngine() {}
+
+  static BackupEngine* NewBackupEngine(Env* db_env,
+                                       const BackupableDBOptions& options);
+
+  virtual Status CreateNewBackup(DB* db, bool flush_before_backup = false) = 0;
+  virtual Status PurgeOldBackups(uint32_t num_backups_to_keep) = 0;
+  virtual Status DeleteBackup(BackupID backup_id) = 0;
+  virtual void StopBackup() = 0;
+
+  virtual void GetBackupInfo(std::vector<BackupInfo>* backup_info) = 0;
+  virtual Status RestoreDBFromBackup(
+      BackupID backup_id, const std::string& db_dir, const std::string& wal_dir,
+      const RestoreOptions& restore_options = RestoreOptions()) = 0;
+  virtual Status RestoreDBFromLatestBackup(
+      const std::string& db_dir, const std::string& wal_dir,
+      const RestoreOptions& restore_options = RestoreOptions()) = 0;
+};
+
+// Stack your DB with BackupableDB to be able to backup the DB
+class BackupableDB : public StackableDB {
+ public:
+  // BackupableDBOptions have to be the same as the ones used in a previous
+  // incarnation of the DB
+  //
+  // BackupableDB ownes the pointer `DB* db` now. You should not delete it or
+  // use it after the invocation of BackupableDB
+  BackupableDB(DB* db, const BackupableDBOptions& options);
+  virtual ~BackupableDB();
+
+  // Captures the state of the database in the latest backup
+  // NOT a thread safe call
+  Status CreateNewBackup(bool flush_before_backup = false);
+  // Returns info about backups in backup_info
+  void GetBackupInfo(std::vector<BackupInfo>* backup_info);
+  // deletes old backups, keeping latest num_backups_to_keep alive
+  Status PurgeOldBackups(uint32_t num_backups_to_keep);
+  // deletes a specific backup
+  Status DeleteBackup(BackupID backup_id);
+  // Call this from another thread if you want to stop the backup
+  // that is currently happening. It will return immediatelly, will
+  // not wait for the backup to stop.
+  // The backup will stop ASAP and the call to CreateNewBackup will
+  // return Status::Incomplete(). It will not clean up after itself, but
+  // the state will remain consistent. The state will be cleaned up
+  // next time you create BackupableDB or RestoreBackupableDB.
+  void StopBackup();
+
+ private:
+  BackupEngine* backup_engine_;
+};
+
+// Use this class to access information about backups and restore from them
+class RestoreBackupableDB {
+ public:
+  RestoreBackupableDB(Env* db_env, const BackupableDBOptions& options);
+  ~RestoreBackupableDB();
+
+  // Returns info about backups in backup_info
+  void GetBackupInfo(std::vector<BackupInfo>* backup_info);
+
+  // restore from backup with backup_id
+  // IMPORTANT -- if options_.share_table_files == true and you restore DB
+  // from some backup that is not the latest, and you start creating new
+  // backups from the new DB, they will probably fail
+  //
+  // Example: Let's say you have backups 1, 2, 3, 4, 5 and you restore 3.
+  // If you add new data to the DB and try creating a new backup now, the
+  // database will diverge from backups 4 and 5 and the new backup will fail.
+  // If you want to create new backup, you will first have to delete backups 4
+  // and 5.
+  Status RestoreDBFromBackup(BackupID backup_id, const std::string& db_dir,
+                             const std::string& wal_dir,
+                             const RestoreOptions& restore_options =
+                                 RestoreOptions());
+
+  // restore from the latest backup
+  Status RestoreDBFromLatestBackup(const std::string& db_dir,
+                                   const std::string& wal_dir,
+                                   const RestoreOptions& restore_options =
+                                       RestoreOptions());
+  // deletes old backups, keeping latest num_backups_to_keep alive
+  Status PurgeOldBackups(uint32_t num_backups_to_keep);
+  // deletes a specific backup
+  Status DeleteBackup(BackupID backup_id);
+
+ private:
+  BackupEngine* backup_engine_;
+};
+
+}  // namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -0,0 +1,68 @@
+//  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 "rocksdb/utilities/stackable_db.h"
+#include "rocksdb/db.h"
+
+namespace rocksdb {
+
+// Database with TTL support.
+//
+// USE-CASES:
+// This API should be used to open the db when key-values inserted are
+//  meant to be removed from the db in a non-strict 'ttl' amount of time
+//  Therefore, this guarantees that key-values inserted will remain in the
+//  db for >= ttl amount of time and the db will make efforts to remove the
+//  key-values as soon as possible after ttl seconds of their insertion.
+//
+// BEHAVIOUR:
+// TTL is accepted in seconds
+// (int32_t)Timestamp(creation) is suffixed to values in Put internally
+// Expired TTL values deleted in compaction only:(Timestamp+ttl<time_now)
+// Get/Iterator may return expired entries(compaction not run on them yet)
+// Different TTL may be used during different Opens
+// Example: Open1 at t=0 with ttl=4 and insert k1,k2, close at t=2
+//          Open2 at t=3 with ttl=5. Now k1,k2 should be deleted at t>=5
+// read_only=true opens in the usual read-only mode. Compactions will not be
+//  triggered(neither manual nor automatic), so no expired entries removed
+//
+// CONSTRAINTS:
+// Not specifying/passing or non-positive TTL behaves like TTL = infinity
+//
+// !!!WARNING!!!:
+// Calling DB::Open directly to re-open a db created by this API will get
+//  corrupt values(timestamp suffixed) and no ttl effect will be there
+//  during the second Open, so use this API consistently to open the db
+// Be careful when passing ttl with a small positive value because the
+//  whole database may be deleted in a small amount of time
+
+class DBWithTTL : public StackableDB {
+ public:
+  virtual Status CreateColumnFamilyWithTtl(
+      const ColumnFamilyOptions& options, const std::string& column_family_name,
+      ColumnFamilyHandle** handle, int ttl) = 0;
+
+  static Status Open(const Options& options, const std::string& dbname,
+                     DBWithTTL** dbptr, int32_t ttl = 0,
+                     bool read_only = false);
+
+  static Status Open(const DBOptions& db_options, const std::string& dbname,
+                     const std::vector<ColumnFamilyDescriptor>& column_families,
+                     std::vector<ColumnFamilyHandle*>* handles,
+                     DBWithTTL** dbptr, std::vector<int32_t> ttls,
+                     bool read_only = false);
+
+ protected:
+  explicit DBWithTTL(DB* db) : StackableDB(db) {}
+};
+
+}  // namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -0,0 +1,149 @@
+//  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 "rocksdb/utilities/stackable_db.h"
+#include "rocksdb/utilities/json_document.h"
+#include "rocksdb/db.h"
+
+namespace rocksdb {
+
+// IMPORTANT: DocumentDB is a work in progress. It is unstable and we might
+// change the API without warning. Talk to RocksDB team before using this in
+// production ;)
+
+// DocumentDB is a layer on top of RocksDB that provides a very simple JSON API.
+// When creating a DB, you specify a list of indexes you want to keep on your
+// data. You can insert a JSON document to the DB, which is automatically
+// indexed. Every document added to the DB needs to have "_id" field which is
+// automatically indexed and is an unique primary key. All other indexes are
+// non-unique.
+
+// NOTE: field names in the JSON are NOT allowed to start with '$' or
+// contain '.'. We don't currently enforce that rule, but will start behaving
+// badly.
+
+// Cursor is what you get as a result of executing query. To get all
+// results from a query, call Next() on a Cursor while  Valid() returns true
+class Cursor {
+ public:
+  Cursor() = default;
+  virtual ~Cursor() {}
+
+  virtual bool Valid() const = 0;
+  virtual void Next() = 0;
+  // Lifecycle of the returned JSONDocument is until the next Next() call
+  virtual const JSONDocument& document() const = 0;
+  virtual Status status() const = 0;
+
+ private:
+  // No copying allowed
+  Cursor(const Cursor&);
+  void operator=(const Cursor&);
+};
+
+struct DocumentDBOptions {
+  int background_threads = 4;
+  uint64_t memtable_size = 128 * 1024 * 1024;    // 128 MB
+  uint64_t cache_size = 1 * 1024 * 1024 * 1024;  // 1 GB
+};
+
+// TODO(icanadi) Add `JSONDocument* info` parameter to all calls that can be
+// used by the caller to get more information about the call execution (number
+// of dropped records, number of updated records, etc.)
+class DocumentDB : public StackableDB {
+ public:
+  struct IndexDescriptor {
+    // Currently, you can only define an index on a single field. To specify an
+    // index on a field X, set index description to JSON "{X: 1}"
+    // Currently the value needs to be 1, which means ascending.
+    // In the future, we plan to also support indexes on multiple keys, where
+    // you could mix ascending sorting (1) with descending sorting indexes (-1)
+    JSONDocument* description;
+    std::string name;
+  };
+
+  // Open DocumentDB with specified indexes. The list of indexes has to be
+  // complete, i.e. include all indexes present in the DB, except the primary
+  // key index.
+  // Otherwise, Open() will return an error
+  static Status Open(const DocumentDBOptions& options, const std::string& name,
+                     const std::vector<IndexDescriptor>& indexes,
+                     DocumentDB** db, bool read_only = false);
+
+  explicit DocumentDB(DB* db) : StackableDB(db) {}
+
+  // Create a new index. It will stop all writes for the duration of the call.
+  // All current documents in the DB are scanned and corresponding index entries
+  // are created
+  virtual Status CreateIndex(const WriteOptions& write_options,
+                             const IndexDescriptor& index) = 0;
+
+  // Drop an index. Client is responsible to make sure that index is not being
+  // used by currently executing queries
+  virtual Status DropIndex(const std::string& name) = 0;
+
+  // Insert a document to the DB. The document needs to have a primary key "_id"
+  // which can either be a string or an integer. Otherwise the write will fail
+  // with InvalidArgument.
+  virtual Status Insert(const WriteOptions& options,
+                        const JSONDocument& document) = 0;
+
+  // Deletes all documents matching a filter atomically
+  virtual Status Remove(const ReadOptions& read_options,
+                        const WriteOptions& write_options,
+                        const JSONDocument& query) = 0;
+
+  // Does this sequence of operations:
+  // 1. Find all documents matching a filter
+  // 2. For all documents, atomically:
+  // 2.1. apply the update operators
+  // 2.2. update the secondary indexes
+  //
+  // Currently only $set update operator is supported.
+  // Syntax is: {$set: {key1: value1, key2: value2, etc...}}
+  // This operator will change a document's key1 field to value1, key2 to
+  // value2, etc. New values will be set even if a document didn't have an entry
+  // for the specified key.
+  //
+  // You can not change a primary key of a document.
+  //
+  // Update example: Update({id: {$gt: 5}, $index: id}, {$set: {enabled: true}})
+  virtual Status Update(const ReadOptions& read_options,
+                        const WriteOptions& write_options,
+                        const JSONDocument& filter,
+                        const JSONDocument& updates) = 0;
+
+  // query has to be an array in which every element is an operator. Currently
+  // only $filter operator is supported. Syntax of $filter operator is:
+  // {$filter: {key1: condition1, key2: condition2, etc.}} where conditions can
+  // be either:
+  // 1) a single value in which case the condition is equality condition, or
+  // 2) a defined operators, like {$gt: 4}, which will match all documents that
+  // have key greater than 4.
+  //
+  // Supported operators are:
+  // 1) $gt -- greater than
+  // 2) $gte -- greater than or equal
+  // 3) $lt -- less than
+  // 4) $lte -- less than or equal
+  // If you want the filter to use an index, you need to specify it like this:
+  // {$filter: {...(conditions)..., $index: index_name}}
+  //
+  // Example query:
+  // * [{$filter: {name: John, age: {$gte: 18}, $index: age}}]
+  // will return all Johns whose age is greater or equal to 18 and it will use
+  // index "age" to satisfy the query.
+  virtual Cursor* Query(const ReadOptions& read_options,
+                        const JSONDocument& query) = 0;
+};
+
+}  // 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.
+//
+
+#ifndef ROCKSDB_LITE
+#pragma once
+#include <string>
+#include <vector>
+
+#include "rocksdb/utilities/stackable_db.h"
+#include "rocksdb/status.h"
+
+namespace rocksdb {
+
+//
+// Configurable options needed for setting up a Geo database
+//
+struct GeoDBOptions {
+  // Backup info and error messages will be written to info_log
+  // if non-nullptr.
+  // Default: nullptr
+  Logger* info_log;
+
+  explicit GeoDBOptions(Logger* _info_log = nullptr):info_log(_info_log) { }
+};
+
+//
+// A position in the earth's geoid
+//
+class GeoPosition {
+ public:
+  double latitude;
+  double longitude;
+
+  explicit GeoPosition(double la = 0, double lo = 0) :
+    latitude(la), longitude(lo) {
+  }
+};
+
+//
+// Description of an object on the Geoid. It is located by a GPS location,
+// and is identified by the id. The value associated with this object is
+// an opaque string 'value'. Different objects identified by unique id's
+// can have the same gps-location associated with them.
+//
+class GeoObject {
+ public:
+  GeoPosition position;
+  std::string id;
+  std::string value;
+
+  GeoObject() {}
+
+  GeoObject(const GeoPosition& pos, const std::string& i,
+            const std::string& val) :
+    position(pos), id(i), value(val) {
+  }
+};
+
+//
+// Stack your DB with GeoDB to be able to get geo-spatial support
+//
+class GeoDB : public StackableDB {
+ public:
+  // GeoDBOptions have to be the same as the ones used in a previous
+  // incarnation of the DB
+  //
+  // GeoDB owns the pointer `DB* db` now. You should not delete it or
+  // use it after the invocation of GeoDB
+  // GeoDB(DB* db, const GeoDBOptions& options) : StackableDB(db) {}
+  GeoDB(DB* db, const GeoDBOptions& options) : StackableDB(db) {}
+  virtual ~GeoDB() {}
+
+  // Insert a new object into the location database. The object is
+  // uniquely identified by the id. If an object with the same id already
+  // exists in the db, then the old one is overwritten by the new
+  // object being inserted here.
+  virtual Status Insert(const GeoObject& object) = 0;
+
+  // Retrieve the value of the object located at the specified GPS
+  // location and is identified by the 'id'.
+  virtual Status GetByPosition(const GeoPosition& pos,
+                               const Slice& id, std::string* value) = 0;
+
+  // Retrieve the value of the object identified by the 'id'. This method
+  // could be potentially slower than GetByPosition
+  virtual Status GetById(const Slice& id, GeoObject*  object) = 0;
+
+  // Delete the specified object
+  virtual Status Remove(const Slice& id) = 0;
+
+  // Returns a list of all items within a circular radius from the
+  // specified gps location. If 'number_of_values' is specified,
+  // then this call returns at most that many number of objects.
+  // The radius is specified in 'meters'.
+  virtual Status SearchRadial(const GeoPosition& pos,
+                              double radius,
+                              std::vector<GeoObject>* values,
+                              int number_of_values = INT_MAX) = 0;
+};
+
+}  // namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -0,0 +1,174 @@
+//  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 <map>
+#include <unordered_map>
+#include <vector>
+
+#include "rocksdb/slice.h"
+
+// We use JSONDocument for DocumentDB API
+// Implementation inspired by folly::dynamic and rapidjson
+
+namespace rocksdb {
+
+// NOTE: none of this is thread-safe
+class JSONDocument {
+ public:
+  // return nullptr on parse failure
+  static JSONDocument* ParseJSON(const char* json);
+
+  enum Type {
+    kNull,
+    kArray,
+    kBool,
+    kDouble,
+    kInt64,
+    kObject,
+    kString,
+  };
+
+  JSONDocument();  // null
+  /* implicit */ JSONDocument(bool b);
+  /* implicit */ JSONDocument(double d);
+  /* implicit */ JSONDocument(int64_t i);
+  /* implicit */ JSONDocument(const std::string& s);
+  /* implicit */ JSONDocument(const char* s);
+  // constructs JSONDocument of specific type with default value
+  explicit JSONDocument(Type type);
+
+  // copy constructor
+  JSONDocument(const JSONDocument& json_document);
+
+  ~JSONDocument();
+
+  Type type() const;
+
+  // REQUIRES: IsObject()
+  bool Contains(const std::string& key) const;
+  // Returns nullptr if !Contains()
+  // don't delete the returned pointer
+  // REQUIRES: IsObject()
+  const JSONDocument* Get(const std::string& key) const;
+  // REQUIRES: IsObject()
+  JSONDocument& operator[](const std::string& key);
+  // REQUIRES: IsObject()
+  const JSONDocument& operator[](const std::string& key) const;
+  // returns `this`, so you can chain operations.
+  // Copies value
+  // REQUIRES: IsObject()
+  JSONDocument* Set(const std::string& key, const JSONDocument& value);
+
+  // REQUIRES: IsArray() == true || IsObject() == true
+  size_t Count() const;
+
+  // REQUIRES: IsArray()
+  const JSONDocument* GetFromArray(size_t i) const;
+  // REQUIRES: IsArray()
+  JSONDocument& operator[](size_t i);
+  // REQUIRES: IsArray()
+  const JSONDocument& operator[](size_t i) const;
+  // returns `this`, so you can chain operations.
+  // Copies the value
+  // REQUIRES: IsArray() && i < Count()
+  JSONDocument* SetInArray(size_t i, const JSONDocument& value);
+  // REQUIRES: IsArray()
+  JSONDocument* PushBack(const JSONDocument& value);
+
+  bool IsNull() const;
+  bool IsArray() const;
+  bool IsBool() const;
+  bool IsDouble() const;
+  bool IsInt64() const;
+  bool IsObject() const;
+  bool IsString() const;
+
+  // REQUIRES: IsBool() == true
+  bool GetBool() const;
+  // REQUIRES: IsDouble() == true
+  double GetDouble() const;
+  // REQUIRES: IsInt64() == true
