Summary:
This PR addresses some build and functional issues on MSVC targets, as a step towards an eventual goal of having RocksDB build successfully for Windows on ARM64.
Addressed issues include:
- BitsSetToOne and CountTrailingZeroBits do not compile on non-x64 MSVC targets. A fallback implementation of BitsSetToOne when Intel intrinsics are not available is added, based on the C++20 `<bit>` popcount implementation in Microsoft's STL.
- The implementation of FloorLog2 for MSVC targets (including x64) gives incorrect results. The unit test easily detects this, but CircleCI is currently configured to only run a specific set of tests for Windows CMake builds, so this seems to have been unnoticed.
- AsmVolatilePause does not use YieldProcessor on Windows ARM64 targets, even though it is available.
- When CondVar::TimedWait calls Microsoft STL's condition_variable::wait_for, it can potentially trigger a bug (just recently fixed in the upcoming VS 16.8's STL) that deadlocks various tests that wait for a timer to execute, since `Timer::Run` doesn't get a chance to execute before being blocked by the test function acquiring the mutex.
- In c_test, `GetTempDir` assumes a POSIX-style temp path.
- `NormalizePath` did not eliminate consecutive POSIX-style path separators on Windows, resulting in test failures in e.g., wal_manager_test.
- Various other test failures.
In a followup PR I hope to modify CircleCI's config.yml to invoke all RocksDB unit tests in Windows CMake builds with CTest, instead of the current use of `run_ci_db_test.ps1` which requires individual tests to be specified and is missing many of the existing tests.
Notes from peterd: FloorLog2 is not yet used in production code (it's for something in progress). I also added a few more inexpensive platform-dependent tests to Windows CircleCI runs. And included facebook/folly#1461 as requested
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7439
Reviewed By: jay-zhuang
Differential Revision: D24021563
Pulled By: pdillinger
fbshipit-source-id: 0ec2027c0d6a494d8a0fe38d9667fc2f7e29f7e7
Summary:
The patch introduces a helper method in `util/compression.h` called `UncompressData`
that dispatches calls to the correct uncompression method based on type, and changes
`UncompressBlockContentsForCompressionType` and `Benchmark::Uncompress` in
`db_bench` so they are implemented in terms of the new method. This eliminates
some code duplication. (`Benchmark::Compress` is also updated to use the previously
introduced `CompressData` helper.)
In addition, the patch brings the implementation of `Snappy_Uncompress` into sync with
the other uncompression methods by making the method compute the buffer size and allocate
the buffer itself. Finally, the patch eliminates some potentially risky back-and-forth conversions
between various unsigned and signed integer types by exposing the size of the allocated buffer
as a `size_t` instead of an `int`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7434
Test Plan:
`make check`
`./db_bench -benchmarks=compress,uncompress --compression_type ...`
Reviewed By: riversand963
Differential Revision: D23900011
Pulled By: ltamasi
fbshipit-source-id: b25df63ceec4639889be94acb22eb53e530c54e0
Summary:
While rocksdb can compile on both macOS and Linux with Buck, it couldn't be
compiled on Windows. The only way to compile it on Windows was with the CMake
build.
To keep the multi-platform complexity low, I've simply included all the Windows
bits in the TARGETS file, and added large #if blocks when not on Windows, the
same was done on the posix specific files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7406
Test Plan:
On my devserver:
buck test //rocksdb/...
On Windows:
buck build mode/win //rocksdb/src:rocksdb_lib
Reviewed By: pdillinger
Differential Revision: D23874358
Pulled By: xavierd
fbshipit-source-id: 8768b5d16d7e8f44b5ca1e2483881ca4b24bffbe
Summary:
Rocksdb is using the c++11 std::threads feature. The issue is that
MINGW only supports it when using Posix threads.
This change will allow rocksdb::port::WindowsThread to be replaced
with std::thread, which in turn will allow Rocksdb to be cross
compiled using MINGW.
At the same time, we'll have to use GetCurrentProcessId instead of _getpid.
