Squashed 'src/leveldb/' changes from f545dfabff4c2e9836efed094dba99a34fbc6b88..f8ae182c1e5176d12e816fb2217ae33a5472fdd7

f8ae182c1e5176d12e816fb2217ae33a5472fdd7 Adds unicode support to Windows environment.
92ae82c78f225de84040c51e07fd0b4a61caed99 Increase maximum read-only mmap()s used from 1000 to 4096 on 64-bit systems
d42e63d49d9df05b12cd00af4ffc5f2b3edf7e21 Do not crash if filesystem can't fsync
bf2c2090b7ee12c5d85b85f08649b6e685f8715f Add filename to corruption errors
0c40829872a9f00f38e11dc370ff8adb3e19f25b Remove redundant PROJECT_SOURCE_DIR usage from CMake config.
5abdf4c019e51fce59d34c21b13bf4e0a948828a Fix installed target definition.
cf4d9ab23de7ec36b8e00536b7450f02c639cd87 Test CMake installation on Travis.
95d0ba1cb046bfd76619b8b80e14ee1b2897d219 Renamed local variable in DBImpl::Write.
657ba514298a726c7533f3106d3778062b59d75f Added return in Version::Get::State::Match to quiet warning.
370d532a00581ca79c87af7d7811e56de0ca52a8 Using CMake's check_cxx_compiler_flag to check support for -Wthread-safety.
45ee61579c1eb3accd6c88c922ec468dd61beea8 Update Travis CI configuration.
60db170a43a373d734c5b9f19693d36c75251c39 Fix tsan problem in env_test.
21304d41f77990b8edabbdab33b222bd5ceb5f18 Merge pull request #698 from neal-zhu:master
5e921896eedf87b0fb06bc8a1fd0991b9ac64131 drop fileds in State that are duplicates of fileds in Saver and fix typo
53e280b56866ac4c90a9f5fcfe02ebdfd4a19832 Simplify unlocking in DeleteObsoleteFiles.
046216a7ca6fb17a40cf8aa5598d90c825212a3d Add "leveldb" subdirectory to public include paths.
9ee91ac747ddf26f484d54f9aa474ccc4a2e0359 Ending sentences with periods in README.md.
e0d5f83a4f80060fe5b5d80025f0ad049bca430e Align EnvPosix and EnvWindows.
69061b464ab1da287da9b7ffec1ed911b754403b Disable exceptions and RTTI in CMake configuration.
107a75b62c19cce901ce10619b63c4b7acc9a0be cache Saver in State object
76ca1162768e5c89f1a49946a1f286c702ae27ae fix bug(uninitialized options pointer in State)
f668239bb262609146496b854e1ec3cea9cd1a83 remove TODO in Version::ForEachOverlapping
177cd08629883c409f7a01f90f7084bc5518f1ef format
8fa7a937ee8f38d8869357b0f27f120c5c58f4c9 fix bug
6a90bb91ee72642241fdbeefa673f88370c7b245 use ForEachOverlapping to impl Get
4cb80b7ddce6ff6089b15d8cfebf746fc1572477 Merge pull request #386 from ivanabc:master
72a38ff7f206b3924ac009a12a1838d6a0bdab03 Replace "> >" with ">>"
863f185970eff21e826e5fe1164a6215a515c23b unsigned char -> uint8_t
a3b71c1ff65e30ced00e85ebbca9ae5786af6626 Use GCC 9 on Travis CI
ae49533210e96bdee9c9479a7fa547f375a39c8b Add explicit typecasts to avoid compiler warning.
63d5315e1c224e52da8ec68d118c5b73ba2a63fc Merge branch 'master' into master
c00e177f3613068eda4bff4abfbd3bd4165a86e8 Guard DBImpl::versions_ by mutex_.
1d0b101165ddd34f26cc5c62b76f2a2e0d622483 Converted two for-loops to while-loops.
28e6d238be73e743c963fc0a26395b783a7565e2 Switch to using C++ 11 override specifier.
85cd40d108d8f8d91f58fd263c0f8428d11c34d5 Added unit test for InternalKey::DecodeFrom with empty string.