+  int64_t GetInt64() const;
+  // REQUIRES: IsString() == true
+  const std::string& GetString() const;
+
+  bool operator==(const JSONDocument& rhs) const;
+
+  std::string DebugString() const;
+
+ private:
+  class ItemsIteratorGenerator;
+
+ public:
+  // REQUIRES: IsObject()
+  ItemsIteratorGenerator Items() const;
+
+  // appends serialized object to dst
+  void Serialize(std::string* dst) const;
+  // returns nullptr if Slice doesn't represent valid serialized JSONDocument
+  static JSONDocument* Deserialize(const Slice& src);
+
+ private:
+  void SerializeInternal(std::string* dst, bool type_prefix) const;
+  // returns false if Slice doesn't represent valid serialized JSONDocument.
+  // Otherwise, true
+  bool DeserializeInternal(Slice* input);
+
+  typedef std::vector<JSONDocument*> Array;
+  typedef std::unordered_map<std::string, JSONDocument*> Object;
+
+  // iteration on objects
+  class const_item_iterator {
+   public:
+    typedef Object::const_iterator It;
+    typedef Object::value_type value_type;
+    /* implicit */ const_item_iterator(It it) : it_(it) {}
+    It& operator++() { return ++it_; }
+    bool operator!=(const const_item_iterator& other) {
+      return it_ != other.it_;
+    }
+    value_type operator*() { return *it_; }
+
+   private:
+    It it_;
+  };
+  class ItemsIteratorGenerator {
+   public:
+    /* implicit */ ItemsIteratorGenerator(const Object& object)
+        : object_(object) {}
+    const_item_iterator begin() { return object_.begin(); }
+    const_item_iterator end() { return object_.end(); }
+
+   private:
+    const Object& object_;
+  };
+
+  union Data {
+    Data() : n(nullptr) {}
+    ~Data() {}
+
+    void* n;
+    Array a;
+    bool b;
+    double d;
+    int64_t i;
+    std::string s;
+    Object o;
+  } data_;
+  const Type type_;
+
+  // Our serialization format's first byte specifies the encoding version. That
+  // way, we can easily change our format while providing backwards
+  // compatibility. This constant specifies the current version of the
+  // serialization format
+  static const char kSerializationFormatVersion;
+};
+
+}  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE
@@ -0,0 +1,236 @@
+//  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 "rocksdb/db.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/utilities/stackable_db.h"
+
+namespace rocksdb {
+namespace spatial {
+
+// NOTE: SpatialDB is experimental and we might change its API without warning.
+// Please talk to us before developing against SpatialDB API.
+//
+// SpatialDB is a support for spatial indexes built on top of RocksDB.
+// When creating a new SpatialDB, clients specifies a list of spatial indexes to
+// build on their data. Each spatial index is defined by the area and
+// granularity. If you're storing map data, different spatial index
+// granularities can be used for different zoom levels.
+//
+// Each element inserted into SpatialDB has:
+// * a bounding box, which determines how will the element be indexed
+// * string blob, which will usually be WKB representation of the polygon
+// (http://en.wikipedia.org/wiki/Well-known_text)
+// * feature set, which is a map of key-value pairs, where value can be null,
+// int, double, bool, string
+// * a list of indexes to insert the element in
+//
+// Each query is executed on a single spatial index. Query guarantees that it
+// will return all elements intersecting the specified bounding box, but it
+// might also return some extra non-intersecting elements.
+
+// Variant is a class that can be many things: null, bool, int, double or string
+// It is used to store different value types in FeatureSet (see below)
+struct Variant {
+  // Don't change the values here, they are persisted on disk
+  enum Type {
+    kNull = 0x0,
+    kBool = 0x1,
+    kInt = 0x2,
+    kDouble = 0x3,
+    kString = 0x4,
+  };
+
+  Variant() : type_(kNull) {}
+  /* implicit */ Variant(bool b) : type_(kBool) { data_.b = b; }
+  /* implicit */ Variant(uint64_t i) : type_(kInt) { data_.i = i; }
+  /* implicit */ Variant(double d) : type_(kDouble) { data_.d = d; }
+  /* implicit */ Variant(const std::string& s) : type_(kString) {
+    new (&data_.s) std::string(s);
+  }
+
+  Variant(const Variant& v);
+
+  ~Variant() {
+    if (type_ == kString) {
+      using std::string;
+      (&data_.s)->~string();
+    }
+  }
+
+  Type type() const { return type_; }
+  bool get_bool() const { return data_.b; }
+  uint64_t get_int() const { return data_.i; }
+  double get_double() const { return data_.d; }
+  const std::string& get_string() const { return data_.s; }
+
+  bool operator==(const Variant& other);
+  bool operator!=(const Variant& other);
+
+ private:
+  Type type_;
+  union Data {
+    Data() {}
+    ~Data() {}
+    bool b;
+    uint64_t i;
+    double d;
+    std::string s;
+  } data_;
+};
+
+// FeatureSet is a map of key-value pairs. One feature set is associated with
+// each element in SpatialDB. It can be used to add rich data about the element.
+class FeatureSet {
+ private:
+  typedef std::unordered_map<std::string, Variant> map;
+
+ public:
+  class iterator {
+   public:
+    /* implicit */ iterator(const map::const_iterator itr) : itr_(itr) {}
+    iterator& operator++() {
+      ++itr_;
+      return *this;
+    }
+    bool operator!=(const iterator& other) { return itr_ != other.itr_; }
+    bool operator==(const iterator& other) { return itr_ == other.itr_; }
+    map::value_type operator*() { return *itr_; }
+
+   private:
+    map::const_iterator itr_;
+  };
+  FeatureSet() = default;
+
+  FeatureSet* Set(const std::string& key, const Variant& value);
+  bool Contains(const std::string& key) const;
+  // REQUIRES: Contains(key)
+  const Variant& Get(const std::string& key) const;
+  iterator Find(const std::string& key) const;
+
+  iterator begin() const { return map_.begin(); }
+  iterator end() const { return map_.end(); }
+
+  void Clear();
+  size_t Size() const { return map_.size(); }
+
+  void Serialize(std::string* output) const;
+  // REQUIRED: empty FeatureSet
+  bool Deserialize(const Slice& input);
+
+  std::string DebugString() const;
+
+ private:
+  map map_;
+};
+
+// BoundingBox is a helper structure for defining rectangles representing
+// bounding boxes of spatial elements.
+template <typename T>
+struct BoundingBox {
+  T min_x, min_y, max_x, max_y;
+  BoundingBox() = default;
+  BoundingBox(T _min_x, T _min_y, T _max_x, T _max_y)
+      : min_x(_min_x), min_y(_min_y), max_x(_max_x), max_y(_max_y) {}
+
+  bool Intersects(const BoundingBox<T>& a) const {
+    return !(min_x > a.max_x || min_y > a.max_y || a.min_x > max_x ||
+             a.min_y > max_y);
+  }
+};
+
+struct SpatialDBOptions {
+  uint64_t cache_size = 1 * 1024 * 1024 * 1024LL;  // 1GB
+  int num_threads = 16;
+  bool bulk_load = true;
+};
+
+// Cursor is used to return data from the query to the client. To get all the
+// data from the query, just call Next() while Valid() is true
+class Cursor {
+ public:
+  Cursor() = default;
+  virtual ~Cursor() {}
+
+  virtual bool Valid() const = 0;
+  // REQUIRES: Valid()
+  virtual void Next() = 0;
+
+  // Lifetime of the underlying storage until the next call to Next()
+  // REQUIRES: Valid()
+  virtual const Slice blob() = 0;
+  // Lifetime of the underlying storage until the next call to Next()
+  // REQUIRES: Valid()
+  virtual const FeatureSet& feature_set() = 0;
+
+  virtual Status status() const = 0;
+
+ private:
+  // No copying allowed
+  Cursor(const Cursor&);
+  void operator=(const Cursor&);
+};
+
+// SpatialIndexOptions defines a spatial index that will be built on the data
+struct SpatialIndexOptions {
+  // Spatial indexes are referenced by names
+  std::string name;
+  // An area that is indexed. If the element is not intersecting with spatial
+  // index's bbox, it will not be inserted into the index
+  BoundingBox<double> bbox;
+  // tile_bits control the granularity of the spatial index. Each dimension of
+  // the bbox will be split into (1 << tile_bits) tiles, so there will be a
+  // total of (1 << tile_bits)^2 tiles. It is recommended to configure a size of
+  // each  tile to be approximately the size of the query on that spatial index
+  uint32_t tile_bits;
+  SpatialIndexOptions() {}
+  SpatialIndexOptions(const std::string& _name,
+                      const BoundingBox<double>& _bbox, uint32_t _tile_bits)
+      : name(_name), bbox(_bbox), tile_bits(_tile_bits) {}
+};
+
+class SpatialDB : public StackableDB {
+ public:
+  // Creates the SpatialDB with specified list of indexes.
+  // REQUIRED: db doesn't exist
+  static Status Create(const SpatialDBOptions& options, const std::string& name,
+                       const std::vector<SpatialIndexOptions>& spatial_indexes);
+
+  // Open the existing SpatialDB.  The resulting db object will be returned
+  // through db parameter.
+  // REQUIRED: db was created using SpatialDB::Create
+  static Status Open(const SpatialDBOptions& options, const std::string& name,
+                     SpatialDB** db, bool read_only = false);
+
+  explicit SpatialDB(DB* db) : StackableDB(db) {}
+
+  // Insert the element into the DB. Element will be inserted into specified
+  // spatial_indexes, based on specified bbox.
+  // REQUIRES: spatial_indexes.size() > 0
+  virtual Status Insert(const WriteOptions& write_options,
+                        const BoundingBox<double>& bbox, const Slice& blob,
+                        const FeatureSet& feature_set,
+                        const std::vector<std::string>& spatial_indexes) = 0;
+
+  // Calling Compact() after inserting a bunch of elements should speed up
+  // reading. This is especially useful if you use SpatialDBOptions::bulk_load
+  virtual Status Compact() = 0;
+
+  // Query the specified spatial_index. Query will return all elements that
+  // intersect bbox, but it may also return some extra elements.
+  virtual Cursor* Query(const ReadOptions& read_options,
+                        const BoundingBox<double>& bbox,
+                        const std::string& spatial_index) = 0;
+};
+
+}  // namespace spatial
+}  // namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -0,0 +1,226 @@
+// 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/db.h"
+
+namespace rocksdb {
+
+// This class contains APIs to stack rocksdb wrappers.Eg. Stack TTL over base d
+class StackableDB : public DB {
+ public:
+  // StackableDB is the owner of db now!
+  explicit StackableDB(DB* db) : db_(db) {}
+
+  ~StackableDB() {
+    delete db_;
+  }
+
+  virtual DB* GetBaseDB() {
+    return db_;
+  }
+
+  virtual Status CreateColumnFamily(const ColumnFamilyOptions& options,
+                                    const std::string& column_family_name,
+                                    ColumnFamilyHandle** handle) {
+    return db_->CreateColumnFamily(options, column_family_name, handle);
+  }
+
+  virtual Status DropColumnFamily(ColumnFamilyHandle* column_family) {
+    return db_->DropColumnFamily(column_family);
+  }
+
+  using DB::Put;
+  virtual Status Put(const WriteOptions& options,
+                     ColumnFamilyHandle* column_family, const Slice& key,
+                     const Slice& val) override {
+    return db_->Put(options, column_family, key, val);
+  }
+
+  using DB::Get;
+  virtual Status Get(const ReadOptions& options,
+                     ColumnFamilyHandle* column_family, const Slice& key,
+                     std::string* value) override {
+    return db_->Get(options, column_family, key, value);
+  }
+
+  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) override {
+    return db_->MultiGet(options, column_family, keys, values);
+  }
+
+  using DB::KeyMayExist;
+  virtual bool KeyMayExist(const ReadOptions& options,
+                           ColumnFamilyHandle* column_family, const Slice& key,
+                           std::string* value,
+                           bool* value_found = nullptr) override {
+    return db_->KeyMayExist(options, column_family, key, value, value_found);
+  }
+
+  using DB::Delete;
+  virtual Status Delete(const WriteOptions& wopts,
+                        ColumnFamilyHandle* column_family,
+                        const Slice& key) override {
+    return db_->Delete(wopts, column_family, key);
+  }
+
+  using DB::Merge;
+  virtual Status Merge(const WriteOptions& options,
+                       ColumnFamilyHandle* column_family, const Slice& key,
+                       const Slice& value) override {
+    return db_->Merge(options, column_family, key, value);
+  }
+
+
+  virtual Status Write(const WriteOptions& opts, WriteBatch* updates)
+    override {
+      return db_->Write(opts, updates);
+  }
+
+  using DB::NewIterator;
+  virtual Iterator* NewIterator(const ReadOptions& opts,
+                                ColumnFamilyHandle* column_family) override {
+    return db_->NewIterator(opts, column_family);
+  }
+
+  virtual Status NewIterators(
+      const ReadOptions& options,
+      const std::vector<ColumnFamilyHandle*>& column_families,
+      std::vector<Iterator*>* iterators) {
+    return db_->NewIterators(options, column_families, iterators);
+  }
+
+
+  virtual const Snapshot* GetSnapshot() override {
+    return db_->GetSnapshot();
+  }
+
+  virtual void ReleaseSnapshot(const Snapshot* snapshot) override {
+    return db_->ReleaseSnapshot(snapshot);
+  }
+
+  using DB::GetProperty;
+  virtual bool GetProperty(ColumnFamilyHandle* column_family,
+                           const Slice& property, std::string* value) override {
+    return db_->GetProperty(column_family, property, value);
+  }
+
+  using DB::GetIntProperty;
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) override {
+    return db_->GetIntProperty(column_family, property, value);
+  }
+
+  using DB::GetApproximateSizes;
+  virtual void GetApproximateSizes(ColumnFamilyHandle* column_family,
+                                   const Range* r, int n,
+                                   uint64_t* sizes) override {
+      return db_->GetApproximateSizes(column_family, r, n, sizes);
+  }
+
+  using DB::CompactRange;
+  virtual Status CompactRange(ColumnFamilyHandle* column_family,
+                              const Slice* begin, const Slice* end,
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0) override {
+    return db_->CompactRange(column_family, begin, end, reduce_level,
+                             target_level, target_path_id);
+  }
+
+  using DB::NumberLevels;
+  virtual int NumberLevels(ColumnFamilyHandle* column_family) override {
+    return db_->NumberLevels(column_family);
+  }
+
+  using DB::MaxMemCompactionLevel;
+  virtual int MaxMemCompactionLevel(ColumnFamilyHandle* column_family)
+      override {
+    return db_->MaxMemCompactionLevel(column_family);
+  }
+
+  using DB::Level0StopWriteTrigger;
+  virtual int Level0StopWriteTrigger(ColumnFamilyHandle* column_family)
+      override {
+    return db_->Level0StopWriteTrigger(column_family);
+  }
+
+  virtual const std::string& GetName() const override {
+    return db_->GetName();
+  }
+
+  virtual Env* GetEnv() const override {
+    return db_->GetEnv();
+  }
+
+  using DB::GetOptions;
+  virtual const Options& GetOptions(ColumnFamilyHandle* column_family) const
+      override {
+    return db_->GetOptions(column_family);
+  }
+
+  using DB::Flush;
+  virtual Status Flush(const FlushOptions& fopts,
+                       ColumnFamilyHandle* column_family) override {
+    return db_->Flush(fopts, column_family);
+  }
+
+  virtual Status DisableFileDeletions() override {
+    return db_->DisableFileDeletions();
+  }
+
+  virtual Status EnableFileDeletions(bool force) override {
+    return db_->EnableFileDeletions(force);
+  }
+
+  virtual void GetLiveFilesMetaData(
+      std::vector<LiveFileMetaData>* metadata) override {
+    db_->GetLiveFilesMetaData(metadata);
+  }
+
+  virtual Status GetLiveFiles(std::vector<std::string>& vec, uint64_t* mfs,
+                              bool flush_memtable = true) override {
+      return db_->GetLiveFiles(vec, mfs, flush_memtable);
+  }
+
+  virtual SequenceNumber GetLatestSequenceNumber() const override {
+    return db_->GetLatestSequenceNumber();
+  }
+
+  virtual Status GetSortedWalFiles(VectorLogPtr& files) override {
+    return db_->GetSortedWalFiles(files);
+  }
+
+  virtual Status DeleteFile(std::string name) override {
+    return db_->DeleteFile(name);
+  }
+
+  virtual Status GetDbIdentity(std::string& identity) {
+    return db_->GetDbIdentity(identity);
+  }
+
+  using DB::GetPropertiesOfAllTables;
+  virtual Status GetPropertiesOfAllTables(ColumnFamilyHandle* column_family,
+                                          TablePropertiesCollection* props) {
+    return db_->GetPropertiesOfAllTables(column_family, props);
+  }
+
+  virtual Status GetUpdatesSince(
+      SequenceNumber seq_number, unique_ptr<TransactionLogIterator>* iter,
+      const TransactionLogIterator::ReadOptions& read_options) override {
+    return db_->GetUpdatesSince(seq_number, iter, read_options);
+  }
+
+  virtual ColumnFamilyHandle* DefaultColumnFamily() const override {
+    return db_->DefaultColumnFamily();
+  }
+
+ protected:
+  DB* db_;
+};
+
+} //  namespace rocksdb
@@ -0,0 +1,30 @@
+// 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
+#ifndef ROCKSDB_LITE
+#include <vector>
+#include <string>
+
+#include "rocksdb/utilities/stackable_db.h"
+#include "rocksdb/utilities/db_ttl.h"
+#include "rocksdb/db.h"
+
+namespace rocksdb {
+
+// Please don't use this class. It's deprecated
+class UtilityDB {
+ public:
+  // This function is here only for backwards compatibility. Please use the
+  // functions defined in DBWithTTl (rocksdb/utilities/db_ttl.h)
+  // (deprecated)
+  __attribute__((deprecated)) static Status OpenTtlDB(const Options& options,
+                                                      const std::string& name,
+                                                      StackableDB** dbptr,
+                                                      int32_t ttl = 0,
+                                                      bool read_only = false);
+};
+
+} //  namespace rocksdb
+#endif  // ROCKSDB_LITE
@@ -6,7 +6,7 @@