Signed-off-by: Lucian Petrut <lpetrut@cloudbasesolutions.com>
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6865
Reviewed By: cheng-chang
Differential Revision: D21864285
Pulled By: ajkr
fbshipit-source-id: 0982eed313e7d34d351b1364c1ccc722da473205
Summary:
IsDirectory() is a common API to check whether a path is a regular file or
directory.
POSIX: call stat() and use S_ISDIR(st_mode)
Windows: PathIsDirectoryA() and PathIsDirectoryW()
HDFS: FileSystem.IsDirectory()
Java: File.IsDirectory()
...
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6711
Test Plan: make check
Reviewed By: anand1976
Differential Revision: D21053520
Pulled By: riversand963
fbshipit-source-id: 680aadfd8ce982b63689190cf31b3145d5a89e27
Summary:
When creating a database backup, the background threads will not only consume IO resources by copying files, but also consuming CPU such as by computing checksums. During peak times, the CPU consumption by the background threads might affect online queries.
This PR makes it possible to decrease CPU priority of these threads when creating a new backup.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6602
Test Plan: make check
Reviewed By: siying, zhichao-cao
Differential Revision: D20683216
Pulled By: cheng-chang
fbshipit-source-id: 9978b9ed9488e8ce135e90ca083e5b4b7221fd84
Summary:
By supporting direct IO in RandomAccessFileReader::MultiRead, the benefits of parallel IO (IO uring) and direct IO can be combined.
In direct IO mode, read requests are aligned and merged together before being issued to RandomAccessFile::MultiRead, so blocks in the original requests might share the same underlying buffer, the shared buffers are returned in `aligned_bufs`, which is a new parameter of the `MultiRead` API.
For example, suppose alignment requirement for direct IO is 4KB, one request is (offset: 1KB, len: 1KB), another request is (offset: 3KB, len: 1KB), then since they all belong to page (offset: 0, len: 4KB), `MultiRead` only reads the page with direct IO into a buffer on heap, and returns 2 Slices referencing regions in that same buffer. See `random_access_file_reader_test.cc` for more examples.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6446
Test Plan: Added a new test `random_access_file_reader_test.cc`.
Reviewed By: anand1976
Differential Revision: D20097518
Pulled By: cheng-chang
fbshipit-source-id: ca48a8faf9c3af146465c102ef6b266a363e78d1
Summary:
Make kPageSize extern const size_t (used in draft https://github.com/facebook/rocksdb/issues/6427)
Make kLitteEndian constexpr bool
Clarify a couple of comments
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6443
Test Plan: make check, CI
Differential Revision: D20044558
Pulled By: pdillinger
fbshipit-source-id: e0c5cc13229c82726280dc0ddcba4078346b8418
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433
Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.
Differential Revision: D19977691
fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
Summary:
A new interface method Env::GetFreeSpace was added in https://github.com/facebook/rocksdb/issues/4164. It needs to be implemented for Windows port. Some error_handler_test cases fail on Windows because recovery cannot succeed without free space being reported.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6265
Differential Revision: D19303065
fbshipit-source-id: 1f1a83e53f334284781cf61feabc996e87b945ca
Summary:
From the reset of the code, it looks this this maybe can be unconditionally given the attribute? But I couldn't test with MSVC so I defensively put under CPP.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6075
Differential Revision: D18723749
fbshipit-source-id: 45fc8732c28dd29aab1644225d68f3c6f39bd69b
Summary:
Since we do not evict a file's blocks from block cache before that file
is deleted, we require a file's cache ID prefix is both unique and
non-reusable. However, the Windows functionality we were relying on only
guaranteed uniqueness. That meant a newly created file could be assigned
the same cache ID prefix as a deleted file. If the newly created file
had block offsets matching the deleted file, full cache keys could be
exactly the same, resulting in obsolete data blocks returned from cache
when trying to read from the new file.
We noticed this when running on FAT32 where compaction was writing out
of order keys due to reading obsolete blocks from its input files. The
functionality is documented as behaving the same on NTFS, although I
wasn't able to repro it there.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5844
Test Plan:
we had a reliable repro of out-of-order keys on FAT32 that
was fixed by this change
Differential Revision: D17752442
fbshipit-source-id: 95d983f9196cf415f269e19293b97341edbf7e00
Summary:
Further apply formatter to more recent commits.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5830
Test Plan: Run all existing tests.