1aae5c9f29ea43ceca745efae012c4aa731e9374 Merge pull request #411 from proller:assert1
b7b86baec9ce47569affc5db54a20a6cc520e0f0 Using std::ostringstream in key DebugString.
3e6c000e18519cb22e0a44d0dea45b34daee4ee1 Merge pull request #457 from jellor:patch-2
1d94fe2f4d1dfdf1a6312bf4b36efcbe0c1bf576 Merge branch 'master' into patch-2
27dc99fb2642cadc87c9aaec82c54a2c725ee0d6 Fix EnvPosix tests on Travis CI.
9521545b062841409cf66eff0655feff09d9fd82 Formatting changes for prior O_CLOEXEC fix.
900f7d37eb3224059dd37afc6614d3158ddaeb8d Merge pull request #624 from adam-azarchs:master
a7528a5d2bd29126b60a277b528ed606b67c1771 Clean up util/coding.{h,cc}.
142035edd4b1ab431c0ecbd547d4a77f1eca0667 Initialize Stats::start_ before first use in Stats::Start().
e22b1cec6e1e0e2dec4c93b658acbfc56fb692c0 Merge pull request #365 from allangj:c-strict-prototypes
cd1ec032cd276409ba403cab4d0b2548dd26b890 Add argument definition for void c functions.
4bd052d7e8b0469b2b87664388e2a99cb212ecdb Consolidate benchmark code to benchmarks/.
506b1722ef1a58d87325575d9bbcd3c8869381c7 Convert missed virtual -> override in db_test.cc.
24424a1ef2c284f4ec30544a3458023362cbeacd Style cleanup.
9a56c49ed415df1b72ba1c84c8e7ed00de497f68 Merge pull request #679 from smartxworks:optimize-readseq
abf441b657c7e75091e2bd59449df6849358b812 Merge pull request #278 from wankai:master
78b39d68c15ba020c0d60a3906fb66dbf1697595 Bump the version number from 1.21 to 1.22.
9bd23c767601a2420478eec158927882b879bada Correct class/structure declaration order.
c784d63b931d07895833fb80185b10d44ad63cce Moved port/README to port/README.md.
297e66afc1dda3f3d7a7cc2022030164c302cb7a Format all files IAW the Google C++ Style Guide.
3724030179716fd8d95cf79339884c49afade8f9 Update Travis CI configuration.
d3d1c8a0f40a7eaa12a5bb702fa01786b7c3a646 don't check current key in DBIter::Next()
3dc9202f78a3eb30ee8c0267e4e4be2e3f986e45 [leveldb] Specifically export the WriteBatch::Handler inner class for Windows link
2ccb45c33aecd8b15000c0c622f45eb119b6b478 Check for possibly invalid offset in test.
7b1174519044339f07a023dc445b0d36425bd6db Changed Windows specific highlighting from bash to cmd.
2f008ac19ec783e4d0ba2161320241c99e9897e1 Initialize class members to default values in constructors.
ffabb1ae86cc4eb4516a7c0824c878c3b2d19e5d Merge pull request #665 from cheng-chang:coding
7da571cf2b954a107fa060698bfbfbba8e8318f8 Merge pull request #669 from pavel-pimenov:fix-readme-windows-mkdir
df4a323aafbf65996fec23de8b2dbb9d7e27ae11 Merge pull request #472 from zhoudayang:patch-1
5a2a472741f36ecf5b994439da5a64c6ab90c47f Fixed missing std namespaces and make_unique.
08e771901f454ac32643bd8e8cb2bcfa08026c0c Simplify issue320_test.
65e86f75ea30e44bc65327f92a16328684269acb Fix formatting of recent snapshot compaction fix.
7711e76766231bf93e0487c4530b2655e8c4c0b1 Merge pull request #339 from richcole-at-amazon:master
71ed7c401ec1b1e38d6f7cb9eb2fcff93c24d1f1 Fixed typo in comment in version_set.h.
09fa8868dbe0cb2701f0560c59ebb63cc17f1271 Align version/soversion CMake setup closer with other repositories.
