Only compiling TrimSpace on linux.

Incorporated change by zmodem at https://github.com/google/leveldb/pull/310 to fix issue #310. This change will only build TrimSace on linux to avoid unused function warning/error. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=105323419
Let LevelDB use xcrun to determine Xcode.app path instead of using a hardcoded path.
2026-08-18 10:33:27 +08:00 · 2015-10-13 14:06:08 -07:00 · 2015-10-13 14:05:43 -07:00 · 2015-10-13 14:05:30 -07:00 · 2015-10-13 14:05:21 -07:00 · 2015-06-17 11:20:27 -07:00
90 changed files with 3558 additions and 752 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@ build_config.mk
 *.so.*
 *_test
 db_bench
+leveldbutil
--- a/4
+++ b/4
@@ -6,3 +6,7 @@ Google Inc.
 # Initial version authors:
 Jeffrey Dean <jeff@google.com>
 Sanjay Ghemawat <sanjay@google.com>
+
+# Partial list of contributors:
+Kevin Regan <kevin.d.regan@gmail.com>
+Johan Bilien <jobi@litl.com>
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -0,0 +1,36 @@
+# Contributing
+
+We'd love to accept your code patches! However, before we can take them, we
+have to jump a couple of legal hurdles.
+
+## Contributor License Agreements
+
+Please fill out either the individual or corporate Contributor License
+Agreement as appropriate.
+
+* If you are an individual writing original source code and you're sure you
+own the intellectual property, then sign an [individual CLA](https://developers.google.com/open-source/cla/individual).
+* If you work for a company that wants to allow you to contribute your work,
+then sign a [corporate CLA](https://developers.google.com/open-source/cla/corporate).
+
+Follow either of the two links above to access the appropriate CLA and
+instructions for how to sign and return it.
+
+## Submitting a Patch
+
+1. Sign the contributors license agreement above.
+2. Decide which code you want to submit. A submission should be a set of changes
+that addresses one issue in the [issue tracker](https://github.com/google/leveldb/issues).
+Please don't mix more than one logical change per submission, because it makes
+the history hard to follow. If you want to make a change
+(e.g. add a sample or feature) that doesn't have a corresponding issue in the
+issue tracker, please create one.
+3. **Submitting**: When you are ready to submit, send us a Pull Request. Be
+sure to include the issue number you fixed and the name you used to sign
+the CLA.
+
+## Writing Code ##
+
+If your contribution contains code, please make sure that it follows 
+[the style guide](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml).
+Otherwise we will have to ask you to make changes, and that's no fun for anyone.
--- a/117
+++ b/117
@@ -2,20 +2,21 @@
 # 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.

-# Inherit some settings from environment variables, if available
-INSTALL_PATH ?= $(CURDIR)
-
 #-----------------------------------------------
 # Uncomment exactly one of the lines labelled (A), (B), and (C) below
 # to switch between compilation modes.

-OPT ?= -O2 -DNDEBUG       # (A) Production use (optimized mode)
-# OPT ?= -g2              # (B) Debug mode, w/ full line-level debugging symbols
-# OPT ?= -O2 -g2 -DNDEBUG # (C) Profiling mode: opt, but w/debugging symbols
+# (A) Production use (optimized mode)
+OPT ?= -O2 -DNDEBUG
+# (B) Debug mode, w/ full line-level debugging symbols
+# OPT ?= -g2
+# (C) Profiling mode: opt, but w/debugging symbols
+# OPT ?= -O2 -g2 -DNDEBUG
 #-----------------------------------------------

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

@@ -23,6 +24,7 @@ CFLAGS += -I. -I./include $(PLATFORM_CCFLAGS) $(OPT)
 CXXFLAGS += -I. -I./include $(PLATFORM_CXXFLAGS) $(OPT)

 LDFLAGS += $(PLATFORM_LDFLAGS)
+LIBS += $(PLATFORM_LIBS)

 LIBOBJECTS = $(SOURCES:.cc=.o)
 MEMENVOBJECTS = $(MEMENV_SOURCES:.cc=.o)
@@ -30,8 +32,14 @@ MEMENVOBJECTS = $(MEMENV_SOURCES:.cc=.o)
 TESTUTIL = ./util/testutil.o
 TESTHARNESS = ./util/testharness.o $(TESTUTIL)

+# Note: iOS should probably be using libtool, not ar.
+ifeq ($(PLATFORM), IOS)
+AR=xcrun ar
+endif
+
 TESTS = \
 	arena_test \
+	autocompact_test \
 	bloom_test \
 	c_test \
 	cache_test \
@@ -41,17 +49,22 @@ TESTS = \
 	db_test \
 	dbformat_test \
 	env_test \
+	fault_injection_test \
 	filename_test \
 	filter_block_test \
+	hash_test \
+	issue178_test \
+	issue200_test \
 	log_test \
 	memenv_test \
+	recovery_test \
 	skiplist_test \
 	table_test \
 	version_edit_test \
 	version_set_test \
 	write_batch_test

-PROGRAMS = db_bench $(TESTS)
+PROGRAMS = db_bench leveldbutil $(TESTS)
 BENCHMARKS = db_bench_sqlite3 db_bench_tree_db

 LIBRARY = libleveldb.a
@@ -70,7 +83,7 @@ SHARED = $(SHARED1)
 else
 # Update db.h if you change these.
 SHARED_MAJOR = 1
-SHARED_MINOR = 5
+SHARED_MINOR = 18
 SHARED1 = libleveldb.$(PLATFORM_SHARED_EXT)
 SHARED2 = $(SHARED1).$(SHARED_MAJOR)
 SHARED3 = $(SHARED1).$(SHARED_MAJOR).$(SHARED_MINOR)
@@ -82,7 +95,7 @@ $(SHARED2): $(SHARED3)
 endif

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

 endif  # PLATFORM_SHARED_EXT

@@ -100,96 +113,116 @@ $(LIBRARY): $(LIBOBJECTS)
 	$(AR) -rs $@ $(LIBOBJECTS)

 db_bench: db/db_bench.o $(LIBOBJECTS) $(TESTUTIL)
-	$(CXX) db/db_bench.o $(LIBOBJECTS) $(TESTUTIL) -o $@  $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/db_bench.o $(LIBOBJECTS) $(TESTUTIL) -o $@ $(LIBS)

 db_bench_sqlite3: doc/bench/db_bench_sqlite3.o $(LIBOBJECTS) $(TESTUTIL)
-	$(CXX) doc/bench/db_bench_sqlite3.o $(LIBOBJECTS) $(TESTUTIL) -o $@ $(LDFLAGS) -lsqlite3
+	$(CXX) $(LDFLAGS) doc/bench/db_bench_sqlite3.o $(LIBOBJECTS) $(TESTUTIL) -o $@ -lsqlite3 $(LIBS)

 db_bench_tree_db: doc/bench/db_bench_tree_db.o $(LIBOBJECTS) $(TESTUTIL)
-	$(CXX) doc/bench/db_bench_tree_db.o $(LIBOBJECTS) $(TESTUTIL) -o $@ $(LDFLAGS) -lkyotocabinet
+	$(CXX) $(LDFLAGS) doc/bench/db_bench_tree_db.o $(LIBOBJECTS) $(TESTUTIL) -o $@ -lkyotocabinet $(LIBS)
+
+leveldbutil: db/leveldb_main.o $(LIBOBJECTS)
+	$(CXX) $(LDFLAGS) db/leveldb_main.o $(LIBOBJECTS) -o $@ $(LIBS)

 arena_test: util/arena_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) util/arena_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) util/arena_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
+
+autocompact_test: db/autocompact_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) $(LDFLAGS) db/autocompact_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 bloom_test: util/bloom_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) util/bloom_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) util/bloom_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 c_test: db/c_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/c_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/c_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 cache_test: util/cache_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) util/cache_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) util/cache_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 coding_test: util/coding_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) util/coding_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) util/coding_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 corruption_test: db/corruption_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/corruption_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/corruption_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 crc32c_test: util/crc32c_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) util/crc32c_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) util/crc32c_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 db_test: db/db_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/db_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/db_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 dbformat_test: db/dbformat_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/dbformat_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/dbformat_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 env_test: util/env_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) util/env_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) util/env_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
+
+fault_injection_test: db/fault_injection_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) $(LDFLAGS) db/fault_injection_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 filename_test: db/filename_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/filename_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/filename_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 filter_block_test: table/filter_block_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) table/filter_block_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) table/filter_block_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
+
+hash_test: util/hash_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) $(LDFLAGS) util/hash_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
+
+issue178_test: issues/issue178_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) $(LDFLAGS) issues/issue178_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
+
+issue200_test: issues/issue200_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) $(LDFLAGS) issues/issue200_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 log_test: db/log_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/log_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/log_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
+
+recovery_test: db/recovery_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) $(LDFLAGS) db/recovery_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 table_test: table/table_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) table/table_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) table/table_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 skiplist_test: db/skiplist_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/skiplist_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/skiplist_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 version_edit_test: db/version_edit_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/version_edit_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/version_edit_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 version_set_test: db/version_set_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/version_set_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/version_set_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 write_batch_test: db/write_batch_test.o $(LIBOBJECTS) $(TESTHARNESS)
-	$(CXX) db/write_batch_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) db/write_batch_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)

 $(MEMENVLIBRARY) : $(MEMENVOBJECTS)
 	rm -f $@
 	$(AR) -rs $@ $(MEMENVOBJECTS)

 memenv_test : helpers/memenv/memenv_test.o $(MEMENVLIBRARY) $(LIBRARY) $(TESTHARNESS)
-	$(CXX) helpers/memenv/memenv_test.o $(MEMENVLIBRARY) $(LIBRARY) $(TESTHARNESS) -o $@ $(LDFLAGS)
+	$(CXX) $(LDFLAGS) helpers/memenv/memenv_test.o $(MEMENVLIBRARY) $(LIBRARY) $(TESTHARNESS) -o $@ $(LIBS)

 ifeq ($(PLATFORM), IOS)
 # For iOS, create universal object files to be used on both the simulator and
 # a device.
-PLATFORMSROOT=/Applications/Xcode.app/Contents/Developer/Platforms
-SIMULATORROOT=$(PLATFORMSROOT)/iPhoneSimulator.platform/Developer
-DEVICEROOT=$(PLATFORMSROOT)/iPhoneOS.platform/Developer
-IOSVERSION=$(shell defaults read $(PLATFORMSROOT)/iPhoneOS.platform/version CFBundleShortVersionString)
+SIMULATORSDK=$(shell xcrun -sdk iphonesimulator --show-sdk-path)
+DEVICESDK=$(shell xcrun -sdk iphoneos --show-sdk-path)
+IOSARCH=-arch armv6 -arch armv7 -arch armv7s -arch arm64

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

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

 else
 .cc.o:
--- a/51
+++ b/51
@@ -1,51 +0,0 @@
-leveldb: A key-value store
-Authors: Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
-
-The code under this directory implements a system for maintaining a
-persistent key/value store.
-
-See doc/index.html for more explanation.
-See doc/impl.html for a brief overview of the implementation.
-
-The public interface is in include/*.h.  Callers should not include or
-rely on the details of any other header files in this package.  Those
-internal APIs may be changed without warning.
-
-Guide to header files:
-
-include/db.h
-    Main interface to the DB: Start here
-
-include/options.h
-    Control over the behavior of an entire database, and also
-    control over the behavior of individual reads and writes.
-
-include/comparator.h
-    Abstraction for user-specified comparison function.  If you want
-    just bytewise comparison of keys, you can use the default comparator,
-    but clients can write their own comparator implementations if they
-    want custom ordering (e.g. to handle different character
-    encodings, etc.)
-
-include/iterator.h
-    Interface for iterating over data. You can get an iterator
-    from a DB object.
-
-include/write_batch.h
-    Interface for atomically applying multiple updates to a database.
-
-include/slice.h
-    A simple module for maintaining a pointer and a length into some
-    other byte array.
-
-include/status.h
-    Status is returned from many of the public interfaces and is used
-    to report success and various kinds of errors.
-
-include/env.h
-    Abstraction of the OS environment.  A posix implementation of
-    this interface is in util/env_posix.cc
-
-include/table.h
-include/table_builder.h
-    Lower-level modules that most clients probably won't use directly
--- a/README.md
+++ b/README.md
@@ -0,0 +1,138 @@
+**LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.**
+
+Authors: Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
+
+# Features
+  * Keys and values are arbitrary byte arrays.
+  * Data is stored sorted by key.
+  * Callers can provide a custom comparison function to override the sort order.
+  * The basic operations are `Put(key,value)`, `Get(key)`, `Delete(key)`.
+  * Multiple changes can be made in one atomic batch.
+  * Users can create a transient snapshot to get a consistent view of data.
+  * Forward and backward iteration is supported over the data.
+  * Data is automatically compressed using the [Snappy compression library](http://code.google.com/p/snappy).
+  * External activity (file system operations etc.) is relayed through a virtual interface so users can customize the operating system interactions.
+  * [Detailed documentation](http://htmlpreview.github.io/?https://github.com/google/leveldb/blob/master/doc/index.html) about how to use the library is included with the source code.
+
+
+# Limitations
+  * This is not a SQL database.  It does not have a relational data model, it does not support SQL queries, and it has no support for indexes.
+  * Only a single process (possibly multi-threaded) can access a particular database at a time.
+  * There is no client-server support builtin to the library.  An application that needs such support will have to wrap their own server around the library.
+
+# Performance
+
+Here is a performance report (with explanations) from the run of the
+included db_bench program.  The results are somewhat noisy, but should
+be enough to get a ballpark performance estimate.
+
+## Setup
+
+We use a database with a million entries.  Each entry has a 16 byte
+key, and a 100 byte value.  Values used by the benchmark compress to
+about half their original size.
+
+    LevelDB:    version 1.1
+    Date:       Sun May  1 12:11:26 2011
+    CPU:        4 x Intel(R) Core(TM)2 Quad CPU    Q6600  @ 2.40GHz
+    CPUCache:   4096 KB
+    Keys:       16 bytes each
+    Values:     100 bytes each (50 bytes after compression)
+    Entries:    1000000
+    Raw Size:   110.6 MB (estimated)
+    File Size:  62.9 MB (estimated)
+
+## Write performance
+
+The "fill" benchmarks create a brand new database, in either
+sequential, or random order.  The "fillsync" benchmark flushes data
+from the operating system to the disk after every operation; the other
+write operations leave the data sitting in the operating system buffer
+cache for a while.  The "overwrite" benchmark does random writes that
+update existing keys in the database.
+
+    fillseq      :       1.765 micros/op;   62.7 MB/s
+    fillsync     :     268.409 micros/op;    0.4 MB/s (10000 ops)
+    fillrandom   :       2.460 micros/op;   45.0 MB/s
+    overwrite    :       2.380 micros/op;   46.5 MB/s
+
+Each "op" above corresponds to a write of a single key/value pair.
+I.e., a random write benchmark goes at approximately 400,000 writes per second.
+
+Each "fillsync" operation costs much less (0.3 millisecond)
+than a disk seek (typically 10 milliseconds).  We suspect that this is
+because the hard disk itself is buffering the update in its memory and
+responding before the data has been written to the platter.  This may
+or may not be safe based on whether or not the hard disk has enough
+power to save its memory in the event of a power failure.
+
+## Read performance
+
+We list the performance of reading sequentially in both the forward
+and reverse direction, and also the performance of a random lookup.
+Note that the database created by the benchmark is quite small.
+Therefore the report characterizes the performance of leveldb when the
+working set fits in memory.  The cost of reading a piece of data that
+is not present in the operating system buffer cache will be dominated
+by the one or two disk seeks needed to fetch the data from disk.
+Write performance will be mostly unaffected by whether or not the
+working set fits in memory.
+
+    readrandom   :      16.677 micros/op;  (approximately 60,000 reads per second)
+    readseq      :       0.476 micros/op;  232.3 MB/s
+    readreverse  :       0.724 micros/op;  152.9 MB/s
+
+LevelDB compacts its underlying storage data in the background to
+improve read performance.  The results listed above were done
+immediately after a lot of random writes.  The results after
+compactions (which are usually triggered automatically) are better.
+
+    readrandom   :      11.602 micros/op;  (approximately 85,000 reads per second)
+    readseq      :       0.423 micros/op;  261.8 MB/s
+    readreverse  :       0.663 micros/op;  166.9 MB/s
+
+Some of the high cost of reads comes from repeated decompression of blocks
+read from disk.  If we supply enough cache to the leveldb so it can hold the
+uncompressed blocks in memory, the read performance improves again:
+
+    readrandom   :       9.775 micros/op;  (approximately 100,000 reads per second before compaction)
+    readrandom   :       5.215 micros/op;  (approximately 190,000 reads per second after compaction)
+
+## Repository contents
+
+See doc/index.html for more explanation. See doc/impl.html for a brief overview of the implementation.
+
+The public interface is in include/*.h.  Callers should not include or
+rely on the details of any other header files in this package.  Those
+internal APIs may be changed without warning.
+
+Guide to header files:
+
+* **include/db.h**: Main interface to the DB: Start here
+
+* **include/options.h**: Control over the behavior of an entire database,
+and also control over the behavior of individual reads and writes.
+
+* **include/comparator.h**: Abstraction for user-specified comparison function. 
+If you want just bytewise comparison of keys, you can use the default
+comparator, but clients can write their own comparator implementations if they
+want custom ordering (e.g. to handle different character encodings, etc.)
+
+* **include/iterator.h**: Interface for iterating over data. You can get
+an iterator from a DB object.
+
+* **include/write_batch.h**: Interface for atomically applying multiple
+updates to a database.
+
+* **include/slice.h**: A simple module for maintaining a pointer and a
+length into some other byte array.
+
+* **include/status.h**: Status is returned from many of the public interfaces
+and is used to report success and various kinds of errors.
+
+* **include/env.h**: 
+Abstraction of the OS environment.  A posix implementation of this interface is
+in util/env_posix.cc
+
+* **include/table.h, include/table_builder.h**: Lower-level modules that most
+clients probably won't use directly
--- a/1
+++ b/1
@@ -7,6 +7,7 @@ db
  within [start_key..end_key]?  For Chrome, deletion of obsolete
  object stores, etc. can be done in the background anyway, so
  probably not that important.
+- There have been requests for MultiGet.

 After a range is completely deleted, what gets rid of the
 corresponding files if we do no future changes to that range.  Make
--- a/103
+++ b/103
@@ -7,8 +7,11 @@
 #   CC                          C Compiler path
 #   CXX                         C++ Compiler path
 #   PLATFORM_LDFLAGS            Linker flags
+#   PLATFORM_LIBS               Libraries flags
 #   PLATFORM_SHARED_EXT         Extension for shared libraries
 #   PLATFORM_SHARED_LDFLAGS     Flags for building shared library
+#                               This flag is embedded just before the name
+#                               of the shared library without intervening spaces
 #   PLATFORM_SHARED_CFLAGS      Flags for compiling objects for shared library
 #   PLATFORM_CCFLAGS            C compiler flags
 #   PLATFORM_CXXFLAGS           C++ compiler flags.  Will contain:
@@ -17,14 +20,15 @@
 #
 # The PLATFORM_CCFLAGS and PLATFORM_CXXFLAGS might include the following:
 #
-#       -DLEVELDB_CSTDATOMIC_PRESENT if <cstdatomic> is present
+#       -DLEVELDB_ATOMIC_PRESENT     if <atomic> is present
 #       -DLEVELDB_PLATFORM_POSIX     for Posix-based platforms
 #       -DSNAPPY                     if the Snappy library is present
 #

 OUTPUT=$1
-if test -z "$OUTPUT"; then
-  echo "usage: $0 <output-filename>" >&2
+PREFIX=$2
+if test -z "$OUTPUT" || test -z "$PREFIX"; then
+  echo "usage: $0 <output-filename> <directory_prefix>" >&2
  exit 1
 fi

@@ -40,6 +44,10 @@ if test -z "$CXX"; then
    CXX=g++
 fi

+if test -z "$TMPDIR"; then
+    TMPDIR=/tmp
+fi
+
 # Detect OS
 if test -z "$TARGET_OS"; then
    TARGET_OS=`uname -s`
@@ -50,63 +58,95 @@ CROSS_COMPILE=
 PLATFORM_CCFLAGS=
 PLATFORM_CXXFLAGS=
 PLATFORM_LDFLAGS=
+PLATFORM_LIBS=
 PLATFORM_SHARED_EXT="so"
 PLATFORM_SHARED_LDFLAGS="-shared -Wl,-soname -Wl,"
 PLATFORM_SHARED_CFLAGS="-fPIC"
 PLATFORM_SHARED_VERSIONED=true

-# On GCC, we pick libc's memcmp over GCC's memcmp via -fno-builtin-memcmp
+MEMCMP_FLAG=
+if [ "$CXX" = "g++" ]; then
+    # Use libc's memcmp instead of GCC's memcmp.  This results in ~40%
+    # performance improvement on readrandom under gcc 4.4.3 on Linux/x86.
+    MEMCMP_FLAG="-fno-builtin-memcmp"
+fi
+
 case "$TARGET_OS" in
+    CYGWIN_*)
+        PLATFORM=OS_LINUX
+        COMMON_FLAGS="$MEMCMP_FLAG -lpthread -DOS_LINUX -DCYGWIN"
+        PLATFORM_LDFLAGS="-lpthread"
+        PORT_FILE=port/port_posix.cc
+        ;;
    Darwin)
        PLATFORM=OS_MACOSX
-        COMMON_FLAGS="-fno-builtin-memcmp -DOS_MACOSX"
+        COMMON_FLAGS="$MEMCMP_FLAG -DOS_MACOSX"
        PLATFORM_SHARED_EXT=dylib
-        PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name "
+        [ -z "$INSTALL_PATH" ] && INSTALL_PATH=`pwd`
+        PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name $INSTALL_PATH/"
        PORT_FILE=port/port_posix.cc
        ;;
    Linux)
        PLATFORM=OS_LINUX
-        COMMON_FLAGS="-fno-builtin-memcmp -pthread -DOS_LINUX"
+        COMMON_FLAGS="$MEMCMP_FLAG -pthread -DOS_LINUX"
        PLATFORM_LDFLAGS="-pthread"
        PORT_FILE=port/port_posix.cc
        ;;
    SunOS)
        PLATFORM=OS_SOLARIS
-        COMMON_FLAGS="-fno-builtin-memcmp -D_REENTRANT -DOS_SOLARIS"
-        PLATFORM_LDFLAGS="-lpthread -lrt"
+        COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_SOLARIS"
+        PLATFORM_LIBS="-lpthread -lrt"
        PORT_FILE=port/port_posix.cc
        ;;
    FreeBSD)
        PLATFORM=OS_FREEBSD
-        COMMON_FLAGS="-fno-builtin-memcmp -D_REENTRANT -DOS_FREEBSD"
-        PLATFORM_LDFLAGS="-lpthread"
+        COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_FREEBSD"
+        PLATFORM_LIBS="-lpthread"
        PORT_FILE=port/port_posix.cc
        ;;
    NetBSD)
        PLATFORM=OS_NETBSD
-        COMMON_FLAGS="-fno-builtin-memcmp -D_REENTRANT -DOS_NETBSD"
-        PLATFORM_LDFLAGS="-lpthread -lgcc_s"
+        COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_NETBSD"
+        PLATFORM_LIBS="-lpthread -lgcc_s"
        PORT_FILE=port/port_posix.cc
        ;;
    OpenBSD)
        PLATFORM=OS_OPENBSD
-        COMMON_FLAGS="-fno-builtin-memcmp -D_REENTRANT -DOS_OPENBSD"
+        COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_OPENBSD"
        PLATFORM_LDFLAGS="-pthread"
        PORT_FILE=port/port_posix.cc
        ;;
    DragonFly)
        PLATFORM=OS_DRAGONFLYBSD
-        COMMON_FLAGS="-fno-builtin-memcmp -D_REENTRANT -DOS_DRAGONFLYBSD"
-        PLATFORM_LDFLAGS="-lpthread"
+        COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_DRAGONFLYBSD"
+        PLATFORM_LIBS="-lpthread"
        PORT_FILE=port/port_posix.cc
        ;;
    OS_ANDROID_CROSSCOMPILE)
        PLATFORM=OS_ANDROID
-        COMMON_FLAGS="-fno-builtin-memcmp -D_REENTRANT -DOS_ANDROID -DLEVELDB_PLATFORM_POSIX"
+        COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_ANDROID -DLEVELDB_PLATFORM_POSIX"
        PLATFORM_LDFLAGS=""  # All pthread features are in the Android C library
        PORT_FILE=port/port_posix.cc
        CROSS_COMPILE=true
        ;;
+    HP-UX)
+        PLATFORM=OS_HPUX
+        COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_HPUX"
+        PLATFORM_LDFLAGS="-pthread"
+        PORT_FILE=port/port_posix.cc
+        # man ld: +h internal_name
+        PLATFORM_SHARED_LDFLAGS="-shared -Wl,+h -Wl,"
+        ;;
+    IOS)
+        PLATFORM=IOS
+        COMMON_FLAGS="$MEMCMP_FLAG -DOS_MACOSX"
+        [ -z "$INSTALL_PATH" ] && INSTALL_PATH=`pwd`
+        PORT_FILE=port/port_posix.cc
+        PLATFORM_SHARED_EXT=
+        PLATFORM_SHARED_LDFLAGS=
+        PLATFORM_SHARED_CFLAGS=
+        PLATFORM_SHARED_VERSIONED=
+        ;;
    *)
        echo "Unknown platform!" >&2
        exit 1
@@ -116,11 +156,14 @@ esac
 # except for the test and benchmark files. By default, find will output a list
 # of all files matching either rule, so we need to append -print to make the
 # prune take effect.
-DIRS="util db table"
+DIRS="$PREFIX/db $PREFIX/util $PREFIX/table"
+
 set -f # temporarily disable globbing so that our patterns aren't expanded
 PRUNE_TEST="-name *test*.cc -prune"
 PRUNE_BENCH="-name *_bench.cc -prune"
-PORTABLE_FILES=`find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cc' -print | sort | tr "\n" " "`
+PRUNE_TOOL="-name leveldb_main.cc -prune"
+PORTABLE_FILES=`find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o $PRUNE_TOOL -o -name '*.cc' -print | sort | sed "s,^$PREFIX/,," | tr "\n" " "`
+
 set +f # re-enable globbing

 # The sources consist of the portable files, plus the platform-specific port
@@ -132,13 +175,16 @@ if [ "$CROSS_COMPILE" = "true" ]; then
    # Cross-compiling; do not try any compilation tests.
    true
 else
-    # If -std=c++0x works, use <cstdatomic>.  Otherwise use port_posix.h.
-    $CXX $CFLAGS -std=c++0x -x c++ - -o /dev/null 2>/dev/null  <<EOF
-      #include <cstdatomic>
+    CXXOUTPUT="${TMPDIR}/leveldb_build_detect_platform-cxx.$$"
+
+    # If -std=c++0x works, use <atomic> as fallback for when memory barriers
+    # are not available.
+    $CXX $CXXFLAGS -std=c++0x -x c++ - -o $CXXOUTPUT 2>/dev/null  <<EOF
+      #include <atomic>
      int main() {}
 EOF
    if [ "$?" = 0 ]; then
-        COMMON_FLAGS="$COMMON_FLAGS -DLEVELDB_PLATFORM_POSIX -DLEVELDB_CSTDATOMIC_PRESENT"
+        COMMON_FLAGS="$COMMON_FLAGS -DLEVELDB_PLATFORM_POSIX -DLEVELDB_ATOMIC_PRESENT"
        PLATFORM_CXXFLAGS="-std=c++0x"
    else
        COMMON_FLAGS="$COMMON_FLAGS -DLEVELDB_PLATFORM_POSIX"
@@ -146,22 +192,24 @@ EOF

    # Test whether Snappy library is installed
    # http://code.google.com/p/snappy/
-    $CXX $CFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
+    $CXX $CXXFLAGS -x c++ - -o $CXXOUTPUT 2>/dev/null  <<EOF
      #include <snappy.h>
      int main() {}
 EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DSNAPPY"
-        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lsnappy"
+        PLATFORM_LIBS="$PLATFORM_LIBS -lsnappy"
    fi

    # Test whether tcmalloc is available
-    $CXX $CFLAGS -x c++ - -o /dev/null -ltcmalloc 2>/dev/null  <<EOF
+    $CXX $CXXFLAGS -x c++ - -o $CXXOUTPUT -ltcmalloc 2>/dev/null  <<EOF
      int main() {}
 EOF
    if [ "$?" = 0 ]; then
-        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -ltcmalloc"
+        PLATFORM_LIBS="$PLATFORM_LIBS -ltcmalloc"
    fi
+
+    rm -f $CXXOUTPUT 2>/dev/null
 fi

 PLATFORM_CCFLAGS="$PLATFORM_CCFLAGS $COMMON_FLAGS"
@@ -171,6 +219,7 @@ echo "CC=$CC" >> $OUTPUT
 echo "CXX=$CXX" >> $OUTPUT
 echo "PLATFORM=$PLATFORM" >> $OUTPUT
 echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> $OUTPUT
+echo "PLATFORM_LIBS=$PLATFORM_LIBS" >> $OUTPUT
 echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> $OUTPUT
 echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> $OUTPUT
 echo "PLATFORM_SHARED_CFLAGS=$PLATFORM_SHARED_CFLAGS" >> $OUTPUT
--- a/db/autocompact_test.cc
+++ b/db/autocompact_test.cc
@@ -0,0 +1,118 @@
+// Copyright (c) 2013 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 "leveldb/db.h"
+#include "db/db_impl.h"
+#include "leveldb/cache.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+namespace leveldb {
+
+class AutoCompactTest {
+ public:
+  std::string dbname_;
+  Cache* tiny_cache_;
+  Options options_;
+  DB* db_;
+
+  AutoCompactTest() {
+    dbname_ = test::TmpDir() + "/autocompact_test";
+    tiny_cache_ = NewLRUCache(100);
+    options_.block_cache = tiny_cache_;
+    DestroyDB(dbname_, options_);
+    options_.create_if_missing = true;
+    options_.compression = kNoCompression;
+    ASSERT_OK(DB::Open(options_, dbname_, &db_));
+  }
+
+  ~AutoCompactTest() {
+    delete db_;
+    DestroyDB(dbname_, Options());
+    delete tiny_cache_;
+  }
+
+  std::string Key(int i) {
+    char buf[100];
+    snprintf(buf, sizeof(buf), "key%06d", i);
+    return std::string(buf);
+  }
+
+  uint64_t Size(const Slice& start, const Slice& limit) {
+    Range r(start, limit);
+    uint64_t size;
+    db_->GetApproximateSizes(&r, 1, &size);
+    return size;
+  }
+
+  void DoReads(int n);
+};
+
+static const int kValueSize = 200 * 1024;
+static const int kTotalSize = 100 * 1024 * 1024;
+static const int kCount = kTotalSize / kValueSize;
+
+// Read through the first n keys repeatedly and check that they get
+// compacted (verified by checking the size of the key space).
+void AutoCompactTest::DoReads(int n) {
+  std::string value(kValueSize, 'x');
+  DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
+
+  // Fill database
+  for (int i = 0; i < kCount; i++) {
+    ASSERT_OK(db_->Put(WriteOptions(), Key(i), value));
+  }
+  ASSERT_OK(dbi->TEST_CompactMemTable());
+
+  // Delete everything
+  for (int i = 0; i < kCount; i++) {
+    ASSERT_OK(db_->Delete(WriteOptions(), Key(i)));
+  }
+  ASSERT_OK(dbi->TEST_CompactMemTable());
+
+  // Get initial measurement of the space we will be reading.
+  const int64_t initial_size = Size(Key(0), Key(n));
+  const int64_t initial_other_size = Size(Key(n), Key(kCount));
+
+  // Read until size drops significantly.
+  std::string limit_key = Key(n);
+  for (int read = 0; true; read++) {
+    ASSERT_LT(read, 100) << "Taking too long to compact";
+    Iterator* iter = db_->NewIterator(ReadOptions());
+    for (iter->SeekToFirst();
+         iter->Valid() && iter->key().ToString() < limit_key;
+         iter->Next()) {
+      // Drop data
+    }
+    delete iter;
+    // Wait a little bit to allow any triggered compactions to complete.
+    Env::Default()->SleepForMicroseconds(1000000);
+    uint64_t size = Size(Key(0), Key(n));
+    fprintf(stderr, "iter %3d => %7.3f MB [other %7.3f MB]\n",
+            read+1, size/1048576.0, Size(Key(n), Key(kCount))/1048576.0);
+    if (size <= initial_size/10) {
+      break;
+    }
+  }
+
+  // Verify that the size of the key space not touched by the reads
+  // is pretty much unchanged.
+  const int64_t final_other_size = Size(Key(n), Key(kCount));
+  ASSERT_LE(final_other_size, initial_other_size + 1048576);
+  ASSERT_GE(final_other_size, initial_other_size/5 - 1048576);
+}
+
+TEST(AutoCompactTest, ReadAll) {
+  DoReads(kCount);
+}
+
+TEST(AutoCompactTest, ReadHalf) {
+  DoReads(kCount/2);
+}
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
--- a/db/c.cc
+++ b/db/c.cc
@@ -24,6 +24,8 @@ using leveldb::Env;
 using leveldb::FileLock;
 using leveldb::FilterPolicy;
 using leveldb::Iterator;
+using leveldb::kMajorVersion;
+using leveldb::kMinorVersion;
 using leveldb::Logger;
 using leveldb::NewBloomFilterPolicy;
 using leveldb::NewLRUCache;
@@ -578,4 +580,16 @@ void leveldb_env_destroy(leveldb_env_t* env) {
  delete env;
 }