 // Also update Makefile if you change these
 #define ROCKSDB_MAJOR 3
-#define ROCKSDB_MINOR 3
+#define ROCKSDB_MINOR 4
 #define ROCKSDB_PATCH 0

 // Do not use these. We made the mistake of declaring macros starting with
@@ -8,244 +8,5 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #pragma once
-#ifndef ROCKSDB_LITE
-
-#define __STDC_FORMAT_MACROS
-#include <inttypes.h>
-#include <string>
-#include <map>
-#include <vector>
-
-#include "utilities/stackable_db.h"
-#include "rocksdb/env.h"
-#include "rocksdb/status.h"
-
-namespace rocksdb {
-
-struct BackupableDBOptions {
-  // Where to keep the backup files. Has to be different than dbname_
-  // Best to set this to dbname_ + "/backups"
-  // Required
-  std::string backup_dir;
-
-  // Backup Env object. It will be used for backup file I/O. If it's
-  // nullptr, backups will be written out using DBs Env. If it's
-  // non-nullptr, backup's I/O will be performed using this object.
-  // If you want to have backups on HDFS, use HDFS Env here!
-  // Default: nullptr
-  Env* backup_env;
-
-  // If share_table_files == true, backup will assume that table files with
-  // same name have the same contents. This enables incremental backups and
-  // avoids unnecessary data copies.
-  // If share_table_files == false, each backup will be on its own and will
-  // not share any data with other backups.
-  // default: true
-  bool share_table_files;
-
-  // Backup info and error messages will be written to info_log
-  // if non-nullptr.
-  // Default: nullptr
-  Logger* info_log;
-
-  // If sync == true, we can guarantee you'll get consistent backup even
-  // on a machine crash/reboot. Backup process is slower with sync enabled.
-  // If sync == false, we don't guarantee anything on machine reboot. However,
-  // chances are some of the backups are consistent.
-  // Default: true
-  bool sync;
-
-  // If true, it will delete whatever backups there are already
-  // Default: false
-  bool destroy_old_data;
-
-  // If false, we won't backup log files. This option can be useful for backing
-  // up in-memory databases where log file are persisted, but table files are in
-  // memory.
-  // Default: true
-  bool backup_log_files;
-
-  // Max bytes that can be transferred in a second during backup.
-  // If 0, go as fast as you can
-  // Default: 0
-  uint64_t backup_rate_limit;
-
-  // Max bytes that can be transferred in a second during restore.
-  // If 0, go as fast as you can
-  // Default: 0
-  uint64_t restore_rate_limit;
-
-  // Only used if share_table_files is set to true. If true, will consider that
-  // backups can come from different databases, hence a sst is not uniquely
-  // identifed by its name, but by the triple (file name, crc32, file length)
-  // Default: false
-  // Note: this is an experimental option, and you'll need to set it manually
-  // *turn it on only if you know what you're doing*
-  bool share_files_with_checksum;
-
-  void Dump(Logger* logger) const;
-
-  explicit BackupableDBOptions(const std::string& _backup_dir,
-                               Env* _backup_env = nullptr,
-                               bool _share_table_files = true,
-                               Logger* _info_log = nullptr, bool _sync = true,
-                               bool _destroy_old_data = false,
-                               bool _backup_log_files = true,
-                               uint64_t _backup_rate_limit = 0,
-                               uint64_t _restore_rate_limit = 0)
-      : backup_dir(_backup_dir),
-        backup_env(_backup_env),
-        share_table_files(_share_table_files),
-        info_log(_info_log),
-        sync(_sync),
-        destroy_old_data(_destroy_old_data),
-        backup_log_files(_backup_log_files),
-        backup_rate_limit(_backup_rate_limit),
-        restore_rate_limit(_restore_rate_limit),
-        share_files_with_checksum(false) {
-    assert(share_table_files || !share_files_with_checksum);
-  }
-};
-
-struct RestoreOptions {
-  // If true, restore won't overwrite the existing log files in wal_dir. It will
-  // also move all log files from archive directory to wal_dir. Use this option
-  // in combination with BackupableDBOptions::backup_log_files = false for
-  // persisting in-memory databases.
-  // Default: false
-  bool keep_log_files;
-
-  explicit RestoreOptions(bool _keep_log_files = false)
-      : keep_log_files(_keep_log_files) {}
-};
-
-typedef uint32_t BackupID;
-
-struct BackupInfo {
-  BackupID backup_id;
-  int64_t timestamp;
-  uint64_t size;
-
-  BackupInfo() {}
-  BackupInfo(BackupID _backup_id, int64_t _timestamp, uint64_t _size)
-      : backup_id(_backup_id), timestamp(_timestamp), size(_size) {}
-};
-
-class BackupEngineReadOnly {
- public:
-  virtual ~BackupEngineReadOnly() {}
-
-  static BackupEngineReadOnly* NewReadOnlyBackupEngine(
-      Env* db_env, const BackupableDBOptions& options);
-
-  // You can GetBackupInfo safely, even with other BackupEngine performing
-  // backups on the same directory
-  virtual void GetBackupInfo(std::vector<BackupInfo>* backup_info) = 0;
-
-  // Restoring DB from backup is NOT safe when there is another BackupEngine
-  // running that might call DeleteBackup() or PurgeOldBackups(). It is caller's
-  // responsibility to synchronize the operation, i.e. don't delete the backup
-  // when you're restoring from it
-  virtual Status RestoreDBFromBackup(
-      BackupID backup_id, const std::string& db_dir, const std::string& wal_dir,
-      const RestoreOptions& restore_options = RestoreOptions()) = 0;
-  virtual Status RestoreDBFromLatestBackup(
-      const std::string& db_dir, const std::string& wal_dir,
-      const RestoreOptions& restore_options = RestoreOptions()) = 0;
-};
-
-// Please see the documentation in BackupableDB and RestoreBackupableDB
-class BackupEngine {
- public:
-  virtual ~BackupEngine() {}
-
-  static BackupEngine* NewBackupEngine(Env* db_env,
-                                       const BackupableDBOptions& options);
-
-  virtual Status CreateNewBackup(DB* db, bool flush_before_backup = false) = 0;
-  virtual Status PurgeOldBackups(uint32_t num_backups_to_keep) = 0;
-  virtual Status DeleteBackup(BackupID backup_id) = 0;
-  virtual void StopBackup() = 0;
-
-  virtual void GetBackupInfo(std::vector<BackupInfo>* backup_info) = 0;
-  virtual Status RestoreDBFromBackup(
-      BackupID backup_id, const std::string& db_dir, const std::string& wal_dir,
-      const RestoreOptions& restore_options = RestoreOptions()) = 0;
-  virtual Status RestoreDBFromLatestBackup(
-      const std::string& db_dir, const std::string& wal_dir,
-      const RestoreOptions& restore_options = RestoreOptions()) = 0;
-};
-
-// Stack your DB with BackupableDB to be able to backup the DB
-class BackupableDB : public StackableDB {
- public:
-  // BackupableDBOptions have to be the same as the ones used in a previous
-  // incarnation of the DB
-  //
-  // BackupableDB ownes the pointer `DB* db` now. You should not delete it or
-  // use it after the invocation of BackupableDB
-  BackupableDB(DB* db, const BackupableDBOptions& options);
-  virtual ~BackupableDB();
-
-  // Captures the state of the database in the latest backup
-  // NOT a thread safe call
-  Status CreateNewBackup(bool flush_before_backup = false);
-  // Returns info about backups in backup_info
-  void GetBackupInfo(std::vector<BackupInfo>* backup_info);
-  // deletes old backups, keeping latest num_backups_to_keep alive
-  Status PurgeOldBackups(uint32_t num_backups_to_keep);
-  // deletes a specific backup
-  Status DeleteBackup(BackupID backup_id);
-  // Call this from another thread if you want to stop the backup
-  // that is currently happening. It will return immediatelly, will
-  // not wait for the backup to stop.
-  // The backup will stop ASAP and the call to CreateNewBackup will
-  // return Status::Incomplete(). It will not clean up after itself, but
-  // the state will remain consistent. The state will be cleaned up
-  // next time you create BackupableDB or RestoreBackupableDB.
-  void StopBackup();
-
- private:
-  BackupEngine* backup_engine_;
-};
-
-// Use this class to access information about backups and restore from them
-class RestoreBackupableDB {
- public:
-  RestoreBackupableDB(Env* db_env, const BackupableDBOptions& options);
-  ~RestoreBackupableDB();
-
-  // Returns info about backups in backup_info
-  void GetBackupInfo(std::vector<BackupInfo>* backup_info);
-
-  // restore from backup with backup_id
-  // IMPORTANT -- if options_.share_table_files == true and you restore DB
-  // from some backup that is not the latest, and you start creating new
-  // backups from the new DB, they will probably fail
-  //
-  // Example: Let's say you have backups 1, 2, 3, 4, 5 and you restore 3.
-  // If you add new data to the DB and try creating a new backup now, the
-  // database will diverge from backups 4 and 5 and the new backup will fail.
-  // If you want to create new backup, you will first have to delete backups 4
-  // and 5.
-  Status RestoreDBFromBackup(BackupID backup_id, const std::string& db_dir,
-                             const std::string& wal_dir,
-                             const RestoreOptions& restore_options =
-                                 RestoreOptions());
-
-  // restore from the latest backup
-  Status RestoreDBFromLatestBackup(const std::string& db_dir,
-                                   const std::string& wal_dir,
-                                   const RestoreOptions& restore_options =
-                                       RestoreOptions());
-  // deletes old backups, keeping latest num_backups_to_keep alive
-  Status PurgeOldBackups(uint32_t num_backups_to_keep);
-  // deletes a specific backup
-  Status DeleteBackup(BackupID backup_id);
-
- private:
-  BackupEngine* backup_engine_;
-};
-
-}  // namespace rocksdb
-#endif  // ROCKSDB_LITE
+#warning This file was moved to rocksdb/utilities/backupable_db.h
+#include "rocksdb/utilities/backupable_db.h"
@@ -4,65 +4,5 @@
 //  of patent rights can be found in the PATENTS file in the same directory.

 #pragma once
-#ifndef ROCKSDB_LITE
-
-#include <string>
-#include <vector>
-
-#include "utilities/stackable_db.h"
-#include "rocksdb/db.h"
-
-namespace rocksdb {
-
-// Database with TTL support.
-//
-// USE-CASES:
-// This API should be used to open the db when key-values inserted are
-//  meant to be removed from the db in a non-strict 'ttl' amount of time
-//  Therefore, this guarantees that key-values inserted will remain in the
-//  db for >= ttl amount of time and the db will make efforts to remove the
-//  key-values as soon as possible after ttl seconds of their insertion.
-//
-// BEHAVIOUR:
-// TTL is accepted in seconds
-// (int32_t)Timestamp(creation) is suffixed to values in Put internally
-// Expired TTL values deleted in compaction only:(Timestamp+ttl<time_now)
-// Get/Iterator may return expired entries(compaction not run on them yet)
-// Different TTL may be used during different Opens
-// Example: Open1 at t=0 with ttl=4 and insert k1,k2, close at t=2
-//          Open2 at t=3 with ttl=5. Now k1,k2 should be deleted at t>=5
-// read_only=true opens in the usual read-only mode. Compactions will not be
-//  triggered(neither manual nor automatic), so no expired entries removed
-//
-// CONSTRAINTS:
-// Not specifying/passing or non-positive TTL behaves like TTL = infinity
-//
-// !!!WARNING!!!:
-// Calling DB::Open directly to re-open a db created by this API will get
-//  corrupt values(timestamp suffixed) and no ttl effect will be there
-//  during the second Open, so use this API consistently to open the db
-// Be careful when passing ttl with a small positive value because the
-//  whole database may be deleted in a small amount of time
-
-class DBWithTTL : public StackableDB {
- public:
-  virtual Status CreateColumnFamilyWithTtl(
-      const ColumnFamilyOptions& options, const std::string& column_family_name,
-      ColumnFamilyHandle** handle, int ttl) = 0;
-
-  static Status Open(const Options& options, const std::string& dbname,
-                     DBWithTTL** dbptr, int32_t ttl = 0,
-                     bool read_only = false);
-
-  static Status Open(const DBOptions& db_options, const std::string& dbname,
-                     const std::vector<ColumnFamilyDescriptor>& column_families,
-                     std::vector<ColumnFamilyHandle*>* handles,
-                     DBWithTTL** dbptr, std::vector<int32_t> ttls,
-                     bool read_only = false);
-
- protected:
-  explicit DBWithTTL(DB* db) : StackableDB(db) {}
-};
-
-}  // namespace rocksdb
-#endif  // ROCKSDB_LITE
+#warning This file was moved to rocksdb/utilities/db_ttl.h
+#include "rocksdb/utilities/db_ttl.h"
@@ -4,146 +4,5 @@
 //  of patent rights can be found in the PATENTS file in the same directory.