20fb601aa9f68ff0aa147df22524b7d01758552b Fix snapshot compaction bug
37300aa54b8256dd2edfd504942eb2bd20823647 Restore soname versioning with CMake build
952be04df6edb936b8f7d0f652861100a7f61e97 Fix mkdir (windows)
56178ddaf4d3ba6c8d1cfb218610b1be3f5aa710 Update the version to 1.21 in preparation for a new release.
35619d248d909b197f68226c7d0a9ff947b82e8a Project import generated by Copybara.
416344de2fdffb3f17c565b984885d0122bfa1e9 leveldb: Register in copybara whitelist.
da94ac67e91679842a56a876f0b19b429d72de25 leveldb: Minor cleanup in ports.
bd24b963060861518c6648925f9708178562c992 leveldb: Silence unused argument warnings in MSVC.
6188a54ce95b47cc6bd398d7f2eb45d061857e45 leveldb: Add tests for empty keys and values.
cf1b5f473259e46c667f3fb5a28bcd884ee3a102 Remove unnecessary bit operation.
7035af5fc36657447054617759854a726d31dbe0 Two small fixes for the Windows implementation (#661)
6571279d6de21fe33caa31b2ea4170d34b15b10e fix a typo in the comment of skiplist_test.cc (#664)
15e227896621d01ebad4c5d4b3cc82a7a9b5b30b Use override consistently in leveldb::test::ErrorEnv.
ea49b27d062c4bc998616cef7944f7f9088a327d Switch corruption_test to use InMemEnv.
ce399ac28af7023b1aff0ede4986cb6d89b3c0b5 Always copy bytes to scratch buffer when reading w/MemEnv.
201f77d137f30ea46e789a2ad60e9119b6f990fc Inline defaults in options.
9ce30510d482f5b2fa2965201453f0fc914f700c Deleted dangling reference to deleted atomic_pointer.h.
7d8e41e49b8fddda66a2c5f0a6a47f1a916e8d26 leveldb: Replace AtomicPointer with std::atomic.
dd906262fd364c08a652dfa914f9995f6b7608a9 Make InMemoryEnv more consistent with filesystem based Env's.
cf1d1ab255de2a741695aec53d83e4f808f9e819 leveldb: Remove unused file port/win/stdint.h.
a20508dc6a18a34e05a6fc476a8d587fa9bb6608 Fix typo (#565)
04470825ac96cab0d9d16e4ed410349d082fbf82 Add AppVeyor (Windows CI) badge to README.
ed76289b259d42d0a57c147e791e2c235ed28805 Align windows_logger with posix_logger.
808e59ec6a160244960cda64b393968ffbdae72c Improve CI configuration.
c69d33b0ec3dad2a8063ad66da9d51a1d6309f4e Added native support for Windows.
75fceae7003e217e16b04433831da7528ae56881 Add O_CLOEXEC to open calls.
fe4494804f5e3a2e25485d32aeb0eb7d2f25732e leveldb: Make WriteBatch::ApproximateSize() const.
296de8d5b8e4e57bd1e46c981114dfbe58a8c4fa leveldb: Fix PosixWritableFile::Sync() on Apple systems.
b70493ca8586285b49e9888e2b528f71806bdc6e Fix fdatasync() feature detection in opensource build.
af7abf06ea061222c2c34d98e1995c5a901f374f Add back space to POSIX Logger.
58d70545af9ec7f30821f973b604f8e2a2f9ebdb Update Travis CI configuration.
1cb384088184be9840bd59b4040503a9fa9aee66 Clean up env_posix.cc.
a7dc502e9f11c2e5c911ba45b999676c43eaa51f Rework once initialization in env_posix.cc.
c43565dd398b2233db8eb49ba05234d62fb42e03 C++11 cleanup for util/mutexlock.h.
0145a94ab6bec48e596df499e8f6103e138a74ab Update .gitignore.
73d5834eceee8efa9a8ccfec77dc096a9e8ba18a Rework threading in env_posix.cc.