Differential Revision: D17488031
fbshipit-source-id: 137458fd94d56dd271b8b40c522b03036943a2ab
Summary:
Use delete to disable automatic generated methods instead of private, and put the constructor together for more clear.This modification cause the unused field warning, so add unused attribute to disable this warning.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5009
Differential Revision: D17288733
fbshipit-source-id: 8a767ce096f185f1db01bd28fc88fef1cdd921f3
Summary:
Many logging related source files are under util/. It will be more structured if they are together.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5387
Differential Revision: D15579036
Pulled By: siying
fbshipit-source-id: 3850134ed50b8c0bb40a0c8ae1f184fa4081303f
Summary:
There are too many types of files under util/. Some test related files don't belong to there or just are just loosely related. Mo
ve them to a new directory test_util/, so that util/ is cleaner.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5377
Differential Revision: D15551366
Pulled By: siying
fbshipit-source-id: 0f5c8653832354ef8caa31749c0143815d719e2c
Summary:
Remove PATENTS related wording from a few stragglers which still reference the old PATENTS file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5326
Differential Revision: D15423297
Pulled By: sagar0
fbshipit-source-id: 4babcddfc120b7d2fed6eb3898287cf8012bf8ea
Summary:
The existing implementation does not guarantee bytes reach disk every `bytes_per_sync` when writing SST files, or every `wal_bytes_per_sync` when writing WALs. This can cause confusing behavior for users who enable this feature to avoid large syncs during flush and compaction, but then end up hitting them anyways.
My understanding of the existing behavior is we used `sync_file_range` with `SYNC_FILE_RANGE_WRITE` to submit ranges for async writeback, such that we could continue processing the next range of bytes while that I/O is happening. I believe we can preserve that benefit while also limiting how far the processing can get ahead of the I/O, which prevents huge syncs from happening when the file finishes.
Consider this `sync_file_range` usage: `sync_file_range(fd_, 0, static_cast<off_t>(offset + nbytes), SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE)`. Expanding the range to start at 0 and adding the `SYNC_FILE_RANGE_WAIT_BEFORE` flag causes any pending writeback (like from a previous call to `sync_file_range`) to finish before it proceeds to submit the latest `nbytes` for writeback. The latest `nbytes` are still written back asynchronously, unless processing exceeds I/O speed, in which case the following `sync_file_range` will need to wait on it.
There is a second change in this PR to use `fdatasync` when `sync_file_range` is unavailable (determined statically) or has some known problem with the underlying filesystem (determined dynamically).
The above two changes only apply when the user enables a new option, `strict_bytes_per_sync`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5183
Differential Revision: D14953553
Pulled By: siying
fbshipit-source-id: 445c3862e019fb7b470f9c7f314fc231b62706e9
Summary:
mv port/dirent.h to port/port_dirent.h to avoid compile err when use port dir as header dir output
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5152
Differential Revision: D14779409
Pulled By: siying
fbshipit-source-id: d4162c47c979c6e8cc6a9e601802864ab3768ecb
Summary:
This PR allows RocksDB to run in single-primary, multi-secondary process mode.
The writer is a regular RocksDB (e.g. an `DBImpl`) instance playing the role of a primary.
Multiple `DBImplSecondary` processes (secondaries) share the same set of SST files, MANIFEST, WAL files with the primary. Secondaries tail the MANIFEST of the primary and apply updates to their own in-memory state of the file system, e.g. `VersionStorageInfo`.
This PR has several components:
1. (Originally in #4745). Add a `PathNotFound` subcode to `IOError` to denote the failure when a secondary tries to open a file which has been deleted by the primary.
2. (Similar to #4602). Add `FragmentBufferedReader` to handle partially-read, trailing record at the end of a log from where future read can continue.
3. (Originally in #4710 and #4820). Add implementation of the secondary, i.e. `DBImplSecondary`.