 #pragma once
-#ifndef ROCKSDB_LITE
-
-#include <string>
-#include <vector>
-
-#include "utilities/stackable_db.h"
-#include "utilities/json_document.h"
-#include "rocksdb/db.h"
-
-namespace rocksdb {
-
-// IMPORTANT: DocumentDB is a work in progress. It is unstable and we might
-// change the API without warning. Talk to RocksDB team before using this in
-// production ;)
-
-// DocumentDB is a layer on top of RocksDB that provides a very simple JSON API.
-// When creating a DB, you specify a list of indexes you want to keep on your
-// data. You can insert a JSON document to the DB, which is automatically
-// indexed. Every document added to the DB needs to have "_id" field which is
-// automatically indexed and is an unique primary key. All other indexes are
-// non-unique.
-
-// NOTE: field names in the JSON are NOT allowed to start with '$' or
-// contain '.'. We don't currently enforce that rule, but will start behaving
-// badly.
-
-// Cursor is what you get as a result of executing query. To get all
-// results from a query, call Next() on a Cursor while  Valid() returns true
-class Cursor {
- public:
-  Cursor() = default;
-  virtual ~Cursor() {}
-
-  virtual bool Valid() const = 0;
-  virtual void Next() = 0;
-  // Lifecycle of the returned JSONDocument is until the next Next() call
-  virtual const JSONDocument& document() const = 0;
-  virtual Status status() const = 0;
-
- private:
-  // No copying allowed
-  Cursor(const Cursor&);
-  void operator=(const Cursor&);
-};
-
-struct DocumentDBOptions {
-  int background_threads = 4;
-  uint64_t memtable_size = 128 * 1024 * 1024;    // 128 MB
-  uint64_t cache_size = 1 * 1024 * 1024 * 1024;  // 1 GB
-};
-
-// TODO(icanadi) Add `JSONDocument* info` parameter to all calls that can be
-// used by the caller to get more information about the call execution (number
-// of dropped records, number of updated records, etc.)
-class DocumentDB : public StackableDB {
- public:
-  struct IndexDescriptor {
-    // Currently, you can only define an index on a single field. To specify an
-    // index on a field X, set index description to JSON "{X: 1}"
-    // Currently the value needs to be 1, which means ascending.
-    // In the future, we plan to also support indexes on multiple keys, where
-    // you could mix ascending sorting (1) with descending sorting indexes (-1)
-    JSONDocument* description;
-    std::string name;
-  };
-
-  // Open DocumentDB with specified indexes. The list of indexes has to be
-  // complete, i.e. include all indexes present in the DB, except the primary
-  // key index.
-  // Otherwise, Open() will return an error
-  static Status Open(const DocumentDBOptions& options, const std::string& name,
-                     const std::vector<IndexDescriptor>& indexes,
-                     DocumentDB** db, bool read_only = false);
-
-  explicit DocumentDB(DB* db) : StackableDB(db) {}
-
-  // Create a new index. It will stop all writes for the duration of the call.
-  // All current documents in the DB are scanned and corresponding index entries
-  // are created
-  virtual Status CreateIndex(const WriteOptions& write_options,
-                             const IndexDescriptor& index) = 0;
-
-  // Drop an index. Client is responsible to make sure that index is not being
-  // used by currently executing queries
-  virtual Status DropIndex(const std::string& name) = 0;
-
-  // Insert a document to the DB. The document needs to have a primary key "_id"
-  // which can either be a string or an integer. Otherwise the write will fail
-  // with InvalidArgument.
-  virtual Status Insert(const WriteOptions& options,
-                        const JSONDocument& document) = 0;
-
-  // Deletes all documents matching a filter atomically
-  virtual Status Remove(const ReadOptions& read_options,
-                        const WriteOptions& write_options,
-                        const JSONDocument& query) = 0;
-
-  // Does this sequence of operations:
-  // 1. Find all documents matching a filter
-  // 2. For all documents, atomically:
-  // 2.1. apply the update operators
-  // 2.2. update the secondary indexes
-  //
-  // Currently only $set update operator is supported.
-  // Syntax is: {$set: {key1: value1, key2: value2, etc...}}
-  // This operator will change a document's key1 field to value1, key2 to
-  // value2, etc. New values will be set even if a document didn't have an entry
-  // for the specified key.
-  //
-  // You can not change a primary key of a document.
-  //
-  // Update example: Update({id: {$gt: 5}, $index: id}, {$set: {enabled: true}})
-  virtual Status Update(const ReadOptions& read_options,
-                        const WriteOptions& write_options,
-                        const JSONDocument& filter,
-                        const JSONDocument& updates) = 0;
-
-  // query has to be an array in which every element is an operator. Currently
-  // only $filter operator is supported. Syntax of $filter operator is:
-  // {$filter: {key1: condition1, key2: condition2, etc.}} where conditions can
-  // be either:
-  // 1) a single value in which case the condition is equality condition, or
-  // 2) a defined operators, like {$gt: 4}, which will match all documents that
-  // have key greater than 4.
-  //
-  // Supported operators are:
-  // 1) $gt -- greater than
-  // 2) $gte -- greater than or equal
-  // 3) $lt -- less than
-  // 4) $lte -- less than or equal
-  // If you want the filter to use an index, you need to specify it like this:
-  // {$filter: {...(conditions)..., $index: index_name}}
-  //
-  // Example query:
-  // * [{$filter: {name: John, age: {$gte: 18}, $index: age}}]
-  // will return all Johns whose age is greater or equal to 18 and it will use
-  // index "age" to satisfy the query.
-  virtual Cursor* Query(const ReadOptions& read_options,
-                        const JSONDocument& query) = 0;
-};
-
-}  // namespace rocksdb
-#endif  // ROCKSDB_LITE
+#warning This file was moved to rocksdb/utilities/document_db.h
+#include "rocksdb/utilities/document_db.h"
@@ -2,104 +2,7 @@
 //  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 <string>
-#include <vector>
-
-#include "utilities/stackable_db.h"
-#include "rocksdb/status.h"
-
-namespace rocksdb {
-
-//
-// Configurable options needed for setting up a Geo database
-//
-struct GeoDBOptions {
-  // Backup info and error messages will be written to info_log
-  // if non-nullptr.
-  // Default: nullptr
-  Logger* info_log;
-
-  explicit GeoDBOptions(Logger* _info_log = nullptr):info_log(_info_log) { }
-};
-
-//
-// A position in the earth's geoid
-//
-class GeoPosition {
- public:
-  double latitude;
-  double longitude;
-
-  explicit GeoPosition(double la = 0, double lo = 0) :
-    latitude(la), longitude(lo) {
-  }
-};
-
-//
-// Description of an object on the Geoid. It is located by a GPS location,
-// and is identified by the id. The value associated with this object is
-// an opaque string 'value'. Different objects identified by unique id's
-// can have the same gps-location associated with them.
-//
-class GeoObject {
- public:
-  GeoPosition position;
-  std::string id;
-  std::string value;
-
-  GeoObject() {}
-
-  GeoObject(const GeoPosition& pos, const std::string& i,
-            const std::string& val) :
-    position(pos), id(i), value(val) {
-  }
-};
-
-//
-// Stack your DB with GeoDB to be able to get geo-spatial support
-//
-class GeoDB : public StackableDB {
- public:
-  // GeoDBOptions have to be the same as the ones used in a previous
-  // incarnation of the DB
-  //
-  // GeoDB owns the pointer `DB* db` now. You should not delete it or
-  // use it after the invocation of GeoDB
-  // GeoDB(DB* db, const GeoDBOptions& options) : StackableDB(db) {}
-  GeoDB(DB* db, const GeoDBOptions& options) : StackableDB(db) {}
-  virtual ~GeoDB() {}
-
-  // Insert a new object into the location database. The object is
-  // uniquely identified by the id. If an object with the same id already
-  // exists in the db, then the old one is overwritten by the new
-  // object being inserted here.
-  virtual Status Insert(const GeoObject& object) = 0;
-
-  // Retrieve the value of the object located at the specified GPS
-  // location and is identified by the 'id'.
-  virtual Status GetByPosition(const GeoPosition& pos,
-                               const Slice& id, std::string* value) = 0;
-
-  // Retrieve the value of the object identified by the 'id'. This method
-  // could be potentially slower than GetByPosition
-  virtual Status GetById(const Slice& id, GeoObject*  object) = 0;
-
-  // Delete the specified object
-  virtual Status Remove(const Slice& id) = 0;
-
-  // Returns a list of all items within a circular radius from the
-  // specified gps location. If 'number_of_values' is specified,
-  // then this call returns at most that many number of objects.
-  // The radius is specified in 'meters'.
-  virtual Status SearchRadial(const GeoPosition& pos,
-                              double radius,
-                              std::vector<GeoObject>* values,
-                              int number_of_values = INT_MAX) = 0;
-};
-
-}  // namespace rocksdb
-#endif  // ROCKSDB_LITE
+#warning This file was moved to rocksdb/utilities/geo_db.h
+#include "rocksdb/utilities/geo_db.h"
@@ -3,172 +3,5 @@
 //  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 <map>
-#include <unordered_map>
-#include <vector>
-
-#include "rocksdb/slice.h"
-
-// We use JSONDocument for DocumentDB API
-// Implementation inspired by folly::dynamic and rapidjson
-
-namespace rocksdb {
-
-// NOTE: none of this is thread-safe
-class JSONDocument {
- public:
-  // return nullptr on parse failure
-  static JSONDocument* ParseJSON(const char* json);
-
-  enum Type {
-    kNull,
-    kArray,
-    kBool,
-    kDouble,
-    kInt64,
-    kObject,
-    kString,
-  };
-
-  JSONDocument();  // null
-  /* implicit */ JSONDocument(bool b);
-  /* implicit */ JSONDocument(double d);
-  /* implicit */ JSONDocument(int64_t i);
-  /* implicit */ JSONDocument(const std::string& s);
-  /* implicit */ JSONDocument(const char* s);
-  // constructs JSONDocument of specific type with default value
-  explicit JSONDocument(Type type);
-
-  // copy constructor
-  JSONDocument(const JSONDocument& json_document);
-
-  ~JSONDocument();
-
-  Type type() const;
-
-  // REQUIRES: IsObject()
-  bool Contains(const std::string& key) const;
-  // Returns nullptr if !Contains()
-  // don't delete the returned pointer
-  // REQUIRES: IsObject()
-  const JSONDocument* Get(const std::string& key) const;
-  // REQUIRES: IsObject()
-  JSONDocument& operator[](const std::string& key);
-  // REQUIRES: IsObject()
-  const JSONDocument& operator[](const std::string& key) const;
-  // returns `this`, so you can chain operations.
-  // Copies value
-  // REQUIRES: IsObject()
-  JSONDocument* Set(const std::string& key, const JSONDocument& value);
-
-  // REQUIRES: IsArray() == true || IsObject() == true
-  size_t Count() const;
-
-  // REQUIRES: IsArray()
-  const JSONDocument* GetFromArray(size_t i) const;
-  // REQUIRES: IsArray()
-  JSONDocument& operator[](size_t i);
-  // REQUIRES: IsArray()
-  const JSONDocument& operator[](size_t i) const;
-  // returns `this`, so you can chain operations.
-  // Copies the value
-  // REQUIRES: IsArray() && i < Count()
-  JSONDocument* SetInArray(size_t i, const JSONDocument& value);
-  // REQUIRES: IsArray()
-  JSONDocument* PushBack(const JSONDocument& value);
-
-  bool IsNull() const;
-  bool IsArray() const;
-  bool IsBool() const;
-  bool IsDouble() const;
-  bool IsInt64() const;
-  bool IsObject() const;
-  bool IsString() const;
-
-  // REQUIRES: IsBool() == true
-  bool GetBool() const;
-  // REQUIRES: IsDouble() == true
-  double GetDouble() const;
-  // REQUIRES: IsInt64() == true
-  int64_t GetInt64() const;
-  // REQUIRES: IsString() == true
-  const std::string& GetString() const;
-
-  bool operator==(const JSONDocument& rhs) const;
-
-  std::string DebugString() const;
-
- private:
-  class ItemsIteratorGenerator;
-
- public:
-  // REQUIRES: IsObject()
-  ItemsIteratorGenerator Items() const;
-
-  // appends serialized object to dst
-  void Serialize(std::string* dst) const;
-  // returns nullptr if Slice doesn't represent valid serialized JSONDocument
-  static JSONDocument* Deserialize(const Slice& src);
-
- private:
-  void SerializeInternal(std::string* dst, bool type_prefix) const;
-  // returns false if Slice doesn't represent valid serialized JSONDocument.
-  // Otherwise, true
-  bool DeserializeInternal(Slice* input);
-
-  typedef std::vector<JSONDocument*> Array;
-  typedef std::unordered_map<std::string, JSONDocument*> Object;
-
-  // iteration on objects
-  class const_item_iterator {
-   public:
-    typedef Object::const_iterator It;
-    typedef Object::value_type value_type;
-    /* implicit */ const_item_iterator(It it) : it_(it) {}
-    It& operator++() { return ++it_; }
-    bool operator!=(const const_item_iterator& other) {
-      return it_ != other.it_;
-    }
-    value_type operator*() { return *it_; }
-
-   private:
-    It it_;
-  };
-  class ItemsIteratorGenerator {
-   public:
-    /* implicit */ ItemsIteratorGenerator(const Object& object)
-        : object_(object) {}
-    const_item_iterator begin() { return object_.begin(); }
-    const_item_iterator end() { return object_.end(); }
-
-   private:
-    const Object& object_;
-  };
-
-  union Data {
-    Data() : n(nullptr) {}
-    ~Data() {}
-
-    void* n;
-    Array a;
-    bool b;
-    double d;
-    int64_t i;
-    std::string s;
-    Object o;
-  } data_;
-  const Type type_;
-
-  // Our serialization format's first byte specifies the encoding version. That
-  // way, we can easily change our format while providing backwards
-  // compatibility. This constant specifies the current version of the
-  // serialization format
-  static const char kSerializationFormatVersion;
-};
-
-}  // namespace rocksdb
-
-#endif  // ROCKSDB_LITE
+#warning This file was moved to rocksdb/utilities/json_document.h
+#include "rocksdb/utilities/json_document.h"
@@ -3,218 +3,5 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #pragma once
-#include "rocksdb/db.h"
-
-namespace rocksdb {
-
-// This class contains APIs to stack rocksdb wrappers.Eg. Stack TTL over base d
-class StackableDB : public DB {
- public:
-  // StackableDB is the owner of db now!
-  explicit StackableDB(DB* db) : db_(db) {}
-
-  ~StackableDB() {
-    delete db_;
-  }
-
-  virtual DB* GetBaseDB() {
-    return db_;
-  }
-
-  virtual Status CreateColumnFamily(const ColumnFamilyOptions& options,
-                                    const std::string& column_family_name,
-                                    ColumnFamilyHandle** handle) {
-    return db_->CreateColumnFamily(options, column_family_name, handle);
-  }
-
-  virtual Status DropColumnFamily(ColumnFamilyHandle* column_family) {
-    return db_->DropColumnFamily(column_family);
-  }
-
-  using DB::Put;
-  virtual Status Put(const WriteOptions& options,
-                     ColumnFamilyHandle* column_family, const Slice& key,
-                     const Slice& val) override {
-    return db_->Put(options, column_family, key, val);
-  }
-
-  using DB::Get;
-  virtual Status Get(const ReadOptions& options,
-                     ColumnFamilyHandle* column_family, const Slice& key,
-                     std::string* value) override {
-    return db_->Get(options, column_family, key, value);
-  }
-
-  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) override {
-    return db_->MultiGet(options, column_family, keys, values);
-  }
-
-  using DB::KeyMayExist;
-  virtual bool KeyMayExist(const ReadOptions& options,
-                           ColumnFamilyHandle* column_family, const Slice& key,
-                           std::string* value,
-                           bool* value_found = nullptr) override {
-    return db_->KeyMayExist(options, column_family, key, value, value_found);
-  }
-
-  using DB::Delete;
-  virtual Status Delete(const WriteOptions& wopts,
-                        ColumnFamilyHandle* column_family,
-                        const Slice& key) override {
-    return db_->Delete(wopts, column_family, key);
-  }
-
-  using DB::Merge;
-  virtual Status Merge(const WriteOptions& options,
-                       ColumnFamilyHandle* column_family, const Slice& key,
-                       const Slice& value) override {
-    return db_->Merge(options, column_family, key, value);
-  }
-
-
-  virtual Status Write(const WriteOptions& opts, WriteBatch* updates)
-    override {
-      return db_->Write(opts, updates);
-  }
-
-  using DB::NewIterator;
-  virtual Iterator* NewIterator(const ReadOptions& opts,
-                                ColumnFamilyHandle* column_family) override {
-    return db_->NewIterator(opts, column_family);
-  }
-
-  virtual Status NewIterators(
-      const ReadOptions& options,
-      const std::vector<ColumnFamilyHandle*>& column_families,
-      std::vector<Iterator*>* iterators) {
-    return db_->NewIterators(options, column_families, iterators);
-  }
-
-
-  virtual const Snapshot* GetSnapshot() override {
-    return db_->GetSnapshot();
-  }
-
-  virtual void ReleaseSnapshot(const Snapshot* snapshot) override {
-    return db_->ReleaseSnapshot(snapshot);
-  }
-
-  using DB::GetProperty;
-  virtual bool GetProperty(ColumnFamilyHandle* column_family,
-                           const Slice& property, std::string* value) override {
-      return db_->GetProperty(column_family, property, value);
-  }
-
-  using DB::GetApproximateSizes;
-  virtual void GetApproximateSizes(ColumnFamilyHandle* column_family,
-                                   const Range* r, int n,
-                                   uint64_t* sizes) override {
-      return db_->GetApproximateSizes(column_family, r, n, sizes);
-  }
-
-  using DB::CompactRange;
-  virtual Status CompactRange(ColumnFamilyHandle* column_family,
-                              const Slice* begin, const Slice* end,
-                              bool reduce_level = false,
-                              int target_level = -1) override {
-    return db_->CompactRange(column_family, begin, end, reduce_level,
-                             target_level);
-  }
-
-  using DB::NumberLevels;
-  virtual int NumberLevels(ColumnFamilyHandle* column_family) override {
-    return db_->NumberLevels(column_family);
-  }
-
-  using DB::MaxMemCompactionLevel;
-  virtual int MaxMemCompactionLevel(ColumnFamilyHandle* column_family)
-      override {
-    return db_->MaxMemCompactionLevel(column_family);
-  }
-
-  using DB::Level0StopWriteTrigger;
-  virtual int Level0StopWriteTrigger(ColumnFamilyHandle* column_family)
-      override {
-    return db_->Level0StopWriteTrigger(column_family);
-  }
-
-  virtual const std::string& GetName() const override {
-    return db_->GetName();
-  }
-
-  virtual Env* GetEnv() const override {
-    return db_->GetEnv();
-  }
-
-  using DB::GetOptions;
-  virtual const Options& GetOptions(ColumnFamilyHandle* column_family) const
-      override {
-    return db_->GetOptions(column_family);
-  }
-
-  using DB::Flush;
-  virtual Status Flush(const FlushOptions& fopts,
-                       ColumnFamilyHandle* column_family) override {
-    return db_->Flush(fopts, column_family);
-  }
-
-  virtual Status DisableFileDeletions() override {
-    return db_->DisableFileDeletions();
-  }
-
-  virtual Status EnableFileDeletions(bool force) override {
-    return db_->EnableFileDeletions(force);
-  }
-
-  virtual void GetLiveFilesMetaData(
-      std::vector<LiveFileMetaData>* metadata) override {
-    db_->GetLiveFilesMetaData(metadata);
-  }
-
-  virtual Status GetLiveFiles(std::vector<std::string>& vec, uint64_t* mfs,
-                              bool flush_memtable = true) override {
-      return db_->GetLiveFiles(vec, mfs, flush_memtable);
-  }
-
-  virtual SequenceNumber GetLatestSequenceNumber() const override {
-    return db_->GetLatestSequenceNumber();
-  }
-
-  virtual Status GetSortedWalFiles(VectorLogPtr& files) override {
-    return db_->GetSortedWalFiles(files);
-  }
-
-  virtual Status DeleteFile(std::string name) override {
-    return db_->DeleteFile(name);
-  }
-
-  virtual Status GetDbIdentity(std::string& identity) {
-    return db_->GetDbIdentity(identity);
-  }
-
-  using DB::GetPropertiesOfAllTables;
-  virtual Status GetPropertiesOfAllTables(ColumnFamilyHandle* column_family,
-                                          TablePropertiesCollection* props) {
-    return db_->GetPropertiesOfAllTables(column_family, props);
-  }
-
-  virtual Status GetUpdatesSince(
-      SequenceNumber seq_number, unique_ptr<TransactionLogIterator>* iter,
-      const TransactionLogIterator::ReadOptions& read_options) override {
-    return db_->GetUpdatesSince(seq_number, iter, read_options);
-  }
-
-  virtual ColumnFamilyHandle* DefaultColumnFamily() const override {
-    return db_->DefaultColumnFamily();
-  }
-
- protected:
-  DB* db_;
-};
-
-} //  namespace rocksdb
+#warning This file was moved to rocksdb/utilities/stackable_db.h
+#include "rocksdb/utilities/stackable_db.h"
@@ -3,28 +3,5 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.