+void leveldb_free(void* ptr) {
+  free(ptr);
+}
+
+int leveldb_major_version() {
+  return kMajorVersion;
+}
+
+int leveldb_minor_version() {
+  return kMinorVersion;
+}
+
 }  // end extern "C"
--- a/db/c_test.c
+++ b/db/c_test.c
@@ -165,6 +165,9 @@ int main(int argc, char** argv) {
  char* err = NULL;
  int run = -1;

+  CheckCondition(leveldb_major_version() >= 1);
+  CheckCondition(leveldb_minor_version() >= 1);
+
  snprintf(dbname, sizeof(dbname),
           "%s/leveldb_c_test-%d",
           GetTempDir(),
@@ -204,6 +207,12 @@ int main(int argc, char** argv) {
  CheckCondition(err != NULL);
  Free(&err);

+  StartPhase("leveldb_free");
+  db = leveldb_open(options, dbname, &err);
+  CheckCondition(err != NULL);
+  leveldb_free(err);
+  err = NULL;
+
  StartPhase("open");
  leveldb_options_set_create_if_missing(options, 1);
  db = leveldb_open(options, dbname, &err);
--- a/db/corruption_test.cc
+++ b/db/corruption_test.cc
@@ -35,7 +35,8 @@ class CorruptionTest {
  CorruptionTest() {
    tiny_cache_ = NewLRUCache(100);
    options_.env = &env_;
-    dbname_ = test::TmpDir() + "/db_test";
+    options_.block_cache = tiny_cache_;
+    dbname_ = test::TmpDir() + "/corruption_test";
    DestroyDB(dbname_, options_);

    db_ = NULL;
@@ -50,17 +51,14 @@ class CorruptionTest {
     delete tiny_cache_;
  }

-  Status TryReopen(Options* options = NULL) {
+  Status TryReopen() {
    delete db_;
    db_ = NULL;
-    Options opt = (options ? *options : options_);
-    opt.env = &env_;
-    opt.block_cache = tiny_cache_;
-    return DB::Open(opt, dbname_, &db_);
+    return DB::Open(options_, dbname_, &db_);
  }

-  void Reopen(Options* options = NULL) {
-    ASSERT_OK(TryReopen(options));
+  void Reopen() {
+    ASSERT_OK(TryReopen());
  }

  void RepairDB() {
@@ -77,7 +75,13 @@ class CorruptionTest {
      Slice key = Key(i, &key_space);
      batch.Clear();
      batch.Put(key, Value(i, &value_space));
-      ASSERT_OK(db_->Write(WriteOptions(), &batch));
+      WriteOptions options;
+      // Corrupt() doesn't work without this sync on windows; stat reports 0 for
+      // the file size.
+      if (i == n - 1) {
+        options.sync = true;
+      }
+      ASSERT_OK(db_->Write(options, &batch));
    }
  }

@@ -92,6 +96,10 @@ class CorruptionTest {
    for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
      uint64_t key;
      Slice in(iter->key());
+      if (in == "" || in == "~") {
+        // Ignore boundary keys.
+        continue;
+      }
      if (!ConsumeDecimalNumber(&in, &key) ||
          !in.empty() ||
          key < next_expected) {
@@ -123,7 +131,7 @@ class CorruptionTest {
    FileType type;
    std::string fname;
    int picked_number = -1;
-    for (int i = 0; i < filenames.size(); i++) {
+    for (size_t i = 0; i < filenames.size(); i++) {
      if (ParseFileName(filenames[i], &number, &type) &&
          type == filetype &&
          int(number) > picked_number) {  // Pick latest file
@@ -233,7 +241,23 @@ TEST(CorruptionTest, TableFile) {
  dbi->TEST_CompactRange(1, NULL, NULL);

  Corrupt(kTableFile, 100, 1);
-  Check(99, 99);
+  Check(90, 99);
+}
+
+TEST(CorruptionTest, TableFileRepair) {
+  options_.block_size = 2 * kValueSize;  // Limit scope of corruption
+  options_.paranoid_checks = true;
+  Reopen();
+  Build(100);
+  DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
+  dbi->TEST_CompactMemTable();
+  dbi->TEST_CompactRange(0, NULL, NULL);
+  dbi->TEST_CompactRange(1, NULL, NULL);
+
+  Corrupt(kTableFile, 100, 1);
+  RepairDB();
+  Reopen();
+  Check(95, 99);
 }

 TEST(CorruptionTest, TableFileIndexData) {
@@ -299,7 +323,7 @@ TEST(CorruptionTest, CompactionInputError) {
  ASSERT_EQ(1, Property("leveldb.num-files-at-level" + NumberToString(last)));

  Corrupt(kTableFile, 100, 1);
-  Check(9, 9);
+  Check(5, 9);

  // Force compactions by writing lots of values
  Build(10000);
@@ -307,32 +331,23 @@ TEST(CorruptionTest, CompactionInputError) {
 }

 TEST(CorruptionTest, CompactionInputErrorParanoid) {
-  Options options;
-  options.paranoid_checks = true;
-  options.write_buffer_size = 1048576;
-  Reopen(&options);
+  options_.paranoid_checks = true;
+  options_.write_buffer_size = 512 << 10;
+  Reopen();
  DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);

-  // Fill levels >= 1 so memtable compaction outputs to level 1
-  for (int level = 1; level < config::kNumLevels; level++) {
-    dbi->Put(WriteOptions(), "", "begin");
-    dbi->Put(WriteOptions(), "~", "end");
+  // Make multiple inputs so we need to compact.
+  for (int i = 0; i < 2; i++) {
+    Build(10);
    dbi->TEST_CompactMemTable();
+    Corrupt(kTableFile, 100, 1);
+    env_.SleepForMicroseconds(100000);
  }
+  dbi->CompactRange(NULL, NULL);

-  Build(10);
-  dbi->TEST_CompactMemTable();
-  ASSERT_EQ(1, Property("leveldb.num-files-at-level0"));
-
-  Corrupt(kTableFile, 100, 1);
-  Check(9, 9);
-
-  // Write must eventually fail because of corrupted table
-  Status s;
+  // Write must fail because of corrupted table
  std::string tmp1, tmp2;
-  for (int i = 0; i < 10000 && s.ok(); i++) {
-    s = db_->Put(WriteOptions(), Key(i, &tmp1), Value(i, &tmp2));
-  }
+  Status s = db_->Put(WriteOptions(), Key(5, &tmp1), Value(5, &tmp2));
  ASSERT_TRUE(!s.ok()) << "write did not fail in corrupted paranoid db";
 }

--- a/db/db_bench.cc
+++ b/db/db_bench.cc
@@ -33,6 +33,7 @@
 //      readmissing   -- read N missing keys in random order
 //      readhot       -- read N times in random order from 1% section of DB
 //      seekrandom    -- N random seeks
+//      open          -- cost of opening a DB
 //      crc32c        -- repeated crc32c of 4K of data
 //      acquireload   -- load N*1000 times
 //   Meta operations:
@@ -99,6 +100,9 @@ static int FLAGS_bloom_bits = -1;
 // benchmark will fail.
 static bool FLAGS_use_existing_db = false;

+// If true, reuse existing log/MANIFEST files when re-opening a database.
+static bool FLAGS_reuse_logs = false;
+
 // Use the db with the following name.
 static const char* FLAGS_db = NULL;

@@ -128,7 +132,7 @@ class RandomGenerator {
    pos_ = 0;
  }

-  Slice Generate(int len) {
+  Slice Generate(size_t len) {
    if (pos_ + len > data_.size()) {
      pos_ = 0;
      assert(len < data_.size());
@@ -138,17 +142,19 @@ class RandomGenerator {
  }
 };

+#if defined(__linux)
 static Slice TrimSpace(Slice s) {
-  int start = 0;
+  size_t start = 0;
  while (start < s.size() && isspace(s[start])) {
    start++;
  }
-  int limit = s.size();
+  size_t limit = s.size();
  while (limit > start && isspace(s[limit-1])) {
    limit--;
  }
  return Slice(s.data() + start, limit - start);
 }
+#endif

 static void AppendWithSpace(std::string* str, Slice msg) {
  if (msg.empty()) return;
@@ -399,7 +405,7 @@ class Benchmark {
    heap_counter_(0) {
    std::vector<std::string> files;
    Env::Default()->GetChildren(FLAGS_db, &files);
-    for (int i = 0; i < files.size(); i++) {
+    for (size_t i = 0; i < files.size(); i++) {
      if (Slice(files[i]).starts_with("heap-")) {
        Env::Default()->DeleteFile(std::string(FLAGS_db) + "/" + files[i]);
      }
@@ -431,7 +437,7 @@ class Benchmark {
        benchmarks = sep + 1;
      }

-      // Reset parameters that may be overriddden bwlow
+      // Reset parameters that may be overridden below
      num_ = FLAGS_num;
      reads_ = (FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads);
      value_size_ = FLAGS_value_size;
@@ -442,7 +448,11 @@ class Benchmark {
      bool fresh_db = false;
      int num_threads = FLAGS_threads;

-      if (name == Slice("fillseq")) {
+      if (name == Slice("open")) {
+        method = &Benchmark::OpenBench;
+        num_ /= 10000;
+        if (num_ < 1) num_ = 1;
+      } else if (name == Slice("fillseq")) {
        fresh_db = true;
        method = &Benchmark::WriteSeq;
      } else if (name == Slice("fillbatch")) {
@@ -693,7 +703,9 @@ class Benchmark {
    options.create_if_missing = !FLAGS_use_existing_db;
    options.block_cache = cache_;
    options.write_buffer_size = FLAGS_write_buffer_size;
+    options.max_open_files = FLAGS_open_files;
    options.filter_policy = filter_policy_;
+    options.reuse_logs = FLAGS_reuse_logs;
    Status s = DB::Open(options, FLAGS_db, &db_);
    if (!s.ok()) {
      fprintf(stderr, "open error: %s\n", s.ToString().c_str());
@@ -701,6 +713,14 @@ class Benchmark {
    }
  }

+  void OpenBench(ThreadState* thread) {
+    for (int i = 0; i < num_; i++) {
+      delete db_;
+      Open();
+      thread->stats.FinishedSingleOp();
+    }
+  }
+
  void WriteSeq(ThreadState* thread) {
    DoWrite(thread, true);
  }
@@ -810,7 +830,6 @@ class Benchmark {

  void SeekRandom(ThreadState* thread) {
    ReadOptions options;
-    std::string value;
    int found = 0;
    for (int i = 0; i < reads_; i++) {
      Iterator* iter = db_->NewIterator(options);
@@ -941,6 +960,9 @@ int main(int argc, char** argv) {
    } else if (sscanf(argv[i], "--use_existing_db=%d%c", &n, &junk) == 1 &&
               (n == 0 || n == 1)) {
      FLAGS_use_existing_db = n;
+    } else if (sscanf(argv[i], "--reuse_logs=%d%c", &n, &junk) == 1 &&
+               (n == 0 || n == 1)) {
+      FLAGS_reuse_logs = n;
    } else if (sscanf(argv[i], "--num=%d%c", &n, &junk) == 1) {
      FLAGS_num = n;
    } else if (sscanf(argv[i], "--reads=%d%c", &n, &junk) == 1) {
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -35,6 +35,8 @@

 namespace leveldb {

+const int kNumNonTableCacheFiles = 10;
+
 // Information kept for every waiting writer
 struct DBImpl::Writer {
  Status status;
@@ -92,9 +94,9 @@ Options SanitizeOptions(const std::string& dbname,
  Options result = src;
  result.comparator = icmp;
  result.filter_policy = (src.filter_policy != NULL) ? ipolicy : NULL;
-  ClipToRange(&result.max_open_files,            20,     50000);
-  ClipToRange(&result.write_buffer_size,         64<<10, 1<<30);
-  ClipToRange(&result.block_size,                1<<10,  4<<20);
+  ClipToRange(&result.max_open_files,    64 + kNumNonTableCacheFiles, 50000);
+  ClipToRange(&result.write_buffer_size, 64<<10,                      1<<30);
+  ClipToRange(&result.block_size,        1<<10,                       4<<20);
  if (result.info_log == NULL) {
    // Open a log file in the same directory as the db
    src.env->CreateDir(dbname);  // In case it does not exist
@@ -111,31 +113,31 @@ Options SanitizeOptions(const std::string& dbname,
  return result;
 }

-DBImpl::DBImpl(const Options& options, const std::string& dbname)
-    : env_(options.env),
-      internal_comparator_(options.comparator),
-      internal_filter_policy_(options.filter_policy),
-      options_(SanitizeOptions(
-          dbname, &internal_comparator_, &internal_filter_policy_, options)),
-      owns_info_log_(options_.info_log != options.info_log),
-      owns_cache_(options_.block_cache != options.block_cache),
+DBImpl::DBImpl(const Options& raw_options, const std::string& dbname)
+    : env_(raw_options.env),
+      internal_comparator_(raw_options.comparator),
+      internal_filter_policy_(raw_options.filter_policy),
+      options_(SanitizeOptions(dbname, &internal_comparator_,
+                               &internal_filter_policy_, raw_options)),
+      owns_info_log_(options_.info_log != raw_options.info_log),
+      owns_cache_(options_.block_cache != raw_options.block_cache),
      dbname_(dbname),
      db_lock_(NULL),
      shutting_down_(NULL),
      bg_cv_(&mutex_),
-      mem_(new MemTable(internal_comparator_)),
+      mem_(NULL),
      imm_(NULL),
      logfile_(NULL),
      logfile_number_(0),
      log_(NULL),
+      seed_(0),
      tmp_batch_(new WriteBatch),
      bg_compaction_scheduled_(false),
      manual_compaction_(NULL) {
-  mem_->Ref();
  has_imm_.Release_Store(NULL);

  // Reserve ten files or so for other uses and give the rest to TableCache.
-  const int table_cache_size = options.max_open_files - 10;
+  const int table_cache_size = options_.max_open_files - kNumNonTableCacheFiles;
  table_cache_ = new TableCache(dbname_, &options_, table_cache_size);

  versions_ = new VersionSet(dbname_, &options_, table_cache_,
@@ -213,6 +215,12 @@ void DBImpl::MaybeIgnoreError(Status* s) const {
 }

 void DBImpl::DeleteObsoleteFiles() {
+  if (!bg_error_.ok()) {
+    // After a background error, we don't know whether a new version may
+    // or may not have been committed, so we cannot safely garbage collect.
+    return;
+  }
+
  // Make a set of all of the live files
  std::set<uint64_t> live = pending_outputs_;
  versions_->AddLiveFiles(&live);
@@ -262,7 +270,7 @@ void DBImpl::DeleteObsoleteFiles() {
  }
 }

-Status DBImpl::Recover(VersionEdit* edit) {
+Status DBImpl::Recover(VersionEdit* edit, bool *save_manifest) {
  mutex_.AssertHeld();

  // Ignore error from CreateDir since the creation of the DB is
@@ -292,58 +300,69 @@ Status DBImpl::Recover(VersionEdit* edit) {
    }
  }

-  s = versions_->Recover();
-  if (s.ok()) {
-    SequenceNumber max_sequence(0);
+  s = versions_->Recover(save_manifest);
+  if (!s.ok()) {
+    return s;
+  }
+  SequenceNumber max_sequence(0);

-    // Recover from all newer log files than the ones named in the
-    // descriptor (new log files may have been added by the previous
-    // incarnation without registering them in the descriptor).
-    //
-    // Note that PrevLogNumber() is no longer used, but we pay
-    // attention to it in case we are recovering a database
-    // produced by an older version of leveldb.
-    const uint64_t min_log = versions_->LogNumber();
-    const uint64_t prev_log = versions_->PrevLogNumber();
-    std::vector<std::string> filenames;
-    s = env_->GetChildren(dbname_, &filenames);
+  // Recover from all newer log files than the ones named in the
+  // descriptor (new log files may have been added by the previous
+  // incarnation without registering them in the descriptor).
+  //
+  // Note that PrevLogNumber() is no longer used, but we pay
+  // attention to it in case we are recovering a database
+  // produced by an older version of leveldb.
+  const uint64_t min_log = versions_->LogNumber();
+  const uint64_t prev_log = versions_->PrevLogNumber();
+  std::vector<std::string> filenames;
+  s = env_->GetChildren(dbname_, &filenames);
+  if (!s.ok()) {
+    return s;
+  }
+  std::set<uint64_t> expected;
+  versions_->AddLiveFiles(&expected);
+  uint64_t number;
+  FileType type;
+  std::vector<uint64_t> logs;
+  for (size_t i = 0; i < filenames.size(); i++) {
+    if (ParseFileName(filenames[i], &number, &type)) {
+      expected.erase(number);
+      if (type == kLogFile && ((number >= min_log) || (number == prev_log)))
+        logs.push_back(number);
+    }
+  }
+  if (!expected.empty()) {
+    char buf[50];
+    snprintf(buf, sizeof(buf), "%d missing files; e.g.",
+             static_cast<int>(expected.size()));
+    return Status::Corruption(buf, TableFileName(dbname_, *(expected.begin())));
+  }
+
+  // Recover in the order in which the logs were generated
+  std::sort(logs.begin(), logs.end());
+  for (size_t i = 0; i < logs.size(); i++) {
+    s = RecoverLogFile(logs[i], (i == logs.size() - 1), save_manifest, edit,
+                       &max_sequence);
    if (!s.ok()) {
      return s;
    }
-    uint64_t number;
-    FileType type;
-    std::vector<uint64_t> logs;
-    for (size_t i = 0; i < filenames.size(); i++) {
-      if (ParseFileName(filenames[i], &number, &type)
-          && type == kLogFile
-          && ((number >= min_log) || (number == prev_log))) {
-        logs.push_back(number);
-      }
-    }

-    // Recover in the order in which the logs were generated
-    std::sort(logs.begin(), logs.end());
-    for (size_t i = 0; i < logs.size(); i++) {
-      s = RecoverLogFile(logs[i], edit, &max_sequence);
-
-      // The previous incarnation may not have written any MANIFEST
-      // records after allocating this log number.  So we manually
-      // update the file number allocation counter in VersionSet.
-      versions_->MarkFileNumberUsed(logs[i]);
-    }
-
-    if (s.ok()) {
-      if (versions_->LastSequence() < max_sequence) {
-        versions_->SetLastSequence(max_sequence);
-      }
-    }
+    // The previous incarnation may not have written any MANIFEST
+    // records after allocating this log number.  So we manually
+    // update the file number allocation counter in VersionSet.
+    versions_->MarkFileNumberUsed(logs[i]);
  }

-  return s;
+  if (versions_->LastSequence() < max_sequence) {
+    versions_->SetLastSequence(max_sequence);
+  }
+
+  return Status::OK();
 }

-Status DBImpl::RecoverLogFile(uint64_t log_number,
-                              VersionEdit* edit,
+Status DBImpl::RecoverLogFile(uint64_t log_number, bool last_log,
+                              bool* save_manifest, VersionEdit* edit,
                              SequenceNumber* max_sequence) {
  struct LogReporter : public log::Reader::Reporter {
    Env* env;
@@ -375,7 +394,7 @@ Status DBImpl::RecoverLogFile(uint64_t log_number,
  reporter.info_log = options_.info_log;
  reporter.fname = fname.c_str();
  reporter.status = (options_.paranoid_checks ? &status : NULL);
-  // We intentially make log::Reader do checksumming even if
+  // We intentionally make log::Reader do checksumming even if
  // paranoid_checks==false so that corruptions cause entire commits
  // to be skipped instead of propagating bad information (like overly
  // large sequence numbers).
@@ -388,6 +407,7 @@ Status DBImpl::RecoverLogFile(uint64_t log_number,
  std::string scratch;
  Slice record;
  WriteBatch batch;
+  int compactions = 0;
  MemTable* mem = NULL;
  while (reader.ReadRecord(&record, &scratch) &&
         status.ok()) {
@@ -415,25 +435,52 @@ Status DBImpl::RecoverLogFile(uint64_t log_number,
    }

    if (mem->ApproximateMemoryUsage() > options_.write_buffer_size) {
+      compactions++;
+      *save_manifest = true;
      status = WriteLevel0Table(mem, edit, NULL);
+      mem->Unref();
+      mem = NULL;
      if (!status.ok()) {
        // Reflect errors immediately so that conditions like full
        // file-systems cause the DB::Open() to fail.
        break;
      }
-      mem->Unref();
-      mem = NULL;
    }
  }

-  if (status.ok() && mem != NULL) {
-    status = WriteLevel0Table(mem, edit, NULL);
-    // Reflect errors immediately so that conditions like full
-    // file-systems cause the DB::Open() to fail.
+  delete file;
+
+  // See if we should keep reusing the last log file.
+  if (status.ok() && options_.reuse_logs && last_log && compactions == 0) {
+    assert(logfile_ == NULL);
+    assert(log_ == NULL);
+    assert(mem_ == NULL);
+    uint64_t lfile_size;
+    if (env_->GetFileSize(fname, &lfile_size).ok() &&
+        env_->NewAppendableFile(fname, &logfile_).ok()) {
+      Log(options_.info_log, "Reusing old log %s \n", fname.c_str());
+      log_ = new log::Writer(logfile_, lfile_size);
+      logfile_number_ = log_number;
+      if (mem != NULL) {
+        mem_ = mem;
+        mem = NULL;
+      } else {
+        // mem can be NULL if lognum exists but was empty.
+        mem_ = new MemTable(internal_comparator_);
+        mem_->Ref();
+      }
+    }
+  }
+
+  if (mem != NULL) {
+    // mem did not get reused; compact it.
+    if (status.ok()) {
+      *save_manifest = true;
+      status = WriteLevel0Table(mem, edit, NULL);
+    }
+    mem->Unref();
  }

-  if (mem != NULL) mem->Unref();
-  delete file;
  return status;
 }

@@ -483,7 +530,7 @@ Status DBImpl::WriteLevel0Table(MemTable* mem, VersionEdit* edit,
  return s;
 }

-Status DBImpl::CompactMemTable() {
+void DBImpl::CompactMemTable() {
  mutex_.AssertHeld();
  assert(imm_ != NULL);

@@ -511,9 +558,9 @@ Status DBImpl::CompactMemTable() {
    imm_ = NULL;
    has_imm_.Release_Store(NULL);
    DeleteObsoleteFiles();
+  } else {
+    RecordBackgroundError(s);
  }
-
-  return s;
 }

 void DBImpl::CompactRange(const Slice* begin, const Slice* end) {
@@ -556,16 +603,18 @@ void DBImpl::TEST_CompactRange(int level, const Slice* begin,const Slice* end) {
  }

  MutexLock l(&mutex_);
-  while (!manual.done) {
-    while (manual_compaction_ != NULL) {
-      bg_cv_.Wait();
-    }
-    manual_compaction_ = &manual;
-    MaybeScheduleCompaction();
-    while (manual_compaction_ == &manual) {
+  while (!manual.done && !shutting_down_.Acquire_Load() && bg_error_.ok()) {
+    if (manual_compaction_ == NULL) {  // Idle
+      manual_compaction_ = &manual;
+      MaybeScheduleCompaction();
+    } else {  // Running either my compaction or another compaction.
      bg_cv_.Wait();
    }
  }
+  if (manual_compaction_ == &manual) {
+    // Cancel my manual compaction since we aborted early for some reason.
+    manual_compaction_ = NULL;
+  }
 }

 Status DBImpl::TEST_CompactMemTable() {
@@ -584,12 +633,22 @@ Status DBImpl::TEST_CompactMemTable() {
  return s;
 }

+void DBImpl::RecordBackgroundError(const Status& s) {
+  mutex_.AssertHeld();
+  if (bg_error_.ok()) {
+    bg_error_ = s;
+    bg_cv_.SignalAll();
+  }
+}
+
 void DBImpl::MaybeScheduleCompaction() {
  mutex_.AssertHeld();
  if (bg_compaction_scheduled_) {
    // Already scheduled
  } else if (shutting_down_.Acquire_Load()) {
    // DB is being deleted; no more background compactions
+  } else if (!bg_error_.ok()) {
+    // Already got an error; no more changes
  } else if (imm_ == NULL &&
             manual_compaction_ == NULL &&
             !versions_->NeedsCompaction()) {
@@ -607,20 +666,12 @@ void DBImpl::BGWork(void* db) {
 void DBImpl::BackgroundCall() {
  MutexLock l(&mutex_);
  assert(bg_compaction_scheduled_);
-  if (!shutting_down_.Acquire_Load()) {
-    Status s = BackgroundCompaction();
-    if (!s.ok()) {
-      // Wait a little bit before retrying background compaction in
-      // case this is an environmental problem and we do not want to
-      // chew up resources for failed compactions for the duration of
-      // the problem.
-      bg_cv_.SignalAll();  // In case a waiter can proceed despite the error
-      Log(options_.info_log, "Waiting after background compaction error: %s",
-          s.ToString().c_str());
-      mutex_.Unlock();
-      env_->SleepForMicroseconds(1000000);
-      mutex_.Lock();
-    }
+  if (shutting_down_.Acquire_Load()) {
+    // No more background work when shutting down.
+  } else if (!bg_error_.ok()) {
+    // No more background work after a background error.
+  } else {
+    BackgroundCompaction();
  }

  bg_compaction_scheduled_ = false;
@@ -631,11 +682,12 @@ void DBImpl::BackgroundCall() {
  bg_cv_.SignalAll();
 }

-Status DBImpl::BackgroundCompaction() {
+void DBImpl::BackgroundCompaction() {
  mutex_.AssertHeld();

  if (imm_ != NULL) {
-    return CompactMemTable();
+    CompactMemTable();
+    return;
  }

  Compaction* c;
@@ -669,6 +721,9 @@ Status DBImpl::BackgroundCompaction() {
    c->edit()->AddFile(c->level() + 1, f->number, f->file_size,
                       f->smallest, f->largest);
    status = versions_->LogAndApply(c->edit(), &mutex_);
+    if (!status.ok()) {
+      RecordBackgroundError(status);
+    }
    VersionSet::LevelSummaryStorage tmp;
    Log(options_.info_log, "Moved #%lld to level-%d %lld bytes %s: %s\n",
        static_cast<unsigned long long>(f->number),
@@ -679,6 +734,9 @@ Status DBImpl::BackgroundCompaction() {
  } else {
    CompactionState* compact = new CompactionState(c);
    status = DoCompactionWork(compact);
+    if (!status.ok()) {
+      RecordBackgroundError(status);
+    }
    CleanupCompaction(compact);
    c->ReleaseInputs();
    DeleteObsoleteFiles();
@@ -692,9 +750,6 @@ Status DBImpl::BackgroundCompaction() {
  } else {
    Log(options_.info_log,
        "Compaction error: %s", status.ToString().c_str());
-    if (options_.paranoid_checks && bg_error_.ok()) {
-      bg_error_ = status;
-    }
  }

  if (is_manual) {
@@ -710,7 +765,6 @@ Status DBImpl::BackgroundCompaction() {
    }
    manual_compaction_ = NULL;
  }
-  return status;
 }

 void DBImpl::CleanupCompaction(CompactionState* compact) {
@@ -980,6 +1034,9 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) {
  if (status.ok()) {
    status = InstallCompactionResults(compact);
  }
+  if (!status.ok()) {
+    RecordBackgroundError(status);
+  }
  VersionSet::LevelSummaryStorage tmp;
  Log(options_.info_log,
      "compacted to: %s", versions_->LevelSummary(&tmp));
@@ -1006,7 +1063,8 @@ static void CleanupIteratorState(void* arg1, void* arg2) {
 }  // namespace

 Iterator* DBImpl::NewInternalIterator(const ReadOptions& options,
-                                      SequenceNumber* latest_snapshot) {
+                                      SequenceNumber* latest_snapshot,
+                                      uint32_t* seed) {
  IterState* cleanup = new IterState;
  mutex_.Lock();
  *latest_snapshot = versions_->LastSequence();
@@ -1030,13 +1088,15 @@ Iterator* DBImpl::NewInternalIterator(const ReadOptions& options,
  cleanup->version = versions_->current();
  internal_iter->RegisterCleanup(CleanupIteratorState, cleanup, NULL);

+  *seed = ++seed_;
  mutex_.Unlock();
  return internal_iter;
 }

 Iterator* DBImpl::TEST_NewInternalIterator() {
  SequenceNumber ignored;
-  return NewInternalIterator(ReadOptions(), &ignored);
+  uint32_t ignored_seed;
+  return NewInternalIterator(ReadOptions(), &ignored, &ignored_seed);
 }

 int64_t DBImpl::TEST_MaxNextLevelOverlappingBytes() {
@@ -1093,12 +1153,21 @@ Status DBImpl::Get(const ReadOptions& options,

 Iterator* DBImpl::NewIterator(const ReadOptions& options) {
  SequenceNumber latest_snapshot;
-  Iterator* internal_iter = NewInternalIterator(options, &latest_snapshot);
+  uint32_t seed;
+  Iterator* iter = NewInternalIterator(options, &latest_snapshot, &seed);
  return NewDBIterator(
-      &dbname_, env_, user_comparator(), internal_iter,
+      this, user_comparator(), iter,
      (options.snapshot != NULL
       ? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
-       : latest_snapshot));
+       : latest_snapshot),
+      seed);
+}
+
+void DBImpl::RecordReadSample(Slice key) {
+  MutexLock l(&mutex_);
+  if (versions_->current()->RecordReadSample(key)) {
+    MaybeScheduleCompaction();
+  }
 }

 const Snapshot* DBImpl::GetSnapshot() {
@@ -1151,13 +1220,23 @@ Status DBImpl::Write(const WriteOptions& options, WriteBatch* my_batch) {
    {
      mutex_.Unlock();
      status = log_->AddRecord(WriteBatchInternal::Contents(updates));
+      bool sync_error = false;
      if (status.ok() && options.sync) {
        status = logfile_->Sync();
+        if (!status.ok()) {
+          sync_error = true;
+        }
      }
      if (status.ok()) {
        status = WriteBatchInternal::InsertInto(updates, mem_);
      }
      mutex_.Lock();
+      if (sync_error) {
+        // The state of the log file is indeterminate: the log record we
+        // just added may or may not show up when the DB is re-opened.
+        // So we force the DB into a mode where all future writes fail.
+        RecordBackgroundError(status);
+      }
    }
    if (updates == tmp_batch_) tmp_batch_->Clear();