3.1 Tail the primary's MANIFEST during recovery.
3.2 Tail the primary's MANIFEST during normal processing by calling `ReadAndApply`.
3.3 Tailing WAL will be in a future PR.
4. Add an example in 'examples/multi_processes_example.cc' to demonstrate the usage of secondary RocksDB instance in a multi-process setting. Instructions to run the example can be found at the beginning of the source code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4899
Differential Revision: D14510945
Pulled By: riversand963
fbshipit-source-id: 4ac1c5693e6012ad23f7b4b42d3c374fecbe8886
Summary:
The original implementation of WinEnvIO::NowNanos() has a constant data overflow by:
li.QuadPart *= std::nano::den;
As a result, the api provides a incorrect result.
e.g.:
li.QuadPart=13477844301545
std::nano::den=1e9
The fix uses pre-computed nano_seconds_per_period_ to present the nano seconds per performance counter period, in the case if nano::den is divisible by perf_counter_frequency_. Otherwise it falls back to use high_resolution_clock.
siying ajkr
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5062
Differential Revision: D14426842
Pulled By: anand1976
fbshipit-source-id: 127f1daf423dd4b30edd0dcf8ea0466f468bec12
Summary:
The patch adds a new config option to LRUCacheOptions that enables
users to choose whether to use an adaptive mutex for the LRU block
cache (on platforms where adaptive mutexes are supported). The default
is true if RocksDB is compiled with -DROCKSDB_DEFAULT_TO_ADAPTIVE_MUTEX,
false otherwise.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5054
Differential Revision: D14542749
Pulled By: ltamasi
fbshipit-source-id: 0065715ab6cf91f10444b737fed8c8aee6a8a0d2
Summary:
Ran the following commands to recursively change all the files under RocksDB:
```
find . -type f -name "*.cc" -exec sed -i 's/ unique_ptr/ std::unique_ptr/g' {} +
find . -type f -name "*.cc" -exec sed -i 's/<unique_ptr/<std::unique_ptr/g' {} +
find . -type f -name "*.cc" -exec sed -i 's/ shared_ptr/ std::shared_ptr/g' {} +
find . -type f -name "*.cc" -exec sed -i 's/<shared_ptr/<std::shared_ptr/g' {} +
```
Running `make format` updated some formatting on the files touched.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4638
Differential Revision: D12934992
Pulled By: sagar0
fbshipit-source-id: 45a15d23c230cdd64c08f9c0243e5183934338a8
Summary:
The default behaviour of rocksdb is to use the `*A(` windows API functions.
These accept filenames in the currently configured system encoding,
be it Latin 1, utf8 or whatever.
If the Application intends to completely work with utf8 strings internally,
converting these to that codepage properly isn't even always possible.
Thus this patch adds a switch to use the `*W(` functions, which accept
UTF-16 filenames, and uses C++11 features to translate the
UTF8 containing std::string to an UTF16 containing std::wstring.
This feature is a compile time options, that can be enabled by setting `WITH_WINDOWS_UTF8_FILENAMES` to true.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4469
Differential Revision: D10356011
Pulled By: yiwu-arbug
fbshipit-source-id: 27b6ae9171f209085894cdf80069e8a896642044
Summary:
As you know, almost all compilers support "pragma once" keyword instead of using include guards. To be keep consistency between header files, all header files are edited.
Besides this, try to fix some warnings about loss of data.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4339
Differential Revision: D9654990
Pulled By: ajkr
fbshipit-source-id: c2cf3d2d03a599847684bed81378c401920ca848
Summary:
We want to sample the file I/O issued by RocksDB and report the function calls. This requires us to include the file paths otherwise it's hard to tell what has been going on.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4039
Differential Revision: D8670178
Pulled By: riversand963
fbshipit-source-id: 97ee806d1c583a2983e28e213ee764dc6ac28f7a
Summary:
Although delete scheduler implementation allows for the interface not to be supported, the delete_scheduler_test does not allow for that.