 #pragma once
-#ifndef ROCKSDB_LITE
-#include <vector>
-#include <string>
-
-#include "utilities/stackable_db.h"
-#include "utilities/db_ttl.h"
-#include "rocksdb/db.h"
-
-namespace rocksdb {
-
-// Please don't use this class. It's deprecated
-class UtilityDB {
- public:
-  // This function is here only for backwards compatibility. Please use the
-  // functions defined in DBWithTTl (utilities/db_ttl.h)
-  // (deprecated)
-  __attribute__((deprecated)) static Status OpenTtlDB(const Options& options,
-                                                      const std::string& name,
-                                                      StackableDB** dbptr,
-                                                      int32_t ttl = 0,
-                                                      bool read_only = false);
-};
-
-} //  namespace rocksdb
-#endif  // ROCKSDB_LITE
+#warning This file was moved to rocksdb/utilities/utility_db.h
+#include "rocksdb/utilities/utility_db.h"
@@ -3,11 +3,6 @@ NATIVE_JAVA_CLASSES = org.rocksdb.RocksDB org.rocksdb.Options org.rocksdb.WriteB
 NATIVE_INCLUDE = ./include
 ROCKSDB_JAR = rocksdbjni.jar

-ROCKSDBJNILIB = ./librocksdbjni.so
-ifeq ($(PLATFORM), OS_MACOSX)
-  ROCKSDBJNILIB = ./librocksdbjni.jnilib
-endif
-
 clean:
 	-find . -name "*.class" -exec rm {} \;
 	-find . -name "hs*.log" -exec rm {} \;
@@ -16,7 +11,6 @@ clean:
 java:
 	javac org/rocksdb/util/*.java org/rocksdb/*.java
 	@cp ../HISTORY.md ./HISTORY-CPP.md
-	jar -cf $(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class HISTORY*.md $(ROCKSDBJNILIB)
 	@rm -f ./HISTORY-CPP.md
 	javah -d $(NATIVE_INCLUDE) -jni $(NATIVE_JAVA_CLASSES)

@@ -44,7 +44,9 @@ public class RocksDBSample {
        .setBlockSize(64 * SizeUnit.KB)
        .setMaxBackgroundCompactions(10)
        .setFilter(filter)
-        .setCompressionType(CompressionType.SNAPPY_COMPRESSION);
+        .setCacheNumShardBits(6)
+        .setCompressionType(CompressionType.SNAPPY_COMPRESSION)
+        .setCompactionStyle(CompactionStyle.UNIVERSAL);
    Statistics stats = options.statisticsPtr();

    assert(options.createIfMissing() == true);
@@ -53,7 +55,9 @@ public class RocksDBSample {
    assert(options.disableSeekCompaction() == true);
    assert(options.blockSize() == 64 * SizeUnit.KB);
    assert(options.maxBackgroundCompactions() == 10);
+    assert(options.cacheNumShardBits() == 6);
    assert(options.compressionType() == CompressionType.SNAPPY_COMPRESSION);
+    assert(options.compactionStyle() == CompactionStyle.UNIVERSAL);

    assert(options.memTableFactoryName().equals("SkipListFactory"));
    options.setMemTableConfig(
@@ -0,0 +1,22 @@
+// Copyright (c) 2014, 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.
+
+package org.rocksdb;
+
+public enum CompactionStyle {
+  LEVEL((byte) 0),
+  UNIVERSAL((byte) 1),
+  FIFO((byte) 2);
+  
+  private final byte value_;
+
+  private CompactionStyle(byte value) {
+    value_ = value;
+  }
+
+  public byte getValue() {
+    return value_;
+  }
+}
@@ -9,11 +9,12 @@ package org.rocksdb;
 * Options to control the behavior of a database.  It will be used
 * during the creation of a RocksDB (i.e., RocksDB.open()).
 *
- * Note that dispose() must be called before an Options instance
- * become out-of-scope to release the allocated memory in c++.
+ * If dispose() function is not called, then it will be GC'd automatically and
+ * native resources will be released as part of the process.
 */
 public class Options extends RocksObject {
  static final long DEFAULT_CACHE_SIZE = 8 << 20;
+  static final int DEFAULT_NUM_SHARD_BITS = -1;
  /**
   * Construct options for opening a RocksDB.
   *
@@ -23,6 +24,7 @@ public class Options extends RocksObject {
  public Options() {
    super();
    cacheSize_ = DEFAULT_CACHE_SIZE;
+    numShardBits_ = DEFAULT_NUM_SHARD_BITS;
    newOptions();
    env_ = RocksEnv.getDefault();
  }
@@ -166,8 +168,11 @@ public class Options extends RocksObject {
  /**
   * Use the specified filter policy to reduce disk reads.
   *
-   * Note that the caller should not dispose the input filter as
-   * Options.dispose() will dispose this filter.
+   * Filter should not be disposed before options instances using this filter is
+   * disposed. If dispose() function is not called, then filter object will be
+   * GC'd automatically.
+   * 
+   * Filter instance can be re-used in multiple options instances. 
   *
   * @param Filter policy java instance.
   * @return the instance of the current Options.
@@ -215,6 +220,7 @@ public class Options extends RocksObject {
   * If cacheSize is non-positive, then cache will not be used.
   *
   * DEFAULT: 8M
+   * @see setCacheNumShardBits()
   */
  public Options setCacheSize(long cacheSize) {
    cacheSize_ = cacheSize;
@@ -223,11 +229,42 @@ public class Options extends RocksObject {

  /**
   * @return the amount of cache in bytes that will be used by RocksDB.
+   *
+   * @see cacheNumShardBits()
   */
  public long cacheSize() {
    return cacheSize_;
  }

+  /**
+   * Controls the number of shards for the block cache.
+   * This is applied only if cacheSize is set to non-negative.
+   *
+   * @param numShardBits the number of shard bits.  The resulting
+   *     number of shards would be 2 ^ numShardBits.  Any negative
+   *     number means use default settings."
+   * @return the reference to the current option.
+   *
+   * @see setCacheSize()
+   */
+  public Options setCacheNumShardBits(int numShardBits) {
+    numShardBits_ = numShardBits;
+    return this;
+  }
+
+  /**
+   * Returns the number of shard bits used in the block cache.
+   * The resulting number of shards would be 2 ^ (returned value).
+   * Any negative number means use default settings.
+   *
+   * @return the number of shard bits used in the block cache.
+   *
+   * @see cacheSize()
+   */
+  public int cacheNumShardBits() {
+    return numShardBits_;
+  }
+
  /**
   * If true, an error will be thrown during RocksDB.open() if the
   * database already exists.
@@ -1335,6 +1372,30 @@ public class Options extends RocksObject {
    return this;
  }
  private native void setCompressionType(long handle, byte compressionType);
+      
+   /**
+   * Compaction style for DB.
+   * 
+   * @return Compaction style.
+   */ 
+  public CompactionStyle compactionStyle() {
+    return CompactionStyle.values()[compactionStyle(nativeHandle_)];
+  }
+  private native byte compactionStyle(long handle);
+      
+  /**
+   * Set compaction style for DB.
+   * 
+   * Default: LEVEL.
+   * 
+   * @param compactionStyle Compaction style.
+   * @return the reference to the current option.
+   */
+  public Options setCompactionStyle(CompactionStyle compactionStyle) {
+    setCompactionStyle(nativeHandle_, compactionStyle.getValue());
+    return this;
+  }
+  private native void setCompactionStyle(long handle, byte compactionStyle);

  /**
   * If true, place whole keys in the filter (not just prefixes).
@@ -2397,6 +2458,7 @@ public class Options extends RocksObject {
      long handle, int prefixLength);

  long cacheSize_;
+  int numShardBits_;
  Filter filter_;
  RocksEnv env_;
 }
@@ -99,6 +99,15 @@ public class RocksDB extends RocksObject {
  /**
   * The factory constructor of RocksDB that opens a RocksDB instance given
   * the path to the database using the specified options and db path.
+   * 
+   * Options instance *should* not be disposed before all DBs using this options
+   * instance have been closed. If user doesn't call options dispose explicitly,
+   * then this options instance will be GC'd automatically.
+   * 
+   * Options instance can be re-used to open multiple DBs if DB statistics is
+   * not used. If DB statistics are required, then its recommended to open DB
+   * with new Options instance as underlying native statistics instance does not
+   * use any locks to prevent concurrent updates.
   */
  public static RocksDB open(Options options, String path)
      throws RocksDBException {
@@ -106,10 +115,16 @@ public class RocksDB extends RocksObject {
    // in RocksDB can prevent Java to GC during the life-time of
    // the currently-created RocksDB.
    RocksDB db = new RocksDB();
-    db.open(options.nativeHandle_, options.cacheSize_, path);
-    db.transferCppRawPointersOwnershipFrom(options);
+    db.open(options.nativeHandle_, options.cacheSize_,
+            options.numShardBits_, path);
+    
+    db.storeOptionsInstance(options);
    return db;
  }
+  
+  private void storeOptionsInstance(Options options) {
+    options_ = options;
+  }

  @Override protected void disposeInternal() {
    assert(isInitialized());
@@ -317,20 +332,10 @@ public class RocksDB extends RocksObject {
    super();
  }

-  /**
-   * Transfer the ownership of all c++ raw-pointers from Options
-   * to RocksDB to ensure the life-time of those raw-pointers
-   * will be at least as long as the life-time of any RocksDB
-   * that uses these raw-pointers.
-   */
-  protected void transferCppRawPointersOwnershipFrom(Options opt) {
-    filter_ = opt.filter_;
-    opt.filter_ = null;
-  }
-
  // native methods
  protected native void open(
-      long optionsHandle, long cacheSize, String path) throws RocksDBException;
+      long optionsHandle, long cacheSize, int numShardBits,
+      String path) throws RocksDBException;
  protected native void put(
      long handle, byte[] key, int keyLen,
      byte[] value, int valueLen) throws RocksDBException;
@@ -363,5 +368,5 @@ public class RocksDB extends RocksObject {
  protected native long iterator0(long optHandle);
  private native void disposeInternal(long handle);

-  protected Filter filter_;
+  protected Options options_;
 }
@@ -5,8 +5,10 @@

 package org.rocksdb;

+import java.util.List;
 import java.util.concurrent.ArrayBlockingQueue;
-import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;

@@ -20,41 +22,43 @@ import java.util.concurrent.atomic.AtomicBoolean;
 * provided in constructor) reference has been disposed.
 */
 public class StatisticsCollector {
-  private final Statistics _statistics;
-  private final ThreadPoolExecutor _threadPoolExecutor;
+  private final List<StatsCollectorInput> _statsCollectorInputList;
+  private final ExecutorService _executorService;
  private final int _statsCollectionInterval;
-  private final StatisticsCollectorCallback _statsCallback;
  private volatile boolean _isRunning = true;

  /**
   * Constructor for statistics collector.
-   * @param statistics Reference of DB statistics.
+   * 
+   * @param statsCollectorInputList List of statistics collector input.
   * @param statsCollectionIntervalInMilliSeconds Statistics collection time 
-   *        period (specified in milliseconds) 
-   * @param statsCallback Reference of statistics callback interface.
+   *        period (specified in milliseconds).
   */
-  public StatisticsCollector(Statistics statistics,
-      int statsCollectionIntervalInMilliSeconds,
-      StatisticsCollectorCallback statsCallback) {
-    _statistics = statistics;
+  public StatisticsCollector(List<StatsCollectorInput> statsCollectorInputList,
+      int statsCollectionIntervalInMilliSeconds) {
+    _statsCollectorInputList = statsCollectorInputList;
    _statsCollectionInterval = statsCollectionIntervalInMilliSeconds;
-    _statsCallback = statsCallback;

-    _threadPoolExecutor = new ThreadPoolExecutor(1, 1, 0, TimeUnit.SECONDS,
-        new ArrayBlockingQueue<Runnable>(1));
+    _executorService = Executors.newSingleThreadExecutor();
  }

  public void start() {
-    _threadPoolExecutor.submit(collectStatistics());
+    _executorService.submit(collectStatistics());
  }

-  public void shutDown() throws InterruptedException {
+  /**
+   * Shuts down statistics collector.
+   * 
+   * @param shutdownTimeout Time in milli-seconds to wait for shutdown before
+   *        killing the collection process.
+   */
+  public void shutDown(int shutdownTimeout) throws InterruptedException {
    _isRunning = false;