@@ -1218,7 +1297,7 @@ WriteBatch* DBImpl::BuildBatchGroup(Writer** last_writer) {
        break;
      }

-      // Append to *reuslt
+      // Append to *result
      if (result == first->batch) {
        // Switch to temporary batch instead of disturbing caller's batch
        result = tmp_batch_;
@@ -1264,10 +1343,11 @@ Status DBImpl::MakeRoomForWrite(bool force) {
    } else if (imm_ != NULL) {
      // We have filled up the current memtable, but the previous
      // one is still being compacted, so we wait.
+      Log(options_.info_log, "Current memtable full; waiting...\n");
      bg_cv_.Wait();
    } else if (versions_->NumLevelFiles(0) >= config::kL0_StopWritesTrigger) {
      // There are too many level-0 files.
-      Log(options_.info_log, "waiting...\n");
+      Log(options_.info_log, "Too many L0 files; waiting...\n");
      bg_cv_.Wait();
    } else {
      // Attempt to switch to a new memtable and trigger compaction of old
@@ -1345,6 +1425,19 @@ bool DBImpl::GetProperty(const Slice& property, std::string* value) {
  } else if (in == "sstables") {
    *value = versions_->current()->DebugString();
    return true;
+  } else if (in == "approximate-memory-usage") {
+    size_t total_usage = options_.block_cache->TotalCharge();
+    if (mem_) {
+      total_usage += mem_->ApproximateMemoryUsage();
+    }
+    if (imm_) {
+      total_usage += imm_->ApproximateMemoryUsage();
+    }
+    char buf[50];
+    snprintf(buf, sizeof(buf), "%llu",
+             static_cast<unsigned long long>(total_usage));
+    value->append(buf);
+    return true;
  }

  return false;
@@ -1399,8 +1492,11 @@ Status DB::Open(const Options& options, const std::string& dbname,
  DBImpl* impl = new DBImpl(options, dbname);
  impl->mutex_.Lock();
  VersionEdit edit;
-  Status s = impl->Recover(&edit); // Handles create_if_missing, error_if_exists
-  if (s.ok()) {
+  // Recover handles create_if_missing, error_if_exists
+  bool save_manifest = false;
+  Status s = impl->Recover(&edit, &save_manifest);
+  if (s.ok() && impl->mem_ == NULL) {
+    // Create new log and a corresponding memtable.
    uint64_t new_log_number = impl->versions_->NewFileNumber();
    WritableFile* lfile;
    s = options.env->NewWritableFile(LogFileName(dbname, new_log_number),
@@ -1410,15 +1506,22 @@ Status DB::Open(const Options& options, const std::string& dbname,
      impl->logfile_ = lfile;
      impl->logfile_number_ = new_log_number;
      impl->log_ = new log::Writer(lfile);
-      s = impl->versions_->LogAndApply(&edit, &impl->mutex_);
-    }
-    if (s.ok()) {
-      impl->DeleteObsoleteFiles();
-      impl->MaybeScheduleCompaction();
+      impl->mem_ = new MemTable(impl->internal_comparator_);
+      impl->mem_->Ref();
    }
  }
+  if (s.ok() && save_manifest) {
+    edit.SetPrevLogNumber(0);  // No older logs needed after recovery.
+    edit.SetLogNumber(impl->logfile_number_);
+    s = impl->versions_->LogAndApply(&edit, &impl->mutex_);
+  }
+  if (s.ok()) {
+    impl->DeleteObsoleteFiles();
+    impl->MaybeScheduleCompaction();
+  }
  impl->mutex_.Unlock();
  if (s.ok()) {
+    assert(impl->mem_ != NULL);
    *dbptr = impl;
  } else {
    delete impl;
--- a/db/db_impl.h
+++ b/db/db_impl.h
@@ -13,6 +13,7 @@
 #include "leveldb/db.h"
 #include "leveldb/env.h"
 #include "port/port.h"
+#include "port/thread_annotations.h"

 namespace leveldb {

@@ -58,20 +59,27 @@ class DBImpl : public DB {
  // file at a level >= 1.
  int64_t TEST_MaxNextLevelOverlappingBytes();

+  // Record a sample of bytes read at the specified internal key.
+  // Samples are taken approximately once every config::kReadBytesPeriod
+  // bytes.
+  void RecordReadSample(Slice key);
+
 private:
  friend class DB;
  struct CompactionState;
  struct Writer;

  Iterator* NewInternalIterator(const ReadOptions&,
-                                SequenceNumber* latest_snapshot);
+                                SequenceNumber* latest_snapshot,
+                                uint32_t* seed);

  Status NewDB();

  // Recover the descriptor from persistent storage.  May do a significant
  // amount of work to recover recently logged updates.  Any changes to
  // be made to the descriptor are added to *edit.
-  Status Recover(VersionEdit* edit);
+  Status Recover(VersionEdit* edit, bool* save_manifest)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);

  void MaybeIgnoreError(Status* s) const;

@@ -80,27 +88,35 @@ class DBImpl : public DB {

  // Compact the in-memory write buffer to disk.  Switches to a new
  // log-file/memtable and writes a new descriptor iff successful.
-  Status CompactMemTable();
+  // Errors are recorded in bg_error_.
+  void CompactMemTable() EXCLUSIVE_LOCKS_REQUIRED(mutex_);

-  Status RecoverLogFile(uint64_t log_number,
-                        VersionEdit* edit,
-                        SequenceNumber* max_sequence);
+  Status RecoverLogFile(uint64_t log_number, bool last_log, bool* save_manifest,
+                        VersionEdit* edit, SequenceNumber* max_sequence)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);

-  Status WriteLevel0Table(MemTable* mem, VersionEdit* edit, Version* base);
+  Status WriteLevel0Table(MemTable* mem, VersionEdit* edit, Version* base)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);

-  Status MakeRoomForWrite(bool force /* compact even if there is room? */);
+  Status MakeRoomForWrite(bool force /* compact even if there is room? */)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);
  WriteBatch* BuildBatchGroup(Writer** last_writer);

-  void MaybeScheduleCompaction();
+  void RecordBackgroundError(const Status& s);
+
+  void MaybeScheduleCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
  static void BGWork(void* db);
  void BackgroundCall();
-  Status BackgroundCompaction();
-  void CleanupCompaction(CompactionState* compact);
-  Status DoCompactionWork(CompactionState* compact);
+  void  BackgroundCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  void CleanupCompaction(CompactionState* compact)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  Status DoCompactionWork(CompactionState* compact)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);

  Status OpenCompactionOutputFile(CompactionState* compact);
  Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
-  Status InstallCompactionResults(CompactionState* compact);
+  Status InstallCompactionResults(CompactionState* compact)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);

  // Constant after construction
  Env* const env_;
@@ -127,6 +143,7 @@ class DBImpl : public DB {
  WritableFile* logfile_;
  uint64_t logfile_number_;
  log::Writer* log_;
+  uint32_t seed_;                // For sampling.

  // Queue of writers.
  std::deque<Writer*> writers_;
--- a/db/db_iter.cc
+++ b/db/db_iter.cc
@@ -5,12 +5,14 @@
 #include "db/db_iter.h"

 #include "db/filename.h"
+#include "db/db_impl.h"
 #include "db/dbformat.h"
 #include "leveldb/env.h"
 #include "leveldb/iterator.h"
 #include "port/port.h"
 #include "util/logging.h"
 #include "util/mutexlock.h"
+#include "util/random.h"

 namespace leveldb {

@@ -46,15 +48,16 @@ class DBIter: public Iterator {
    kReverse
  };

-  DBIter(const std::string* dbname, Env* env,
-         const Comparator* cmp, Iterator* iter, SequenceNumber s)
-      : dbname_(dbname),
-        env_(env),
+  DBIter(DBImpl* db, const Comparator* cmp, Iterator* iter, SequenceNumber s,
+         uint32_t seed)
+      : db_(db),
        user_comparator_(cmp),
        iter_(iter),
        sequence_(s),
        direction_(kForward),
-        valid_(false) {
+        valid_(false),
+        rnd_(seed),
+        bytes_counter_(RandomPeriod()) {
  }
  virtual ~DBIter() {
    delete iter_;
@@ -100,8 +103,12 @@ class DBIter: public Iterator {
    }
  }

-  const std::string* const dbname_;
-  Env* const env_;
+  // Pick next gap with average value of config::kReadBytesPeriod.
+  ssize_t RandomPeriod() {
+    return rnd_.Uniform(2*config::kReadBytesPeriod);
+  }
+
+  DBImpl* db_;
  const Comparator* const user_comparator_;
  Iterator* const iter_;
  SequenceNumber const sequence_;
@@ -112,13 +119,23 @@ class DBIter: public Iterator {
  Direction direction_;
  bool valid_;

+  Random rnd_;
+  ssize_t bytes_counter_;
+
  // No copying allowed
  DBIter(const DBIter&);
  void operator=(const DBIter&);
 };

 inline bool DBIter::ParseKey(ParsedInternalKey* ikey) {
-  if (!ParseInternalKey(iter_->key(), ikey)) {
+  Slice k = iter_->key();
+  ssize_t n = k.size() + iter_->value().size();
+  bytes_counter_ -= n;
+  while (bytes_counter_ < 0) {
+    bytes_counter_ += RandomPeriod();
+    db_->RecordReadSample(k);
+  }
+  if (!ParseInternalKey(k, ikey)) {
    status_ = Status::Corruption("corrupted internal key in DBIter");
    return false;
  } else {
@@ -144,12 +161,13 @@ void DBIter::Next() {
      saved_key_.clear();
      return;
    }
+    // saved_key_ already contains the key to skip past.
+  } else {
+    // Store in saved_key_ the current key so we skip it below.
+    SaveKey(ExtractUserKey(iter_->key()), &saved_key_);
  }

-  // Temporarily use saved_key_ as storage for key to skip.
-  std::string* skip = &saved_key_;
-  SaveKey(ExtractUserKey(iter_->key()), skip);
-  FindNextUserEntry(true, skip);
+  FindNextUserEntry(true, &saved_key_);
 }

 void DBIter::FindNextUserEntry(bool skipping, std::string* skip) {
@@ -288,12 +306,12 @@ void DBIter::SeekToLast() {
 }  // anonymous namespace

 Iterator* NewDBIterator(
-    const std::string* dbname,
-    Env* env,
+    DBImpl* db,
    const Comparator* user_key_comparator,
    Iterator* internal_iter,
-    const SequenceNumber& sequence) {
-  return new DBIter(dbname, env, user_key_comparator, internal_iter, sequence);
+    SequenceNumber sequence,
+    uint32_t seed) {
+  return new DBIter(db, user_key_comparator, internal_iter, sequence, seed);
 }

 }  // namespace leveldb
--- a/db/db_iter.h
+++ b/db/db_iter.h
@@ -11,15 +11,17 @@

 namespace leveldb {

+class DBImpl;
+
 // Return a new iterator that converts internal keys (yielded by
 // "*internal_iter") that were live at the specified "sequence" number
 // into appropriate user keys.
 extern Iterator* NewDBIterator(
-    const std::string* dbname,
-    Env* env,
+    DBImpl* db,
    const Comparator* user_key_comparator,
    Iterator* internal_iter,
-    const SequenceNumber& sequence);
+    SequenceNumber sequence,
+    uint32_t seed);

 }  // namespace leveldb

--- a/db/db_test.cc
+++ b/db/db_test.cc
@@ -33,8 +33,11 @@ class AtomicCounter {
 public:
  AtomicCounter() : count_(0) { }
  void Increment() {
+    IncrementBy(1);
+  }
+  void IncrementBy(int count) {
    MutexLock l(&mu_);
-    count_++;
+    count_ += count;
  }
  int Read() {
    MutexLock l(&mu_);
@@ -45,13 +48,20 @@ class AtomicCounter {
    count_ = 0;
  }
 };
+
+void DelayMilliseconds(int millis) {
+  Env::Default()->SleepForMicroseconds(millis * 1000);
+}
 }

 // Special Env used to delay background operations
 class SpecialEnv : public EnvWrapper {
 public:
-  // sstable Sync() calls are blocked while this pointer is non-NULL.
-  port::AtomicPointer delay_sstable_sync_;
+  // sstable/log Sync() calls are blocked while this pointer is non-NULL.
+  port::AtomicPointer delay_data_sync_;
+
+  // sstable/log Sync() calls return an error.
+  port::AtomicPointer data_sync_error_;

  // Simulate no-space errors while this pointer is non-NULL.
  port::AtomicPointer no_space_;
@@ -59,30 +69,37 @@ class SpecialEnv : public EnvWrapper {
  // Simulate non-writable file system while this pointer is non-NULL
  port::AtomicPointer non_writable_;

+  // Force sync of manifest files to fail while this pointer is non-NULL
+  port::AtomicPointer manifest_sync_error_;
+
+  // Force write to manifest files to fail while this pointer is non-NULL
+  port::AtomicPointer manifest_write_error_;
+
  bool count_random_reads_;
  AtomicCounter random_read_counter_;

-  AtomicCounter sleep_counter_;
-
  explicit SpecialEnv(Env* base) : EnvWrapper(base) {
-    delay_sstable_sync_.Release_Store(NULL);
+    delay_data_sync_.Release_Store(NULL);
+    data_sync_error_.Release_Store(NULL);
    no_space_.Release_Store(NULL);
    non_writable_.Release_Store(NULL);
    count_random_reads_ = false;
+    manifest_sync_error_.Release_Store(NULL);
+    manifest_write_error_.Release_Store(NULL);
  }

  Status NewWritableFile(const std::string& f, WritableFile** r) {
-    class SSTableFile : public WritableFile {
+    class DataFile : public WritableFile {
     private:
      SpecialEnv* env_;
      WritableFile* base_;

     public:
-      SSTableFile(SpecialEnv* env, WritableFile* base)
+      DataFile(SpecialEnv* env, WritableFile* base)
          : env_(env),
            base_(base) {
      }
-      ~SSTableFile() { delete base_; }
+      ~DataFile() { delete base_; }
      Status Append(const Slice& data) {
        if (env_->no_space_.Acquire_Load() != NULL) {
          // Drop writes on the floor
@@ -94,12 +111,39 @@ class SpecialEnv : public EnvWrapper {
      Status Close() { return base_->Close(); }
      Status Flush() { return base_->Flush(); }
      Status Sync() {
-        while (env_->delay_sstable_sync_.Acquire_Load() != NULL) {
-          env_->SleepForMicroseconds(100000);
+        if (env_->data_sync_error_.Acquire_Load() != NULL) {
+          return Status::IOError("simulated data sync error");
+        }
+        while (env_->delay_data_sync_.Acquire_Load() != NULL) {
+          DelayMilliseconds(100);
        }
        return base_->Sync();
      }
    };
+    class ManifestFile : public WritableFile {
+     private:
+      SpecialEnv* env_;
+      WritableFile* base_;
+     public:
+      ManifestFile(SpecialEnv* env, WritableFile* b) : env_(env), base_(b) { }
+      ~ManifestFile() { delete base_; }
+      Status Append(const Slice& data) {
+        if (env_->manifest_write_error_.Acquire_Load() != NULL) {
+          return Status::IOError("simulated writer error");
+        } else {
+          return base_->Append(data);
+        }
+      }
+      Status Close() { return base_->Close(); }
+      Status Flush() { return base_->Flush(); }
+      Status Sync() {
+        if (env_->manifest_sync_error_.Acquire_Load() != NULL) {
+          return Status::IOError("simulated sync error");
+        } else {
+          return base_->Sync();
+        }
+      }
+    };

    if (non_writable_.Acquire_Load() != NULL) {
      return Status::IOError("simulated write error");
@@ -107,8 +151,11 @@ class SpecialEnv : public EnvWrapper {

    Status s = target()->NewWritableFile(f, r);
    if (s.ok()) {
-      if (strstr(f.c_str(), ".sst") != NULL) {
-        *r = new SSTableFile(this, *r);
+      if (strstr(f.c_str(), ".ldb") != NULL ||
+          strstr(f.c_str(), ".log") != NULL) {
+        *r = new DataFile(this, *r);
+      } else if (strstr(f.c_str(), "MANIFEST") != NULL) {
+        *r = new ManifestFile(this, *r);
      }
    }
    return s;
@@ -137,11 +184,6 @@ class SpecialEnv : public EnvWrapper {
    }
    return s;
  }
-
-  virtual void SleepForMicroseconds(int micros) {
-    sleep_counter_.Increment();
-    target()->SleepForMicroseconds(micros);
-  }
 };

 class DBTest {
@@ -151,6 +193,7 @@ class DBTest {
  // Sequence of option configurations to try
  enum OptionConfig {
    kDefault,
+    kReuse,
    kFilter,
    kUncompressed,
    kEnd
@@ -195,7 +238,11 @@ class DBTest {
  // Return the current option configuration.
  Options CurrentOptions() {
    Options options;
+    options.reuse_logs = false;
    switch (option_config_) {
+      case kReuse:
+        options.reuse_logs = true;
+        break;
      case kFilter:
        options.filter_policy = filter_policy_;
        break;
@@ -279,7 +326,7 @@ class DBTest {
    }

    // Check reverse iteration results are the reverse of forward results
-    int matched = 0;
+    size_t matched = 0;
    for (iter->SeekToLast(); iter->Valid(); iter->Prev()) {
      ASSERT_LT(matched, forward.size());
      ASSERT_EQ(IterStatus(iter), forward[forward.size() - matched - 1]);
@@ -427,6 +474,38 @@ class DBTest {
    }
    return result;
  }
+
+  bool DeleteAnSSTFile() {
+    std::vector<std::string> filenames;
+    ASSERT_OK(env_->GetChildren(dbname_, &filenames));
+    uint64_t number;
+    FileType type;
+    for (size_t i = 0; i < filenames.size(); i++) {
+      if (ParseFileName(filenames[i], &number, &type) && type == kTableFile) {
+        ASSERT_OK(env_->DeleteFile(TableFileName(dbname_, number)));
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // Returns number of files renamed.
+  int RenameLDBToSST() {
+    std::vector<std::string> filenames;
+    ASSERT_OK(env_->GetChildren(dbname_, &filenames));
+    uint64_t number;
+    FileType type;
+    int files_renamed = 0;
+    for (size_t i = 0; i < filenames.size(); i++) {
+      if (ParseFileName(filenames[i], &number, &type) && type == kTableFile) {
+        const std::string from = TableFileName(dbname_, number);
+        const std::string to = SSTTableFileName(dbname_, number);
+        ASSERT_OK(env_->RenameFile(from, to));
+        files_renamed++;
+      }
+    }
+    return files_renamed;
+  }
 };

 TEST(DBTest, Empty) {
@@ -468,11 +547,11 @@ TEST(DBTest, GetFromImmutableLayer) {
    ASSERT_OK(Put("foo", "v1"));
    ASSERT_EQ("v1", Get("foo"));

-    env_->delay_sstable_sync_.Release_Store(env_);   // Block sync calls
+    env_->delay_data_sync_.Release_Store(env_);      // Block sync calls
    Put("k1", std::string(100000, 'x'));             // Fill memtable
    Put("k2", std::string(100000, 'y'));             // Trigger compaction
    ASSERT_EQ("v1", Get("foo"));
-    env_->delay_sstable_sync_.Release_Store(NULL);   // Release sync calls
+    env_->delay_data_sync_.Release_Store(NULL);      // Release sync calls
  } while (ChangeOptions());
 }

@@ -484,6 +563,17 @@ TEST(DBTest, GetFromVersions) {
  } while (ChangeOptions());
 }

+TEST(DBTest, GetMemUsage) {
+  do {
+    ASSERT_OK(Put("foo", "v1"));
+    std::string val;
+    ASSERT_TRUE(db_->GetProperty("leveldb.approximate-memory-usage", &val));
+    int mem_usage = atoi(val.c_str());
+    ASSERT_GT(mem_usage, 0);
+    ASSERT_LT(mem_usage, 5*1024*1024);
+  } while (ChangeOptions());
+}
+
 TEST(DBTest, GetSnapshot) {
  do {
    // Try with both a short key and a long key
@@ -552,7 +642,7 @@ TEST(DBTest, GetEncountersEmptyLevel) {
    //   * sstable B in level 2
    // Then do enough Get() calls to arrange for an automatic compaction
    // of sstable A.  A bug would cause the compaction to be marked as
-    // occuring at level 1 (instead of the correct level 0).
+    // occurring at level 1 (instead of the correct level 0).

    // Step 1: First place sstables in levels 0 and 2
    int compaction_count = 0;
@@ -577,7 +667,7 @@ TEST(DBTest, GetEncountersEmptyLevel) {
    }

    // Step 4: Wait for compaction to finish
-    env_->SleepForMicroseconds(1000000);
+    DelayMilliseconds(1000);

    ASSERT_EQ(NumTableFilesAtLevel(0), 0);
  } while (ChangeOptions());
@@ -1006,6 +1096,14 @@ TEST(DBTest, ApproximateSizes) {
    // 0 because GetApproximateSizes() does not account for memtable space
    ASSERT_TRUE(Between(Size("", Key(50)), 0, 0));

+    if (options.reuse_logs) {
+      // Recovery will reuse memtable, and GetApproximateSizes() does not
+      // account for memtable usage;
+      Reopen(&options);
+      ASSERT_TRUE(Between(Size("", Key(50)), 0, 0));
+      continue;
+    }
+
    // Check sizes across recovery by reopening a few times
    for (int run = 0; run < 3; run++) {
      Reopen(&options);
@@ -1049,6 +1147,11 @@ TEST(DBTest, ApproximateSizes_MixOfSmallAndLarge) {
    ASSERT_OK(Put(Key(6), RandomString(&rnd, 300000)));
    ASSERT_OK(Put(Key(7), RandomString(&rnd, 10000)));

+    if (options.reuse_logs) {
+      // Need to force a memtable compaction since recovery does not do so.
+      ASSERT_OK(dbfull()->TEST_CompactMemTable());
+    }
+
    // Check sizes across recovery by reopening a few times
    for (int run = 0; run < 3; run++) {
      Reopen(&options);
@@ -1261,7 +1364,7 @@ TEST(DBTest, L0_CompactionBug_Issue44_a) {
  Reopen();
  Reopen();
  ASSERT_EQ("(a->v)", Contents());
-  env_->SleepForMicroseconds(1000000);  // Wait for compaction to finish
+  DelayMilliseconds(1000);  // Wait for compaction to finish
  ASSERT_EQ("(a->v)", Contents());
 }

@@ -1277,7 +1380,7 @@ TEST(DBTest, L0_CompactionBug_Issue44_b) {
  Put("","");
  Reopen();
  Put("","");
-  env_->SleepForMicroseconds(1000000);  // Wait for compaction to finish
+  DelayMilliseconds(1000);  // Wait for compaction to finish
  Reopen();
  Put("d","dv");
  Reopen();
@@ -1287,7 +1390,7 @@ TEST(DBTest, L0_CompactionBug_Issue44_b) {
  Delete("b");
  Reopen();
  ASSERT_EQ("(->)(c->cv)", Contents());
-  env_->SleepForMicroseconds(1000000);  // Wait for compaction to finish
+  DelayMilliseconds(1000);  // Wait for compaction to finish
  ASSERT_EQ("(->)(c->cv)", Contents());
 }

@@ -1442,6 +1545,12 @@ TEST(DBTest, DBOpen_Options) {
  db = NULL;
 }

+TEST(DBTest, Locking) {
+  DB* db2 = NULL;
+  Status s = DB::Open(CurrentOptions(), dbname_, &db2);
+  ASSERT_TRUE(!s.ok()) << "Locking did not prevent re-opening db";
+}
+
 // Check that number of files does not grow when we are out of space
 TEST(DBTest, NoSpace) {
  Options options = CurrentOptions();
@@ -1453,17 +1562,13 @@ TEST(DBTest, NoSpace) {
  Compact("a", "z");
  const int num_files = CountFiles();
  env_->no_space_.Release_Store(env_);   // Force out-of-space errors
-  env_->sleep_counter_.Reset();
-  for (int i = 0; i < 5; i++) {
+  for (int i = 0; i < 10; i++) {
    for (int level = 0; level < config::kNumLevels-1; level++) {
      dbfull()->TEST_CompactRange(level, NULL, NULL);
    }
  }
  env_->no_space_.Release_Store(NULL);
  ASSERT_LT(CountFiles(), num_files + 3);
-
-  // Check that compaction attempts slept after errors
-  ASSERT_GE(env_->sleep_counter_.Read(), 5);
 }

 TEST(DBTest, NonWritableFileSystem) {
@@ -1479,13 +1584,119 @@ TEST(DBTest, NonWritableFileSystem) {
    fprintf(stderr, "iter %d; errors %d\n", i, errors);
    if (!Put("foo", big).ok()) {
      errors++;
-      env_->SleepForMicroseconds(100000);
+      DelayMilliseconds(100);
    }
  }
  ASSERT_GT(errors, 0);
  env_->non_writable_.Release_Store(NULL);
 }

+TEST(DBTest, WriteSyncError) {
+  // Check that log sync errors cause the DB to disallow future writes.
+
+  // (a) Cause log sync calls to fail
+  Options options = CurrentOptions();
+  options.env = env_;
+  Reopen(&options);
+  env_->data_sync_error_.Release_Store(env_);
+
+  // (b) Normal write should succeed
+  WriteOptions w;
+  ASSERT_OK(db_->Put(w, "k1", "v1"));
+  ASSERT_EQ("v1", Get("k1"));
+
+  // (c) Do a sync write; should fail
+  w.sync = true;
+  ASSERT_TRUE(!db_->Put(w, "k2", "v2").ok());
+  ASSERT_EQ("v1", Get("k1"));
+  ASSERT_EQ("NOT_FOUND", Get("k2"));
+
+  // (d) make sync behave normally
+  env_->data_sync_error_.Release_Store(NULL);
+
+  // (e) Do a non-sync write; should fail
+  w.sync = false;
+  ASSERT_TRUE(!db_->Put(w, "k3", "v3").ok());
+  ASSERT_EQ("v1", Get("k1"));
+  ASSERT_EQ("NOT_FOUND", Get("k2"));
+  ASSERT_EQ("NOT_FOUND", Get("k3"));
+}
+
+TEST(DBTest, ManifestWriteError) {
+  // Test for the following problem:
+  // (a) Compaction produces file F
+  // (b) Log record containing F is written to MANIFEST file, but Sync() fails
+  // (c) GC deletes F
+  // (d) After reopening DB, reads fail since deleted F is named in log record
+
+  // We iterate twice.  In the second iteration, everything is the
+  // same except the log record never makes it to the MANIFEST file.
+  for (int iter = 0; iter < 2; iter++) {
+    port::AtomicPointer* error_type = (iter == 0)
+        ? &env_->manifest_sync_error_
+        : &env_->manifest_write_error_;
+
+    // Insert foo=>bar mapping
+    Options options = CurrentOptions();
+    options.env = env_;
+    options.create_if_missing = true;
+    options.error_if_exists = false;
+    DestroyAndReopen(&options);
+    ASSERT_OK(Put("foo", "bar"));
+    ASSERT_EQ("bar", Get("foo"));
+
+    // Memtable compaction (will succeed)
+    dbfull()->TEST_CompactMemTable();
+    ASSERT_EQ("bar", Get("foo"));
+    const int last = config::kMaxMemCompactLevel;
+    ASSERT_EQ(NumTableFilesAtLevel(last), 1);   // foo=>bar is now in last level
+
+    // Merging compaction (will fail)
+    error_type->Release_Store(env_);
+    dbfull()->TEST_CompactRange(last, NULL, NULL);  // Should fail
+    ASSERT_EQ("bar", Get("foo"));
+
+    // Recovery: should not lose data
+    error_type->Release_Store(NULL);
+    Reopen(&options);
+    ASSERT_EQ("bar", Get("foo"));
+  }
+}
+
+TEST(DBTest, MissingSSTFile) {
+  ASSERT_OK(Put("foo", "bar"));
+  ASSERT_EQ("bar", Get("foo"));
+
+  // Dump the memtable to disk.
+  dbfull()->TEST_CompactMemTable();
+  ASSERT_EQ("bar", Get("foo"));
+
+  Close();
+  ASSERT_TRUE(DeleteAnSSTFile());
+  Options options = CurrentOptions();
+  options.paranoid_checks = true;
+  Status s = TryReopen(&options);
+  ASSERT_TRUE(!s.ok());
+  ASSERT_TRUE(s.ToString().find("issing") != std::string::npos)
+      << s.ToString();
+}
+
+TEST(DBTest, StillReadSST) {
+  ASSERT_OK(Put("foo", "bar"));
+  ASSERT_EQ("bar", Get("foo"));
+
+  // Dump the memtable to disk.
+  dbfull()->TEST_CompactMemTable();
+  ASSERT_EQ("bar", Get("foo"));
+  Close();
+  ASSERT_GT(RenameLDBToSST(), 0);
+  Options options = CurrentOptions();
+  options.paranoid_checks = true;
+  Status s = TryReopen(&options);
+  ASSERT_TRUE(s.ok());
+  ASSERT_EQ("bar", Get("foo"));
+}
+
 TEST(DBTest, FilesDeletedAfterCompaction) {
  ASSERT_OK(Put("foo", "v2"));
  Compact("a", "z");
@@ -1517,7 +1728,7 @@ TEST(DBTest, BloomFilter) {
  dbfull()->TEST_CompactMemTable();

  // Prevent auto compactions triggered by seeks
-  env_->delay_sstable_sync_.Release_Store(env_);
+  env_->delay_data_sync_.Release_Store(env_);

  // Lookup present keys.  Should rarely read from small sstable.
  env_->random_read_counter_.Reset();
@@ -1538,7 +1749,7 @@ TEST(DBTest, BloomFilter) {
  fprintf(stderr, "%d missing => %d reads\n", N, reads);
  ASSERT_LE(reads, 3*N/100);

-  env_->delay_sstable_sync_.Release_Store(NULL);
+  env_->delay_data_sync_.Release_Store(NULL);
  Close();
  delete options.block_cache;
  delete options.filter_policy;
@@ -1598,7 +1809,7 @@ static void MTThreadBody(void* arg) {
        ASSERT_EQ(k, key);
        ASSERT_GE(w, 0);
        ASSERT_LT(w, kNumThreads);
-        ASSERT_LE(c, reinterpret_cast<uintptr_t>(
+        ASSERT_LE(static_cast<uintptr_t>(c), reinterpret_cast<uintptr_t>(
            t->state->counter[w].Acquire_Load()));
      }
    }
@@ -1630,13 +1841,13 @@ TEST(DBTest, MultiThreaded) {
    }

    // Let them run for a while
-    env_->SleepForMicroseconds(kTestSeconds * 1000000);
+    DelayMilliseconds(kTestSeconds * 1000);

    // Stop the threads and wait for them to finish
    mt.stop.Release_Store(&mt);
    for (int id = 0; id < kNumThreads; id++) {
      while (mt.thread_done[id].Acquire_Load() == NULL) {
-        env_->SleepForMicroseconds(100000);
+        DelayMilliseconds(100);
      }
    }
  } while (ChangeOptions());
@@ -1902,7 +2113,8 @@ void BM_LogAndApply(int iters, int num_base_files) {
  InternalKeyComparator cmp(BytewiseComparator());
  Options options;
  VersionSet vset(dbname, &options, NULL, &cmp);
-  ASSERT_OK(vset.Recover());
+  bool save_manifest;
+  ASSERT_OK(vset.Recover(&save_manifest));
  VersionEdit vbase;
  uint64_t fnum = 1;
  for (int i = 0; i < num_base_files; i++) {
--- a/db/dbformat.cc
+++ b/db/dbformat.cc
@@ -26,7 +26,7 @@ std::string ParsedInternalKey::DebugString() const {
           (unsigned long long) sequence,
           int(type));
  std::string result = "'";
-  result += user_key.ToString();
+  result += EscapeString(user_key.ToString());
  result += buf;
  return result;
 }
--- a/db/dbformat.h
+++ b/db/dbformat.h
@@ -2,8 +2,8 @@
 // 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.