05709fb43eea34936c9f535edcb74d5e91a0b495 Remove InitOnce from the port API.
bb88f25115d20a6d73dfb6b16cc298db2f66948b Clean up PosixWritableFile in env_posix.cc.
7b945f200339aa47c24788d3ee9910c09c513843 Clean up posix_logger.h.
89af27bde59fbbb3025653812b45fec10a655cb7 Remove ssize_t from code that is not POSIX-specific.
03064cbbb2c00c3e6e41a78e8111d14a020f7d6f Simplify Limiter in env_posix.cc.
9b44da73d9b1d839c437e3fdaaa14ea08260dce4 Clarify comments for leveldb::Env file reading methods.
0ef2310f67f0c0b4ba3e6ad86d8138440af30d67 Remove GCC on OSX from the Travis CI matrix.
16a2b8bb3af5b1f54676256e55a5d3f0ec02da42 Expose WriteBatch::Append in the C API.
f7b0e1d901da26ac5ce6ad7f0a9806ce1440197e Expose WriteBatch::Append().
6caf73ad9dae0ee91873bcb39554537b85163770 Clean up Iterator.
6a6bdafcf10f5d4bef1ca52697c38d10c28b1a8b Corrected typo in docs: "cache" to "block_cache".
18683981505dc374ce29211c80a9552f8f2f4571 Clean up SnapshotImpl.
e7840de9f3db1a5eddedfecbbbc1ff72a4c2631a Fix documentation for log file growth.
bc23e00f955eadb9e26f8ce07c1c664e7b985ff0 Update default log file size in doc.
4de9594f6fbfd69043239a5705b5f32065f02d34 Add move constructor to Status.
d177a0263cce4344d05188521ad53459c369b940 Replace port_posix with port_stdcxx.
14cce848e7b8a040a8f457d5a796722a55e19597 Fix sign mismatch warnings in GCC.
8046a51b21114d3575421bfc78b1d98b1678720a Add forgotten <limits> header to util/logging.cc.
a0008deb679480fd30e845d7e52421af72160c2c Reimplement ConsumeDecimalNumber.
1f7dd5d5f6822f2b0b9f9e4c7d87d4535c122c0e Add tests for ConsumeDecimalNumber.
1cc8b10b8232e174d5bd1313959825727e03faa7 Document the building process.
09217fd0677a4fd9713c7a4d774c494a7d3c1f15 Replace NULL with nullptr in C++ files.
6a3b915166fce75aaf9ac209114a3ad9caa34171 Remove PLATFORM_IS_LITTLE_ENDIAN from port/posix.h.
260655b4c294991fe03bf6ab8b6d722ccfc41d32 Define LEVELDB_HAS_PORT_CONFIG_H for old compilers.
6fa45666703add49f77652b2eadd874d49aedaf6 Rename CMake project / targets from Leveldb to leveldb.
0db30413a4cfa8c980e675ba5cb96717d688af92 leveldb: Add more thread safety annotations.
04f39105c5a418905da8b7657ca244d672c99d3b Take <atomic> for granted in port/atomic_pointer.h.
74f032ff6f2465160366d865b1bb89a45dc2046b leveldb: Require C++11.
8e75db8623703cdc25ec3cd06f82129296672489 Remove build configuration for make.
df9a841a4fc9a04c7713542d75f50e749fb64b7b Add export.h to CMakeLists.txt
50fbc87e8c62a816d6afd4740e0652a13ac6dc3e Replace SIZE_MAX with std::numeric_limits.
739c25100e46576cdcdfff2d6f43f9f7008103c7 Add CMake build support.
0fa5a4f7b1ad9dc16b705bcad1f3ca913f187325 Extend thread safety annotations.
8143c12f3fc483b1ba61cdce11f9c1faf6d01bea Fix includes in util/testharness.h.
aece2068d7375f987685b8b145288c5557f9ce50 Remove extern from function declarations.
ddab751002588fe58955357d68d12b062e038d0d Add tests for {Old}InfoLogFileName().
7fd7c0072159abbca2660d91fc0667d5c17c4d16 Remove unused function ExtractValueType.