-    _threadPoolExecutor.shutdown();
+    _executorService.shutdownNow();
    // Wait for collectStatistics runnable to finish so that disposal of
    // statistics does not cause any exceptions to be thrown.
-    _threadPoolExecutor.awaitTermination(Integer.MAX_VALUE, TimeUnit.SECONDS);
+    _executorService.awaitTermination(shutdownTimeout, TimeUnit.MILLISECONDS);
  }

  private Runnable collectStatistics() {
@@ -64,24 +68,34 @@ public class StatisticsCollector {
      public void run() {
        while (_isRunning) {
          try {
-            // Collect ticker data
-            for(TickerType ticker : TickerType.values()) {
-              long tickerValue = _statistics.getTickerCount(ticker);
-              _statsCallback.tickerCallback(ticker, tickerValue);
-            }
+            if(Thread.currentThread().isInterrupted()) {
+              break;
+            }  
+            for(StatsCollectorInput statsCollectorInput :
+                _statsCollectorInputList) {
+              Statistics statistics = statsCollectorInput.getStatistics();
+              StatisticsCollectorCallback statsCallback =
+                  statsCollectorInput.getCallback();
+              
+                // Collect ticker data
+              for(TickerType ticker : TickerType.values()) {
+                long tickerValue = statistics.getTickerCount(ticker);
+                statsCallback.tickerCallback(ticker, tickerValue);
+              }

-            // Collect histogram data
-            for(HistogramType histogramType : HistogramType.values()) {
-              HistogramData histogramData =
-                  _statistics.geHistogramData(histogramType);
-              _statsCallback.histogramCallback(histogramType, histogramData);
-            }
+              // Collect histogram data
+              for(HistogramType histogramType : HistogramType.values()) {
+                HistogramData histogramData =
+                    statistics.geHistogramData(histogramType);
+                statsCallback.histogramCallback(histogramType, histogramData);
+              }

-            Thread.sleep(_statsCollectionInterval);
+              Thread.sleep(_statsCollectionInterval);
+            }
          }
          catch (InterruptedException e) {
            Thread.currentThread().interrupt();
-            throw new RuntimeException("Thread got interrupted!", e);
+            break;
          }
          catch (Exception e) {
            throw new RuntimeException("Error while calculating statistics", e);
@@ -12,7 +12,7 @@ package org.rocksdb;
 * StatisticsCollector doesn't make any guarantees about thread safety. 
 * If the same reference of StatisticsCollectorCallback is passed to multiple
 * StatisticsCollector references, then its the responsibility of the 
- * user to make StatisticsCollectorCallback' implementation thread-safe.
+ * user to make StatisticsCollectorCallback's implementation thread-safe.
 * 
 * @param tickerType
 * @param tickerCount
@@ -0,0 +1,35 @@
+// Copyright (c) 2014, 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.
+
+package org.rocksdb;
+
+/**
+ * Contains all information necessary to collect statistics from one instance
+ * of DB statistics.
+ */
+public class StatsCollectorInput {
+  private final Statistics _statistics;
+  private final StatisticsCollectorCallback _statsCallback;
+      
+  /**
+   * Constructor for StatsCollectorInput.
+   * 
+   * @param statistics Reference of DB statistics.
+   * @param statsCallback Reference of statistics callback interface.
+   */
+  public StatsCollectorInput(Statistics statistics,
+      StatisticsCollectorCallback statsCallback) {
+    _statistics = statistics;
+    _statsCallback = statsCallback;
+  }
+  
+  public Statistics getStatistics() {
+    return _statistics;
+  }
+  
+  public StatisticsCollectorCallback getCallback() {
+    return _statsCallback;
+  }
+}
@@ -534,6 +534,8 @@ public class DbBenchmark {
        (Integer)flags_.get(Flag.max_background_flushes));
    options.setCacheSize(
        (Long)flags_.get(Flag.cache_size));
+    options.setCacheNumShardBits(
+        (Integer)flags_.get(Flag.cache_numshardbits));
    options.setBlockSize(
        (Long)flags_.get(Flag.block_size));
    options.setMaxOpenFiles(
@@ -616,7 +618,6 @@ public class DbBenchmark {
    options.setCompressionLevel((Integer)flags_.get(Flag.compression_level));
    options.setMinLevelToCompress((Integer)flags_.get(Flag.min_level_to_compress));
    options.setHdfs((String)flags_.get(Flag.hdfs)); // env
-    options.setCacheNumshardbits((Integer)flags_.get(Flag.cache_numshardbits));
    options.setStatistics((Boolean)flags_.get(Flag.statistics));
    options.setUniversalSizeRatio(
        (Integer)flags_.get(Flag.universal_size_ratio));
@@ -5,6 +5,7 @@

 package org.rocksdb.test;

+import java.util.Collections;
 import org.rocksdb.*;

 public class StatisticsCollectorTest {
@@ -21,8 +22,10 @@ public class StatisticsCollectorTest {
    RocksDB db = RocksDB.open(db_path);

    StatsCallbackMock callback = new StatsCallbackMock();
-    StatisticsCollector statsCollector = new StatisticsCollector(stats, 100,
-        callback);
+    StatsCollectorInput statsInput = new StatsCollectorInput(stats, callback);
+    
+    StatisticsCollector statsCollector = new StatisticsCollector(
+        Collections.singletonList(statsInput), 100);
    statsCollector.start();

    Thread.sleep(1000);
@@ -30,7 +33,7 @@ public class StatisticsCollectorTest {
    assert(callback.tickerCallbackCount > 0);
    assert(callback.histCallbackCount > 0);

-    statsCollector.shutDown();
+    statsCollector.shutDown(1000);

    db.close();
    opt.dispose();
@@ -15,7 +15,7 @@
 #include "include/org_rocksdb_BackupableDB.h"
 #include "include/org_rocksdb_BackupableDBOptions.h"
 #include "rocksjni/portal.h"
-#include "utilities/backupable_db.h"
+#include "rocksdb/utilities/backupable_db.h"

 /*
 * Class:     org_rocksdb_BackupableDB
@@ -956,6 +956,27 @@ jbyte Java_org_rocksdb_Options_compressionType(
  return reinterpret_cast<rocksdb::Options*>(jhandle)->compression;
 }

+/*
+ * Class:     org_rocksdb_Options
+ * Method:    setCompactionStyle
+ * Signature: (JB)V
+ */
+void Java_org_rocksdb_Options_setCompactionStyle(
+    JNIEnv* env, jobject jobj, jlong jhandle, jbyte compaction_style) {
+  reinterpret_cast<rocksdb::Options*>(jhandle)->compaction_style =
+      static_cast<rocksdb::CompactionStyle>(compaction_style);
+}
+
+/*
+ * Class:     org_rocksdb_Options
+ * Method:    compactionStyle
+ * Signature: (J)B
+ */
+jbyte Java_org_rocksdb_Options_compactionStyle(
+    JNIEnv* env, jobject jobj, jlong jhandle) {
+  return reinterpret_cast<rocksdb::Options*>(jhandle)->compaction_style;
+}
+
 /*
 * Class:     org_rocksdb_Options
 * Method:    wholeKeyFiltering
@@ -13,7 +13,7 @@
 #include <jni.h>
 #include "rocksdb/db.h"
 #include "rocksdb/filter_policy.h"
-#include "utilities/backupable_db.h"
+#include "rocksdb/utilities/backupable_db.h"

 namespace rocksdb {

@@ -16,7 +16,7 @@
 #include "include/org_rocksdb_RestoreOptions.h"
 #include "include/org_rocksdb_RestoreBackupableDB.h"
 #include "rocksjni/portal.h"
-#include "utilities/backupable_db.h"
+#include "rocksdb/utilities/backupable_db.h"
 /*
 * Class:     org_rocksdb_RestoreOptions
 * Method:    newRestoreOptions
@@ -27,11 +27,15 @@
 */
 void Java_org_rocksdb_RocksDB_open(
    JNIEnv* env, jobject jdb, jlong jopt_handle,
-    jlong jcache_size, jstring jdb_path) {
+    jlong jcache_size, jint jnum_shardbits, jstring jdb_path) {
  auto opt = reinterpret_cast<rocksdb::Options*>(jopt_handle);
  if (jcache_size > 0) {
    opt->no_block_cache = false;
-    opt->block_cache = rocksdb::NewLRUCache(jcache_size);
+    if (jnum_shardbits >= 1) {
+      opt->block_cache = rocksdb::NewLRUCache(jcache_size, jnum_shardbits);
+    } else {
+      opt->block_cache = rocksdb::NewLRUCache(jcache_size);
+    }
  } else {
    opt->no_block_cache = true;
    opt->block_cache = nullptr;
@@ -17,9 +17,10 @@
 jlong Java_org_rocksdb_PlainTableConfig_newTableFactoryHandle(
    JNIEnv* env, jobject jobj, jint jkey_size, jint jbloom_bits_per_key,
    jdouble jhash_table_ratio, jint jindex_sparseness) {
-  return reinterpret_cast<jlong>(rocksdb::NewPlainTableFactory(
-          static_cast<uint32_t>(jkey_size),
-          static_cast<int>(jbloom_bits_per_key),
-          static_cast<double>(jhash_table_ratio),
-          static_cast<size_t>(jindex_sparseness)));
+  rocksdb::PlainTableOptions options = rocksdb::PlainTableOptions();
+  options.user_key_len = jkey_size;
+  options.bloom_bits_per_key = jbloom_bits_per_key;
+  options.hash_table_ratio = jhash_table_ratio;
+  options.index_sparseness = jindex_sparseness;
+  return reinterpret_cast<jlong>(rocksdb::NewPlainTableFactory(options));
 }
@@ -20,7 +20,9 @@ void PrintStack(int first_frames_to_skip) {}
 #include <execinfo.h>
 #include <signal.h>
 #include <stdio.h>
-#include <stdlib.h>
+// It's odd that including this breaks in GCC 7 but the build doesn't break
+// if I remove it even under GCC 4.8.
+// #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <cxxabi.h>
@@ -17,43 +17,14 @@
 #include <vector>

 #include "rocksdb/comparator.h"
+#include "table/format.h"
 #include "table/block_hash_index.h"
 #include "table/block_prefix_index.h"
-#include "table/format.h"
 #include "util/coding.h"
 #include "util/logging.h"

 namespace rocksdb {

-uint32_t Block::NumRestarts() const {
-  assert(size_ >= 2*sizeof(uint32_t));
-  return DecodeFixed32(data_ + size_ - sizeof(uint32_t));
-}
-
-Block::Block(const BlockContents& contents)
-    : data_(contents.data.data()),
-      size_(contents.data.size()),
-      owned_(contents.heap_allocated),
-      cachable_(contents.cachable),
-      compression_type_(contents.compression_type) {
-  if (size_ < sizeof(uint32_t)) {
-    size_ = 0;  // Error marker
-  } else {
-    restart_offset_ = size_ - (1 + NumRestarts()) * sizeof(uint32_t);
-    if (restart_offset_ > size_ - sizeof(uint32_t)) {
-      // The size is too small for NumRestarts() and therefore
-      // restart_offset_ wrapped around.
-      size_ = 0;
-    }
-  }
-}
-
-Block::~Block() {
-  if (owned_) {
-    delete[] data_;
-  }
-}
-
 // Helper routine: decode the next block entry starting at "p",
 // storing the number of shared key bytes, non_shared key bytes,
 // and the length of the value in "*shared", "*non_shared", and
@@ -84,142 +55,85 @@ static inline const char* DecodeEntry(const char* p, const char* limit,
  return p;
 }

-class Block::Iter : public Iterator {
- private:
-  const Comparator* const comparator_;
-  const char* const data_;      // underlying block contents
-  uint32_t const restarts_;     // Offset of restart array (list of fixed32)
-  uint32_t const num_restarts_; // Number of uint32_t entries in restart array
+void BlockIter::Next() {
+  assert(Valid());
+  ParseNextKey();
+}

-  // current_ is offset in data_ of current entry.  >= restarts_ if !Valid
-  uint32_t current_;
-  uint32_t restart_index_;  // Index of restart block in which current_ falls
-  std::string key_;
-  Slice value_;
-  Status status_;
-  BlockHashIndex* hash_index_;
-  BlockPrefixIndex* prefix_index_;
+void BlockIter::Prev() {
+  assert(Valid());

-  inline int Compare(const Slice& a, const Slice& b) const {
-    return comparator_->Compare(a, b);
-  }
-
-  // Return the offset in data_ just past the end of the current entry.
-  inline uint32_t NextEntryOffset() const {
-    return (value_.data() + value_.size()) - data_;
-  }
-
-  uint32_t GetRestartPoint(uint32_t index) {
-    assert(index < num_restarts_);
-    return DecodeFixed32(data_ + restarts_ + index * sizeof(uint32_t));
-  }
-
-  void SeekToRestartPoint(uint32_t index) {
-    key_.clear();
-    restart_index_ = index;
-    // current_ will be fixed by ParseNextKey();
-
-    // ParseNextKey() starts at the end of value_, so set value_ accordingly
-    uint32_t offset = GetRestartPoint(index);
-    value_ = Slice(data_ + offset, 0);
-  }
-
- public:
-  Iter(const Comparator* comparator, const char* data, uint32_t restarts,
-       uint32_t num_restarts, BlockHashIndex* hash_index,
-       BlockPrefixIndex* prefix_index)
-      : comparator_(comparator),
-        data_(data),
-        restarts_(restarts),
-        num_restarts_(num_restarts),
-        current_(restarts_),
-        restart_index_(num_restarts_),
-        hash_index_(hash_index),
-        prefix_index_(prefix_index) {
-    assert(num_restarts_ > 0);
-  }
-
-  virtual bool Valid() const { return current_ < restarts_; }
-  virtual Status status() const { return status_; }
-  virtual Slice key() const {
-    assert(Valid());
-    return key_;
-  }
-  virtual Slice value() const {
-    assert(Valid());
-    return value_;
-  }
-
-  virtual void Next() {
-    assert(Valid());
-    ParseNextKey();
-  }
-
-  virtual void Prev() {
-    assert(Valid());
-
-    // Scan backwards to a restart point before current_
-    const uint32_t original = current_;
-    while (GetRestartPoint(restart_index_) >= original) {
-      if (restart_index_ == 0) {
-        // No more entries
-        current_ = restarts_;
-        restart_index_ = num_restarts_;
-        return;
-      }
-      restart_index_--;
-    }
-
-    SeekToRestartPoint(restart_index_);
-    do {
-      // Loop until end of current entry hits the start of original entry
-    } while (ParseNextKey() && NextEntryOffset() < original);
-  }
-
-  virtual void Seek(const Slice& target) {
-    uint32_t index = 0;
-    bool ok = false;
-    if (prefix_index_) {
-      ok = PrefixSeek(target, &index);
-    } else {
-      ok = hash_index_ ? HashSeek(target, &index)
-        : BinarySeek(target, 0, num_restarts_ - 1, &index);
-    }
-
-    if (!ok) {
+  // Scan backwards to a restart point before current_
+  const uint32_t original = current_;
+  while (GetRestartPoint(restart_index_) >= original) {
+    if (restart_index_ == 0) {
+      // No more entries
+      current_ = restarts_;
+      restart_index_ = num_restarts_;
      return;
    }
-    SeekToRestartPoint(index);
-    // Linear search (within restart block) for first key >= target
+    restart_index_--;
+  }

-    while (true) {
-      if (!ParseNextKey() || Compare(key_, target) >= 0) {
-        return;
-      }
+  SeekToRestartPoint(restart_index_);
+  do {
+    // Loop until end of current entry hits the start of original entry
+  } while (ParseNextKey() && NextEntryOffset() < original);
+}
+
+void BlockIter::Seek(const Slice& target) {
+  if (data_ == nullptr) {  // Not init yet
+    return;
+  }
+  uint32_t index = 0;
+  bool ok = false;
+  if (prefix_index_) {
+    ok = PrefixSeek(target, &index);
+  } else {
+    ok = hash_index_ ? HashSeek(target, &index)
+      : BinarySeek(target, 0, num_restarts_ - 1, &index);
+  }
+
+  if (!ok) {
+    return;
+  }
+  SeekToRestartPoint(index);
+  // Linear search (within restart block) for first key >= target
+
+  while (true) {
+    if (!ParseNextKey() || Compare(key_.GetKey(), target) >= 0) {
+      return;
    }
  }
-  virtual void SeekToFirst() {
-    SeekToRestartPoint(0);
-    ParseNextKey();
-  }
+}