-#ifndef STORAGE_LEVELDB_DB_FORMAT_H_
-#define STORAGE_LEVELDB_DB_FORMAT_H_
+#ifndef STORAGE_LEVELDB_DB_DBFORMAT_H_
+#define STORAGE_LEVELDB_DB_DBFORMAT_H_

 #include <stdio.h>
 #include "leveldb/comparator.h"
@@ -38,6 +38,9 @@ static const int kL0_StopWritesTrigger = 12;
 // space if the same key space is being repeatedly overwritten.
 static const int kMaxMemCompactLevel = 2;

+// Approximate gap in bytes between samples of data read during iteration.
+static const int kReadBytesPeriod = 1048576;
+
 }  // namespace config

 class InternalKey;
@@ -224,4 +227,4 @@ inline LookupKey::~LookupKey() {

 }  // namespace leveldb

-#endif  // STORAGE_LEVELDB_DB_FORMAT_H_
+#endif  // STORAGE_LEVELDB_DB_DBFORMAT_H_
--- a/db/dumpfile.cc
+++ b/db/dumpfile.cc
@@ -0,0 +1,225 @@
+// Copyright (c) 2012 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 <stdio.h>
+#include "db/dbformat.h"
+#include "db/filename.h"
+#include "db/log_reader.h"
+#include "db/version_edit.h"
+#include "db/write_batch_internal.h"
+#include "leveldb/env.h"
+#include "leveldb/iterator.h"
+#include "leveldb/options.h"
+#include "leveldb/status.h"
+#include "leveldb/table.h"
+#include "leveldb/write_batch.h"
+#include "util/logging.h"
+
+namespace leveldb {
+
+namespace {
+
+bool GuessType(const std::string& fname, FileType* type) {
+  size_t pos = fname.rfind('/');
+  std::string basename;
+  if (pos == std::string::npos) {
+    basename = fname;
+  } else {
+    basename = std::string(fname.data() + pos + 1, fname.size() - pos - 1);
+  }
+  uint64_t ignored;
+  return ParseFileName(basename, &ignored, type);
+}
+
+// Notified when log reader encounters corruption.
+class CorruptionReporter : public log::Reader::Reporter {
+ public:
+  WritableFile* dst_;
+  virtual void Corruption(size_t bytes, const Status& status) {
+    std::string r = "corruption: ";
+    AppendNumberTo(&r, bytes);
+    r += " bytes; ";
+    r += status.ToString();
+    r.push_back('\n');
+    dst_->Append(r);
+  }
+};
+
+// Print contents of a log file. (*func)() is called on every record.
+Status PrintLogContents(Env* env, const std::string& fname,
+                        void (*func)(uint64_t, Slice, WritableFile*),
+                        WritableFile* dst) {
+  SequentialFile* file;
+  Status s = env->NewSequentialFile(fname, &file);
+  if (!s.ok()) {
+    return s;
+  }
+  CorruptionReporter reporter;
+  reporter.dst_ = dst;
+  log::Reader reader(file, &reporter, true, 0);
+  Slice record;
+  std::string scratch;
+  while (reader.ReadRecord(&record, &scratch)) {
+    (*func)(reader.LastRecordOffset(), record, dst);
+  }
+  delete file;
+  return Status::OK();
+}
+
+// Called on every item found in a WriteBatch.
+class WriteBatchItemPrinter : public WriteBatch::Handler {
+ public:
+  WritableFile* dst_;
+  virtual void Put(const Slice& key, const Slice& value) {
+    std::string r = "  put '";
+    AppendEscapedStringTo(&r, key);
+    r += "' '";
+    AppendEscapedStringTo(&r, value);
+    r += "'\n";
+    dst_->Append(r);
+  }
+  virtual void Delete(const Slice& key) {
+    std::string r = "  del '";
+    AppendEscapedStringTo(&r, key);
+    r += "'\n";
+    dst_->Append(r);
+  }
+};
+
+
+// Called on every log record (each one of which is a WriteBatch)
+// found in a kLogFile.
+static void WriteBatchPrinter(uint64_t pos, Slice record, WritableFile* dst) {
+  std::string r = "--- offset ";
+  AppendNumberTo(&r, pos);
+  r += "; ";
+  if (record.size() < 12) {
+    r += "log record length ";
+    AppendNumberTo(&r, record.size());
+    r += " is too small\n";
+    dst->Append(r);
+    return;
+  }
+  WriteBatch batch;
+  WriteBatchInternal::SetContents(&batch, record);
+  r += "sequence ";
+  AppendNumberTo(&r, WriteBatchInternal::Sequence(&batch));
+  r.push_back('\n');
+  dst->Append(r);
+  WriteBatchItemPrinter batch_item_printer;
+  batch_item_printer.dst_ = dst;
+  Status s = batch.Iterate(&batch_item_printer);
+  if (!s.ok()) {
+    dst->Append("  error: " + s.ToString() + "\n");
+  }
+}
+
+Status DumpLog(Env* env, const std::string& fname, WritableFile* dst) {
+  return PrintLogContents(env, fname, WriteBatchPrinter, dst);
+}
+
+// Called on every log record (each one of which is a WriteBatch)
+// found in a kDescriptorFile.
+static void VersionEditPrinter(uint64_t pos, Slice record, WritableFile* dst) {
+  std::string r = "--- offset ";
+  AppendNumberTo(&r, pos);
+  r += "; ";
+  VersionEdit edit;
+  Status s = edit.DecodeFrom(record);
+  if (!s.ok()) {
+    r += s.ToString();
+    r.push_back('\n');
+  } else {
+    r += edit.DebugString();
+  }
+  dst->Append(r);
+}
+
+Status DumpDescriptor(Env* env, const std::string& fname, WritableFile* dst) {
+  return PrintLogContents(env, fname, VersionEditPrinter, dst);
+}
+
+Status DumpTable(Env* env, const std::string& fname, WritableFile* dst) {
+  uint64_t file_size;
+  RandomAccessFile* file = NULL;
+  Table* table = NULL;
+  Status s = env->GetFileSize(fname, &file_size);
+  if (s.ok()) {
+    s = env->NewRandomAccessFile(fname, &file);
+  }
+  if (s.ok()) {
+    // We use the default comparator, which may or may not match the
+    // comparator used in this database. However this should not cause
+    // problems since we only use Table operations that do not require
+    // any comparisons.  In particular, we do not call Seek or Prev.
+    s = Table::Open(Options(), file, file_size, &table);
+  }
+  if (!s.ok()) {
+    delete table;
+    delete file;
+    return s;
+  }
+
+  ReadOptions ro;
+  ro.fill_cache = false;
+  Iterator* iter = table->NewIterator(ro);
+  std::string r;
+  for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
+    r.clear();
+    ParsedInternalKey key;
+    if (!ParseInternalKey(iter->key(), &key)) {
+      r = "badkey '";
+      AppendEscapedStringTo(&r, iter->key());
+      r += "' => '";
+      AppendEscapedStringTo(&r, iter->value());
+      r += "'\n";
+      dst->Append(r);
+    } else {
+      r = "'";
+      AppendEscapedStringTo(&r, key.user_key);
+      r += "' @ ";
+      AppendNumberTo(&r, key.sequence);
+      r += " : ";
+      if (key.type == kTypeDeletion) {
+        r += "del";
+      } else if (key.type == kTypeValue) {
+        r += "val";
+      } else {
+        AppendNumberTo(&r, key.type);
+      }
+      r += " => '";
+      AppendEscapedStringTo(&r, iter->value());
+      r += "'\n";
+      dst->Append(r);
+    }
+  }
+  s = iter->status();
+  if (!s.ok()) {
+    dst->Append("iterator error: " + s.ToString() + "\n");
+  }
+
+  delete iter;
+  delete table;
+  delete file;
+  return Status::OK();
+}
+
+}  // namespace
+
+Status DumpFile(Env* env, const std::string& fname, WritableFile* dst) {
+  FileType ftype;
+  if (!GuessType(fname, &ftype)) {
+    return Status::InvalidArgument(fname + ": unknown file type");
+  }
+  switch (ftype) {
+    case kLogFile:         return DumpLog(env, fname, dst);
+    case kDescriptorFile:  return DumpDescriptor(env, fname, dst);
+    case kTableFile:       return DumpTable(env, fname, dst);
+    default:
+      break;
+  }
+  return Status::InvalidArgument(fname + ": not a dump-able file type");
+}
+
+}  // namespace leveldb
--- a/db/fault_injection_test.cc
+++ b/db/fault_injection_test.cc
@@ -0,0 +1,554 @@
+// Copyright 2014 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.
+
+// This test uses a custom Env to keep track of the state of a filesystem as of
+// the last "sync". It then checks for data loss errors by purposely dropping
+// file data (or entire files) not protected by a "sync".
+
+#include "leveldb/db.h"
+
+#include <map>
+#include <set>
+#include "db/db_impl.h"
+#include "db/filename.h"
+#include "db/log_format.h"
+#include "db/version_set.h"
+#include "leveldb/cache.h"
+#include "leveldb/env.h"
+#include "leveldb/table.h"
+#include "leveldb/write_batch.h"
+#include "util/logging.h"
+#include "util/mutexlock.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+namespace leveldb {
+
+static const int kValueSize = 1000;
+static const int kMaxNumValues = 2000;
+static const size_t kNumIterations = 3;
+
+class FaultInjectionTestEnv;
+
+namespace {
+
+// Assume a filename, and not a directory name like "/foo/bar/"
+static std::string GetDirName(const std::string filename) {
+  size_t found = filename.find_last_of("/\\");
+  if (found == std::string::npos) {
+    return "";
+  } else {
+    return filename.substr(0, found);
+  }
+}
+
+Status SyncDir(const std::string& dir) {
+  // As this is a test it isn't required to *actually* sync this directory.
+  return Status::OK();
+}
+
+// A basic file truncation function suitable for this test.
+Status Truncate(const std::string& filename, uint64_t length) {
+  leveldb::Env* env = leveldb::Env::Default();
+
+  SequentialFile* orig_file;
+  Status s = env->NewSequentialFile(filename, &orig_file);
+  if (!s.ok())
+    return s;
+
+  char* scratch = new char[length];
+  leveldb::Slice result;
+  s = orig_file->Read(length, &result, scratch);
+  delete orig_file;
+  if (s.ok()) {
+    std::string tmp_name = GetDirName(filename) + "/truncate.tmp";
+    WritableFile* tmp_file;
+    s = env->NewWritableFile(tmp_name, &tmp_file);
+    if (s.ok()) {
+      s = tmp_file->Append(result);
+      delete tmp_file;
+      if (s.ok()) {
+        s = env->RenameFile(tmp_name, filename);
+      } else {
+        env->DeleteFile(tmp_name);
+      }
+    }
+  }
+
+  delete[] scratch;
+
+  return s;
+}
+
+struct FileState {
+  std::string filename_;
+  ssize_t pos_;
+  ssize_t pos_at_last_sync_;
+  ssize_t pos_at_last_flush_;
+
+  FileState(const std::string& filename)
+      : filename_(filename),
+        pos_(-1),
+        pos_at_last_sync_(-1),
+        pos_at_last_flush_(-1) { }
+
+  FileState() : pos_(-1), pos_at_last_sync_(-1), pos_at_last_flush_(-1) {}
+
+  bool IsFullySynced() const { return pos_ <= 0 || pos_ == pos_at_last_sync_; }
+
+  Status DropUnsyncedData() const;
+};
+
+}  // anonymous namespace
+
+// A wrapper around WritableFile which informs another Env whenever this file
+// is written to or sync'ed.
+class TestWritableFile : public WritableFile {
+ public:
+  TestWritableFile(const FileState& state,
+                   WritableFile* f,
+                   FaultInjectionTestEnv* env);
+  virtual ~TestWritableFile();
+  virtual Status Append(const Slice& data);
+  virtual Status Close();
+  virtual Status Flush();
+  virtual Status Sync();
+
+ private:
+  FileState state_;
+  WritableFile* target_;
+  bool writable_file_opened_;
+  FaultInjectionTestEnv* env_;
+
+  Status SyncParent();
+};
+
+class FaultInjectionTestEnv : public EnvWrapper {
+ public:
+  FaultInjectionTestEnv() : EnvWrapper(Env::Default()), filesystem_active_(true) {}
+  virtual ~FaultInjectionTestEnv() { }
+  virtual Status NewWritableFile(const std::string& fname,
+                                 WritableFile** result);
+  virtual Status NewAppendableFile(const std::string& fname,
+                                   WritableFile** result);
+  virtual Status DeleteFile(const std::string& f);
+  virtual Status RenameFile(const std::string& s, const std::string& t);
+
+  void WritableFileClosed(const FileState& state);
+  Status DropUnsyncedFileData();
+  Status DeleteFilesCreatedAfterLastDirSync();
+  void DirWasSynced();
+  bool IsFileCreatedSinceLastDirSync(const std::string& filename);
+  void ResetState();
+  void UntrackFile(const std::string& f);
+  // Setting the filesystem to inactive is the test equivalent to simulating a
+  // system reset. Setting to inactive will freeze our saved filesystem state so
+  // that it will stop being recorded. It can then be reset back to the state at
+  // the time of the reset.
+  bool IsFilesystemActive() const { return filesystem_active_; }
+  void SetFilesystemActive(bool active) { filesystem_active_ = active; }
+
+ private:
+  port::Mutex mutex_;
+  std::map<std::string, FileState> db_file_state_;
+  std::set<std::string> new_files_since_last_dir_sync_;
+  bool filesystem_active_;  // Record flushes, syncs, writes
+};
+
+TestWritableFile::TestWritableFile(const FileState& state,
+                                   WritableFile* f,
+                                   FaultInjectionTestEnv* env)
+    : state_(state),
+      target_(f),
+      writable_file_opened_(true),
+      env_(env) {
+  assert(f != NULL);
+}
+
+TestWritableFile::~TestWritableFile() {
+  if (writable_file_opened_) {
+    Close();
+  }
+  delete target_;
+}
+
+Status TestWritableFile::Append(const Slice& data) {
+  Status s = target_->Append(data);
+  if (s.ok() && env_->IsFilesystemActive()) {
+    state_.pos_ += data.size();
+  }
+  return s;
+}
+
+Status TestWritableFile::Close() {
+  writable_file_opened_ = false;
+  Status s = target_->Close();
+  if (s.ok()) {
+    env_->WritableFileClosed(state_);
+  }
+  return s;
+}
+
+Status TestWritableFile::Flush() {
+  Status s = target_->Flush();
+  if (s.ok() && env_->IsFilesystemActive()) {
+    state_.pos_at_last_flush_ = state_.pos_;
+  }
+  return s;
+}
+
+Status TestWritableFile::SyncParent() {
+  Status s = SyncDir(GetDirName(state_.filename_));
+  if (s.ok()) {
+    env_->DirWasSynced();
+  }
+  return s;
+}
+
+Status TestWritableFile::Sync() {
+  if (!env_->IsFilesystemActive()) {
+    return Status::OK();
+  }
+  // Ensure new files referred to by the manifest are in the filesystem.
+  Status s = target_->Sync();
+  if (s.ok()) {
+    state_.pos_at_last_sync_ = state_.pos_;
+  }
+  if (env_->IsFileCreatedSinceLastDirSync(state_.filename_)) {
+    Status ps = SyncParent();
+    if (s.ok() && !ps.ok()) {
+      s = ps;
+    }
+  }
+  return s;
+}
+
+Status FaultInjectionTestEnv::NewWritableFile(const std::string& fname,
+                                              WritableFile** result) {
+  WritableFile* actual_writable_file;
+  Status s = target()->NewWritableFile(fname, &actual_writable_file);
+  if (s.ok()) {
+    FileState state(fname);
+    state.pos_ = 0;
+    *result = new TestWritableFile(state, actual_writable_file, this);
+    // NewWritableFile doesn't append to files, so if the same file is
+    // opened again then it will be truncated - so forget our saved
+    // state.
+    UntrackFile(fname);
+    MutexLock l(&mutex_);
+    new_files_since_last_dir_sync_.insert(fname);
+  }
+  return s;
+}
+
+Status FaultInjectionTestEnv::NewAppendableFile(const std::string& fname,
+                                                WritableFile** result) {
+  WritableFile* actual_writable_file;
+  Status s = target()->NewAppendableFile(fname, &actual_writable_file);
+  if (s.ok()) {
+    FileState state(fname);
+    state.pos_ = 0;
+    {
+      MutexLock l(&mutex_);
+      if (db_file_state_.count(fname) == 0) {
+        new_files_since_last_dir_sync_.insert(fname);
+      } else {
+        state = db_file_state_[fname];
+      }
+    }
+    *result = new TestWritableFile(state, actual_writable_file, this);
+  }
+  return s;
+}
+
+Status FaultInjectionTestEnv::DropUnsyncedFileData() {
+  Status s;
+  MutexLock l(&mutex_);
+  for (std::map<std::string, FileState>::const_iterator it =
+           db_file_state_.begin();
+       s.ok() && it != db_file_state_.end(); ++it) {
+    const FileState& state = it->second;
+    if (!state.IsFullySynced()) {
+      s = state.DropUnsyncedData();
+    }
+  }
+  return s;
+}
+
+void FaultInjectionTestEnv::DirWasSynced() {
+  MutexLock l(&mutex_);
+  new_files_since_last_dir_sync_.clear();
+}
+
+bool FaultInjectionTestEnv::IsFileCreatedSinceLastDirSync(
+    const std::string& filename) {
+  MutexLock l(&mutex_);
+  return new_files_since_last_dir_sync_.find(filename) !=
+         new_files_since_last_dir_sync_.end();
+}
+
+void FaultInjectionTestEnv::UntrackFile(const std::string& f) {
+  MutexLock l(&mutex_);
+  db_file_state_.erase(f);
+  new_files_since_last_dir_sync_.erase(f);
+}
+
+Status FaultInjectionTestEnv::DeleteFile(const std::string& f) {
+  Status s = EnvWrapper::DeleteFile(f);
+  ASSERT_OK(s);
+  if (s.ok()) {
+    UntrackFile(f);
+  }
+  return s;
+}
+
+Status FaultInjectionTestEnv::RenameFile(const std::string& s,
+                                         const std::string& t) {
+  Status ret = EnvWrapper::RenameFile(s, t);
+
+  if (ret.ok()) {
+    MutexLock l(&mutex_);
+    if (db_file_state_.find(s) != db_file_state_.end()) {
+      db_file_state_[t] = db_file_state_[s];
+      db_file_state_.erase(s);
+    }
+
+    if (new_files_since_last_dir_sync_.erase(s) != 0) {
+      assert(new_files_since_last_dir_sync_.find(t) ==
+             new_files_since_last_dir_sync_.end());
+      new_files_since_last_dir_sync_.insert(t);
+    }
+  }
+
+  return ret;
+}
+
+void FaultInjectionTestEnv::ResetState() {
+  // Since we are not destroying the database, the existing files
+  // should keep their recorded synced/flushed state. Therefore
+  // we do not reset db_file_state_ and new_files_since_last_dir_sync_.
+  MutexLock l(&mutex_);
+  SetFilesystemActive(true);
+}
+
+Status FaultInjectionTestEnv::DeleteFilesCreatedAfterLastDirSync() {
+  // Because DeleteFile access this container make a copy to avoid deadlock
+  mutex_.Lock();
+  std::set<std::string> new_files(new_files_since_last_dir_sync_.begin(),
+                                  new_files_since_last_dir_sync_.end());
+  mutex_.Unlock();
+  Status s;
+  std::set<std::string>::const_iterator it;
+  for (it = new_files.begin(); s.ok() && it != new_files.end(); ++it) {
+    s = DeleteFile(*it);
+  }
+  return s;
+}
+
+void FaultInjectionTestEnv::WritableFileClosed(const FileState& state) {
+  MutexLock l(&mutex_);
+  db_file_state_[state.filename_] = state;
+}
+
+Status FileState::DropUnsyncedData() const {
+  ssize_t sync_pos = pos_at_last_sync_ == -1 ? 0 : pos_at_last_sync_;
+  return Truncate(filename_, sync_pos);
+}
+
+class FaultInjectionTest {
+ public:
+  enum ExpectedVerifResult { VAL_EXPECT_NO_ERROR, VAL_EXPECT_ERROR };
+  enum ResetMethod { RESET_DROP_UNSYNCED_DATA, RESET_DELETE_UNSYNCED_FILES };
+
+  FaultInjectionTestEnv* env_;
+  std::string dbname_;
+  Cache* tiny_cache_;
+  Options options_;
+  DB* db_;
+
+  FaultInjectionTest()
+      : env_(new FaultInjectionTestEnv),
+        tiny_cache_(NewLRUCache(100)),
+        db_(NULL) {
+    dbname_ = test::TmpDir() + "/fault_test";
+    DestroyDB(dbname_, Options());  // Destroy any db from earlier run
+    options_.reuse_logs = true;
+    options_.env = env_;
+    options_.paranoid_checks = true;
+    options_.block_cache = tiny_cache_;
+    options_.create_if_missing = true;
+  }
+
+  ~FaultInjectionTest() {
+    CloseDB();
+    DestroyDB(dbname_, Options());
+    delete tiny_cache_;
+    delete env_;
+  }
+
+  void ReuseLogs(bool reuse) {
+    options_.reuse_logs = reuse;
+  }
+
+  void Build(int start_idx, int num_vals) {
+    std::string key_space, value_space;
+    WriteBatch batch;
+    for (int i = start_idx; i < start_idx + num_vals; i++) {
+      Slice key = Key(i, &key_space);
+      batch.Clear();
+      batch.Put(key, Value(i, &value_space));
+      WriteOptions options;
+      ASSERT_OK(db_->Write(options, &batch));
+    }
+  }
+
+  Status ReadValue(int i, std::string* val) const {
+    std::string key_space, value_space;
+    Slice key = Key(i, &key_space);
+    Value(i, &value_space);
+    ReadOptions options;
+    return db_->Get(options, key, val);
+  }
+
+  Status Verify(int start_idx, int num_vals,
+                ExpectedVerifResult expected) const {
+    std::string val;
+    std::string value_space;
+    Status s;
+    for (int i = start_idx; i < start_idx + num_vals && s.ok(); i++) {
+      Value(i, &value_space);
+      s = ReadValue(i, &val);
+      if (expected == VAL_EXPECT_NO_ERROR) {
+        if (s.ok()) {
+          ASSERT_EQ(value_space, val);
+        }
+      } else if (s.ok()) {
+        fprintf(stderr, "Expected an error at %d, but was OK\n", i);
+        s = Status::IOError(dbname_, "Expected value error:");
+      } else {
+        s = Status::OK();  // An expected error
+      }
+    }
+    return s;
+  }
+
+  // Return the ith key
+  Slice Key(int i, std::string* storage) const {
+    char buf[100];
+    snprintf(buf, sizeof(buf), "%016d", i);
+    storage->assign(buf, strlen(buf));
+    return Slice(*storage);
+  }
+
+  // Return the value to associate with the specified key
+  Slice Value(int k, std::string* storage) const {
+    Random r(k);
+    return test::RandomString(&r, kValueSize, storage);
+  }
+
+  Status OpenDB() {
+    delete db_;
+    db_ = NULL;
+    env_->ResetState();
+    return DB::Open(options_, dbname_, &db_);
+  }
+
+  void CloseDB() {
+    delete db_;
+    db_ = NULL;
+  }
+
+  void DeleteAllData() {
+    Iterator* iter = db_->NewIterator(ReadOptions());
+    WriteOptions options;
+    for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
+      ASSERT_OK(db_->Delete(WriteOptions(), iter->key()));
+    }
+
+    delete iter;
+  }
+
+  void ResetDBState(ResetMethod reset_method) {
+    switch (reset_method) {
+      case RESET_DROP_UNSYNCED_DATA:
+        ASSERT_OK(env_->DropUnsyncedFileData());
+        break;
+      case RESET_DELETE_UNSYNCED_FILES:
+        ASSERT_OK(env_->DeleteFilesCreatedAfterLastDirSync());
+        break;
+      default:
+        assert(false);
+    }
+  }
+
+  void PartialCompactTestPreFault(int num_pre_sync, int num_post_sync) {
+    DeleteAllData();
+    Build(0, num_pre_sync);
+    db_->CompactRange(NULL, NULL);
+    Build(num_pre_sync, num_post_sync);
+  }
+
+  void PartialCompactTestReopenWithFault(ResetMethod reset_method,
+                                         int num_pre_sync,
+                                         int num_post_sync) {
+    env_->SetFilesystemActive(false);
+    CloseDB();
+    ResetDBState(reset_method);
+    ASSERT_OK(OpenDB());
+    ASSERT_OK(Verify(0, num_pre_sync, FaultInjectionTest::VAL_EXPECT_NO_ERROR));
+    ASSERT_OK(Verify(num_pre_sync, num_post_sync, FaultInjectionTest::VAL_EXPECT_ERROR));
+  }
+
+  void NoWriteTestPreFault() {
+  }
+
+  void NoWriteTestReopenWithFault(ResetMethod reset_method) {
+    CloseDB();
+    ResetDBState(reset_method);
+    ASSERT_OK(OpenDB());
+  }
+
+  void DoTest() {
+    Random rnd(0);
+    ASSERT_OK(OpenDB());
+    for (size_t idx = 0; idx < kNumIterations; idx++) {
+      int num_pre_sync = rnd.Uniform(kMaxNumValues);
+      int num_post_sync = rnd.Uniform(kMaxNumValues);
+
+      PartialCompactTestPreFault(num_pre_sync, num_post_sync);
+      PartialCompactTestReopenWithFault(RESET_DROP_UNSYNCED_DATA,
+                                        num_pre_sync,
+                                        num_post_sync);
+
+      NoWriteTestPreFault();
+      NoWriteTestReopenWithFault(RESET_DROP_UNSYNCED_DATA);
+
+      PartialCompactTestPreFault(num_pre_sync, num_post_sync);
+      // No new files created so we expect all values since no files will be
+      // dropped.
+      PartialCompactTestReopenWithFault(RESET_DELETE_UNSYNCED_FILES,
+                                        num_pre_sync + num_post_sync,
+                                        0);
+
+      NoWriteTestPreFault();
+      NoWriteTestReopenWithFault(RESET_DELETE_UNSYNCED_FILES);
+    }
+  }
+};
+
+TEST(FaultInjectionTest, FaultTestNoLogReuse) {
+  ReuseLogs(false);
+  DoTest();
+}
+
+TEST(FaultInjectionTest, FaultTestWithLogReuse) {
+  ReuseLogs(true);
+  DoTest();
+}
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
--- a/db/filename.cc
+++ b/db/filename.cc
@@ -30,6 +30,11 @@ std::string LogFileName(const std::string& name, uint64_t number) {
 }

 std::string TableFileName(const std::string& name, uint64_t number) {
+  assert(number > 0);
+  return MakeFileName(name, number, "ldb");
+}
+
+std::string SSTTableFileName(const std::string& name, uint64_t number) {
  assert(number > 0);
  return MakeFileName(name, number, "sst");
 }
@@ -71,7 +76,7 @@ std::string OldInfoLogFileName(const std::string& dbname) {
 //    dbname/LOG
 //    dbname/LOG.old
 //    dbname/MANIFEST-[0-9]+
-//    dbname/[0-9]+.(log|sst)
+//    dbname/[0-9]+.(log|sst|ldb)
 bool ParseFileName(const std::string& fname,
                   uint64_t* number,
                   FileType* type) {
@@ -106,7 +111,7 @@ bool ParseFileName(const std::string& fname,
    Slice suffix = rest;
    if (suffix == Slice(".log")) {
      *type = kLogFile;
-    } else if (suffix == Slice(".sst")) {
+    } else if (suffix == Slice(".sst") || suffix == Slice(".ldb")) {
      *type = kTableFile;
    } else if (suffix == Slice(".dbtmp")) {
      *type = kTempFile;
--- a/db/filename.h
+++ b/db/filename.h
@@ -37,6 +37,11 @@ extern std::string LogFileName(const std::string& dbname, uint64_t number);
 // "dbname".
 extern std::string TableFileName(const std::string& dbname, uint64_t number);

+// Return the legacy file name for an sstable with the specified number
+// in the db named by "dbname". The result will be prefixed with
+// "dbname".
+extern std::string SSTTableFileName(const std::string& dbname, uint64_t number);
+
 // Return the name of the descriptor file for the db named by
 // "dbname" and the specified incarnation number.  The result will be
 // prefixed with "dbname".
--- a/db/filename_test.cc
+++ b/db/filename_test.cc
@@ -27,6 +27,7 @@ TEST(FileNameTest, Parse) {
    { "100.log",            100,   kLogFile },
    { "0.log",              0,     kLogFile },
    { "0.sst",              0,     kTableFile },
+    { "0.ldb",              0,     kTableFile },
    { "CURRENT",            0,     kCurrentFile },
    { "LOCK",               0,     kDBLockFile },
    { "MANIFEST-2",         2,     kDescriptorFile },
@@ -70,7 +71,7 @@ TEST(FileNameTest, Parse) {
  for (int i = 0; i < sizeof(errors) / sizeof(errors[0]); i++) {
    std::string f = errors[i];
    ASSERT_TRUE(!ParseFileName(f, &number, &type)) << f;
-  };
+  }
 }

 TEST(FileNameTest, Construction) {
--- a/db/leveldb_main.cc
+++ b/db/leveldb_main.cc
@@ -0,0 +1,64 @@
+// Copyright (c) 2012 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 <stdio.h>
+#include "leveldb/dumpfile.h"
+#include "leveldb/env.h"
+#include "leveldb/status.h"
+
+namespace leveldb {
+namespace {
+
+class StdoutPrinter : public WritableFile {
+ public:
+  virtual Status Append(const Slice& data) {
+    fwrite(data.data(), 1, data.size(), stdout);
+    return Status::OK();
+  }
+  virtual Status Close() { return Status::OK(); }
+  virtual Status Flush() { return Status::OK(); }
+  virtual Status Sync() { return Status::OK(); }
+};
+
+bool HandleDumpCommand(Env* env, char** files, int num) {
+  StdoutPrinter printer;
+  bool ok = true;
+  for (int i = 0; i < num; i++) {
+    Status s = DumpFile(env, files[i], &printer);
+    if (!s.ok()) {
+      fprintf(stderr, "%s\n", s.ToString().c_str());
+      ok = false;
+    }
+  }
+  return ok;
+}
+
+}  // namespace
+}  // namespace leveldb
+
+static void Usage() {
+  fprintf(
+      stderr,
+      "Usage: leveldbutil command...\n"
+      "   dump files...         -- dump contents of specified files\n"
+      );
+}
+
+int main(int argc, char** argv) {
+  leveldb::Env* env = leveldb::Env::Default();
+  bool ok = true;
+  if (argc < 2) {
+    Usage();
+    ok = false;
+  } else {
+    std::string command = argv[1];
+    if (command == "dump") {
+      ok = leveldb::HandleDumpCommand(env, argv+2, argc-2);
+    } else {
+      Usage();
+      ok = false;
+    }
+  }
+  return (ok ? 0 : 1);
+}
--- a/db/log_format.h
+++ b/db/log_format.h
@@ -26,8 +26,8 @@ static const int kMaxRecordType = kLastType;

 static const int kBlockSize = 32768;

-// Header is checksum (4 bytes), type (1 byte), length (2 bytes).
-static const int kHeaderSize = 4 + 1 + 2;
+// Header is checksum (4 bytes), length (2 bytes), type (1 byte).
+static const int kHeaderSize = 4 + 2 + 1;