594cc987af2e0af6417c4ac2b947ee8cdad59e5e Bypass OSMemoryBarrier() warning on Mac.
49f35d3fc940a1e2d599d6ee3306eeb31a205e4b leveldb: Update Travis CI configuration for open source build.
623d014a54f8cf9b74ad6aaba9181ca1e65c43a1 Expose Env::GetTempDirectory() for use in C test.
8c8024ea33d8efc8c415597fb7fa1745002961d6 Switch HAVE_ library detection macros to 0/1.
41172a24016bc29fc795ed504737392587f54e3d Enable thread safety annotations in open source version.
47cb9e2a211e1d7157078ba7bab536beb29e56dc Add leveldb_options_set_max_file_size to the C API.
b5d4a22e64c7a6615b412f464026c808b58b1d34 Fixed style guide link in CONTRIBUTING.md
3da4d8b9899257386aeb5ffa345a6477c62ff7bf Deleted unused assignments in Reader.
0509414f858ae7c7225e29f3659a709afb324355 leveldb::DestroyDB will now delete empty directories.
23162ca1c6d891a9c5fe0e0fab1193cd54ed1b4f Fix typo (forgotten reference operator) in test.
5c39524f3639e6bf6ab49215152d24273e662986 Replace SSE-optimized CRC32C in POSIX port with external library.
ca216e493f32278f50a823811ab95f64cf0f839b leveldb: Rename SNAPPY to HAVE_SNAPPY.
25767d066ca995c055f04b78a31a6e518087e667 leveldb: Remove *_unlocked feature detection from POSIX port.
4a7e7f50dcf661cfffe71737650b0fb18e195d18 Add LEVELDB_EXPORT macro to export public symbols.
542590d2a8eee3838f40b01405baa6d2f6f8c700 leveldb: Include <algorithm> in util/env_test.cc.
8ae7998aabae4f208d77afcb930dafabade1b28d Fix FD leak in POSIX Env.
d9a9e02edf2b8187aa481416b36c49710026ab37 leveldb: Add tests for CL 170769101.
4447f9caced2bd09585c90f1b203c3aa8f4bbc40 Remove handling for unused LRUHandle representation special case.
2372ac574fdeb1235e70cdd86a2681d1ce05cf65 Fix file writing bug in CL 170738066.
1c75e88055e06da2939f9f4bd294625b76792815 Fix use of uninitialized value in LRUHandle.
7e12c00ecf1bb725e212618e7026e4d34d6cd3bb Fix issue 474: a race between the f*_unlocked() STDIO calls in env_posix.cc and concurrent application calls to fflush(NULL).
bcd9a8ea4a8aad23a3e101a23c61615bab2a093f Use portable CRC32C from google/crc32c.
ea0a7586b8615fd39c6b8f5a8a21a1f242129c2f Remove confusing and unnecessary if.
141e7671359d5e6c65ff70460774b53b94371df1 Simplify Table::Open() flow and remove a delete call.
09a3c8e7417547829b94bcdaa62cdf9e896f29a9 Switched variable type from int to uint64_t in ConsumeDecimalNumber.
2964b803b857932ff7499d7bebb61dc5514dab7c leveldb: Fix alignment code in SSE4.2-optimized CRC32C.
02f43c0fcde39823830493503e8a3f72fed43d24 Remove dead code.
0b402e96a76b19cd98e82402de636449a2613228 Use __APPLE__ instead of OS_MACOS. The former is compiler-provided.
8415f00eeedd96934d3578572d3802900e61a556 leveldb: Report missing CURRENT manifest file as database corruption.
69e2bd224b7f11e021527cb95bab18f1ee6e1b3b LevelDB: Add WriteBatch::ApproximateSize().