-  virtual void SeekToLast() {
-    SeekToRestartPoint(num_restarts_ - 1);
-    while (ParseNextKey() && NextEntryOffset() < restarts_) {
-      // Keep skipping
-    }
+void BlockIter::SeekToFirst() {
+  if (data_ == nullptr) {  // Not init yet
+    return;
  }
+  SeekToRestartPoint(0);
+  ParseNextKey();
+}

- private:
-  void CorruptionError() {
-    current_ = restarts_;
-    restart_index_ = num_restarts_;
-    status_ = Status::Corruption("bad entry in block");
-    key_.clear();
-    value_.clear();
+void BlockIter::SeekToLast() {
+  if (data_ == nullptr) {  // Not init yet
+    return;
  }
+  SeekToRestartPoint(num_restarts_ - 1);
+  while (ParseNextKey() && NextEntryOffset() < restarts_) {
+    // Keep skipping
+  }
+}

-  bool ParseNextKey() {
+void BlockIter::CorruptionError() {
+  current_ = restarts_;
+  restart_index_ = num_restarts_;
+  status_ = Status::Corruption("bad entry in block");
+  key_.Clear();
+  value_.clear();
+}
+
+bool BlockIter::ParseNextKey() {
    current_ = NextEntryOffset();
    const char* p = data_ + current_;
    const char* limit = data_ + restarts_;  // Restarts come right after data
@@ -233,12 +147,11 @@ class Block::Iter : public Iterator {
    // Decode next entry
    uint32_t shared, non_shared, value_length;
    p = DecodeEntry(p, limit, &shared, &non_shared, &value_length);
-    if (p == nullptr || key_.size() < shared) {
+    if (p == nullptr || key_.Size() < shared) {
      CorruptionError();
      return false;
    } else {
-      key_.resize(shared);
-      key_.append(p, non_shared);
+      key_.TrimAppend(shared, p, non_shared);
      value_ = Slice(p + non_shared, value_length);
      while (restart_index_ + 1 < num_restarts_ &&
             GetRestartPoint(restart_index_ + 1) < current_) {
@@ -248,127 +161,194 @@ class Block::Iter : public Iterator {
    }
  }

-  // Binary search in restart array to find the first restart point
-  // with a key >= target (TODO: this comment is inaccurate)
-  bool BinarySeek(const Slice& target, uint32_t left, uint32_t right,
+// Binary search in restart array to find the first restart point
+// with a key >= target (TODO: this comment is inaccurate)
+bool BlockIter::BinarySeek(const Slice& target, uint32_t left, uint32_t right,
                  uint32_t* index) {
-    assert(left <= right);
+  assert(left <= right);

-    while (left < right) {
-      uint32_t mid = (left + right + 1) / 2;
-      uint32_t region_offset = GetRestartPoint(mid);
-      uint32_t shared, non_shared, value_length;
-      const char* key_ptr =
-          DecodeEntry(data_ + region_offset, data_ + restarts_, &shared,
-                      &non_shared, &value_length);
-      if (key_ptr == nullptr || (shared != 0)) {
-        CorruptionError();
-        return false;
-      }
-      Slice mid_key(key_ptr, non_shared);
-      int cmp = Compare(mid_key, target);
-      if (cmp < 0) {
-        // Key at "mid" is smaller than "target". Therefore all
-        // blocks before "mid" are uninteresting.
-        left = mid;
-      } else if (cmp > 0) {
-        // Key at "mid" is >= "target". Therefore all blocks at or
-        // after "mid" are uninteresting.
-        right = mid - 1;
-      } else {
-        left = right = mid;
-      }
+  while (left < right) {
+    uint32_t mid = (left + right + 1) / 2;
+    uint32_t region_offset = GetRestartPoint(mid);
+    uint32_t shared, non_shared, value_length;
+    const char* key_ptr =
+        DecodeEntry(data_ + region_offset, data_ + restarts_, &shared,
+                    &non_shared, &value_length);
+    if (key_ptr == nullptr || (shared != 0)) {
+      CorruptionError();
+      return false;
    }
-
-    *index = left;
-    return true;
-  }
-
-  // Binary search in block_ids to find the first block
-  // with a key >= target
-  bool BinaryBlockIndexSeek(const Slice& target, uint32_t* block_ids,
-                            uint32_t left, uint32_t right,
-                            uint32_t* index) {
-    assert(left <= right);
-
-    while (left <= right) {
-      uint32_t mid = (left + right) / 2;
-      uint32_t region_offset = GetRestartPoint(block_ids[mid]);
-      uint32_t shared, non_shared, value_length;
-      const char* key_ptr =
-          DecodeEntry(data_ + region_offset, data_ + restarts_, &shared,
-                      &non_shared, &value_length);
-      if (key_ptr == nullptr || (shared != 0)) {
-        CorruptionError();
-        return false;
-      }
-      Slice mid_key(key_ptr, non_shared);
-      int cmp = Compare(mid_key, target);
-      if (cmp < 0) {
-        // Key at "target" is larger than "mid". Therefore all
-        // blocks before or at "mid" are uninteresting.
-        left = mid + 1;
-      } else {
-        // Key at "target" is <= "mid". Therefore all blocks
-        // after "mid" are uninteresting.
-        // If there is only one block left, we found it.
-        if (left == right) break;
-        right = mid;
-      }
-    }
-
-    if (left == right) {
-      *index = block_ids[left];
-      return true;
+    Slice mid_key(key_ptr, non_shared);
+    int cmp = Compare(mid_key, target);
+    if (cmp < 0) {
+      // Key at "mid" is smaller than "target". Therefore all
+      // blocks before "mid" are uninteresting.
+      left = mid;
+    } else if (cmp > 0) {
+      // Key at "mid" is >= "target". Therefore all blocks at or
+      // after "mid" are uninteresting.
+      right = mid - 1;
    } else {
-      assert(left > right);
-      // Mark iterator invalid
-      current_ = restarts_;
-      return false;
+      left = right = mid;
    }
  }

-  bool HashSeek(const Slice& target, uint32_t* index) {
-    assert(hash_index_);
-    auto restart_index = hash_index_->GetRestartIndex(target);
-    if (restart_index == nullptr) {
+  *index = left;
+  return true;
+}
+
+// Compare target key and the block key of the block of `block_index`.
+// Return -1 if error.
+int BlockIter::CompareBlockKey(uint32_t block_index, const Slice& target) {
+  uint32_t region_offset = GetRestartPoint(block_index);
+  uint32_t shared, non_shared, value_length;
+  const char* key_ptr = DecodeEntry(data_ + region_offset, data_ + restarts_,
+                                    &shared, &non_shared, &value_length);
+  if (key_ptr == nullptr || (shared != 0)) {
+    CorruptionError();
+    return 1;  // Return target is smaller
+  }
+  Slice block_key(key_ptr, non_shared);
+  return Compare(block_key, target);
+}
+
+// Binary search in block_ids to find the first block
+// with a key >= target
+bool BlockIter::BinaryBlockIndexSeek(const Slice& target, uint32_t* block_ids,
+                          uint32_t left, uint32_t right,
+                          uint32_t* index) {
+  assert(left <= right);
+  uint32_t left_bound = left;
+
+  while (left <= right) {
+    uint32_t mid = (left + right) / 2;
+
+    int cmp = CompareBlockKey(block_ids[mid], target);
+    if (!status_.ok()) {
+      return false;
+    }
+    if (cmp < 0) {
+      // Key at "target" is larger than "mid". Therefore all
+      // blocks before or at "mid" are uninteresting.
+      left = mid + 1;
+    } else {
+      // Key at "target" is <= "mid". Therefore all blocks
+      // after "mid" are uninteresting.
+      // If there is only one block left, we found it.
+      if (left == right) break;
+      right = mid;
+    }
+  }
+
+  if (left == right) {
+    // In one of the two following cases:
+    // (1) left is the first one of block_ids
+    // (2) there is a gap of blocks between block of `left` and `left-1`.
+    // we can further distinguish the case of key in the block or key not
+    // existing, by comparing the target key and the key of the previous
+    // block to the left of the block found.
+    if (block_ids[left] > 0 &&
+        (left == left_bound || block_ids[left - 1] != block_ids[left] - 1) &&
+        CompareBlockKey(block_ids[left] - 1, target) > 0) {
      current_ = restarts_;
      return false;
    }

-    // the elements in restart_array[index : index + num_blocks]
-    // are all with same prefix. We'll do binary search in that small range.
-    auto left = restart_index->first_index;
-    auto right = restart_index->first_index + restart_index->num_blocks - 1;
-    return BinarySeek(target, left, right, index);
+    *index = block_ids[left];
+    return true;
+  } else {
+    assert(left > right);
+    // Mark iterator invalid
+    current_ = restarts_;
+    return false;
+  }
+}
+
+bool BlockIter::HashSeek(const Slice& target, uint32_t* index) {
+  assert(hash_index_);
+  auto restart_index = hash_index_->GetRestartIndex(target);
+  if (restart_index == nullptr) {
+    current_ = restarts_;
+    return false;
  }

-  bool PrefixSeek(const Slice& target, uint32_t* index) {
-    assert(prefix_index_);
-    uint32_t* block_ids = nullptr;
-    uint32_t num_blocks = prefix_index_->GetBlocks(target, &block_ids);
+  // the elements in restart_array[index : index + num_blocks]
+  // are all with same prefix. We'll do binary search in that small range.
+  auto left = restart_index->first_index;
+  auto right = restart_index->first_index + restart_index->num_blocks - 1;
+  return BinarySeek(target, left, right, index);
+}

+bool BlockIter::PrefixSeek(const Slice& target, uint32_t* index) {
+  assert(prefix_index_);
+  uint32_t* block_ids = nullptr;
+  uint32_t num_blocks = prefix_index_->GetBlocks(target, &block_ids);

-    if (num_blocks == 0) {
-      current_ = restarts_;
-      return false;
-    } else  {
-      return BinaryBlockIndexSeek(target, block_ids, 0, num_blocks - 1, index);
+  if (num_blocks == 0) {
+    current_ = restarts_;
+    return false;
+  } else  {
+    return BinaryBlockIndexSeek(target, block_ids, 0, num_blocks - 1, index);
+  }
+}
+
+uint32_t Block::NumRestarts() const {
+  assert(size_ >= 2*sizeof(uint32_t));
+  return DecodeFixed32(data_ + size_ - sizeof(uint32_t));
+}
+
+Block::Block(const BlockContents& contents)
+    : data_(contents.data.data()),
+      size_(contents.data.size()),
+      owned_(contents.heap_allocated),
+      cachable_(contents.cachable),
+      compression_type_(contents.compression_type) {
+  if (size_ < sizeof(uint32_t)) {
+    size_ = 0;  // Error marker
+  } else {
+    restart_offset_ = size_ - (1 + NumRestarts()) * sizeof(uint32_t);
+    if (restart_offset_ > size_ - sizeof(uint32_t)) {
+      // The size is too small for NumRestarts() and therefore
+      // restart_offset_ wrapped around.
+      size_ = 0;
    }
  }
-};
+}

-Iterator* Block::NewIterator(const Comparator* cmp) {
+Block::~Block() {
+  if (owned_) {
+    delete[] data_;
+  }
+}
+
+Iterator* Block::NewIterator(const Comparator* cmp, BlockIter* iter) {
  if (size_ < 2*sizeof(uint32_t)) {
-    return NewErrorIterator(Status::Corruption("bad block contents"));
+    if (iter != nullptr) {
+      iter->SetStatus(Status::Corruption("bad block contents"));
+      return iter;
+    } else {
+      return NewErrorIterator(Status::Corruption("bad block contents"));
+    }
  }
  const uint32_t num_restarts = NumRestarts();
  if (num_restarts == 0) {
-    return NewEmptyIterator();
+    if (iter != nullptr) {
+      iter->SetStatus(Status::OK());
+      return iter;
+    } else {
+      return NewEmptyIterator();
+    }
  } else {
-    return new Iter(cmp, data_, restart_offset_, num_restarts,
+    if (iter != nullptr) {
+      iter->Initialize(cmp, data_, restart_offset_, num_restarts,
                    hash_index_.get(), prefix_index_.get());
+    } else {
+      iter = new BlockIter(cmp, data_, restart_offset_, num_restarts,
+                    hash_index_.get(), prefix_index_.get());
+    }
  }
+
+  return iter;
 }

 void Block::SetBlockHashIndex(BlockHashIndex* hash_index) {
@@ -379,4 +359,15 @@ void Block::SetBlockPrefixIndex(BlockPrefixIndex* prefix_index) {
  prefix_index_.reset(prefix_index);
 }

+size_t Block::ApproximateMemoryUsage() const {
+  size_t usage = size();
+  if (hash_index_) {
+    usage += hash_index_->ApproximateMemoryUsage();
+  }
+  if (prefix_index_) {
+    usage += prefix_index_->ApproximateMemoryUsage();
+  }
+  return usage;
+}
+
 }  // namespace rocksdb
@@ -13,11 +13,13 @@

 #include "rocksdb/iterator.h"
 #include "rocksdb/options.h"
+#include "db/dbformat.h"

 namespace rocksdb {

 struct BlockContents;
 class Comparator;
+class BlockIter;
 class BlockHashIndex;
 class BlockPrefixIndex;

@@ -40,10 +42,17 @@ class Block {
  // NOTE: for the hash based lookup, if a key prefix doesn't match any key,
  // the iterator will simply be set as "invalid", rather than returning
  // the key that is just pass the target key.
-  Iterator* NewIterator(const Comparator* comparator);
+  //
+  // If iter is null, return new Iterator
+  // If iter is not null, update this one and return it as Iterator*
+  Iterator* NewIterator(const Comparator* comparator,
+      BlockIter* iter = nullptr);
  void SetBlockHashIndex(BlockHashIndex* hash_index);
  void SetBlockPrefixIndex(BlockPrefixIndex* prefix_index);

+  // Report an approximation of how much memory has been used.
+  size_t ApproximateMemoryUsage() const;
+
 private:
  const char* data_;
  size_t size_;
@@ -57,8 +66,126 @@ class Block {
  // No copying allowed
  Block(const Block&);
  void operator=(const Block&);
+};
+
+class BlockIter : public Iterator {
+ public:
+  BlockIter()
+      : comparator_(nullptr),
+        data_(nullptr),
+        restarts_(0),
+        num_restarts_(0),
+        current_(0),
+        restart_index_(0),
+        status_(Status::OK()),
+        hash_index_(nullptr),
+        prefix_index_(nullptr) {}
+
+  BlockIter(const Comparator* comparator, const char* data, uint32_t restarts,
+       uint32_t num_restarts, BlockHashIndex* hash_index,
+       BlockPrefixIndex* prefix_index)
+      : BlockIter() {
+    Initialize(comparator, data, restarts, num_restarts,
+        hash_index, prefix_index);
+  }
+
+  void Initialize(const Comparator* comparator, const char* data,
+      uint32_t restarts, uint32_t num_restarts, BlockHashIndex* hash_index,
+      BlockPrefixIndex* prefix_index) {
+    assert(data_ == nullptr);           // Ensure it is called only once
+    assert(num_restarts > 0);           // Ensure the param is valid
+
+    comparator_ = comparator;
+    data_ = data;
+    restarts_ = restarts;
+    num_restarts_ = num_restarts;
+    current_ = restarts_;
+    restart_index_ = num_restarts_;
+    hash_index_ = hash_index;
+    prefix_index_ = prefix_index;
+  }
+
+  void SetStatus(Status s) {
+    status_ = s;
+  }
+
+  virtual bool Valid() const override { return current_ < restarts_; }
+  virtual Status status() const override { return status_; }
+  virtual Slice key() const override {
+    assert(Valid());
+    return key_.GetKey();
+  }
+  virtual Slice value() const override {
+    assert(Valid());
+    return value_;
+  }
+
+  virtual void Next() override;
+
+  virtual void Prev() override;
+
+  virtual void Seek(const Slice& target) override;
+
+  virtual void SeekToFirst() override;
+
+  virtual void SeekToLast() override;
+
+ private:
+  const Comparator* comparator_;
+  const char* data_;       // underlying block contents
+  uint32_t restarts_;      // Offset of restart array (list of fixed32)
+  uint32_t num_restarts_;  // Number of uint32_t entries in restart array
+
+  // current_ is offset in data_ of current entry.  >= restarts_ if !Valid
+  uint32_t current_;
+  uint32_t restart_index_;  // Index of restart block in which current_ falls
+  IterKey key_;
+  Slice value_;
+  Status status_;
+  BlockHashIndex* hash_index_;
+  BlockPrefixIndex* prefix_index_;
+
+  inline int Compare(const Slice& a, const Slice& b) const {
+    return comparator_->Compare(a, b);
+  }
+
+  // Return the offset in data_ just past the end of the current entry.
+  inline uint32_t NextEntryOffset() const {
+    return (value_.data() + value_.size()) - data_;
+  }
+
+  uint32_t GetRestartPoint(uint32_t index) {
+    assert(index < num_restarts_);
+    return DecodeFixed32(data_ + restarts_ + index * sizeof(uint32_t));
+  }
+
+  void SeekToRestartPoint(uint32_t index) {
+    key_.Clear();
+    restart_index_ = index;
+    // current_ will be fixed by ParseNextKey();
+
+    // ParseNextKey() starts at the end of value_, so set value_ accordingly
+    uint32_t offset = GetRestartPoint(index);
+    value_ = Slice(data_ + offset, 0);
+  }
+
+  void CorruptionError();
+
+  bool ParseNextKey();
+
+  bool BinarySeek(const Slice& target, uint32_t left, uint32_t right,
+                  uint32_t* index);
+
+  int CompareBlockKey(uint32_t block_index, const Slice& target);
+
+  bool BinaryBlockIndexSeek(const Slice& target, uint32_t* block_ids,
+                            uint32_t left, uint32_t right,
+                            uint32_t* index);
+
+  bool HashSeek(const Slice& target, uint32_t* index);
+
+  bool PrefixSeek(const Slice& target, uint32_t* index);