 }  // namespace log
 }  // namespace leveldb
--- a/db/log_reader.cc
+++ b/db/log_reader.cc
@@ -133,7 +133,9 @@ bool Reader::ReadRecord(Slice* record, std::string* scratch) {

      case kEof:
        if (in_fragmented_record) {
-          ReportCorruption(scratch->size(), "partial record without end(3)");
+          // This can be caused by the writer dying immediately after
+          // writing a physical record but before completing the next; don't
+          // treat it as a corruption, just ignore the entire logical record.
          scratch->clear();
        }
        return false;
@@ -165,14 +167,14 @@ uint64_t Reader::LastRecordOffset() {
  return last_record_offset_;
 }

-void Reader::ReportCorruption(size_t bytes, const char* reason) {
+void Reader::ReportCorruption(uint64_t bytes, const char* reason) {
  ReportDrop(bytes, Status::Corruption(reason));
 }

-void Reader::ReportDrop(size_t bytes, const Status& reason) {
+void Reader::ReportDrop(uint64_t bytes, const Status& reason) {
  if (reporter_ != NULL &&
      end_of_buffer_offset_ - buffer_.size() - bytes >= initial_offset_) {
-    reporter_->Corruption(bytes, reason);
+    reporter_->Corruption(static_cast<size_t>(bytes), reason);
  }
 }

@@ -193,13 +195,12 @@ unsigned int Reader::ReadPhysicalRecord(Slice* result) {
          eof_ = true;
        }
        continue;
-      } else if (buffer_.size() == 0) {
-        // End of file
-        return kEof;
      } else {
-        size_t drop_size = buffer_.size();
+        // Note that if buffer_ is non-empty, we have a truncated header at the
+        // end of the file, which can be caused by the writer crashing in the
+        // middle of writing the header. Instead of considering this an error,
+        // just report EOF.
        buffer_.clear();
-        ReportCorruption(drop_size, "truncated record at end of file");
        return kEof;
      }
    }
@@ -213,8 +214,14 @@ unsigned int Reader::ReadPhysicalRecord(Slice* result) {
    if (kHeaderSize + length > buffer_.size()) {
      size_t drop_size = buffer_.size();
      buffer_.clear();
-      ReportCorruption(drop_size, "bad record length");
-      return kBadRecord;
+      if (!eof_) {
+        ReportCorruption(drop_size, "bad record length");
+        return kBadRecord;
+      }
+      // If the end of the file has been reached without reading |length| bytes
+      // of payload, assume the writer died in the middle of writing the record.
+      // Don't report a corruption.
+      return kEof;
    }

    if (type == kZeroType && length == 0) {
--- a/db/log_reader.h
+++ b/db/log_reader.h
@@ -94,8 +94,8 @@ class Reader {

  // Reports dropped bytes to the reporter.
  // buffer_ must be updated to remove the dropped bytes prior to invocation.
-  void ReportCorruption(size_t bytes, const char* reason);
-  void ReportDrop(size_t bytes, const Status& reason);
+  void ReportCorruption(uint64_t bytes, const char* reason);
+  void ReportDrop(uint64_t bytes, const Status& reason);

  // No copying allowed
  Reader(const Reader&);
--- a/db/log_test.cc
+++ b/db/log_test.cc
@@ -104,7 +104,7 @@ class LogTest {
  StringSource source_;
  ReportCollector report_;
  bool reading_;
-  Writer writer_;
+  Writer* writer_;
  Reader reader_;

  // Record metadata for testing initial offset functionality
@@ -113,14 +113,23 @@ class LogTest {

 public:
  LogTest() : reading_(false),
-              writer_(&dest_),
+              writer_(new Writer(&dest_)),
              reader_(&source_, &report_, true/*checksum*/,
                      0/*initial_offset*/) {
  }

+  ~LogTest() {
+    delete writer_;
+  }
+
+  void ReopenForAppend() {
+    delete writer_;
+    writer_ = new Writer(&dest_, dest_.contents_.size());
+  }
+
  void Write(const std::string& msg) {
    ASSERT_TRUE(!reading_) << "Write() after starting to read";
-    writer_.AddRecord(Slice(msg));
+    writer_->AddRecord(Slice(msg));
  }

  size_t WrittenBytes() const {
@@ -318,6 +327,15 @@ TEST(LogTest, AlignedEof) {
  ASSERT_EQ("EOF", Read());
 }

+TEST(LogTest, OpenForAppend) {
+  Write("hello");
+  ReopenForAppend();
+  Write("world");
+  ASSERT_EQ("hello", Read());
+  ASSERT_EQ("world", Read());
+  ASSERT_EQ("EOF", Read());
+}
+
 TEST(LogTest, RandomRead) {
  const int N = 500;
  Random write_rnd(301);
@@ -351,20 +369,32 @@ TEST(LogTest, BadRecordType) {
  ASSERT_EQ("OK", MatchError("unknown record type"));
 }

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

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

 TEST(LogTest, ChecksumMismatch) {
@@ -415,6 +445,24 @@ TEST(LogTest, UnexpectedFirstType) {
  ASSERT_EQ("OK", MatchError("partial record without end"));
 }

+TEST(LogTest, MissingLastIsIgnored) {
+  Write(BigString("bar", kBlockSize));
+  // Remove the LAST block, including header.
+  ShrinkSize(14);
+  ASSERT_EQ("EOF", Read());
+  ASSERT_EQ("", ReportMessage());
+  ASSERT_EQ(0, DroppedBytes());
+}
+
+TEST(LogTest, PartialLastIsIgnored) {
+  Write(BigString("bar", kBlockSize));
+  // Cause a bad record length in the LAST block.
+  ShrinkSize(1);
+  ASSERT_EQ("EOF", Read());
+  ASSERT_EQ("", ReportMessage());
+  ASSERT_EQ(0, DroppedBytes());
+}
+
 TEST(LogTest, ErrorJoinsRecords) {
  // Consider two fragmented records:
  //    first(R1) last(R1) first(R2) last(R2)
@@ -433,7 +481,7 @@ TEST(LogTest, ErrorJoinsRecords) {

  ASSERT_EQ("correct", Read());
  ASSERT_EQ("EOF", Read());
-  const int dropped = DroppedBytes();
+  const size_t dropped = DroppedBytes();
  ASSERT_LE(dropped, 2*kBlockSize + 100);
  ASSERT_GE(dropped, 2*kBlockSize);
 }
--- a/db/log_writer.cc
+++ b/db/log_writer.cc
@@ -12,13 +12,22 @@
 namespace leveldb {
 namespace log {

+static void InitTypeCrc(uint32_t* type_crc) {
+  for (int i = 0; i <= kMaxRecordType; i++) {
+    char t = static_cast<char>(i);
+    type_crc[i] = crc32c::Value(&t, 1);
+  }
+}
+
 Writer::Writer(WritableFile* dest)
    : dest_(dest),
      block_offset_(0) {
-  for (int i = 0; i <= kMaxRecordType; i++) {
-    char t = static_cast<char>(i);
-    type_crc_[i] = crc32c::Value(&t, 1);
-  }
+  InitTypeCrc(type_crc_);
+}
+
+Writer::Writer(WritableFile* dest, uint64_t dest_length)
+    : dest_(dest), block_offset_(dest_length % kBlockSize) {
+  InitTypeCrc(type_crc_);
 }

 Writer::~Writer() {
--- a/db/log_writer.h
+++ b/db/log_writer.h
@@ -22,6 +22,12 @@ class Writer {
  // "*dest" must be initially empty.
  // "*dest" must remain live while this Writer is in use.
  explicit Writer(WritableFile* dest);
+
+  // Create a writer that will append data to "*dest".
+  // "*dest" must have initial length "dest_length".
+  // "*dest" must remain live while this Writer is in use.
+  Writer(WritableFile* dest, uint64_t dest_length);
+
  ~Writer();

  Status AddRecord(const Slice& slice);
--- a/db/recovery_test.cc
+++ b/db/recovery_test.cc
@@ -0,0 +1,324 @@
+// Copyright (c) 2014 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 "db/filename.h"
+#include "db/version_set.h"
+#include "db/write_batch_internal.h"
+#include "leveldb/db.h"
+#include "leveldb/env.h"
+#include "leveldb/write_batch.h"
+#include "util/logging.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+namespace leveldb {
+
+class RecoveryTest {
+ public:
+  RecoveryTest() : env_(Env::Default()), db_(NULL) {
+    dbname_ = test::TmpDir() + "/recovery_test";
+    DestroyDB(dbname_, Options());
+    Open();
+  }
+
+  ~RecoveryTest() {
+    Close();
+    DestroyDB(dbname_, Options());
+  }
+
+  DBImpl* dbfull() const { return reinterpret_cast<DBImpl*>(db_); }
+  Env* env() const { return env_; }
+
+  bool CanAppend() {
+    WritableFile* tmp;
+    Status s = env_->NewAppendableFile(CurrentFileName(dbname_), &tmp);
+    delete tmp;
+    if (s.IsNotSupportedError()) {
+      return false;
+    } else {
+      return true;
+    }
+  }
+
+  void Close() {
+    delete db_;
+    db_ = NULL;
+  }
+
+  void Open(Options* options = NULL) {
+    Close();
+    Options opts;
+    if (options != NULL) {
+      opts = *options;
+    } else {
+      opts.reuse_logs = true;  // TODO(sanjay): test both ways
+      opts.create_if_missing = true;
+    }
+    if (opts.env == NULL) {
+      opts.env = env_;
+    }
+    ASSERT_OK(DB::Open(opts, dbname_, &db_));
+    ASSERT_EQ(1, NumLogs());
+  }
+
+  Status Put(const std::string& k, const std::string& v) {
+    return db_->Put(WriteOptions(), k, v);
+  }
+
+  std::string Get(const std::string& k, const Snapshot* snapshot = NULL) {
+    std::string result;
+    Status s = db_->Get(ReadOptions(), k, &result);
+    if (s.IsNotFound()) {
+      result = "NOT_FOUND";
+    } else if (!s.ok()) {
+      result = s.ToString();
+    }
+    return result;
+  }
+
+  std::string ManifestFileName() {
+    std::string current;
+    ASSERT_OK(ReadFileToString(env_, CurrentFileName(dbname_), &current));
+    size_t len = current.size();
+    if (len > 0 && current[len-1] == '\n') {
+      current.resize(len - 1);
+    }
+    return dbname_ + "/" + current;
+  }
+
+  std::string LogName(uint64_t number) {
+    return LogFileName(dbname_, number);
+  }
+
+  size_t DeleteLogFiles() {
+    std::vector<uint64_t> logs = GetFiles(kLogFile);
+    for (size_t i = 0; i < logs.size(); i++) {
+      ASSERT_OK(env_->DeleteFile(LogName(logs[i]))) << LogName(logs[i]);
+    }
+    return logs.size();
+  }
+
+  uint64_t FirstLogFile() {
+    return GetFiles(kLogFile)[0];
+  }
+
+  std::vector<std::uint64_t> GetFiles(FileType t) {
+    std::vector<std::string> filenames;
+    ASSERT_OK(env_->GetChildren(dbname_, &filenames));
+    std::vector<std::uint64_t> result;
+    for (size_t i = 0; i < filenames.size(); i++) {
+      uint64_t number;
+      FileType type;
+      if (ParseFileName(filenames[i], &number, &type) && type == t) {
+        result.push_back(number);
+      }
+    }
+    return result;
+  }
+
+  int NumLogs() {
+    return GetFiles(kLogFile).size();
+  }
+
+  int NumTables() {
+    return GetFiles(kTableFile).size();
+  }
+
+  uint64_t FileSize(const std::string& fname) {
+    uint64_t result;
+    ASSERT_OK(env_->GetFileSize(fname, &result)) << fname;
+    return result;
+  }
+
+  void CompactMemTable() {
+    dbfull()->TEST_CompactMemTable();
+  }
+
+  // Directly construct a log file that sets key to val.
+  void MakeLogFile(uint64_t lognum, SequenceNumber seq, Slice key, Slice val) {
+    std::string fname = LogFileName(dbname_, lognum);
+    WritableFile* file;
+    ASSERT_OK(env_->NewWritableFile(fname, &file));
+    log::Writer writer(file);
+    WriteBatch batch;
+    batch.Put(key, val);
+    WriteBatchInternal::SetSequence(&batch, seq);
+    ASSERT_OK(writer.AddRecord(WriteBatchInternal::Contents(&batch)));
+    ASSERT_OK(file->Flush());
+    delete file;
+  }
+
+ private:
+  std::string dbname_;
+  Env* env_;
+  DB* db_;
+};
+
+TEST(RecoveryTest, ManifestReused) {
+  if (!CanAppend()) {
+    fprintf(stderr, "skipping test because env does not support appending\n");
+    return;
+  }
+  ASSERT_OK(Put("foo", "bar"));
+  Close();
+  std::string old_manifest = ManifestFileName();
+  Open();
+  ASSERT_EQ(old_manifest, ManifestFileName());
+  ASSERT_EQ("bar", Get("foo"));
+  Open();
+  ASSERT_EQ(old_manifest, ManifestFileName());
+  ASSERT_EQ("bar", Get("foo"));
+}
+
+TEST(RecoveryTest, LargeManifestCompacted) {
+  if (!CanAppend()) {
+    fprintf(stderr, "skipping test because env does not support appending\n");
+    return;
+  }
+  ASSERT_OK(Put("foo", "bar"));
+  Close();
+  std::string old_manifest = ManifestFileName();
+
+  // Pad with zeroes to make manifest file very big.
+  {
+    uint64_t len = FileSize(old_manifest);
+    WritableFile* file;
+    ASSERT_OK(env()->NewAppendableFile(old_manifest, &file));
+    std::string zeroes(3*1048576 - static_cast<size_t>(len), 0);
+    ASSERT_OK(file->Append(zeroes));
+    ASSERT_OK(file->Flush());
+    delete file;
+  }
+
+  Open();
+  std::string new_manifest = ManifestFileName();
+  ASSERT_NE(old_manifest, new_manifest);
+  ASSERT_GT(10000, FileSize(new_manifest));
+  ASSERT_EQ("bar", Get("foo"));
+
+  Open();
+  ASSERT_EQ(new_manifest, ManifestFileName());
+  ASSERT_EQ("bar", Get("foo"));
+}
+
+TEST(RecoveryTest, NoLogFiles) {
+  ASSERT_OK(Put("foo", "bar"));
+  ASSERT_EQ(1, DeleteLogFiles());
+  Open();
+  ASSERT_EQ("NOT_FOUND", Get("foo"));
+  Open();
+  ASSERT_EQ("NOT_FOUND", Get("foo"));
+}
+
+TEST(RecoveryTest, LogFileReuse) {
+  if (!CanAppend()) {
+    fprintf(stderr, "skipping test because env does not support appending\n");
+    return;
+  }
+  for (int i = 0; i < 2; i++) {
+    ASSERT_OK(Put("foo", "bar"));
+    if (i == 0) {
+      // Compact to ensure current log is empty
+      CompactMemTable();
+    }
+    Close();
+    ASSERT_EQ(1, NumLogs());
+    uint64_t number = FirstLogFile();
+    if (i == 0) {
+      ASSERT_EQ(0, FileSize(LogName(number)));
+    } else {
+      ASSERT_LT(0, FileSize(LogName(number)));
+    }
+    Open();
+    ASSERT_EQ(1, NumLogs());
+    ASSERT_EQ(number, FirstLogFile()) << "did not reuse log file";
+    ASSERT_EQ("bar", Get("foo"));
+    Open();
+    ASSERT_EQ(1, NumLogs());
+    ASSERT_EQ(number, FirstLogFile()) << "did not reuse log file";
+    ASSERT_EQ("bar", Get("foo"));
+  }
+}
+
+TEST(RecoveryTest, MultipleMemTables) {
+  // Make a large log.
+  const int kNum = 1000;
+  for (int i = 0; i < kNum; i++) {
+    char buf[100];
+    snprintf(buf, sizeof(buf), "%050d", i);
+    ASSERT_OK(Put(buf, buf));
+  }
+  ASSERT_EQ(0, NumTables());
+  Close();
+  ASSERT_EQ(0, NumTables());
+  ASSERT_EQ(1, NumLogs());
+  uint64_t old_log_file = FirstLogFile();
+
+  // Force creation of multiple memtables by reducing the write buffer size.
+  Options opt;
+  opt.reuse_logs = true;
+  opt.write_buffer_size = (kNum*100) / 2;
+  Open(&opt);
+  ASSERT_LE(2, NumTables());
+  ASSERT_EQ(1, NumLogs());
+  ASSERT_NE(old_log_file, FirstLogFile()) << "must not reuse log";
+  for (int i = 0; i < kNum; i++) {
+    char buf[100];
+    snprintf(buf, sizeof(buf), "%050d", i);
+    ASSERT_EQ(buf, Get(buf));
+  }
+}
+
+TEST(RecoveryTest, MultipleLogFiles) {
+  ASSERT_OK(Put("foo", "bar"));
+  Close();
+  ASSERT_EQ(1, NumLogs());
+
+  // Make a bunch of uncompacted log files.
+  uint64_t old_log = FirstLogFile();
+  MakeLogFile(old_log+1, 1000, "hello", "world");
+  MakeLogFile(old_log+2, 1001, "hi", "there");
+  MakeLogFile(old_log+3, 1002, "foo", "bar2");
+
+  // Recover and check that all log files were processed.
+  Open();
+  ASSERT_LE(1, NumTables());
+  ASSERT_EQ(1, NumLogs());
+  uint64_t new_log = FirstLogFile();
+  ASSERT_LE(old_log+3, new_log);
+  ASSERT_EQ("bar2", Get("foo"));
+  ASSERT_EQ("world", Get("hello"));
+  ASSERT_EQ("there", Get("hi"));
+
+  // Test that previous recovery produced recoverable state.
+  Open();
+  ASSERT_LE(1, NumTables());
+  ASSERT_EQ(1, NumLogs());
+  if (CanAppend()) {
+    ASSERT_EQ(new_log, FirstLogFile());
+  }
+  ASSERT_EQ("bar2", Get("foo"));
+  ASSERT_EQ("world", Get("hello"));
+  ASSERT_EQ("there", Get("hi"));
+
+  // Check that introducing an older log file does not cause it to be re-read.
+  Close();
+  MakeLogFile(old_log+1, 2000, "hello", "stale write");
+  Open();
+  ASSERT_LE(1, NumTables());
+  ASSERT_EQ(1, NumLogs());
+  if (CanAppend()) {
+    ASSERT_EQ(new_log, FirstLogFile());
+  }
+  ASSERT_EQ("bar2", Get("foo"));
+  ASSERT_EQ("world", Get("hello"));
+  ASSERT_EQ("there", Get("hi"));
+}
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
--- a/db/repair.cc
+++ b/db/repair.cc
@@ -186,7 +186,7 @@ class Repairer {
    reporter.env = env_;
    reporter.info_log = options_.info_log;
    reporter.lognum = log;
-    // We intentially make log::Reader do checksumming so that
+    // We intentionally make log::Reader do checksumming so that
    // corruptions cause entire commits to be skipped instead of
    // propagating bad information (like overly large sequence
    // numbers).
@@ -242,62 +242,134 @@ class Repairer {
  }

  void ExtractMetaData() {
-    std::vector<TableInfo> kept;
    for (size_t i = 0; i < table_numbers_.size(); i++) {
-      TableInfo t;
-      t.meta.number = table_numbers_[i];
-      Status status = ScanTable(&t);
-      if (!status.ok()) {
-        std::string fname = TableFileName(dbname_, table_numbers_[i]);
-        Log(options_.info_log, "Table #%llu: ignoring %s",
-            (unsigned long long) table_numbers_[i],
-            status.ToString().c_str());
-        ArchiveFile(fname);
-      } else {
-        tables_.push_back(t);
-      }
+      ScanTable(table_numbers_[i]);
    }
  }

-  Status ScanTable(TableInfo* t) {
-    std::string fname = TableFileName(dbname_, t->meta.number);
-    int counter = 0;
-    Status status = env_->GetFileSize(fname, &t->meta.file_size);
-    if (status.ok()) {
-      Iterator* iter = table_cache_->NewIterator(
-          ReadOptions(), t->meta.number, t->meta.file_size);
-      bool empty = true;
-      ParsedInternalKey parsed;
-      t->max_sequence = 0;
-      for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
-        Slice key = iter->key();
-        if (!ParseInternalKey(key, &parsed)) {
-          Log(options_.info_log, "Table #%llu: unparsable key %s",
-              (unsigned long long) t->meta.number,
-              EscapeString(key).c_str());
-          continue;
-        }
+  Iterator* NewTableIterator(const FileMetaData& meta) {
+    // Same as compaction iterators: if paranoid_checks are on, turn
+    // on checksum verification.
+    ReadOptions r;
+    r.verify_checksums = options_.paranoid_checks;
+    return table_cache_->NewIterator(r, meta.number, meta.file_size);
+  }

-        counter++;
-        if (empty) {
-          empty = false;
-          t->meta.smallest.DecodeFrom(key);
-        }
-        t->meta.largest.DecodeFrom(key);
-        if (parsed.sequence > t->max_sequence) {
-          t->max_sequence = parsed.sequence;
-        }
+  void ScanTable(uint64_t number) {
+    TableInfo t;
+    t.meta.number = number;
+    std::string fname = TableFileName(dbname_, number);
+    Status status = env_->GetFileSize(fname, &t.meta.file_size);
+    if (!status.ok()) {
+      // Try alternate file name.
+      fname = SSTTableFileName(dbname_, number);
+      Status s2 = env_->GetFileSize(fname, &t.meta.file_size);
+      if (s2.ok()) {
+        status = Status::OK();
      }
-      if (!iter->status().ok()) {
-        status = iter->status();
-      }
-      delete iter;
    }
+    if (!status.ok()) {
+      ArchiveFile(TableFileName(dbname_, number));
+      ArchiveFile(SSTTableFileName(dbname_, number));
+      Log(options_.info_log, "Table #%llu: dropped: %s",
+          (unsigned long long) t.meta.number,
+          status.ToString().c_str());
+      return;
+    }
+
+    // Extract metadata by scanning through table.
+    int counter = 0;
+    Iterator* iter = NewTableIterator(t.meta);
+    bool empty = true;
+    ParsedInternalKey parsed;
+    t.max_sequence = 0;
+    for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
+      Slice key = iter->key();
+      if (!ParseInternalKey(key, &parsed)) {
+        Log(options_.info_log, "Table #%llu: unparsable key %s",
+            (unsigned long long) t.meta.number,
+            EscapeString(key).c_str());
+        continue;
+      }
+
+      counter++;
+      if (empty) {
+        empty = false;
+        t.meta.smallest.DecodeFrom(key);
+      }
+      t.meta.largest.DecodeFrom(key);
+      if (parsed.sequence > t.max_sequence) {
+        t.max_sequence = parsed.sequence;
+      }
+    }
+    if (!iter->status().ok()) {
+      status = iter->status();
+    }
+    delete iter;
    Log(options_.info_log, "Table #%llu: %d entries %s",
-        (unsigned long long) t->meta.number,
+        (unsigned long long) t.meta.number,
        counter,
        status.ToString().c_str());
-    return status;
+
+    if (status.ok()) {
+      tables_.push_back(t);
+    } else {
+      RepairTable(fname, t);  // RepairTable archives input file.
+    }
+  }
+
+  void RepairTable(const std::string& src, TableInfo t) {
+    // We will copy src contents to a new table and then rename the
+    // new table over the source.
+
+    // Create builder.
+    std::string copy = TableFileName(dbname_, next_file_number_++);
+    WritableFile* file;
+    Status s = env_->NewWritableFile(copy, &file);
+    if (!s.ok()) {
+      return;
+    }
+    TableBuilder* builder = new TableBuilder(options_, file);
+
+    // Copy data.
+    Iterator* iter = NewTableIterator(t.meta);
+    int counter = 0;
+    for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
+      builder->Add(iter->key(), iter->value());
+      counter++;
+    }
+    delete iter;
+
+    ArchiveFile(src);
+    if (counter == 0) {
+      builder->Abandon();  // Nothing to save
+    } else {
+      s = builder->Finish();
+      if (s.ok()) {
+        t.meta.file_size = builder->FileSize();
+      }
+    }
+    delete builder;
+    builder = NULL;
+
+    if (s.ok()) {
+      s = file->Close();
+    }
+    delete file;
+    file = NULL;
+
+    if (counter > 0 && s.ok()) {
+      std::string orig = TableFileName(dbname_, t.meta.number);
+      s = env_->RenameFile(copy, orig);
+      if (s.ok()) {
+        Log(options_.info_log, "Table #%llu: %d entries repaired",
+            (unsigned long long) t.meta.number, counter);
+        tables_.push_back(t);
+      }
+    }
+    if (!s.ok()) {
+      env_->DeleteFile(copy);
+    }
  }

  Status WriteDescriptor() {
--- a/db/skiplist.h
+++ b/db/skiplist.h
@@ -1,7 +1,10 @@
 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
-//
+
+#ifndef STORAGE_LEVELDB_DB_SKIPLIST_H_
+#define STORAGE_LEVELDB_DB_SKIPLIST_H_
+
 // Thread safety
 // -------------
 //
@@ -377,3 +380,5 @@ bool SkipList<Key,Comparator>::Contains(const Key& key) const {
 }

 }  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_DB_SKIPLIST_H_
--- a/db/snapshot.h
+++ b/db/snapshot.h
@@ -5,6 +5,7 @@
 #ifndef STORAGE_LEVELDB_DB_SNAPSHOT_H_
 #define STORAGE_LEVELDB_DB_SNAPSHOT_H_

+#include "db/dbformat.h"
 #include "leveldb/db.h"

 namespace leveldb {
--- a/db/table_cache.cc
+++ b/db/table_cache.cc
@@ -54,6 +54,12 @@ Status TableCache::FindTable(uint64_t file_number, uint64_t file_size,
    RandomAccessFile* file = NULL;
    Table* table = NULL;
    s = env_->NewRandomAccessFile(fname, &file);
+    if (!s.ok()) {
+      std::string old_fname = SSTTableFileName(dbname_, file_number);
+      if (env_->NewRandomAccessFile(old_fname, &file).ok()) {
+        s = Status::OK();
+      }
+    }
    if (s.ok()) {
      s = Table::Open(*options_, file, file_size, &table);
    }
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -54,20 +54,6 @@ static int64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
  return sum;
 }

-namespace {
-std::string IntSetToString(const std::set<uint64_t>& s) {
-  std::string result = "{";
-  for (std::set<uint64_t>::const_iterator it = s.begin();
-       it != s.end();
-       ++it) {
-    result += (result.size() > 1) ? "," : "";
-    result += NumberToString(*it);
-  }
-  result += "}";
-  return result;
-}
-}  // namespace
-
 Version::~Version() {
  assert(refs_ == 0);

@@ -289,6 +275,51 @@ static bool NewestFirst(FileMetaData* a, FileMetaData* b) {
  return a->number > b->number;
 }

+void Version::ForEachOverlapping(Slice user_key, Slice internal_key,
+                                 void* arg,
+                                 bool (*func)(void*, int, FileMetaData*)) {
+  // TODO(sanjay): Change Version::Get() to use this function.
+  const Comparator* ucmp = vset_->icmp_.user_comparator();
+
+  // Search level-0 in order from newest to oldest.
+  std::vector<FileMetaData*> tmp;
+  tmp.reserve(files_[0].size());
+  for (uint32_t i = 0; i < files_[0].size(); i++) {
+    FileMetaData* f = files_[0][i];
+    if (ucmp->Compare(user_key, f->smallest.user_key()) >= 0 &&
+        ucmp->Compare(user_key, f->largest.user_key()) <= 0) {
+      tmp.push_back(f);
+    }
+  }
+  if (!tmp.empty()) {
+    std::sort(tmp.begin(), tmp.end(), NewestFirst);
+    for (uint32_t i = 0; i < tmp.size(); i++) {
+      if (!(*func)(arg, 0, tmp[i])) {
+        return;
+      }
+    }
+  }
+
+  // Search other levels.
+  for (int level = 1; level < config::kNumLevels; level++) {
+    size_t num_files = files_[level].size();
+    if (num_files == 0) continue;
+
+    // Binary search to find earliest index whose largest key >= internal_key.
+    uint32_t index = FindFile(vset_->icmp_, files_[level], internal_key);
+    if (index < num_files) {
+      FileMetaData* f = files_[level][index];
+      if (ucmp->Compare(user_key, f->smallest.user_key()) < 0) {
+        // All of "f" is past any data for user_key
+      } else {
+        if (!(*func)(arg, level, f)) {
+          return;
+        }
+      }
+    }
+  }
+}
+
 Status Version::Get(const ReadOptions& options,
                    const LookupKey& k,
                    std::string* value,
@@ -401,6 +432,44 @@ bool Version::UpdateStats(const GetStats& stats) {
  return false;
 }

+bool Version::RecordReadSample(Slice internal_key) {
+  ParsedInternalKey ikey;
+  if (!ParseInternalKey(internal_key, &ikey)) {
+    return false;
+  }
+
+  struct State {
+    GetStats stats;  // Holds first matching file
+    int matches;
+
+    static bool Match(void* arg, int level, FileMetaData* f) {
+      State* state = reinterpret_cast<State*>(arg);
+      state->matches++;
+      if (state->matches == 1) {
+        // Remember first match.
+        state->stats.seek_file = f;
+        state->stats.seek_file_level = level;
+      }
+      // We can stop iterating once we have a second match.
+      return state->matches < 2;
+    }
+  };
+
+  State state;
+  state.matches = 0;
+  ForEachOverlapping(ikey.user_key, internal_key, &state, &State::Match);
+
+  // Must have at least two matches since we want to merge across
+  // files. But what if we have a single file that contains many
+  // overwrites and deletions?  Should we have another mechanism for
+  // finding such files?
+  if (state.matches >= 2) {
+    // 1MB cost is about 1 seek (see comment in Builder::Apply).
+    return UpdateStats(state.stats);
+  }
+  return false;
+}
+
 void Version::Ref() {
  ++refs_;
 }
@@ -435,10 +504,13 @@ int Version::PickLevelForMemTableOutput(
      if (OverlapInLevel(level + 1, &smallest_user_key, &largest_user_key)) {
        break;
      }
-      GetOverlappingInputs(level + 2, &start, &limit, &overlaps);
-      const int64_t sum = TotalFileSize(overlaps);
-      if (sum > kMaxGrandParentOverlapBytes) {
-        break;
+      if (level + 2 < config::kNumLevels) {
+        // Check that file does not overlap too many grandparent bytes.
+        GetOverlappingInputs(level + 2, &start, &limit, &overlaps);
+        const int64_t sum = TotalFileSize(overlaps);
+        if (sum > kMaxGrandParentOverlapBytes) {
+          break;
+        }
      }
      level++;
    }
@@ -452,6 +524,8 @@ void Version::GetOverlappingInputs(
    const InternalKey* begin,
    const InternalKey* end,
    std::vector<FileMetaData*>* inputs) {
+  assert(level >= 0);
+  assert(level < config::kNumLevels);
  inputs->clear();
  Slice user_begin, user_end;
  if (begin != NULL) {
@@ -786,6 +860,9 @@ Status VersionSet::LogAndApply(VersionEdit* edit, port::Mutex* mu) {
      if (s.ok()) {
        s = descriptor_file_->Sync();
      }
+      if (!s.ok()) {
+        Log(options_->info_log, "MANIFEST write: %s\n", s.ToString().c_str());
+      }
    }

    // If we just created a new descriptor file, install it by writing a
@@ -816,7 +893,7 @@ Status VersionSet::LogAndApply(VersionEdit* edit, port::Mutex* mu) {
  return s;
 }