471f0b84ec3420c7565511eb6e2fee8e0a0550e8 fix comment
5b817400a0a5afe3badbb8859706a571882ababc fix comment
7d060117fa0d5cab7cb15b0cf127533bea9ffbc7 broken db: fix assertion in leveldb::InternalKey::Encode, mark base as corrupt
2883fcd849ca7b479d8a2f4fc929f0b6c7b9e372 set const property
e5f0a51fa44115fb083c1e71d5ddcd07a7aba719 reduce lock's range in DeleteObsoleteFiles
dd598676cd655dc2a2aaef47715ce18175d4a550 block_builder header file dependency fixed
REVERT: f545dfabff4c2e9836efed094dba99a34fbc6b88 Merge #18: Use utf-8 to decode filename
REVERT: f8e797a058b7a3993314e985dfdff8124214ba99 Use utf-8 to decode filename
REVERT: 2fc114812a04e6b88852fa37eedc556a464241f7 Merge #14: Fixes to allow building with msvc.
REVERT: 524b7e36a8e3bce6fcbcd1b5df09024283f325ba Merge #19: Increase maximum read-only mmap()s used from 1000 to 4096 on 64-bit systems
REVERT: 4874cb8d3e1dc7b9026b9faf51b9282c91f8ef40 Increase maximum number of read-only mmap()s used from 1000 to 4096 on 64 bit systems.
REVERT: 64052c76c567cff3dad32d1db0ef969d97b5882f Merge #15: Add filename to corruption errors
REVERT: 135ed0fb4e5d6440b174c4b80c147e915dd58969 Add filename to corruption errors
REVERT: d6eab93138884ee6c466fad5dadf2a1bfeb7cffd Fixes to allow building with msvc.
REVERT: c521b3ac654cfbe009c575eacf7e5a6e189bb5bb Merge #11: fixup define checks. Cleans up some oopses from #5.
REVERT: 8b1cd3753b184341e837b30383832645135d3d73 fixup define checks. Cleans up some oopses from #5.
REVERT: 6b1508d6d58caabf76cec2688b3428c9070b7bc9 Merge #6: Fixes typo
REVERT: fceb805426c66c8b79e2d75b83b4a35c57ad3a6e Merge #10: Clean up compile-time warnings (gcc 7.1)
REVERT: 0ec2a343f3be66ef6e25f9b9badc0256ac0911b7 Clean up compile-time warnings (gcc 7.1)
REVERT: d4c268a3571a66b3712ad24dfaf4b9f9671bcdf2 Merge #5: Move helper functions out of sse4.2 object
REVERT: 8d4eb0847041a26377dc99b1c4fb5c22d4841d5e Add HasAcceleratedCRC32C to port_win.h
REVERT: 77cfbfd250a690978a3b81d364054039467ed549 crc32: move helper functions out of port_posix_sse.cc
REVERT: 4c1e9e01688864a32217e541102fa8d2df9a3d59 silence compiler warnings about uninitialized variables
REVERT: 4953164851d1bc2fc653f60a98df5aa5c1dfcebd Merge #2: Prefer std::atomic over MemoryBarrier
REVERT: 2953978ef8cd8f0babcac86a52f5c688a5ad8fa8 Fixes typo
REVERT: f134284a1ce6e8e3ccc375a0a44300d9a87c51ab Merge #1: Merge upstream LevelDB 1.20
REVERT: 196962ff01c39b4705d8117df5c3f8c205349950 Add AcceleratedCRC32C to port_win.h
REVERT: ba8a445fdaa7cf3cb888a151e055330483b946f6 Prefer std::atomic over MemoryBarrier
REVERT: 1bdf1c34c5d903e466673a15103124568d995db4 Merge upstream LevelDB v1.20
REVERT: d31721eb0a115ac55506bb6735034bf915adc914 Merge #17: Fixed file sharing errors
REVERT: fecd449021504dc647c1a1226d72ab0d5efb84ad Fixed file sharing error in Win32Env::GetFileSize(), Win32SequentialFile::_Init(), Win32RandomAccessFile::_Init() Fixed error checking in Win32SequentialFile::_Init()
REVERT: 5b7510f1b79d9af1c5fe272a4587517a2579d3b7 Merge #14: Merge upstream LevelDB 1.19
REVERT: 0d969fd5708c9fd559d63be28664e1e840beb8ca Merge #16: [LevelDB] Do no crash if filesystem can't fsync
REVERT: c8c029b5b5793d3c9afef34afa53d10a910adf4e [LevelDB] Do no crash if filesystem can't fsync
REVERT: a31c8aa408d5594830f7cb20ead1ef1dff51b79e Add NewAppendableFile for win32 environment
REVERT: d40bc3fa5aaa5438d4d8f55ee83e6b3cd161ce02 Merge #13: Typo
REVERT: ebbd772d33d8596e5765a4d1251308d732d61355 Typo
REVERT: 1913d718ef8b07288229a75553862fcb343bf3ab Merge upstream LevelDB 1.19
REVERT: 20ca81f08fb7fa108923a091668e447dcf5c6b9d Merge pull request #9
REVERT: 7aa105e1a34e6e52b1e0de16d9d659a2af26fa0a leveldb: Win32WritableFile without memory mapping
REVERT: 7d41e6f89ff04ce9e6a742932924796f69c6e23d Merge upstream LevelDB 1.18
REVERT: 42dcc7edfc98c50038e4604fa630c626db17bf42 Merge upstream LevelDB 1.17.