-  class Iter;
 };

 }  // namespace rocksdb
@@ -45,7 +45,6 @@ namespace rocksdb {

 extern const std::string kHashIndexPrefixesBlock;
 extern const std::string kHashIndexPrefixesMetadataBlock;
-namespace {

 typedef BlockBasedTableOptions::IndexType IndexType;

@@ -335,8 +334,6 @@ Slice CompressBlock(const Slice& raw,
  return raw;
 }

-}  // anonymous namespace
-
 // kBlockBasedTableMagicNumber was picked by running
 //    echo rocksdb.table.block_based | sha1sum
 // and taking the leading 64 bits.
@@ -612,8 +609,8 @@ static void DeleteCachedBlock(const Slice& key, void* value) {
 // Make a copy of the block contents and insert into compressed block cache
 //
 Status BlockBasedTableBuilder::InsertBlockInCache(const Slice& block_contents,
-                                 const CompressionType type,
-                                 const BlockHandle* handle) {
+                                                  const CompressionType type,
+                                                  const BlockHandle* handle) {
  Rep* r = rep_;
  Cache* block_cache_compressed = r->options.block_cache_compressed.get();

@@ -622,8 +619,9 @@ Status BlockBasedTableBuilder::InsertBlockInCache(const Slice& block_contents,
    Cache::Handle* cache_handle = nullptr;
    size_t size = block_contents.size();

-    char* ubuf = new char[size];             // make a new copy
+    char* ubuf = new char[size + 1];  // make a new copy
    memcpy(ubuf, block_contents.data(), size);
+    ubuf[size] = type;

    BlockContents results;
    Slice sl(ubuf, size);
@@ -135,11 +135,17 @@ class BlockBasedTable::IndexReader {
  virtual ~IndexReader() {}

  // Create an iterator for index access.
-  virtual Iterator* NewIterator() = 0;
+  // An iter is passed in, if it is not null, update this one and return it
+  // If it is null, create a new Iterator
+  virtual Iterator* NewIterator(BlockIter* iter = nullptr) = 0;

  // The size of the index.
  virtual size_t size() const = 0;

+  // Report an approximation of how much memory has been used other than memory
+  // that was allocated in block cache.
+  virtual size_t ApproximateMemoryUsage() const = 0;
+
 protected:
  const Comparator* comparator_;
 };
@@ -168,12 +174,17 @@ class BinarySearchIndexReader : public IndexReader {
    return s;
  }

-  virtual Iterator* NewIterator() override {
-    return index_block_->NewIterator(comparator_);
+  virtual Iterator* NewIterator(BlockIter* iter = nullptr) override {
+    return index_block_->NewIterator(comparator_, iter);
  }

  virtual size_t size() const override { return index_block_->size(); }

+  virtual size_t ApproximateMemoryUsage() const override {
+    assert(index_block_);
+    return index_block_->ApproximateMemoryUsage();
+  }
+
 private:
  BinarySearchIndexReader(const Comparator* comparator, Block* index_block)
      : IndexReader(comparator), index_block_(index_block) {
@@ -284,12 +295,18 @@ class HashIndexReader : public IndexReader {
    return Status::OK();
  }

-  virtual Iterator* NewIterator() override {
-    return index_block_->NewIterator(comparator_);
+  virtual Iterator* NewIterator(BlockIter* iter = nullptr) override {
+    return index_block_->NewIterator(comparator_, iter);
  }

  virtual size_t size() const override { return index_block_->size(); }

+  virtual size_t ApproximateMemoryUsage() const override {
+    assert(index_block_);
+    return index_block_->ApproximateMemoryUsage() +
+           prefixes_contents_.data.size();
+  }
+
 private:
  HashIndexReader(const Comparator* comparator, Block* index_block)
      : IndexReader(comparator),
@@ -542,6 +559,17 @@ std::shared_ptr<const TableProperties> BlockBasedTable::GetTableProperties()
  return rep_->table_properties;
 }

+size_t BlockBasedTable::ApproximateMemoryUsage() const {
+  size_t usage = 0;
+  if (rep_->filter) {
+    usage += rep_->filter->ApproximateMemoryUsage();
+  }
+  if (rep_->index_reader) {
+    usage += rep_->index_reader->ApproximateMemoryUsage();
+  }
+  return usage;
+}
+
 // Load the meta-block from the file. On success, return the loaded meta block
 // and its iterator.
 Status BlockBasedTable::ReadMetaBlock(
@@ -779,10 +807,11 @@ BlockBasedTable::CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
  return { filter, cache_handle };
 }

-Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {
+Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options,
+        BlockIter* input_iter) {
  // index reader has already been pre-populated.
  if (rep_->index_reader) {
-    return rep_->index_reader->NewIterator();
+    return rep_->index_reader->NewIterator(input_iter);
  }

  bool no_io = read_options.read_tier == kBlockCacheTier;
@@ -796,7 +825,12 @@ Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {
                        BLOCK_CACHE_INDEX_HIT, statistics);

  if (cache_handle == nullptr && no_io) {
-    return NewErrorIterator(Status::Incomplete("no blocking io"));
+    if (input_iter != nullptr) {
+      input_iter->SetStatus(Status::Incomplete("no blocking io"));
+      return input_iter;
+    } else {
+      return NewErrorIterator(Status::Incomplete("no blocking io"));
+    }
  }

  IndexReader* index_reader = nullptr;
@@ -811,7 +845,12 @@ Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {
    if (!s.ok()) {
      // make sure if something goes wrong, index_reader shall remain intact.
      assert(index_reader == nullptr);
-      return NewErrorIterator(s);
+      if (input_iter != nullptr) {
+        input_iter->SetStatus(s);
+        return input_iter;
+      } else {
+        return NewErrorIterator(s);
+      }
    }

    cache_handle = block_cache->Insert(key, index_reader, index_reader->size(),
@@ -820,7 +859,8 @@ Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {
  }

  assert(cache_handle);
-  auto iter = index_reader->NewIterator();
+  Iterator* iter;
+  iter = index_reader->NewIterator(input_iter);
  iter->RegisterCleanup(&ReleaseCachedEntry, block_cache, cache_handle);

  return iter;
@@ -828,8 +868,11 @@ Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options) {

 // Convert an index iterator value (i.e., an encoded BlockHandle)
 // into an iterator over the contents of the corresponding block.
+// If input_iter is null, new a iterator
+// If input_iter is not null, update this iter and return it
 Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
-    const ReadOptions& ro, const Slice& index_value) {
+    const ReadOptions& ro, const Slice& index_value,
+    BlockIter* input_iter) {
  const bool no_io = (ro.read_tier == kBlockCacheTier);
  Cache* block_cache = rep->options.block_cache.get();
  Cache* block_cache_compressed = rep->options.
@@ -843,7 +886,12 @@ Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
  Status s = handle.DecodeFrom(&input);

  if (!s.ok()) {
-    return NewErrorIterator(s);
+    if (input_iter != nullptr) {
+      input_iter->SetStatus(s);
+      return input_iter;
+    } else {
+      return NewErrorIterator(s);
+    }
  }

  // If either block cache is enabled, we'll try to read from it.
@@ -870,10 +918,9 @@ Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
                              statistics, ro, &block);

    if (block.value == nullptr && !no_io && ro.fill_cache) {
-      Histograms histogram = READ_BLOCK_GET_MICROS;
      Block* raw_block = nullptr;
      {
-        StopWatch sw(rep->options.env, statistics, histogram);
+        StopWatch sw(rep->options.env, statistics, READ_BLOCK_GET_MICROS);
        s = ReadBlockFromFile(rep->file.get(), rep->footer, ro, handle,
                              &raw_block, rep->options.env,
                              block_cache_compressed == nullptr);
@@ -890,7 +937,12 @@ Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
  if (block.value == nullptr) {
    if (no_io) {
      // Could not read from block_cache and can't do IO
-      return NewErrorIterator(Status::Incomplete("no blocking io"));
+      if (input_iter != nullptr) {
+        input_iter->SetStatus(Status::Incomplete("no blocking io"));
+        return input_iter;
+      } else {
+        return NewErrorIterator(Status::Incomplete("no blocking io"));
+      }
    }
    s = ReadBlockFromFile(rep->file.get(), rep->footer, ro, handle,
                          &block.value, rep->options.env);
@@ -898,15 +950,20 @@ Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,

  Iterator* iter;
  if (block.value != nullptr) {
-    iter = block.value->NewIterator(&rep->internal_comparator);
+    iter = block.value->NewIterator(&rep->internal_comparator, input_iter);
    if (block.cache_handle != nullptr) {
      iter->RegisterCleanup(&ReleaseCachedEntry, block_cache,
-                            block.cache_handle);
+          block.cache_handle);
    } else {
      iter->RegisterCleanup(&DeleteHeldResource<Block>, block.value, nullptr);
    }
  } else {
-    iter = NewErrorIterator(s);
+    if (input_iter != nullptr) {
+      input_iter->SetStatus(s);
+      iter = input_iter;
+    } else {
+      iter = NewErrorIterator(s);
+    }
  }
  return iter;
 }
@@ -1024,12 +1081,14 @@ Status BlockBasedTable::Get(
                           const Slice& v),
    void (*mark_key_may_exist_handler)(void* handle_context)) {
  Status s;
-  Iterator* iiter = NewIndexIterator(read_options);
+  BlockIter iiter;
+  NewIndexIterator(read_options, &iiter);
+
  auto filter_entry = GetFilter(read_options.read_tier == kBlockCacheTier);
  FilterBlockReader* filter = filter_entry.value;
  bool done = false;
-  for (iiter->Seek(key); iiter->Valid() && !done; iiter->Next()) {
-    Slice handle_value = iiter->value();
+  for (iiter.Seek(key); iiter.Valid() && !done; iiter.Next()) {
+    Slice handle_value = iiter.value();

    BlockHandle handle;
    bool may_not_exist_in_filter =
@@ -1044,39 +1103,43 @@ Status BlockBasedTable::Get(
      RecordTick(rep_->options.statistics.get(), BLOOM_FILTER_USEFUL);
      break;
    } else {
-      unique_ptr<Iterator> block_iter(
-          NewDataBlockIterator(rep_, read_options, iiter->value()));
+      BlockIter biter;
+      NewDataBlockIterator(rep_, read_options, iiter.value(), &biter);

-      if (read_options.read_tier && block_iter->status().IsIncomplete()) {
+      if (read_options.read_tier && biter.status().IsIncomplete()) {
        // couldn't get block from block_cache
        // Update Saver.state to Found because we are only looking for whether
        // we can guarantee the key is not there when "no_io" is set
        (*mark_key_may_exist_handler)(handle_context);
        break;
      }
+      if (!biter.status().ok()) {
+        s = biter.status();
+        break;
+      }

      // Call the *saver function on each entry/block until it returns false
-      for (block_iter->Seek(key); block_iter->Valid(); block_iter->Next()) {
+      for (biter.Seek(key); biter.Valid(); biter.Next()) {
        ParsedInternalKey parsed_key;
-        if (!ParseInternalKey(block_iter->key(), &parsed_key)) {
+        if (!ParseInternalKey(biter.key(), &parsed_key)) {
          s = Status::Corruption(Slice());
        }

        if (!(*result_handler)(handle_context, parsed_key,
-                               block_iter->value())) {
+                               biter.value())) {
          done = true;
          break;
        }
      }
-      s = block_iter->status();
+      s = biter.status();
    }
  }

  filter_entry.Release(rep_->options.block_cache.get());
  if (s.ok()) {
-    s = iiter->status();
+    s = iiter.status();
  }
-  delete iiter;
+
  return s;
 }

@@ -23,6 +23,7 @@
 namespace rocksdb {

 class Block;
+class BlockIter;
 class BlockHandle;
 class Cache;
 class FilterBlockReader;
@@ -95,6 +96,8 @@ class BlockBasedTable : public TableReader {

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

+  size_t ApproximateMemoryUsage() const override;
+
  ~BlockBasedTable();

  bool TEST_filter_block_preloaded() const;
@@ -111,8 +114,10 @@ class BlockBasedTable : public TableReader {
  bool compaction_optimized_;

  class BlockEntryIteratorState;
+  // input_iter: if it is not null, update this one and return it as Iterator
  static Iterator* NewDataBlockIterator(Rep* rep, const ReadOptions& ro,
-                                        const Slice& index_value);
+                                        const Slice& index_value,
+                                        BlockIter* input_iter = nullptr);

  // For the following two functions:
  // if `no_io == true`, we will not try to read filter/index from sst file
@@ -120,6 +125,8 @@ class BlockBasedTable : public TableReader {
  CachableEntry<FilterBlockReader> GetFilter(bool no_io = false) const;

  // Get the iterator from the index reader.
+  // If input_iter is not set, return new Iterator
+  // If input_iter is set, update it and return it as Iterator
  //
  // Note: ErrorIterator with Status::Incomplete shall be returned if all the
  // following conditions are met:
@@ -127,7 +134,8 @@ class BlockBasedTable : public TableReader {
  //  2. index is not present in block cache.
  //  3. We disallowed any io to be performed, that is, read_options ==
  //     kBlockCacheTier
-  Iterator* NewIndexIterator(const ReadOptions& read_options);
+  Iterator* NewIndexIterator(const ReadOptions& read_options,
+                             BlockIter* input_iter = nullptr);

  // Read block cache from block caches (if set): block_cache and
  // block_cache_compressed.
@@ -16,8 +16,6 @@

 namespace rocksdb {

-namespace {
-
 inline uint32_t Hash(const Slice& s) {
  return rocksdb::Hash(s.data(), s.size(), 0);
 }
@@ -26,8 +24,6 @@ inline uint32_t PrefixToBucket(const Slice& prefix, uint32_t num_buckets) {
  return Hash(prefix) % num_buckets;
 }

-
-
 // The prefix block index is simply a bucket array, with each entry pointing to
 // the blocks that span the prefixes hashed to this bucket.
 //
@@ -64,7 +60,6 @@ inline uint32_t EncodeIndex(uint32_t index) {
  return index | kBlockArrayMask;
 }

-
 // temporary storage for prefix information during index building
 struct PrefixRecord {
  Slice prefix;
@@ -74,8 +69,6 @@ struct PrefixRecord {
  PrefixRecord* next;
 };

-}  // anonymous namespace
-
 class BlockPrefixIndex::Builder {
 public:
  explicit Builder(const SliceTransform* internal_prefix_extractor)
@@ -0,0 +1,23 @@
+//  Copyright (c) 2014, 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 "table/bloom_block.h"
+
+#include <string>
+#include "rocksdb/slice.h"
+#include "util/dynamic_bloom.h"
+
+namespace rocksdb {
+
+void BloomBlockBuilder::AddKeysHashes(const std::vector<uint32_t> keys_hashes) {
+  for (auto hash : keys_hashes) {
+    bloom_.AddHash(hash);
+  }
+}
+
+Slice BloomBlockBuilder::Finish() { return bloom_.GetRawData(); }
+
+const std::string BloomBlockBuilder::kBloomBlock = "kBloomBlock";
+}  // namespace rocksdb
--- a/Show More
+++ b/Show More