-Status VersionSet::Recover() {
+Status VersionSet::Recover(bool *save_manifest) {
  struct LogReporter : public log::Reader::Reporter {
    Status* status;
    virtual void Corruption(size_t bytes, const Status& s) {
@@ -865,7 +942,7 @@ Status VersionSet::Recover() {
        if (edit.has_comparator_ &&
            edit.comparator_ != icmp_.user_comparator()->Name()) {
          s = Status::InvalidArgument(
-              edit.comparator_ + "does not match existing comparator ",
+              edit.comparator_ + " does not match existing comparator ",
              icmp_.user_comparator()->Name());
        }
      }
@@ -926,11 +1003,49 @@ Status VersionSet::Recover() {
    last_sequence_ = last_sequence;
    log_number_ = log_number;
    prev_log_number_ = prev_log_number;
+
+    // See if we can reuse the existing MANIFEST file.
+    if (ReuseManifest(dscname, current)) {
+      // No need to save new manifest
+    } else {
+      *save_manifest = true;
+    }
  }

  return s;
 }

+bool VersionSet::ReuseManifest(const std::string& dscname,
+                               const std::string& dscbase) {
+  if (!options_->reuse_logs) {
+    return false;
+  }
+  FileType manifest_type;
+  uint64_t manifest_number;
+  uint64_t manifest_size;
+  if (!ParseFileName(dscbase, &manifest_number, &manifest_type) ||
+      manifest_type != kDescriptorFile ||
+      !env_->GetFileSize(dscname, &manifest_size).ok() ||
+      // Make new compacted MANIFEST if old one is too big
+      manifest_size >= kTargetFileSize) {
+    return false;
+  }
+
+  assert(descriptor_file_ == NULL);
+  assert(descriptor_log_ == NULL);
+  Status r = env_->NewAppendableFile(dscname, &descriptor_file_);
+  if (!r.ok()) {
+    Log(options_->info_log, "Reuse MANIFEST: %s\n", r.ToString().c_str());
+    assert(descriptor_file_ == NULL);
+    return false;
+  }
+
+  Log(options_->info_log, "Reusing MANIFEST %s\n", dscname.c_str());
+  descriptor_log_ = new log::Writer(descriptor_file_, manifest_size);
+  manifest_file_number_ = manifest_number;
+  return true;
+}
+
 void VersionSet::MarkFileNumberUsed(uint64_t number) {
  if (next_file_number_ <= number) {
    next_file_number_ = number + 1;
@@ -1295,14 +1410,19 @@ Compaction* VersionSet::CompactRange(
  }

  // Avoid compacting too much in one shot in case the range is large.
-  const uint64_t limit = MaxFileSizeForLevel(level);
-  uint64_t total = 0;
-  for (size_t i = 0; i < inputs.size(); i++) {
-    uint64_t s = inputs[i]->file_size;
-    total += s;
-    if (total >= limit) {
-      inputs.resize(i + 1);
-      break;
+  // But we cannot do this for level-0 since level-0 files can overlap
+  // and we must not pick one file and drop another older file if the
+  // two files overlap.
+  if (level > 0) {
+    const uint64_t limit = MaxFileSizeForLevel(level);
+    uint64_t total = 0;
+    for (size_t i = 0; i < inputs.size(); i++) {
+      uint64_t s = inputs[i]->file_size;
+      total += s;
+      if (total >= limit) {
+        inputs.resize(i + 1);
+        break;
+      }
    }
  }

--- a/db/version_set.h
+++ b/db/version_set.h
@@ -21,6 +21,7 @@
 #include "db/dbformat.h"
 #include "db/version_edit.h"
 #include "port/port.h"
+#include "port/thread_annotations.h"

 namespace leveldb {

@@ -77,6 +78,12 @@ class Version {
  // REQUIRES: lock is held
  bool UpdateStats(const GetStats& stats);

+  // Record a sample of bytes read at the specified internal key.
+  // Samples are taken approximately once every config::kReadBytesPeriod
+  // bytes.  Returns true if a new compaction may need to be triggered.
+  // REQUIRES: lock is held
+  bool RecordReadSample(Slice key);
+
  // Reference count management (so Versions do not disappear out from
  // under live iterators)
  void Ref();
@@ -113,6 +120,15 @@ class Version {
  class LevelFileNumIterator;
  Iterator* NewConcatenatingIterator(const ReadOptions&, int level) const;

+  // Call func(arg, level, f) for every file that overlaps user_key in
+  // order from newest to oldest.  If an invocation of func returns
+  // false, makes no more calls.
+  //
+  // REQUIRES: user portion of internal_key == user_key.
+  void ForEachOverlapping(Slice user_key, Slice internal_key,
+                          void* arg,
+                          bool (*func)(void*, int, FileMetaData*));
+
  VersionSet* vset_;            // VersionSet to which this Version belongs
  Version* next_;               // Next version in linked list
  Version* prev_;               // Previous version in linked list
@@ -159,10 +175,11 @@ class VersionSet {
  // current version.  Will release *mu while actually writing to the file.
  // REQUIRES: *mu is held on entry.
  // REQUIRES: no other thread concurrently calls LogAndApply()
-  Status LogAndApply(VersionEdit* edit, port::Mutex* mu);
+  Status LogAndApply(VersionEdit* edit, port::Mutex* mu)
+      EXCLUSIVE_LOCKS_REQUIRED(mu);

  // Recover the last saved descriptor from persistent storage.
-  Status Recover();
+  Status Recover(bool *save_manifest);

  // Return the current version.
  Version* current() const { return current_; }
@@ -257,6 +274,8 @@ class VersionSet {
  friend class Compaction;
  friend class Version;

+  bool ReuseManifest(const std::string& dscname, const std::string& dscbase);
+
  void Finalize(Version* v);

  void GetRange(const std::vector<FileMetaData*>& inputs,
--- a/db/write_batch_internal.h
+++ b/db/write_batch_internal.h
@@ -5,6 +5,7 @@
 #ifndef STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_
 #define STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_

+#include "db/dbformat.h"
 #include "leveldb/write_batch.h"

 namespace leveldb {
@@ -21,10 +22,10 @@ class WriteBatchInternal {
  // Set the count for the number of entries in the batch.
  static void SetCount(WriteBatch* batch, int n);

-  // Return the seqeunce number for the start of this batch.
+  // Return the sequence number for the start of this batch.
  static SequenceNumber Sequence(const WriteBatch* batch);

-  // Store the specified number as the seqeunce number for the start of
+  // Store the specified number as the sequence number for the start of
  // this batch.
  static void SetSequence(WriteBatch* batch, SequenceNumber seq);

--- a/doc/bench/db_bench_sqlite3.cc
+++ b/doc/bench/db_bench_sqlite3.cc
@@ -618,7 +618,7 @@ class Benchmark {
        ErrorCheck(status);

        // Execute read statement
-        while ((status = sqlite3_step(read_stmt)) == SQLITE_ROW);
+        while ((status = sqlite3_step(read_stmt)) == SQLITE_ROW) {}
        StepErrorCheck(status);

        // Reset SQLite statement for another use
--- a/doc/bench/db_bench_tree_db.cc
+++ b/doc/bench/db_bench_tree_db.cc
@@ -338,7 +338,7 @@ class Benchmark {
      bool write_sync = false;
      if (name == Slice("fillseq")) {
        Write(write_sync, SEQUENTIAL, FRESH, num_, FLAGS_value_size, 1);
-        
+        DBSynchronize(db_);
      } else if (name == Slice("fillrandom")) {
        Write(write_sync, RANDOM, FRESH, num_, FLAGS_value_size, 1);
        DBSynchronize(db_);
--- a/doc/impl.html
+++ b/doc/impl.html
@@ -11,7 +11,7 @@

 The implementation of leveldb is similar in spirit to the
 representation of a single
-<a href="http://labs.google.com/papers/bigtable.html">
+<a href="http://research.google.com/archive/bigtable.html">
 Bigtable tablet (section 5.3)</a>.
 However the organization of the files that make up the representation
 is somewhat different and is explained below.
@@ -111,7 +111,7 @@ A compaction merges the contents of the picked files to produce a
 sequence of level-(L+1) files.  We switch to producing a new
 level-(L+1) file after the current output file has reached the target
 file size (2MB).  We also switch to a new output file when the key
-range of the current output file has grown enough to overlap more then
+range of the current output file has grown enough to overlap more than
 ten level-(L+2) files.  This last rule ensures that a later compaction
 of a level-(L+1) file will not pick up too much data from level-(L+2).

@@ -151,7 +151,7 @@ compaction cost will be approximately 0.5 second.
 If we throttle the background writing to something small, say 10% of
 the full 100MB/s speed, a compaction may take up to 5 seconds.  If the
 user is writing at 10MB/s, we might build up lots of level-0 files
-(~50 to hold the 5*10MB).  This may signficantly increase the cost of
+(~50 to hold the 5*10MB).  This may significantly increase the cost of
 reads due to the overhead of merging more files together on every
 read.

--- a/doc/index.html
+++ b/doc/index.html
@@ -408,7 +408,7 @@ The optional <code>FilterPolicy</code> mechanism can be used to reduce
 the number of disk reads substantially.
 <pre>
   leveldb::Options options;
-   options.filter_policy = NewBloomFilter(10);
+   options.filter_policy = NewBloomFilterPolicy(10);
   leveldb::DB* db;
   leveldb::DB::Open(options, "/tmp/testdb", &amp;db);
   ... use the database ...
@@ -420,7 +420,7 @@ The preceding code associates a
 based filtering policy with the database.  Bloom filter based
 filtering relies on keeping some number of bits of data in memory per
 key (in this case 10 bits per key since that is the argument we passed
-to NewBloomFilter).  This filter will reduce the number of unnecessary
+to NewBloomFilterPolicy).  This filter will reduce the number of unnecessary
 disk reads needed for <code>Get()</code> calls by a factor of
 approximately a 100.  Increasing the bits per key will lead to a
 larger reduction at the cost of more memory usage.  We recommend that
@@ -430,7 +430,7 @@ lot of random reads set a filter policy.
 If you are using a custom comparator, you should ensure that the filter
 policy you are using is compatible with your comparator.  For example,
 consider a comparator that ignores trailing spaces when comparing keys.
-<code>NewBloomFilter</code> must not be used with such a comparator.
+<code>NewBloomFilterPolicy</code> must not be used with such a comparator.
 Instead, the application should provide a custom filter policy that
 also ignores trailing spaces.  For example:
 <pre>
@@ -438,7 +438,7 @@ also ignores trailing spaces.  For example:
   private:
    FilterPolicy* builtin_policy_;
   public:
-    CustomFilterPolicy() : builtin_policy_(NewBloomFilter(10)) { }
+    CustomFilterPolicy() : builtin_policy_(NewBloomFilterPolicy(10)) { }
    ~CustomFilterPolicy() { delete builtin_policy_; }

    const char* Name() const { return "IgnoreTrailingSpacesFilter"; }
--- a/doc/log_format.txt
+++ b/doc/log_format.txt
@@ -4,14 +4,14 @@ exception is that the tail of the file may contain a partial block.
 Each block consists of a sequence of records:
   block := record* trailer?
   record :=
-	checksum: uint32	// crc32c of type and data[]
-	length: uint16
+	checksum: uint32	// crc32c of type and data[] ; little-endian
+	length: uint16		// little-endian
 	type: uint8		// One of FULL, FIRST, MIDDLE, LAST
 	data: uint8[length]

 A record never starts within the last six bytes of a block (since it
 won't fit).  Any leftover bytes here form the trailer, which must
-consist entirely of zero bytes and must be skipped by readers.  
+consist entirely of zero bytes and must be skipped by readers.

 Aside: if exactly seven bytes are left in the current block, and a new
 non-zero length record is added, the writer must emit a FIRST record
@@ -33,8 +33,8 @@ The FULL record contains the contents of an entire user record.
 FIRST, MIDDLE, LAST are types used for user records that have been
 split into multiple fragments (typically because of block boundaries).
 FIRST is the type of the first fragment of a user record, LAST is the
-type of the last fragment of a user record, and MID is the type of all
-interior fragments of a user record.
+type of the last fragment of a user record, and MIDDLE is the type of
+all interior fragments of a user record.

 Example: consider a sequence of user records:
   A: length 1000
--- a/doc/table_format.txt
+++ b/doc/table_format.txt
@@ -18,6 +18,8 @@ The file contains internal pointers.  Each such pointer is called
 a BlockHandle and contains the following information:
  offset:	    varint64
  size:		    varint64
+See https://developers.google.com/protocol-buffers/docs/encoding#varints
+for an explanation of varint64 format.

 (1) The sequence of key/value pairs in the file are stored in sorted
 order and partitioned into a sequence of data blocks.  These blocks
@@ -41,11 +43,11 @@ BlockHandle for the data block.

 (6) At the very end of the file is a fixed length footer that contains
 the BlockHandle of the metaindex and index blocks as well as a magic number.
-       metaindex_handle:       char[p];    // Block handle for metaindex
-       index_handle:	       char[q];    // Block handle for index
-       padding:		       char[40-p-q]; // 0 bytes to make fixed length
-       			 	       // (40==2*BlockHandle::kMaxEncodedLength)
-       magic:		       fixed64;    // == 0xdb4775248b80fb57
+       metaindex_handle: char[p];    // Block handle for metaindex
+       index_handle:     char[q];    // Block handle for index
+       padding:          char[40-p-q]; // zeroed bytes to make fixed length
+                                       // (40==2*BlockHandle::kMaxEncodedLength)
+       magic:            fixed64;    // == 0xdb4775248b80fb57 (little-endian)

 "filter" Meta Block
 -------------------
--- a/helpers/memenv/memenv.cc
+++ b/helpers/memenv/memenv.cc
@@ -55,14 +55,15 @@ class FileState {
    }
    const uint64_t available = size_ - offset;
    if (n > available) {
-      n = available;
+      n = static_cast<size_t>(available);
    }
    if (n == 0) {
      *result = Slice();
      return Status::OK();
    }

-    size_t block = offset / kBlockSize;
+    assert(offset / kBlockSize <= SIZE_MAX);
+    size_t block = static_cast<size_t>(offset / kBlockSize);
    size_t block_offset = offset % kBlockSize;

    if (n <= kBlockSize - block_offset) {
@@ -167,7 +168,7 @@ class SequentialFileImpl : public SequentialFile {
    if (pos_ > file_->Size()) {
      return Status::IOError("pos_ > file_->Size()");
    }
-    const size_t available = file_->Size() - pos_;
+    const uint64_t available = file_->Size() - pos_;
    if (n > available) {
      n = available;
    }
@@ -177,7 +178,7 @@ class SequentialFileImpl : public SequentialFile {

 private:
  FileState* file_;
-  size_t pos_;
+  uint64_t pos_;
 };

 class RandomAccessFileImpl : public RandomAccessFile {
@@ -221,6 +222,11 @@ class WritableFileImpl : public WritableFile {
  FileState* file_;
 };

+class NoOpLogger : public Logger {
+ public:
+  virtual void Logv(const char* format, va_list ap) { }
+};
+
 class InMemoryEnv : public EnvWrapper {
 public:
  explicit InMemoryEnv(Env* base_env) : EnvWrapper(base_env) { }
@@ -271,6 +277,19 @@ class InMemoryEnv : public EnvWrapper {
    return Status::OK();
  }

+  virtual Status NewAppendableFile(const std::string& fname,
+                                   WritableFile** result) {
+    MutexLock lock(&mutex_);
+    FileState** sptr = &file_map_[fname];
+    FileState* file = *sptr;
+    if (file == NULL) {
+      file = new FileState();
+      file->Ref();
+    }
+    *result = new WritableFileImpl(file);
+    return Status::OK();
+  }
+
  virtual bool FileExists(const std::string& fname) {
    MutexLock lock(&mutex_);
    return file_map_.find(fname) != file_map_.end();
@@ -358,6 +377,11 @@ class InMemoryEnv : public EnvWrapper {
    return Status::OK();
  }

+  virtual Status NewLogger(const std::string& fname, Logger** result) {
+    *result = new NoOpLogger;
+    return Status::OK();
+  }
+
 private:
  // Map from filenames to FileState objects, representing a simple file system.
  typedef std::map<std::string, FileState*> FileSystem;
--- a/helpers/memenv/memenv_test.cc
+++ b/helpers/memenv/memenv_test.cc
@@ -40,6 +40,8 @@ TEST(MemEnvTest, Basics) {

  // Create a file.
  ASSERT_OK(env_->NewWritableFile("/dir/f", &writable_file));
+  ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
+  ASSERT_EQ(0, file_size);
  delete writable_file;

  // Check that the file exists.
@@ -55,9 +57,16 @@ TEST(MemEnvTest, Basics) {
  ASSERT_OK(writable_file->Append("abc"));
  delete writable_file;

-  // Check for expected size.
+  // Check that append works.
+  ASSERT_OK(env_->NewAppendableFile("/dir/f", &writable_file));
  ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
  ASSERT_EQ(3, file_size);
+  ASSERT_OK(writable_file->Append("hello"));
+  delete writable_file;
+
+  // Check for expected size.
+  ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
+  ASSERT_EQ(8, file_size);

  // Check that renaming works.
  ASSERT_TRUE(!env_->RenameFile("/dir/non_existent", "/dir/g").ok());
@@ -65,7 +74,7 @@ TEST(MemEnvTest, Basics) {
  ASSERT_TRUE(!env_->FileExists("/dir/f"));
  ASSERT_TRUE(env_->FileExists("/dir/g"));
  ASSERT_OK(env_->GetFileSize("/dir/g", &file_size));
-  ASSERT_EQ(3, file_size);
+  ASSERT_EQ(8, file_size);

  // Check that opening non-existent file fails.
  SequentialFile* seq_file;
--- a/include/leveldb/c.h
+++ b/include/leveldb/c.h
@@ -9,7 +9,6 @@
  Does not support:
  . getters for the option types
  . custom comparators that implement key shortening
-  . capturing post-write-snapshot
  . custom iter, db, env, cache implementations using just the C bindings

  Some conventions:
@@ -28,6 +27,7 @@
  be true on entry:
     *errptr == NULL
     *errptr points to a malloc()ed null-terminated error message
+       (On Windows, *errptr must have been malloc()-ed by this library.)
  On success, a leveldb routine leaves *errptr unchanged.
  On failure, leveldb frees the old value of *errptr and
  set *errptr to a malloc()ed error message.
@@ -268,6 +268,21 @@ extern void leveldb_cache_destroy(leveldb_cache_t* cache);
 extern leveldb_env_t* leveldb_create_default_env();
 extern void leveldb_env_destroy(leveldb_env_t*);

+/* Utility */
+
+/* Calls free(ptr).
+   REQUIRES: ptr was malloc()-ed and returned by one of the routines
+   in this file.  Note that in certain cases (typically on Windows), you
+   may need to call this routine instead of free(ptr) to dispose of
+   malloc()-ed memory returned by this library. */
+extern void leveldb_free(void* ptr);
+
+/* Return the major version number for this release. */
+extern int leveldb_major_version();
+
+/* Return the minor version number for this release. */
+extern int leveldb_minor_version();
+
 #ifdef __cplusplus
 }  /* end extern "C" */
 #endif
--- a/include/leveldb/cache.h
+++ b/include/leveldb/cache.h
@@ -81,6 +81,17 @@ class Cache {
  // its cache keys.
  virtual uint64_t NewId() = 0;

+  // Remove all cache entries that are not actively in use.  Memory-constrained
+  // applications may wish to call this method to reduce memory usage.
+  // Default implementation of Prune() does nothing.  Subclasses are strongly
+  // encouraged to override the default implementation.  A future release of
+  // leveldb may change Prune() to a pure abstract method.
+  virtual void Prune() {}
+
+  // Return an estimate of the combined charges of all elements stored in the
+  // cache.
+  virtual size_t TotalCharge() const = 0;
+
 private:
  void LRU_Remove(Handle* e);
  void LRU_Append(Handle* e);
@@ -96,4 +107,4 @@ class Cache {

 }  // namespace leveldb

-#endif  // STORAGE_LEVELDB_UTIL_CACHE_H_
+#endif  // STORAGE_LEVELDB_INCLUDE_CACHE_H_
--- a/include/leveldb/db.h
+++ b/include/leveldb/db.h
@@ -14,7 +14,7 @@ namespace leveldb {

 // Update Makefile if you change these
 static const int kMajorVersion = 1;
-static const int kMinorVersion = 5;
+static const int kMinorVersion = 18;

 struct Options;
 struct ReadOptions;
@@ -115,6 +115,8 @@ class DB {
  //     about the internal operation of the DB.
  //  "leveldb.sstables" - returns a multi-line string that describes all
  //     of the sstables that make up the db contents.
+  //  "leveldb.approximate-memory-usage" - returns the approximate number of
+  //     bytes of memory in use by the DB.
  virtual bool GetProperty(const Slice& property, std::string* value) = 0;

  // For each i in [0,n-1], store in "sizes[i]", the approximate
--- a/include/leveldb/dumpfile.h
+++ b/include/leveldb/dumpfile.h
@@ -0,0 +1,25 @@
+// Copyright (c) 2014 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef STORAGE_LEVELDB_INCLUDE_DUMPFILE_H_
+#define STORAGE_LEVELDB_INCLUDE_DUMPFILE_H_
+
+#include <string>
+#include "leveldb/env.h"
+#include "leveldb/status.h"
+
+namespace leveldb {
+
+// Dump the contents of the file named by fname in text format to
+// *dst.  Makes a sequence of dst->Append() calls; each call is passed
+// the newline-terminated text corresponding to a single item found
+// in the file.
+//
+// Returns a non-OK result if fname does not name a leveldb storage
+// file, or if the file cannot be read.
+Status DumpFile(Env* env, const std::string& fname, WritableFile* dst);
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_INCLUDE_DUMPFILE_H_
--- a/include/leveldb/env.h
+++ b/include/leveldb/env.h
@@ -13,9 +13,9 @@
 #ifndef STORAGE_LEVELDB_INCLUDE_ENV_H_
 #define STORAGE_LEVELDB_INCLUDE_ENV_H_

-#include <cstdarg>
 #include <string>
 #include <vector>
+#include <stdarg.h>
 #include <stdint.h>
 #include "leveldb/status.h"

@@ -69,6 +69,21 @@ class Env {
  virtual Status NewWritableFile(const std::string& fname,
                                 WritableFile** result) = 0;

+  // Create an object that either appends to an existing file, or
+  // writes to a new file (if the file does not exist to begin with).
+  // On success, stores a pointer to the new file in *result and
+  // returns OK.  On failure stores NULL in *result and returns
+  // non-OK.
+  //
+  // The returned file will only be accessed by one thread at a time.
+  //
+  // May return an IsNotSupportedError error if this Env does
+  // not allow appending to an existing file.  Users of Env (including
+  // the leveldb implementation) must be prepared to deal with
+  // an Env that does not support appending.
+  virtual Status NewAppendableFile(const std::string& fname,
+                                   WritableFile** result);
+
  // Returns true iff the named file exists.
  virtual bool FileExists(const std::string& fname) = 0;

@@ -142,7 +157,7 @@ class Env {
  // useful for computing deltas of time.
  virtual uint64_t NowMicros() = 0;

-  // Sleep/delay the thread for the perscribed number of micro-seconds.
+  // Sleep/delay the thread for the prescribed number of micro-seconds.
  virtual void SleepForMicroseconds(int micros) = 0;

 private:
@@ -175,6 +190,11 @@ class SequentialFile {
  //
  // REQUIRES: External synchronization
  virtual Status Skip(uint64_t n) = 0;
+
+ private:
+  // No copying allowed
+  SequentialFile(const SequentialFile&);
+  void operator=(const SequentialFile&);
 };

 // A file abstraction for randomly reading the contents of a file.
@@ -194,6 +214,11 @@ class RandomAccessFile {
  // Safe for concurrent use by multiple threads.
  virtual Status Read(uint64_t offset, size_t n, Slice* result,
                      char* scratch) const = 0;
+
+ private:
+  // No copying allowed
+  RandomAccessFile(const RandomAccessFile&);
+  void operator=(const RandomAccessFile&);
 };

 // A file abstraction for sequential writing.  The implementation
@@ -279,6 +304,9 @@ class EnvWrapper : public Env {
  Status NewWritableFile(const std::string& f, WritableFile** r) {
    return target_->NewWritableFile(f, r);
  }
+  Status NewAppendableFile(const std::string& f, WritableFile** r) {
+    return target_->NewAppendableFile(f, r);
+  }
  bool FileExists(const std::string& f) { return target_->FileExists(f); }
  Status GetChildren(const std::string& dir, std::vector<std::string>* r) {
    return target_->GetChildren(dir, r);
--- a/include/leveldb/iterator.h
+++ b/include/leveldb/iterator.h
@@ -37,7 +37,7 @@ class Iterator {
  // Valid() after this call iff the source is not empty.
  virtual void SeekToLast() = 0;

-  // Position at the first key in the source that at or past target
+  // Position at the first key in the source that is at or past target.
  // The iterator is Valid() after this call iff the source contains
  // an entry that comes at or past target.
  virtual void Seek(const Slice& target) = 0;
@@ -61,7 +61,7 @@ class Iterator {
  // Return the value for the current entry.  The underlying storage for
  // the returned slice is valid only until the next modification of
  // the iterator.
-  // REQUIRES: !AtEnd() && !AtStart()
+  // REQUIRES: Valid()
  virtual Slice value() const = 0;

  // If an error has occurred, return it.  Else return an ok status.
--- a/include/leveldb/options.h
+++ b/include/leveldb/options.h
@@ -128,6 +128,12 @@ struct Options {
  // efficiently detect that and will switch to uncompressed mode.
  CompressionType compression;

+  // EXPERIMENTAL: If true, append to existing MANIFEST and log files
+  // when a database is opened.  This can significantly speed up open.
+  //
+  // Default: currently false, but may become true later.
+  bool reuse_logs;
+
  // If non-NULL, use the specified filter policy to reduce disk reads.
  // Many applications will benefit from passing the result of
  // NewBloomFilterPolicy() here.
@@ -153,7 +159,7 @@ struct ReadOptions {

  // If "snapshot" is non-NULL, read as of the supplied snapshot
  // (which must belong to the DB that is being read and which must
-  // not have been released).  If "snapshot" is NULL, use an impliicit
+  // not have been released).  If "snapshot" is NULL, use an implicit
  // snapshot of the state at the beginning of this read operation.
  // Default: NULL
  const Snapshot* snapshot;
--- a/include/leveldb/slice.h
+++ b/include/leveldb/slice.h
@@ -94,7 +94,7 @@ inline bool operator!=(const Slice& x, const Slice& y) {
 }

 inline int Slice::compare(const Slice& b) const {
-  const int min_len = (size_ < b.size_) ? size_ : b.size_;
+  const size_t min_len = (size_ < b.size_) ? size_ : b.size_;
  int r = memcmp(data_, b.data_, min_len);
  if (r == 0) {
    if (size_ < b.size_) r = -1;
--- a/include/leveldb/status.h
+++ b/include/leveldb/status.h
@@ -60,6 +60,9 @@ class Status {
  // Returns true iff the status indicates an IOError.
  bool IsIOError() const { return code() == kIOError; }

+  // Returns true iff the status indicates a NotSupportedError.
+  bool IsNotSupportedError() const { return code() == kNotSupported; }
+
  // Return a string representation of this status suitable for printing.
  // Returns the string "OK" for success.
  std::string ToString() const;
--- a/issues/issue178_test.cc
+++ b/issues/issue178_test.cc
@@ -0,0 +1,92 @@
+// Copyright (c) 2013 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.
+
+// Test for issue 178: a manual compaction causes deleted data to reappear.
+#include <iostream>
+#include <sstream>
+#include <cstdlib>
+
+#include "leveldb/db.h"
+#include "leveldb/write_batch.h"
+#include "util/testharness.h"
+
+namespace {
+
+const int kNumKeys = 1100000;
+
+std::string Key1(int i) {
+  char buf[100];
+  snprintf(buf, sizeof(buf), "my_key_%d", i);
+  return buf;
+}
+
+std::string Key2(int i) {
+  return Key1(i) + "_xxx";
+}
+
+class Issue178 { };
+
+TEST(Issue178, Test) {
+  // Get rid of any state from an old run.
+  std::string dbpath = leveldb::test::TmpDir() + "/leveldb_cbug_test";
+  DestroyDB(dbpath, leveldb::Options());
+
+  // Open database.  Disable compression since it affects the creation
+  // of layers and the code below is trying to test against a very
+  // specific scenario.
+  leveldb::DB* db;
+  leveldb::Options db_options;
+  db_options.create_if_missing = true;
+  db_options.compression = leveldb::kNoCompression;
+  ASSERT_OK(leveldb::DB::Open(db_options, dbpath, &db));
+
+  // create first key range
+  leveldb::WriteBatch batch;
+  for (size_t i = 0; i < kNumKeys; i++) {
+    batch.Put(Key1(i), "value for range 1 key");
+  }
+  ASSERT_OK(db->Write(leveldb::WriteOptions(), &batch));
+
+  // create second key range
+  batch.Clear();
+  for (size_t i = 0; i < kNumKeys; i++) {
+    batch.Put(Key2(i), "value for range 2 key");
+  }
+  ASSERT_OK(db->Write(leveldb::WriteOptions(), &batch));
+
+  // delete second key range
+  batch.Clear();
+  for (size_t i = 0; i < kNumKeys; i++) {
+    batch.Delete(Key2(i));
+  }
+  ASSERT_OK(db->Write(leveldb::WriteOptions(), &batch));
+
+  // compact database
+  std::string start_key = Key1(0);
+  std::string end_key = Key1(kNumKeys - 1);
+  leveldb::Slice least(start_key.data(), start_key.size());
+  leveldb::Slice greatest(end_key.data(), end_key.size());
+
+  // commenting out the line below causes the example to work correctly
+  db->CompactRange(&least, &greatest);
+
+  // count the keys
+  leveldb::Iterator* iter = db->NewIterator(leveldb::ReadOptions());
+  size_t num_keys = 0;
+  for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
+    num_keys++;
+  }
+  delete iter;
+  ASSERT_EQ(kNumKeys, num_keys) << "Bad number of keys";
+
+  // close database
+  delete db;
+  DestroyDB(dbpath, leveldb::Options());
+}
+
+}  // anonymous namespace
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
--- a/issues/issue200_test.cc
+++ b/issues/issue200_test.cc
@@ -0,0 +1,59 @@
+// Copyright (c) 2013 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.
+
+// Test for issue 200: when iterator switches direction from backward
+// to forward, the current key can be yielded unexpectedly if a new
+// mutation has been added just before the current key.
+
+#include "leveldb/db.h"
+#include "util/testharness.h"
+
+namespace leveldb {
+
+class Issue200 { };
+
+TEST(Issue200, Test) {
+  // Get rid of any state from an old run.
+  std::string dbpath = test::TmpDir() + "/leveldb_issue200_test";
+  DestroyDB(dbpath, Options());
+
+  DB *db;
+  Options options;
+  options.create_if_missing = true;
+  ASSERT_OK(DB::Open(options, dbpath, &db));
+
+  WriteOptions write_options;
+  ASSERT_OK(db->Put(write_options, "1", "b"));
+  ASSERT_OK(db->Put(write_options, "2", "c"));
+  ASSERT_OK(db->Put(write_options, "3", "d"));
+  ASSERT_OK(db->Put(write_options, "4", "e"));
+  ASSERT_OK(db->Put(write_options, "5", "f"));
+
+  ReadOptions read_options;
+  Iterator *iter = db->NewIterator(read_options);
+
+  // Add an element that should not be reflected in the iterator.
+  ASSERT_OK(db->Put(write_options, "25", "cd"));
+
+  iter->Seek("5");
+  ASSERT_EQ(iter->key().ToString(), "5");
+  iter->Prev();
+  ASSERT_EQ(iter->key().ToString(), "4");
+  iter->Prev();
+  ASSERT_EQ(iter->key().ToString(), "3");
+  iter->Next();
+  ASSERT_EQ(iter->key().ToString(), "4");
+  iter->Next();
+  ASSERT_EQ(iter->key().ToString(), "5");
+
+  delete iter;
+  delete db;
+  DestroyDB(dbpath, options);
+}
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
--- a/port/atomic_pointer.h
+++ b/port/atomic_pointer.h
@@ -5,14 +5,13 @@
 // AtomicPointer provides storage for a lock-free pointer.
 // Platform-dependent implementation of AtomicPointer:
 // - If the platform provides a cheap barrier, we use it with raw pointers
-// - If cstdatomic is present (on newer versions of gcc, it is), we use
-//   a cstdatomic-based AtomicPointer.  However we prefer the memory
+// - If <atomic> is present (on newer versions of gcc, it is), we use
+//   a <atomic>-based AtomicPointer.  However we prefer the memory
 //   barrier based version, because at least on a gcc 4.4 32-bit build
-//   on linux, we have encountered a buggy <cstdatomic>
-//   implementation.  Also, some <cstdatomic> implementations are much
-//   slower than a memory-barrier based implementation (~16ns for
-//   <cstdatomic> based acquire-load vs. ~1ns for a barrier based
-//   acquire-load).
+//   on linux, we have encountered a buggy <atomic> implementation.
+//   Also, some <atomic> implementations are much slower than a memory-barrier
+//   based implementation (~16ns for <atomic> based acquire-load vs. ~1ns for
+//   a barrier based acquire-load).
 // This code is based on atomicops-internals-* in Google's perftools:
 // http://code.google.com/p/google-perftools/source/browse/#svn%2Ftrunk%2Fsrc%2Fbase