Address compiler warnings
Make sst_dump_test use test directory structure as the current execution directory may not be writiable.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4221
Differential Revision: D9210152
Pulled By: siying
fbshipit-source-id: 381a74511e969ecb8089d5c4b4df87dc30c8df63
Summary:
Lint is not happy with some new code recently committed. Format them.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4161
Differential Revision: D8940582
Pulled By: siying
fbshipit-source-id: c9b43b1ef8c88b5e923911058b44eb77234b36b7
Summary: Windows requires new/delete for memory allocations to be overriden. Refactor to be less intrusive.
Differential Revision: D8878047
Pulled By: siying
fbshipit-source-id: 35f2b5fec2f88ea48c9be926539c6469060aab36
Summary:
We potentially need this information for tracing, profiling and diagnosis.
Closes https://github.com/facebook/rocksdb/pull/4026
Differential Revision: D8555214
Pulled By: riversand963
fbshipit-source-id: 4263e06c00b6d5410b46aa46eb4e358ff2161dd2
Summary:
so they could be overriden
Closes https://github.com/facebook/rocksdb/pull/4025
Differential Revision: D8526287
Pulled By: siying
fbshipit-source-id: 9537b299dc907b4d1eeaf77a8784b13cb058280d
Summary:
Fix a crash in `WinEnvIO::GetSectorSize` that happens on old Windows systems (e.g Windows 7).
On old Windows systems that don't support querying StorageAccessAlignmentProperty using IOCTL_STORAGE_QUERY_PROPERTY, the flow calls a different DeviceIoControl with nullptr as lpBytesReturned.
When the code reaches this point, we get an access violation.
Closes https://github.com/facebook/rocksdb/pull/3975
Differential Revision: D8385186
Pulled By: ajkr
fbshipit-source-id: fae4c9b4b0a52c8a10182e1b35bcaa30dc393bbb
Summary:
PR https://github.com/facebook/rocksdb/pull/3838 made some changes that triggers lint warnings.
Run `make format` to fix formatting as suggested by siying .
Also piggyback two changes:
1) fix singleton destruction order for windows and posix env
2) fix two clang warnings
Closes https://github.com/facebook/rocksdb/pull/3954
Differential Revision: D8272041
Pulled By: miasantreble
fbshipit-source-id: 7c4fd12bd17aac13534520de0c733328aa3c6c9f
Summary:
Windows does not have LD_PRELOAD mechanism to override all memory allocation functions and ZSTD makes use of C-tuntime calloc. During flushes and compactions default system allocator fragments and the system slows down considerably.
For builds with jemalloc we employ an advanced ZSTD context creation API that re-directs memory allocation to jemalloc. To reduce the cost of context creation on each block we cache ZSTD context within the block based table builder while a new SST file is being built, this will help all platform builds including those w/o jemalloc. This avoids system allocator fragmentation and improves the performance.
The change does not address random reads and currently on Windows reads with ZSTD regress as compared with SNAPPY compression.
Closes https://github.com/facebook/rocksdb/pull/3838
Differential Revision: D8229794
Pulled By: miasantreble
fbshipit-source-id: 719b622ab7bf4109819bc44f45ec66f0dd3ee80d
Summary:
Catch up with Posix features
NewWritableRWFile must fail when file does not exists
Implement Env::Truncate()
Adjust Env options optimization functions
Implement MemoryMappedBuffer on Windows.
Closes https://github.com/facebook/rocksdb/pull/3857
Differential Revision: D8053610
Pulled By: ajkr
fbshipit-source-id: ccd0d46c29648a9f6f496873bc1c9d6c5547487e
Summary:
Delete archive directory before WAL folder
since archive may be contained as a subfolder.
Also improve loop readability.
Closes https://github.com/facebook/rocksdb/pull/3797
Differential Revision: D7866378
Pulled By: riversand963
fbshipit-source-id: 0c45d97677ce6fbefa3f8d602ef5e2a2a925e6f5
Summary:
Returning bytes_read causes the caller to call GetLastError()
to report failure but the lasterror may be overwritten by then
so we lose the error code.
Fix up CMake file to include xpress source code only when needed.
Fix warning for the uninitialized var.
Closes https://github.com/facebook/rocksdb/pull/3795
Differential Revision: D7832935
Pulled By: anand1976
fbshipit-source-id: 4be21affb9b85d361b96244f4ef459f492b7cb2b
Summary:
This patch addressed several issues.