REVERT: e991315d7fe4ca84a98902578106cbffa3dcccfd Merge upstream LevelDB 1.15.
REVERT: 02ac9f170b1c47e2c613cd47b8d7da45743af575 Merge upstream LevelDB 1.14.
REVERT: 936b4613ea4551992e6096b1e05eeefc09a20e3b Merge upstream LevelDB 1.13.
REVERT: be1b0ff1fcd6ad820a7fd111ac671fb51cc68001 On Mac OS X fsync does not guarantee write to disk. Use fcntl F_FULLFSYNC instead.
REVERT: a02ddf9b14d145e88185ee209ab8b01d8826663a Added GNU/kFreeBSD kernel name (TARGET_OS)
REVERT: 848746862caf337254a8a3e3a6bd3fa355db4fc8 CondVar::SignalAll was broken, leading to deadlocks on Windows builds. http://code.google.com/p/leveldb/issues/detail?id=149
REVERT: f6d84d1baf74a15ee8a0f73a81c647058bf816e9 Allow files to be opened for reading multiple times
REVERT: cb8e3f7adfaa48e09fb7a467086d69e4b6f948bd Checking whether closing succeeds
REVERT: d5317e8eda06d8dbbf04f08866c92323ccdbb43f Print actual Win32 error that occurred on file creation failure.
REVERT: 907f3084998fa4ce96b7abc6d9b12c7aa7b81c8c Port leveldb to MinGW32
REVERT: 9def2bfbf18dfbc0c3c95e90c91f043a6de3c1cb Mingw support for Windows LevelDB port
REVERT: 0a7b0748c71e64fd920eed94c26d69bc9ae77870 Pre-Vista leveldb::port::InitOnce implementation
REVERT: 31a2b09985842c833fbbd81e17f207c377217754 Native Windows LevelDB port
REVERT: 058a0357cd9650b214a199f81669a07d3eb4a298 Remove Snappy support

git-subtree-dir: src/leveldb
git-subtree-split: f8ae182c1e5176d12e816fb2217ae33a5472fdd7

1 files changed, 8 insertions, 6 deletions

diff --git a/doc/impl.md b/doc/impl.md
index 4b13f2a6ba..cacabb96fc 100644
--- a/doc/impl.md
+++ b/doc/impl.md
@@ -64,13 +64,15 @@ Other files used for miscellaneous purposes may also be present (LOCK, *.dbtmp).
 
 ## Level 0
 
-When the log file grows above a certain size (1MB by default):
-Create a brand new memtable and log file and direct future updates here
+When the log file grows above a certain size (4MB by default):
+Create a brand new memtable and log file and direct future updates here.
+
 In the background:
-Write the contents of the previous memtable to an sstable
-Discard the memtable
-Delete the old log file and the old memtable
-Add the new sstable to the young (level-0) level.
+
+1. Write the contents of the previous memtable to an sstable.
+2. Discard the memtable.
+3. Delete the old log file and the old memtable.
+4. Add the new sstable to the young (level-0) level.
 
 ## Compactions