@@ -20,8 +19,8 @@
 #define PORT_ATOMIC_POINTER_H_

 #include <stdint.h>
-#ifdef LEVELDB_CSTDATOMIC_PRESENT
-#include <cstdatomic>
+#ifdef LEVELDB_ATOMIC_PRESENT
+#include <atomic>
 #endif
 #ifdef OS_WIN
 #include <windows.h>
@@ -36,6 +35,10 @@
 #define ARCH_CPU_X86_FAMILY 1
 #elif defined(__ARMEL__)
 #define ARCH_CPU_ARM_FAMILY 1
+#elif defined(__aarch64__)
+#define ARCH_CPU_ARM64_FAMILY 1
+#elif defined(__ppc__) || defined(__powerpc__) || defined(__powerpc64__)
+#define ARCH_CPU_PPC_FAMILY 1
 #endif

 namespace leveldb {
@@ -48,6 +51,13 @@ namespace port {
 // http://msdn.microsoft.com/en-us/library/ms684208(v=vs.85).aspx
 #define LEVELDB_HAVE_MEMORY_BARRIER

+// Mac OS
+#elif defined(OS_MACOSX)
+inline void MemoryBarrier() {
+  OSMemoryBarrier();
+}
+#define LEVELDB_HAVE_MEMORY_BARRIER
+
 // Gcc on x86
 #elif defined(ARCH_CPU_X86_FAMILY) && defined(__GNUC__)
 inline void MemoryBarrier() {
@@ -66,13 +76,6 @@ inline void MemoryBarrier() {
 }
 #define LEVELDB_HAVE_MEMORY_BARRIER

-// Mac OS
-#elif defined(OS_MACOSX)
-inline void MemoryBarrier() {
-  OSMemoryBarrier();
-}
-#define LEVELDB_HAVE_MEMORY_BARRIER
-
 // ARM Linux
 #elif defined(ARCH_CPU_ARM_FAMILY) && defined(__linux__)
 typedef void (*LinuxKernelMemoryBarrierFunc)(void);
@@ -91,6 +94,22 @@ inline void MemoryBarrier() {
 }
 #define LEVELDB_HAVE_MEMORY_BARRIER

+// ARM64
+#elif defined(ARCH_CPU_ARM64_FAMILY)
+inline void MemoryBarrier() {
+  asm volatile("dmb sy" : : : "memory");
+}
+#define LEVELDB_HAVE_MEMORY_BARRIER
+
+// PPC
+#elif defined(ARCH_CPU_PPC_FAMILY) && defined(__GNUC__)
+inline void MemoryBarrier() {
+  // TODO for some powerpc expert: is there a cheaper suitable variant?
+  // Perhaps by having separate barriers for acquire and release ops.
+  asm volatile("sync" : : : "memory");
+}
+#define LEVELDB_HAVE_MEMORY_BARRIER
+
 #endif

 // AtomicPointer built using platform-specific MemoryBarrier()
@@ -115,7 +134,7 @@ class AtomicPointer {
 };

 // AtomicPointer based on <cstdatomic>
-#elif defined(LEVELDB_CSTDATOMIC_PRESENT)
+#elif defined(LEVELDB_ATOMIC_PRESENT)
 class AtomicPointer {
 private:
  std::atomic<void*> rep_;
@@ -136,7 +155,67 @@ class AtomicPointer {
  }
 };

-// We have neither MemoryBarrier(), nor <cstdatomic>
+// Atomic pointer based on sparc memory barriers
+#elif defined(__sparcv9) && defined(__GNUC__)
+class AtomicPointer {
+ private:
+  void* rep_;
+ public:
+  AtomicPointer() { }
+  explicit AtomicPointer(void* v) : rep_(v) { }
+  inline void* Acquire_Load() const {
+    void* val;
+    __asm__ __volatile__ (
+        "ldx [%[rep_]], %[val] \n\t"
+         "membar #LoadLoad|#LoadStore \n\t"
+        : [val] "=r" (val)
+        : [rep_] "r" (&rep_)
+        : "memory");
+    return val;
+  }
+  inline void Release_Store(void* v) {
+    __asm__ __volatile__ (
+        "membar #LoadStore|#StoreStore \n\t"
+        "stx %[v], [%[rep_]] \n\t"
+        :
+        : [rep_] "r" (&rep_), [v] "r" (v)
+        : "memory");
+  }
+  inline void* NoBarrier_Load() const { return rep_; }
+  inline void NoBarrier_Store(void* v) { rep_ = v; }
+};
+
+// Atomic pointer based on ia64 acq/rel
+#elif defined(__ia64) && defined(__GNUC__)
+class AtomicPointer {
+ private:
+  void* rep_;
+ public:
+  AtomicPointer() { }
+  explicit AtomicPointer(void* v) : rep_(v) { }
+  inline void* Acquire_Load() const {
+    void* val    ;
+    __asm__ __volatile__ (
+        "ld8.acq %[val] = [%[rep_]] \n\t"
+        : [val] "=r" (val)
+        : [rep_] "r" (&rep_)
+        : "memory"
+        );
+    return val;
+  }
+  inline void Release_Store(void* v) {
+    __asm__ __volatile__ (
+        "st8.rel [%[rep_]] = %[v]  \n\t"
+        :
+        : [rep_] "r" (&rep_), [v] "r" (v)
+        : "memory"
+        );
+  }
+  inline void* NoBarrier_Load() const { return rep_; }
+  inline void NoBarrier_Store(void* v) { rep_ = v; }
+};
+
+// We have neither MemoryBarrier(), nor <atomic>
 #else
 #error Please implement AtomicPointer for this platform.

@@ -145,6 +224,8 @@ class AtomicPointer {
 #undef LEVELDB_HAVE_MEMORY_BARRIER
 #undef ARCH_CPU_X86_FAMILY
 #undef ARCH_CPU_ARM_FAMILY
+#undef ARCH_CPU_ARM64_FAMILY
+#undef ARCH_CPU_PPC_FAMILY

 }  // namespace port
 }  // namespace leveldb
--- a/port/port_posix.h
+++ b/port/port_posix.h
@@ -21,13 +21,23 @@
  #else
    #define PLATFORM_IS_LITTLE_ENDIAN false
  #endif
-#elif defined(OS_FREEBSD) || defined(OS_OPENBSD) || defined(OS_NETBSD) ||\
-      defined(OS_DRAGONFLYBSD) || defined(OS_ANDROID)
+#elif defined(OS_FREEBSD) || defined(OS_OPENBSD) ||\
+      defined(OS_NETBSD) || defined(OS_DRAGONFLYBSD)
  #include <sys/types.h>
  #include <sys/endian.h>
+  #define PLATFORM_IS_LITTLE_ENDIAN (_BYTE_ORDER == _LITTLE_ENDIAN)
+#elif defined(OS_HPUX)
+  #define PLATFORM_IS_LITTLE_ENDIAN false
+#elif defined(OS_ANDROID)
+  // Due to a bug in the NDK x86 <sys/endian.h> definition,
+  // _BYTE_ORDER must be used instead of __BYTE_ORDER on Android.
+  // See http://code.google.com/p/android/issues/detail?id=39824
+  #include <endian.h>
+  #define PLATFORM_IS_LITTLE_ENDIAN  (_BYTE_ORDER == _LITTLE_ENDIAN)
 #else
  #include <endian.h>
 #endif
+
 #include <pthread.h>
 #ifdef SNAPPY
 #include <snappy.h>
@@ -42,7 +52,7 @@

 #if defined(OS_MACOSX) || defined(OS_SOLARIS) || defined(OS_FREEBSD) ||\
    defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_DRAGONFLYBSD) ||\
-    defined(OS_ANDROID)
+    defined(OS_ANDROID) || defined(OS_HPUX) || defined(CYGWIN)
 // Use fread/fwrite/fflush on platforms without _unlocked variants
 #define fread_unlocked fread
 #define fwrite_unlocked fwrite
--- a/port/thread_annotations.h
+++ b/port/thread_annotations.h
@@ -0,0 +1,60 @@
+// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef STORAGE_LEVELDB_PORT_THREAD_ANNOTATIONS_H_
+#define STORAGE_LEVELDB_PORT_THREAD_ANNOTATIONS_H_
+
+// Some environments provide custom macros to aid in static thread-safety
+// analysis.  Provide empty definitions of such macros unless they are already
+// defined.
+
+#ifndef EXCLUSIVE_LOCKS_REQUIRED
+#define EXCLUSIVE_LOCKS_REQUIRED(...)
+#endif
+
+#ifndef SHARED_LOCKS_REQUIRED
+#define SHARED_LOCKS_REQUIRED(...)
+#endif
+
+#ifndef LOCKS_EXCLUDED
+#define LOCKS_EXCLUDED(...)
+#endif
+
+#ifndef LOCK_RETURNED
+#define LOCK_RETURNED(x)
+#endif
+
+#ifndef LOCKABLE
+#define LOCKABLE
+#endif
+
+#ifndef SCOPED_LOCKABLE
+#define SCOPED_LOCKABLE
+#endif
+
+#ifndef EXCLUSIVE_LOCK_FUNCTION
+#define EXCLUSIVE_LOCK_FUNCTION(...)
+#endif
+
+#ifndef SHARED_LOCK_FUNCTION
+#define SHARED_LOCK_FUNCTION(...)
+#endif
+
+#ifndef EXCLUSIVE_TRYLOCK_FUNCTION
+#define EXCLUSIVE_TRYLOCK_FUNCTION(...)
+#endif
+
+#ifndef SHARED_TRYLOCK_FUNCTION
+#define SHARED_TRYLOCK_FUNCTION(...)
+#endif
+
+#ifndef UNLOCK_FUNCTION
+#define UNLOCK_FUNCTION(...)
+#endif
+
+#ifndef NO_THREAD_SAFETY_ANALYSIS
+#define NO_THREAD_SAFETY_ANALYSIS
+#endif
+
+#endif  // STORAGE_LEVELDB_PORT_THREAD_ANNOTATIONS_H_
--- a/table/block.cc
+++ b/table/block.cc
@@ -16,7 +16,7 @@
 namespace leveldb {

 inline uint32_t Block::NumRestarts() const {
-  assert(size_ >= 2*sizeof(uint32_t));
+  assert(size_ >= sizeof(uint32_t));
  return DecodeFixed32(data_ + size_ - sizeof(uint32_t));
 }

@@ -27,11 +27,12 @@ Block::Block(const BlockContents& contents)
  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_t max_restarts_allowed = (size_-sizeof(uint32_t)) / sizeof(uint32_t);
+    if (NumRestarts() > max_restarts_allowed) {
+      // The size is too small for NumRestarts()
      size_ = 0;
+    } else {
+      restart_offset_ = size_ - (1 + NumRestarts()) * sizeof(uint32_t);
    }
  }
 }
@@ -45,7 +46,7 @@ Block::~Block() {
 // 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
-// "*value_length", respectively.  Will not derefence past "limit".
+// "*value_length", respectively.  Will not dereference past "limit".
 //
 // If any errors are detected, returns NULL.  Otherwise, returns a
 // pointer to the key delta (just past the three decoded values).
@@ -162,8 +163,8 @@ class Block::Iter : public Iterator {
  }

  virtual void Seek(const Slice& target) {
-    // Binary search in restart array to find the first restart point
-    // with a key >= target
+    // Binary search in restart array to find the last restart point
+    // with a key < target
    uint32_t left = 0;
    uint32_t right = num_restarts_ - 1;
    while (left < right) {
@@ -253,7 +254,7 @@ class Block::Iter : public Iterator {
 };

 Iterator* Block::NewIterator(const Comparator* cmp) {
-  if (size_ < 2*sizeof(uint32_t)) {
+  if (size_ < sizeof(uint32_t)) {
    return NewErrorIterator(Status::Corruption("bad block contents"));
  }
  const uint32_t num_restarts = NumRestarts();
--- a/table/block_builder.h
+++ b/table/block_builder.h
@@ -21,7 +21,7 @@ class BlockBuilder {
  // Reset the contents as if the BlockBuilder was just constructed.
  void Reset();

-  // REQUIRES: Finish() has not been callled since the last call to Reset().
+  // REQUIRES: Finish() has not been called since the last call to Reset().
  // REQUIRES: key is larger than any previously added key
  void Add(const Slice& key, const Slice& value);

--- a/table/filter_block_test.cc
+++ b/table/filter_block_test.cc
@@ -29,7 +29,7 @@ class TestHashFilter : public FilterPolicy {

  virtual bool KeyMayMatch(const Slice& key, const Slice& filter) const {
    uint32_t h = Hash(key.data(), key.size(), 1);
-    for (int i = 0; i + 4 <= filter.size(); i += 4) {
+    for (size_t i = 0; i + 4 <= filter.size(); i += 4) {
      if (h == DecodeFixed32(filter.data() + i)) {
        return true;
      }
--- a/table/format.cc
+++ b/table/format.cc
@@ -48,7 +48,7 @@ Status Footer::DecodeFrom(Slice* input) {
  const uint64_t magic = ((static_cast<uint64_t>(magic_hi) << 32) |
                          (static_cast<uint64_t>(magic_lo)));
  if (magic != kTableMagicNumber) {
-    return Status::InvalidArgument("not an sstable (bad magic number)");
+    return Status::Corruption("not an sstable (bad magic number)");
  }

  Status result = metaindex_handle_.DecodeFrom(input);
--- a/table/iterator_wrapper.h
+++ b/table/iterator_wrapper.h
@@ -5,6 +5,9 @@
 #ifndef STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_
 #define STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_

+#include "leveldb/iterator.h"
+#include "leveldb/slice.h"
+
 namespace leveldb {

 // A internal wrapper class with an interface similar to Iterator that
--- a/table/table.cc
+++ b/table/table.cc
@@ -41,7 +41,7 @@ Status Table::Open(const Options& options,
                   Table** table) {
  *table = NULL;
  if (size < Footer::kEncodedLength) {
-    return Status::InvalidArgument("file is too short to be an sstable");
+    return Status::Corruption("file is too short to be an sstable");
  }

  char footer_space[Footer::kEncodedLength];
@@ -58,7 +58,11 @@ Status Table::Open(const Options& options,
  BlockContents contents;
  Block* index_block = NULL;
  if (s.ok()) {
-    s = ReadBlock(file, ReadOptions(), footer.index_handle(), &contents);
+    ReadOptions opt;
+    if (options.paranoid_checks) {
+      opt.verify_checksums = true;
+    }
+    s = ReadBlock(file, opt, footer.index_handle(), &contents);
    if (s.ok()) {
      index_block = new Block(contents);
    }
@@ -92,6 +96,9 @@ void Table::ReadMeta(const Footer& footer) {
  // TODO(sanjay): Skip this if footer.metaindex_handle() size indicates
  // it is an empty block.
  ReadOptions opt;
+  if (rep_->options.paranoid_checks) {
+    opt.verify_checksums = true;
+  }
  BlockContents contents;
  if (!ReadBlock(rep_->file, opt, footer.metaindex_handle(), &contents).ok()) {
    // Do not propagate errors since meta info is not needed for operation
@@ -120,6 +127,9 @@ void Table::ReadFilter(const Slice& filter_handle_value) {
  // We might want to unify with ReadBlock() if we start
  // requiring checksum verification in Table::Open.
  ReadOptions opt;
+  if (rep_->options.paranoid_checks) {
+    opt.verify_checksums = true;
+  }
  BlockContents block;
  if (!ReadBlock(rep_->file, opt, filter_handle, &block).ok()) {
    return;
@@ -228,7 +238,6 @@ Status Table::InternalGet(const ReadOptions& options, const Slice& k,
        !filter->KeyMayMatch(handle.offset(), k)) {
      // Not found
    } else {
-      Slice handle = iiter->value();
      Iterator* block_iter = BlockReader(this, options, iiter->value());
      block_iter->Seek(k);
      if (block_iter->Valid()) {
--- a/table/table_test.cc
+++ b/table/table_test.cc
@@ -644,6 +644,36 @@ class Harness {
  Constructor* constructor_;
 };

+// Test empty table/block.
+TEST(Harness, Empty) {
+  for (int i = 0; i < kNumTestArgs; i++) {
+    Init(kTestArgList[i]);
+    Random rnd(test::RandomSeed() + 1);
+    Test(&rnd);
+  }
+}
+
+// Special test for a block with no restart entries.  The C++ leveldb
+// code never generates such blocks, but the Java version of leveldb
+// seems to.
+TEST(Harness, ZeroRestartPointsInBlock) {
+  char data[sizeof(uint32_t)];
+  memset(data, 0, sizeof(data));
+  BlockContents contents;
+  contents.data = Slice(data, sizeof(data));
+  contents.cachable = false;
+  contents.heap_allocated = false;
+  Block block(contents);
+  Iterator* iter = block.NewIterator(BytewiseComparator());
+  iter->SeekToFirst();
+  ASSERT_TRUE(!iter->Valid());
+  iter->SeekToLast();
+  ASSERT_TRUE(!iter->Valid());
+  iter->Seek("foo");
+  ASSERT_TRUE(!iter->Valid());
+  delete iter;
+}
+
 // Test the empty key
 TEST(Harness, SimpleEmptyKey) {
  for (int i = 0; i < kNumTestArgs; i++) {
--- a/util/arena.cc
+++ b/util/arena.cc
@@ -40,7 +40,7 @@ char* Arena::AllocateFallback(size_t bytes) {
 }

 char* Arena::AllocateAligned(size_t bytes) {
-  const int align = sizeof(void*);    // We'll align to pointer size
+  const int align = (sizeof(void*) > 8) ? sizeof(void*) : 8;
  assert((align & (align-1)) == 0);   // Pointer size should be a power of 2
  size_t current_mod = reinterpret_cast<uintptr_t>(alloc_ptr_) & (align-1);
  size_t slop = (current_mod == 0 ? 0 : align - current_mod);
--- a/util/arena.h
+++ b/util/arena.h
@@ -5,9 +5,9 @@
 #ifndef STORAGE_LEVELDB_UTIL_ARENA_H_
 #define STORAGE_LEVELDB_UTIL_ARENA_H_

-#include <cstddef>
 #include <vector>
 #include <assert.h>
+#include <stddef.h>
 #include <stdint.h>

 namespace leveldb {
--- a/util/arena_test.cc
+++ b/util/arena_test.cc
@@ -40,7 +40,7 @@ TEST(ArenaTest, Simple) {
      r = arena.Allocate(s);
    }

-    for (int b = 0; b < s; b++) {
+    for (size_t b = 0; b < s; b++) {
      // Fill the "i"th allocation with a known bit pattern
      r[b] = i % 256;
    }
@@ -51,10 +51,10 @@ TEST(ArenaTest, Simple) {
      ASSERT_LE(arena.MemoryUsage(), bytes * 1.10);
    }
  }
-  for (int i = 0; i < allocated.size(); i++) {
+  for (size_t i = 0; i < allocated.size(); i++) {
    size_t num_bytes = allocated[i].first;
    const char* p = allocated[i].second;
-    for (int b = 0; b < num_bytes; b++) {
+    for (size_t b = 0; b < num_bytes; b++) {
      // Check the "i"th allocation for the known bit pattern
      ASSERT_EQ(int(p[b]) & 0xff, i % 256);
    }
--- a/util/bloom.cc
+++ b/util/bloom.cc
@@ -29,7 +29,7 @@ class BloomFilterPolicy : public FilterPolicy {
  }

  virtual const char* Name() const {
-    return "leveldb.BuiltinBloomFilter";
+    return "leveldb.BuiltinBloomFilter2";
  }

  virtual void CreateFilter(const Slice* keys, int n, std::string* dst) const {
--- a/util/bloom_test.cc
+++ b/util/bloom_test.cc
@@ -4,6 +4,7 @@

 #include "leveldb/filter_policy.h"

+#include "util/coding.h"
 #include "util/logging.h"
 #include "util/testharness.h"
 #include "util/testutil.h"
@@ -13,8 +14,8 @@ namespace leveldb {
 static const int kVerbose = 1;

 static Slice Key(int i, char* buffer) {
-  memcpy(buffer, &i, sizeof(i));
-  return Slice(buffer, sizeof(i));
+  EncodeFixed32(buffer, i);
+  return Slice(buffer, sizeof(uint32_t));
 }

 class BloomTest {
@@ -125,7 +126,8 @@ TEST(BloomTest, VaryingLengths) {
    }
    Build();

-    ASSERT_LE(FilterSize(), (length * 10 / 8) + 40) << length;
+    ASSERT_LE(FilterSize(), static_cast<size_t>((length * 10 / 8) + 40))
+        << length;

    // All added keys must match
    for (int i = 0; i < length; i++) {
--- a/util/cache.cc
+++ b/util/cache.cc
@@ -116,7 +116,6 @@ class HandleTable {
      LRUHandle* h = list_[i];
      while (h != NULL) {
        LRUHandle* next = h->next_hash;
-        Slice key = h->key();
        uint32_t hash = h->hash;
        LRUHandle** ptr = &new_list[hash & (new_length - 1)];
        h->next_hash = *ptr;
@@ -148,6 +147,11 @@ class LRUCache {
  Cache::Handle* Lookup(const Slice& key, uint32_t hash);
  void Release(Cache::Handle* handle);
  void Erase(const Slice& key, uint32_t hash);
+  void Prune();
+  size_t TotalCharge() const {
+    MutexLock l(&mutex_);
+    return usage_;
+  }

 private:
  void LRU_Remove(LRUHandle* e);
@@ -158,9 +162,8 @@ class LRUCache {
  size_t capacity_;

  // mutex_ protects the following state.
-  port::Mutex mutex_;
+  mutable port::Mutex mutex_;
  size_t usage_;
-  uint64_t last_id_;

  // Dummy head of LRU list.
  // lru.prev is newest entry, lru.next is oldest entry.
@@ -170,8 +173,7 @@ class LRUCache {
 };

 LRUCache::LRUCache()
-    : usage_(0),
-      last_id_(0) {
+    : usage_(0) {
  // Make empty circular linked list
  lru_.next = &lru_;
  lru_.prev = &lru_;
@@ -267,6 +269,19 @@ void LRUCache::Erase(const Slice& key, uint32_t hash) {
  }
 }

+void LRUCache::Prune() {
+  MutexLock l(&mutex_);
+  for (LRUHandle* e = lru_.next; e != &lru_; ) {
+    LRUHandle* next = e->next;
+    if (e->refs == 1) {
+      table_.Remove(e->key(), e->hash);
+      LRU_Remove(e);
+      Unref(e);
+    }
+    e = next;
+  }
+}
+
 static const int kNumShardBits = 4;
 static const int kNumShards = 1 << kNumShardBits;

@@ -317,6 +332,18 @@ class ShardedLRUCache : public Cache {
    MutexLock l(&id_mutex_);
    return ++(last_id_);
  }
+  virtual void Prune() {
+    for (int s = 0; s < kNumShards; s++) {
+      shard_[s].Prune();
+    }
+  }
+  virtual size_t TotalCharge() const {
+    size_t total = 0;
+    for (int s = 0; s < kNumShards; s++) {
+      total += shard_[s].TotalCharge();
+    }
+    return total;
+  }
 };

 }  // end anonymous namespace
--- a/util/cache_test.cc
+++ b/util/cache_test.cc
@@ -179,6 +179,19 @@ TEST(CacheTest, NewId) {
  ASSERT_NE(a, b);
 }

+TEST(CacheTest, Prune) {
+  Insert(1, 100);
+  Insert(2, 200);
+
+  Cache::Handle* handle = cache_->Lookup(EncodeKey(1));
+  ASSERT_TRUE(handle);
+  cache_->Prune();
+  cache_->Release(handle);
+
+  ASSERT_EQ(100, Lookup(1));
+  ASSERT_EQ(-1, Lookup(2));
+}
+
 }  // namespace leveldb

 int main(int argc, char** argv) {
--- a/util/coding.cc
+++ b/util/coding.cc
@@ -7,29 +7,29 @@
 namespace leveldb {

 void EncodeFixed32(char* buf, uint32_t value) {
-#if __BYTE_ORDER == __LITTLE_ENDIAN
-  memcpy(buf, &value, sizeof(value));
-#else
-  buf[0] = value & 0xff;
-  buf[1] = (value >> 8) & 0xff;
-  buf[2] = (value >> 16) & 0xff;
-  buf[3] = (value >> 24) & 0xff;
-#endif
+  if (port::kLittleEndian) {
+    memcpy(buf, &value, sizeof(value));
+  } else {
+    buf[0] = value & 0xff;
+    buf[1] = (value >> 8) & 0xff;
+    buf[2] = (value >> 16) & 0xff;
+    buf[3] = (value >> 24) & 0xff;
+  }
 }

 void EncodeFixed64(char* buf, uint64_t value) {
-#if __BYTE_ORDER == __LITTLE_ENDIAN
-  memcpy(buf, &value, sizeof(value));
-#else
-  buf[0] = value & 0xff;
-  buf[1] = (value >> 8) & 0xff;
-  buf[2] = (value >> 16) & 0xff;
-  buf[3] = (value >> 24) & 0xff;
-  buf[4] = (value >> 32) & 0xff;
-  buf[5] = (value >> 40) & 0xff;
-  buf[6] = (value >> 48) & 0xff;
-  buf[7] = (value >> 56) & 0xff;
-#endif
+  if (port::kLittleEndian) {
+    memcpy(buf, &value, sizeof(value));
+  } else {
+    buf[0] = value & 0xff;
+    buf[1] = (value >> 8) & 0xff;
+    buf[2] = (value >> 16) & 0xff;
+    buf[3] = (value >> 24) & 0xff;
+    buf[4] = (value >> 32) & 0xff;
+    buf[5] = (value >> 40) & 0xff;
+    buf[6] = (value >> 48) & 0xff;
+    buf[7] = (value >> 56) & 0xff;
+  }
 }

 void PutFixed32(std::string* dst, uint32_t value) {
--- a/util/coding_test.cc
+++ b/util/coding_test.cc
@@ -109,16 +109,16 @@ TEST(Coding, Varint64) {
    values.push_back(power);
    values.push_back(power-1);
    values.push_back(power+1);
-  };
+  }

  std::string s;
-  for (int i = 0; i < values.size(); i++) {
+  for (size_t i = 0; i < values.size(); i++) {
    PutVarint64(&s, values[i]);
  }

  const char* p = s.data();
  const char* limit = p + s.size();
-  for (int i = 0; i < values.size(); i++) {
+  for (size_t i = 0; i < values.size(); i++) {
    ASSERT_TRUE(p < limit);
    uint64_t actual;
    const char* start = p;
@@ -143,7 +143,7 @@ TEST(Coding, Varint32Truncation) {
  std::string s;
  PutVarint32(&s, large_value);
  uint32_t result;
-  for (int len = 0; len < s.size() - 1; len++) {
+  for (size_t len = 0; len < s.size() - 1; len++) {
    ASSERT_TRUE(GetVarint32Ptr(s.data(), s.data() + len, &result) == NULL);
  }
  ASSERT_TRUE(GetVarint32Ptr(s.data(), s.data() + s.size(), &result) != NULL);
@@ -162,7 +162,7 @@ TEST(Coding, Varint64Truncation) {
  std::string s;
  PutVarint64(&s, large_value);
  uint64_t result;
-  for (int len = 0; len < s.size() - 1; len++) {
+  for (size_t len = 0; len < s.size() - 1; len++) {
    ASSERT_TRUE(GetVarint64Ptr(s.data(), s.data() + len, &result) == NULL);
  }
  ASSERT_TRUE(GetVarint64Ptr(s.data(), s.data() + s.size(), &result) != NULL);
--- a/util/env.cc
+++ b/util/env.cc
@@ -9,6 +9,10 @@ namespace leveldb {
 Env::~Env() {
 }

+Status Env::NewAppendableFile(const std::string& fname, WritableFile** result) {
+  return Status::NotSupported("NewAppendableFile", fname);
+}
+
 SequentialFile::~SequentialFile() {
 }

--- a/util/env_posix.cc
+++ b/util/env_posix.cc
@@ -2,7 +2,6 @@
 // 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 <deque>
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -16,13 +15,13 @@
 #include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
-#if defined(LEVELDB_PLATFORM_ANDROID)
-#include <sys/stat.h>
-#endif
+#include <deque>
+#include <set>
 #include "leveldb/env.h"
 #include "leveldb/slice.h"
 #include "port/port.h"
 #include "util/logging.h"
+#include "util/mutexlock.h"
 #include "util/posix_logger.h"

 namespace leveldb {
@@ -90,18 +89,75 @@ class PosixRandomAccessFile: public RandomAccessFile {
  }
 };

+// Helper class to limit mmap file usage so that we do not end up
+// running out virtual memory or running into kernel performance
+// problems for very large databases.
+class MmapLimiter {
+ public:
+  // Up to 1000 mmaps for 64-bit binaries; none for smaller pointer sizes.
+  MmapLimiter() {
+    SetAllowed(sizeof(void*) >= 8 ? 1000 : 0);
+  }
+
+  // If another mmap slot is available, acquire it and return true.
+  // Else return false.
+  bool Acquire() {
+    if (GetAllowed() <= 0) {
+      return false;
+    }
+    MutexLock l(&mu_);
+    intptr_t x = GetAllowed();
+    if (x <= 0) {
+      return false;
+    } else {
+      SetAllowed(x - 1);
+      return true;
+    }
+  }
+
+  // Release a slot acquired by a previous call to Acquire() that returned true.
+  void Release() {
+    MutexLock l(&mu_);
+    SetAllowed(GetAllowed() + 1);
+  }
+
+ private:
+  port::Mutex mu_;
+  port::AtomicPointer allowed_;
+
+  intptr_t GetAllowed() const {
+    return reinterpret_cast<intptr_t>(allowed_.Acquire_Load());
+  }
+
+  // REQUIRES: mu_ must be held
+  void SetAllowed(intptr_t v) {
+    allowed_.Release_Store(reinterpret_cast<void*>(v));
+  }
+
+  MmapLimiter(const MmapLimiter&);
+  void operator=(const MmapLimiter&);
+};
+
 // mmap() based random-access
 class PosixMmapReadableFile: public RandomAccessFile {
 private:
  std::string filename_;
  void* mmapped_region_;
  size_t length_;
+  MmapLimiter* limiter_;

 public:
  // base[0,length-1] contains the mmapped contents of the file.
-  PosixMmapReadableFile(const std::string& fname, void* base, size_t length)
-      : filename_(fname), mmapped_region_(base), length_(length) { }
-  virtual ~PosixMmapReadableFile() { munmap(mmapped_region_, length_); }
+  PosixMmapReadableFile(const std::string& fname, void* base, size_t length,
+                        MmapLimiter* limiter)
+      : filename_(fname), mmapped_region_(base), length_(length),
+        limiter_(limiter) {
+  }
+
+  virtual ~PosixMmapReadableFile() {
+    munmap(mmapped_region_, length_);
+    limiter_->Release();
+  }

  virtual Status Read(uint64_t offset, size_t n, Slice* result,
                      char* scratch) const {
@@ -116,172 +172,83 @@ class PosixMmapReadableFile: public RandomAccessFile {
  }
 };