Portability including db_test std::thread -> port::Thread Cc: @
and %z to ROCKSDB portable macro. Cc: maysamyabandeh
Implement Env::AreFilesSame
Make the implementation of file unique number more robust
Get rid of C-runtime and go directly to Windows API when dealing
with file primitives.
Implement GetSectorSize() and aling unbuffered read on the value if
available.
Adjust Windows Logger for the new interface, implement CloseImpl() Cc: anand1976
Fix test running script issue where $status var was of incorrect scope
so the failures were swallowed and not reported.
DestroyDB() creates a logger and opens a LOG file in the directory
being cleaned up. This holds a lock on the folder and the cleanup is
prevented. This fails one of the checkpoin tests. We observe the same in production.
We close the log file in this change.
Fix DBTest2.ReadAmpBitmapLiveInCacheAfterDBClose failure where the test
attempts to open a directory with NewRandomAccessFile which does not
work on Windows.
Fix DBTest.SoftLimit as it is dependent on thread timing. CC: yiwu-arbug
Closes https://github.com/facebook/rocksdb/pull/3552
Differential Revision: D7156304
Pulled By: siying
fbshipit-source-id: 43db0a757f1dfceffeb2b7988043156639173f5b
Summary:
_endthreadex does not return and thus objects
for stack destructors do not run. This creates a memory leak.
We remove the calls since _enthreadex called automatically after the
threadproc returns i.e. thread exits.
Closes https://github.com/facebook/rocksdb/pull/3542
Differential Revision: D7088713
Pulled By: ajkr
fbshipit-source-id: 749ecafc6a9572f587f76e516547e07734349a54
Summary:
Right now, users will encounter unexpected bahavior if they use key or value larger than 4GB. We should explicitly fail the queriers.
Closes https://github.com/facebook/rocksdb/pull/3484
Differential Revision: D6953895
Pulled By: siying
fbshipit-source-id: b60491e1af064fc5d52971956661f6c18ceac24f
Summary:
BlockTest.BlockReadAmpBitmap is too slow and times out in some environments. Speed it up by:
(1) improve the way the verification is done. With this it is 5 times faster
(2) run fewer tests for large blocks. This cut it down by another 10 times.
Now it can finish in similar time as other tests.
Closes https://github.com/facebook/rocksdb/pull/3313
Differential Revision: D6643711
Pulled By: siying
fbshipit-source-id: c2397d666eab5421a78ca87e1e45491e0f832a6d
Summary:
FILE_FLAG_WRITE_THROUGH is for disabling device on-board cache in windows API, which should be disabled if user doesn't need system cache.
There was a perf issue related with this, we found during memtable flush, the high percentile latency jumps significantly. During profiling, we found those high latency (P99.9) read requests got queue-jumped by write requests from memtable flush and takes 80ms or even more time to wait, even when SSD overall IO throughput is relatively low.
After enabling FILE_FLAG_WRITE_THROUGH, we rerun the test found high percentile latency drops a lot without observable impact on writes.
Scenario 1: 40MB/s + 40MB/s R/W compaction throughput
Original | FILE_FLAG_WRITE_THROUGH | Percentage reduction
---------------------------------------------------------------
P99.9 | 56.897 ms | 35.593 ms | -37.4%
P99 | 3.905 ms | 3.896 ms | -2.8%
Scenario 2: 14MB/s + 14MB/s R/W compaction throughput, cohosted with 100+ other rocksdb instances have manually triggered memtable flush operations (memtable is tiny), creating a lot of randomized the small file writes operations during test.
Original | FILE_FLAG_WRITE_THROUGH | Percentage reduction
---------------------------------------------------------------
P99.9 | 86.227 ms | 50.436 ms | -41.5%
P99 | 8.415 ms | 3.356 ms | -60.1%
Closes https://github.com/facebook/rocksdb/pull/3225
Differential Revision: D6624174
Pulled By: miasantreble
fbshipit-source-id: 321b86aee9d74470840c70e5d0d4fa9880660a91