-// We preallocate up to an extra megabyte and use memcpy to append new
-// data to the file.  This is safe since we either properly close the
-// file before reading from it, or for log files, the reading code
-// knows enough to skip zero suffixes.
-class PosixMmapFile : public WritableFile {
+class PosixWritableFile : public WritableFile {
 private:
  std::string filename_;
-  int fd_;
-  size_t page_size_;
-  size_t map_size_;       // How much extra memory to map at a time
-  char* base_;            // The mapped region
-  char* limit_;           // Limit of the mapped region
-  char* dst_;             // Where to write next  (in range [base_,limit_])
-  char* last_sync_;       // Where have we synced up to
-  uint64_t file_offset_;  // Offset of base_ in file
-
-  // Have we done an munmap of unsynced data?
-  bool pending_sync_;
-
-  // Roundup x to a multiple of y
-  static size_t Roundup(size_t x, size_t y) {
-    return ((x + y - 1) / y) * y;
-  }
-
-  size_t TruncateToPageBoundary(size_t s) {
-    s -= (s & (page_size_ - 1));
-    assert((s % page_size_) == 0);
-    return s;
-  }
-
-  bool UnmapCurrentRegion() {
-    bool result = true;
-    if (base_ != NULL) {
-      if (last_sync_ < limit_) {
-        // Defer syncing this data until next Sync() call, if any
-        pending_sync_ = true;
-      }
-      if (munmap(base_, limit_ - base_) != 0) {
-        result = false;
-      }
-      file_offset_ += limit_ - base_;
-      base_ = NULL;
-      limit_ = NULL;
-      last_sync_ = NULL;
-      dst_ = NULL;
-
-      // Increase the amount we map the next time, but capped at 1MB
-      if (map_size_ < (1<<20)) {
-        map_size_ *= 2;
-      }
-    }
-    return result;
-  }
-
-  bool MapNewRegion() {
-    assert(base_ == NULL);
-    if (ftruncate(fd_, file_offset_ + map_size_) < 0) {
-      return false;
-    }
-    void* ptr = mmap(NULL, map_size_, PROT_READ | PROT_WRITE, MAP_SHARED,
-                     fd_, file_offset_);
-    if (ptr == MAP_FAILED) {
-      return false;
-    }
-    base_ = reinterpret_cast<char*>(ptr);
-    limit_ = base_ + map_size_;
-    dst_ = base_;
-    last_sync_ = base_;
-    return true;
-  }
+  FILE* file_;

 public:
-  PosixMmapFile(const std::string& fname, int fd, size_t page_size)
-      : filename_(fname),
-        fd_(fd),
-        page_size_(page_size),
-        map_size_(Roundup(65536, page_size)),
-        base_(NULL),
-        limit_(NULL),
-        dst_(NULL),
-        last_sync_(NULL),
-        file_offset_(0),
-        pending_sync_(false) {
-    assert((page_size & (page_size - 1)) == 0);
-  }
+  PosixWritableFile(const std::string& fname, FILE* f)
+      : filename_(fname), file_(f) { }

-
-  ~PosixMmapFile() {
-    if (fd_ >= 0) {
-      PosixMmapFile::Close();
+  ~PosixWritableFile() {
+    if (file_ != NULL) {
+      // Ignoring any potential errors
+      fclose(file_);
    }
  }

  virtual Status Append(const Slice& data) {
-    const char* src = data.data();
-    size_t left = data.size();
-    while (left > 0) {
-      assert(base_ <= dst_);
-      assert(dst_ <= limit_);
-      size_t avail = limit_ - dst_;
-      if (avail == 0) {
-        if (!UnmapCurrentRegion() ||
-            !MapNewRegion()) {
-          return IOError(filename_, errno);
-        }
-      }
-
-      size_t n = (left <= avail) ? left : avail;
-      memcpy(dst_, src, n);
-      dst_ += n;
-      src += n;
-      left -= n;
+    size_t r = fwrite_unlocked(data.data(), 1, data.size(), file_);
+    if (r != data.size()) {
+      return IOError(filename_, errno);
    }
    return Status::OK();
  }

  virtual Status Close() {
-    Status s;
-    size_t unused = limit_ - dst_;
-    if (!UnmapCurrentRegion()) {
-      s = IOError(filename_, errno);
-    } else if (unused > 0) {
-      // Trim the extra space at the end of the file
-      if (ftruncate(fd_, file_offset_ - unused) < 0) {
-        s = IOError(filename_, errno);
-      }
+    Status result;
+    if (fclose(file_) != 0) {
+      result = IOError(filename_, errno);
    }
-
-    if (close(fd_) < 0) {
-      if (s.ok()) {
-        s = IOError(filename_, errno);
-      }
-    }
-
-    fd_ = -1;
-    base_ = NULL;
-    limit_ = NULL;
-    return s;
+    file_ = NULL;
+    return result;
  }

  virtual Status Flush() {
+    if (fflush_unlocked(file_) != 0) {
+      return IOError(filename_, errno);
+    }
    return Status::OK();
  }

-  virtual Status Sync() {
+  Status SyncDirIfManifest() {
+    const char* f = filename_.c_str();
+    const char* sep = strrchr(f, '/');
+    Slice basename;
+    std::string dir;
+    if (sep == NULL) {
+      dir = ".";
+      basename = f;
+    } else {
+      dir = std::string(f, sep - f);
+      basename = sep + 1;
+    }
    Status s;
-
-    if (pending_sync_) {
-      // Some unmapped data was not synced
-      pending_sync_ = false;
-      if (fdatasync(fd_) < 0) {
-        s = IOError(filename_, errno);
+    if (basename.starts_with("MANIFEST")) {
+      int fd = open(dir.c_str(), O_RDONLY);
+      if (fd < 0) {
+        s = IOError(dir, errno);
+      } else {
+        if (fsync(fd) < 0) {
+          s = IOError(dir, errno);
+        }
+        close(fd);
      }
    }
+    return s;
+  }

-    if (dst_ > last_sync_) {
-      // Find the beginnings of the pages that contain the first and last
-      // bytes to be synced.
-      size_t p1 = TruncateToPageBoundary(last_sync_ - base_);
-      size_t p2 = TruncateToPageBoundary(dst_ - base_ - 1);
-      last_sync_ = dst_;
-      if (msync(base_ + p1, p2 - p1 + page_size_, MS_SYNC) < 0) {
-        s = IOError(filename_, errno);
-      }
+  virtual Status Sync() {
+    // Ensure new files referred to by the manifest are in the filesystem.
+    Status s = SyncDirIfManifest();
+    if (!s.ok()) {
+      return s;
+    }
+    if (fflush_unlocked(file_) != 0 ||
+        fdatasync(fileno(file_)) != 0) {
+      s = Status::IOError(filename_, strerror(errno));
    }
-
    return s;
  }
 };
@@ -300,14 +267,34 @@ static int LockOrUnlock(int fd, bool lock) {
 class PosixFileLock : public FileLock {
 public:
  int fd_;
+  std::string name_;
+};
+
+// Set of locked files.  We keep a separate set instead of just
+// relying on fcntrl(F_SETLK) since fcntl(F_SETLK) does not provide
+// any protection against multiple uses from the same process.
+class PosixLockTable {
+ private:
+  port::Mutex mu_;
+  std::set<std::string> locked_files_;
+ public:
+  bool Insert(const std::string& fname) {
+    MutexLock l(&mu_);
+    return locked_files_.insert(fname).second;
+  }
+  void Remove(const std::string& fname) {
+    MutexLock l(&mu_);
+    locked_files_.erase(fname);
+  }
 };

 class PosixEnv : public Env {
 public:
  PosixEnv();
  virtual ~PosixEnv() {
-    fprintf(stderr, "Destroying Env::Default()\n");
-    exit(1);
+    char msg[] = "Destroying Env::Default()\n";
+    fwrite(msg, 1, sizeof(msg), stderr);
+    abort();
  }

  virtual Status NewSequentialFile(const std::string& fname,
@@ -329,19 +316,21 @@ class PosixEnv : public Env {
    int fd = open(fname.c_str(), O_RDONLY);
    if (fd < 0) {
      s = IOError(fname, errno);
-    } else if (sizeof(void*) >= 8) {
-      // Use mmap when virtual address-space is plentiful.
+    } else if (mmap_limit_.Acquire()) {
      uint64_t size;
      s = GetFileSize(fname, &size);
      if (s.ok()) {
        void* base = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
        if (base != MAP_FAILED) {
-          *result = new PosixMmapReadableFile(fname, base, size);
+          *result = new PosixMmapReadableFile(fname, base, size, &mmap_limit_);
        } else {
          s = IOError(fname, errno);
        }
      }
      close(fd);
+      if (!s.ok()) {
+        mmap_limit_.Release();
+      }
    } else {
      *result = new PosixRandomAccessFile(fname, fd);
    }
@@ -351,12 +340,25 @@ class PosixEnv : public Env {
  virtual Status NewWritableFile(const std::string& fname,
                                 WritableFile** result) {
    Status s;
-    const int fd = open(fname.c_str(), O_CREAT | O_RDWR | O_TRUNC, 0644);
-    if (fd < 0) {
+    FILE* f = fopen(fname.c_str(), "w");
+    if (f == NULL) {
      *result = NULL;
      s = IOError(fname, errno);
    } else {
-      *result = new PosixMmapFile(fname, fd, page_size_);
+      *result = new PosixWritableFile(fname, f);
+    }
+    return s;
+  }
+
+  virtual Status NewAppendableFile(const std::string& fname,
+                                   WritableFile** result) {
+    Status s;
+    FILE* f = fopen(fname.c_str(), "a");
+    if (f == NULL) {
+      *result = NULL;
+      s = IOError(fname, errno);
+    } else {
+      *result = new PosixWritableFile(fname, f);
    }
    return s;
  }
@@ -386,7 +388,7 @@ class PosixEnv : public Env {
      result = IOError(fname, errno);
    }
    return result;
-  };
+  }

  virtual Status CreateDir(const std::string& name) {
    Status result;
@@ -394,7 +396,7 @@ class PosixEnv : public Env {
      result = IOError(name, errno);
    }
    return result;
-  };
+  }

  virtual Status DeleteDir(const std::string& name) {
    Status result;
@@ -402,7 +404,7 @@ class PosixEnv : public Env {
      result = IOError(name, errno);
    }
    return result;
-  };
+  }

  virtual Status GetFileSize(const std::string& fname, uint64_t* size) {
    Status s;
@@ -430,12 +432,17 @@ class PosixEnv : public Env {
    int fd = open(fname.c_str(), O_RDWR | O_CREAT, 0644);
    if (fd < 0) {
      result = IOError(fname, errno);
+    } else if (!locks_.Insert(fname)) {
+      close(fd);
+      result = Status::IOError("lock " + fname, "already held by process");
    } else if (LockOrUnlock(fd, true) == -1) {
      result = IOError("lock " + fname, errno);
      close(fd);
+      locks_.Remove(fname);
    } else {
      PosixFileLock* my_lock = new PosixFileLock;
      my_lock->fd_ = fd;
+      my_lock->name_ = fname;
      *lock = my_lock;
    }
    return result;
@@ -447,6 +454,7 @@ class PosixEnv : public Env {
    if (LockOrUnlock(my_lock->fd_, false) == -1) {
      result = IOError("unlock", errno);
    }
+    locks_.Remove(my_lock->name_);
    close(my_lock->fd_);
    delete my_lock;
    return result;
@@ -502,7 +510,7 @@ class PosixEnv : public Env {
  void PthreadCall(const char* label, int result) {
    if (result != 0) {
      fprintf(stderr, "pthread %s: %s\n", label, strerror(result));
-      exit(1);
+      abort();
    }
  }

@@ -513,7 +521,6 @@ class PosixEnv : public Env {
    return NULL;
  }

-  size_t page_size_;
  pthread_mutex_t mu_;
  pthread_cond_t bgsignal_;
  pthread_t bgthread_;
@@ -523,10 +530,12 @@ class PosixEnv : public Env {
  struct BGItem { void* arg; void (*function)(void*); };
  typedef std::deque<BGItem> BGQueue;
  BGQueue queue_;
+
+  PosixLockTable locks_;
+  MmapLimiter mmap_limit_;
 };

-PosixEnv::PosixEnv() : page_size_(getpagesize()),
-                       started_bgthread_(false) {
+PosixEnv::PosixEnv() : started_bgthread_(false) {
  PthreadCall("mutex_init", pthread_mutex_init(&mu_, NULL));
  PthreadCall("cvar_init", pthread_cond_init(&bgsignal_, NULL));
 }
--- a/util/hash.cc
+++ b/util/hash.cc
@@ -6,6 +6,13 @@
 #include "util/coding.h"
 #include "util/hash.h"

+// The FALLTHROUGH_INTENDED macro can be used to annotate implicit fall-through
+// between switch labels. The real definition should be provided externally.
+// This one is a fallback version for unsupported compilers.
+#ifndef FALLTHROUGH_INTENDED
+#define FALLTHROUGH_INTENDED do { } while (0)
+#endif
+
 namespace leveldb {

 uint32_t Hash(const char* data, size_t n, uint32_t seed) {
@@ -27,13 +34,13 @@ uint32_t Hash(const char* data, size_t n, uint32_t seed) {
  // Pick up remaining bytes
  switch (limit - data) {
    case 3:
-      h += data[2] << 16;
-      // fall through
+      h += static_cast<unsigned char>(data[2]) << 16;
+      FALLTHROUGH_INTENDED;
    case 2:
-      h += data[1] << 8;
-      // fall through
+      h += static_cast<unsigned char>(data[1]) << 8;
+      FALLTHROUGH_INTENDED;
    case 1:
-      h += data[0];
+      h += static_cast<unsigned char>(data[0]);
      h *= m;
      h ^= (h >> r);
      break;
--- a/util/hash_test.cc
+++ b/util/hash_test.cc
@@ -0,0 +1,54 @@
+// 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 "util/hash.h"
+#include "util/testharness.h"
+
+namespace leveldb {
+
+class HASH { };
+
+TEST(HASH, SignedUnsignedIssue) {
+  const unsigned char data1[1] = {0x62};
+  const unsigned char data2[2] = {0xc3, 0x97};
+  const unsigned char data3[3] = {0xe2, 0x99, 0xa5};
+  const unsigned char data4[4] = {0xe1, 0x80, 0xb9, 0x32};
+  const unsigned char data5[48] = {
+    0x01, 0xc0, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+    0x14, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x04, 0x00,
+    0x00, 0x00, 0x00, 0x14,
+    0x00, 0x00, 0x00, 0x18,
+    0x28, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+    0x02, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+  };
+
+  ASSERT_EQ(Hash(0, 0, 0xbc9f1d34), 0xbc9f1d34);
+  ASSERT_EQ(
+      Hash(reinterpret_cast<const char*>(data1), sizeof(data1), 0xbc9f1d34),
+      0xef1345c4);
+  ASSERT_EQ(
+      Hash(reinterpret_cast<const char*>(data2), sizeof(data2), 0xbc9f1d34),
+      0x5b663814);
+  ASSERT_EQ(
+      Hash(reinterpret_cast<const char*>(data3), sizeof(data3), 0xbc9f1d34),
+      0x323c078f);
+  ASSERT_EQ(
+      Hash(reinterpret_cast<const char*>(data4), sizeof(data4), 0xbc9f1d34),
+      0xed21633a);
+  ASSERT_EQ(
+      Hash(reinterpret_cast<const char*>(data5), sizeof(data5), 0x12345678),
+      0xf333dabb);
+}
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
--- a/util/logging.cc
+++ b/util/logging.cc
@@ -45,15 +45,6 @@ std::string EscapeString(const Slice& value) {
  return r;
 }

-bool ConsumeChar(Slice* in, char c) {
-  if (!in->empty() && (*in)[0] == c) {
-    in->remove_prefix(1);
-    return true;
-  } else {
-    return false;
-  }
-}
-
 bool ConsumeDecimalNumber(Slice* in, uint64_t* val) {
  uint64_t v = 0;
  int digits = 0;
--- a/util/logging.h
+++ b/util/logging.h
@@ -32,10 +32,6 @@ extern std::string NumberToString(uint64_t num);
 // Escapes any non-printable characters found in "value".
 extern std::string EscapeString(const Slice& value);

-// If *in starts with "c", advances *in past the first character and
-// returns true.  Otherwise, returns false.
-extern bool ConsumeChar(Slice* in, char c);
-
 // Parse a human-readable number from "*in" into *value.  On success,
 // advances "*in" past the consumed number and sets "*val" to the
 // numeric value.  Otherwise, returns false and leaves *in in an
--- a/util/mutexlock.h
+++ b/util/mutexlock.h
@@ -6,6 +6,7 @@
 #define STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_

 #include "port/port.h"
+#include "port/thread_annotations.h"

 namespace leveldb {

@@ -19,12 +20,13 @@ namespace leveldb {
 //     ... some complex code, possibly with multiple return paths ...
 //   }

-class MutexLock {
+class SCOPED_LOCKABLE MutexLock {
 public:
-  explicit MutexLock(port::Mutex *mu) : mu_(mu) {
+  explicit MutexLock(port::Mutex *mu) EXCLUSIVE_LOCK_FUNCTION(mu)
+      : mu_(mu)  {
    this->mu_->Lock();
  }
-  ~MutexLock() { this->mu_->Unlock(); }
+  ~MutexLock() UNLOCK_FUNCTION() { this->mu_->Unlock(); }

 private:
  port::Mutex *const mu_;
--- a/util/options.cc
+++ b/util/options.cc
@@ -22,8 +22,8 @@ Options::Options()
      block_size(4096),
      block_restart_interval(16),
      compression(kSnappyCompression),
+      reuse_logs(false),
      filter_policy(NULL) {
 }

-
 }  // namespace leveldb
--- a/util/random.h
+++ b/util/random.h
@@ -16,7 +16,12 @@ class Random {
 private:
  uint32_t seed_;
 public:
-  explicit Random(uint32_t s) : seed_(s & 0x7fffffffu) { }
+  explicit Random(uint32_t s) : seed_(s & 0x7fffffffu) {
+    // Avoid bad seeds.
+    if (seed_ == 0 || seed_ == 2147483647L) {
+      seed_ = 1;
+    }
+  }
  uint32_t Next() {
    static const uint32_t M = 2147483647L;   // 2^31-1
    static const uint64_t A = 16807;  // bits 14, 8, 7, 5, 2, 1, 0
--- a/util/testharness.cc
+++ b/util/testharness.cc
@@ -38,7 +38,7 @@ int RunAllTests() {

  int num = 0;
  if (tests != NULL) {
-    for (int i = 0; i < tests->size(); i++) {
+    for (size_t i = 0; i < tests->size(); i++) {
      const Test& t = (*tests)[i];
      if (matcher != NULL) {
        std::string name = t.base;
--- a/util/testutil.cc
+++ b/util/testutil.cc
@@ -32,7 +32,7 @@ std::string RandomKey(Random* rnd, int len) {


 extern Slice CompressibleString(Random* rnd, double compressed_fraction,
-                                int len, std::string* dst) {
+                                size_t len, std::string* dst) {
  int raw = static_cast<int>(len * compressed_fraction);
  if (raw < 1) raw = 1;
  std::string raw_data;
--- a/util/testutil.h
+++ b/util/testutil.h
@@ -24,7 +24,7 @@ extern std::string RandomKey(Random* rnd, int len);
 // "N*compressed_fraction" bytes and return a Slice that references
 // the generated data.
 extern Slice CompressibleString(Random* rnd, double compressed_fraction,
-                                int len, std::string* dst);
+                                size_t len, std::string* dst);

 // A wrapper that allows injection of errors.
 class ErrorEnv : public EnvWrapper {
@@ -45,6 +45,16 @@ class ErrorEnv : public EnvWrapper {
    }
    return target()->NewWritableFile(fname, result);
  }
+
+  virtual Status NewAppendableFile(const std::string& fname,
+                                   WritableFile** result) {
+    if (writable_file_error_) {
+      ++num_writable_file_errors_;
+      *result = NULL;
+      return Status::IOError(fname, "fake error");
+    }
+    return target()->NewAppendableFile(fname, result);
+  }
 };

 }  // namespace test
Author	SHA1	Message	Date
cmumford	1a9648e1f5	Only compiling TrimSpace on linux. Incorporated change by zmodem at https://github.com/google/leveldb/pull/310 to fix issue #310. This change will only build TrimSace on linux to avoid unused function warning/error. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=105323419	2015-10-13 14:06:08 -07:00
ndmatthews	f79f4180cc	Let LevelDB use xcrun to determine Xcode.app path instead of using a hardcoded path. This allows build agents to select from multiple Xcode installations. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=104859097	2015-10-13 14:05:43 -07:00
ssid	36fc955971	Add "approximate-memory-usage" property to leveldb::DB::GetProperty The approximate RAM usage of the database is calculated from the memory allocated for write buffers and the block cache. This is to give an estimate of memory usage to leveldb clients. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=104222307	2015-10-13 14:05:30 -07:00
tzik	bb61e00815	Add leveldb::Cache::Prune Prune() drops on-memory read cache of the database, so that the client can relief its memory shortage. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=101335710	2015-10-13 14:05:21 -07:00
Chris Mumford	40c17c0b84	Will not reuse manifest if reuse_logs options is false. Prior implementation would always try to reuse the manifest, even if reuse_logs was false (the default). This was missed because the stock Env::NewAppendableFile implementation returns false forcing the creation of a new log.	2015-06-17 11:20:27 -07:00
Sanjay Ghemawat	251ebf5dc7	LevelDB now attempts to reuse the preceding MANIFEST and log file when re-opened. (Based on a suggestion by cmumford.) "open" benchmark on my workstation speeds up significantly since we can now avoid three fdatasync calls and a compaction per open: Before: ~80000 microseconds After: ~130 microseconds Details: (1) Added Options::reuse_logs (currently defaults to false) to control new behavior. The intention is to change the default to true after some baking. (2) Added Env::NewAppendableFile() whose default implementation returns a not-supported error. (3) VersionSet::Recovery attempts to reuse the MANIFEST from which it is recovering. (4) DBImpl recovery attempts to reuse the last log file and memtable. (5) db_test.cc now tests a new configuration that sets reuse_logs to true. (6) fault_injection_test also tests a reuse_logs==true config. (7) Added a new recovery_test.	2014-12-11 08:13:18 -08:00
Sanjay Ghemawat	77948e7eec	Add benchmark that measures cost of repeatedly opening the database.	2014-12-11 08:08:57 -08:00
Chris Mumford	34ad72e3e9	Move header guard below copyright banner.	2014-12-11 08:04:40 -08:00
Chris Mumford	a75d435d1d	Clean up layering of storage/leveldb/... With these changes, this package should be properly cleaned up and not require any further changes.	2014-12-11 08:02:45 -08:00
Chris Mumford	b234f65b34	Added a new fault injection test. This test is intended to ensure leveldb properly detects and recovers from faults - specifically unwritten file data lost as a result of a system reset.	2014-12-11 07:59:38 -08:00
Chris Mumford	c4c38f9c1f	Add arm64 support to leveldb.	2014-12-11 07:58:00 -08:00
Chris Mumford	cea9b10e5b	Fixed incorrect comment wording for Iterator::Seek.	2014-12-11 07:52:09 -08:00
Chris Mumford	c00c569f27	Deleted old README file. README was superseded by README.md and should have been deleted in `803d692`.	2014-12-11 07:42:50 -08:00
Chris Mumford	803d69203a	Release 1.18 Changes are: * Update version number to 1.18 * Replace the basic fprintf call with a call to fwrite in order to work around the apparent compiler optimization/rewrite failure that we are seeing with the new toolchain/iOS SDKs provided with Xcode6 and iOS8. * Fix ALL the header guards. * Createed a README.md with the LevelDB project description. * A new CONTRIBUTING file. * Don't implicitly convert uint64_t to size_t or int. Either preserve it as uint64_t, or explicitly cast. This fixes MSVC warnings about possible value truncation when compiling this code in Chromium. * Added a DumpFile() library function that encapsulates the guts of the "leveldbutil dump" command. This will allow clients to dump data to their log files instead of stdout. It will also allow clients to supply their own environment. * leveldb: Remove unused function 'ConsumeChar'. * leveldbutil: Remove unused member variables from WriteBatchItemPrinter. * OpenBSD, NetBSD and DragonflyBSD have _LITTLE_ENDIAN, so define PLATFORM_IS_LITTLE_ENDIAN like on FreeBSD. This fixes: * issue #143 * issue #198 * issue #249 * Switch from <cstdatomic> to <atomic>. The former never made it into the standard and doesn't exist in modern gcc versions at all. The later contains everything that leveldb was using from the former. This problem was noticed when porting to Portable Native Client where no memory barrier is defined. The fact that <cstdatomic> is missing normally goes unnoticed since memory barriers are defined for most architectures. * Make Hash() treat its input as unsigned. Before this change LevelDB files from platforms with different signedness of char were not compatible. This change fixes: issue #243 * Verify checksums of index/meta/filter blocks when paranoid_checks set. * Invoke all tools for iOS with xcrun. (This was causing problems with the new XCode 5.1.1 image on pulse.) * include <sys/stat.h> only once, and fix the following linter warning: "Found C system header after C++ system header" * When encountering a corrupted table file, return Status::Corruption instead of Status::InvalidArgument. * Support cygwin as build platform, patch is from https://code.google.com/p/leveldb/issues/detail?id=188 * Fix typo, merge patch from https://code.google.com/p/leveldb/issues/detail?id=159 * Fix typos and comments, and address the following two issues: * issue #166 * issue #241 * Add missing db synchronize after "fillseq" in the benchmark. * Removed unused variable in SeekRandom: value (issue #201)	2014-09-16 14:19:52 -07:00
Chris Mumford	e353fbc7ea	Release LevelDB 1.17 - Cleanup: delete unused IntSetToString It was added in http://cr/19491949 (and was referenced at the time). The last reference was removed in http://cr/19507363. This fixes warning/error with pre-release crosstoolv18: 'std::string leveldb::{anonymous}::IntSetToString(const std::set<long unsigned int>&)' defined but not used [-Werror=unused-function] - Added arm64 and and armv7s to IOS build as suggested on leveldb mailing list. - Changed local variable type from int to size_t This eliminates compiler warning/error and resolves https://code.google.com/p/leveldb/issues/detail?id=140	2014-05-01 13:44:03 -07:00
David Grogan	269fc6ca94	Release LevelDB 1.16 - Make Log::Reader not report a corruption when the last record in a log file is truncated. - Fix issue 224: variable created but not utilized. - Remove comment that referenced a removed feature.	2014-02-10 11:36:06 -08:00
David Grogan	0cfb990d58	Release LevelDB 1.15 - switched from mmap based writing to simpler stdio based writing. Has a minor impact (0.5 microseconds) on microbenchmarks for asynchronous writes. Synchronous writes speed up from 30ms to 10ms on linux/ext4. Should be much more reliable on diverse platforms. - compaction errors now immediately put the database into a read-only mode (until it is re-opened). As a downside, a disk going out of space and then space being created will require a re-open to recover from, whereas previously that would happen automatically. On the plus side, many corruption possibilities go away. - force the DB to enter an error-state so that all future writes fail when a synchronous log write succeeds but the sync fails. - repair now regenerates sstables that exhibit problems - fix issue 218 - Use native memory barriers on OSX - fix issue 212 - QNX build is broken - fix build on iOS with xcode 5 - make tests compile and pass on windows	2013-12-10 10:36:31 -08:00
David Grogan	0b9a89f40e	Release LevelDB 1.14 Fix issues 200, 201 Also, * Fix link to bigtable paper in docs. * New sstables will have the file extension .ldb. .sst files will continue to be recognized. * When building for iOS, use xcrun to execute the compiler. This may affect issue 177.	2013-09-19 13:49:19 -07:00
David Grogan	748539c183	LevelDB 1.13 Fix issues 77, 87, 182, 190. Additionally, fix the bug described in https://groups.google.com/d/msg/leveldb/yL6h1mAOc20/vLU64RylIdMJ where a large contiguous keyspace of deleted data was not getting compacted. Also fix a bug where options.max_open_files was not getting clamped properly.	2013-08-21 11:12:47 -07:00
David Grogan	5bd76dc10d	Release leveldb 1.12 Non-functional changes only: 1) Add Kevin Regan to the AUTHORS file 2) Add standard license header to issues/issue178_test.cc	2013-06-18 11:00:13 -07:00
David Grogan	7b094f12e4	Release leveldb 1.11 Fixes issues 161 174 178 As well as the issue reported by edouarda14@gmail.com about MissingSSTFile unit test failing on windows.	2013-06-13 16:14:06 -07:00
David Grogan	28dad918f2	Release leveldb 1.10 Fixes issues 147 - thanks feniksgordonfreeman 153 156 166 Additionally, * Remove calls to exit(1). * Fix unused-variable warnings from clang. * Fix possible overflow error related to num_restart value >= (2^32/4). * Add leveldbutil to .gitignore. * Add better log messages when Write is stalled on a compaction.	2013-05-14 17:03:07 -07:00
David Grogan	514c943a8e	Make DB::Open fail if sst files are missing. Also, cleanup for Clang's -Wimplicit-fallthrough warning.	2013-02-06 18:03:32 -08:00
David Grogan	d84c825a70	Fix corruption bug found and analyzed by dhruba@gmail.com https://groups.google.com/d/msg/leveldb/Kc9JxuIUu5A/9P0N9RL4ar8J	2013-01-07 13:17:43 -08:00
Sanjay Ghemawat	ea2e9195fc	added utility to dump leveldb files	2012-12-27 10:38:48 -08:00
Sanjay Ghemawat	40768657bc	Small fixes. Details: * Fix shared library building. * Reorganize linking commands so flags like --as-needed can be passed. * C binding exports version numbers. * Fix small typos in documention.	2012-10-16 16:17:53 -07:00
David Grogan	946e5b5a4c	Update to leveldb 1.6 Highlights ---------- Mmap at most 1000 files on Posix to improve performance for large databases. Support for more architectures (thanks to Alexander K.) Building and porting -------------------- HP/UX support (issue 126) AtomicPointer for ia64 (issue 123) Sparc v9 support (issue 124) Atomic ops for powerpc Use -fno-builtin-memcmp only when using g++ Simplify IOS build rules (issue 114) Use CXXFLAGS instead of CFLAGS when invoking C++ compiler (issue 118) Fix snappy shared library problem (issue 94) Fix shared library installation path regression Endian-ness detection tweak for FreeBSD Bug fixes --------- Stop ignoring FLAGS_open_files in db_bench Make bloom test behavior agnostic to endian-ness Performance ----------- Limit number of mmapped files to 1000 to improve perf for large dbs Do not delay for 1 second on shutdown path (issue 125) Misc ---- Make InMemoryEnv return a no-op logger C binding now has a wrapper for free (issue 117) Add thread-safety annotations Added an in-process lock table (issue 120) Make RandomAccessFile and SequentialFile non-copyable	2012-10-12 11:53:12 -07:00