Summary:
`DBTest.FileCreationRandomFailure` frequently times out during our
continuous test runs. (It's a case of "stress test posing as unit test.")
The patch reduces the number of iterations to avoid this. Note that
the lower numbers are still sufficient to trigger both flushes and
compactions, so test coverage is still the same.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7481
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D24034712
Pulled By: ltamasi
fbshipit-source-id: 8731a9446e5a121a1041b00f0df473b9f714935a
Summary:
Introduce an new option options.check_flush_compaction_key_order, by default set to true, which checks key order of flush and compaction, and fail the operation if the order is violated.
Also did minor refactor hash checking code, which consolidates the hashing logic to a vlidation class, where the key ordering logic is added.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7467
Test Plan: Add unit tests to validate the check can catch reordering in flush and compaction, and can be properly disabled.
Reviewed By: riversand963
Differential Revision: D24010683
fbshipit-source-id: 8dd6292d2cda8006054e9ded7cfa4bf405f0527c
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:
Do not assert the number of files after intra-L0 compaction is eligible to run since it could complete (and reduce the number of files) before the assertion executes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7477
Reviewed By: pdillinger
Differential Revision: D24032049
Pulled By: ajkr
fbshipit-source-id: e838ac7a24651ebd643b9e5a9d39d2e789c46929
Summary:
This has been running in production on some key workloads, so
we believe it to be safe and extremely low cost. Nevertheless, I've
added code to ensure that "force_consistency_checks" is mentioned in
any corruption reports so that people know how to disable in case of
false positive corruption reports.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7446
Test Plan:
make check, CI, temporary debug print new message with
./version_builder_test
Reviewed By: ajkr
Differential Revision: D23972101
Pulled By: pdillinger
fbshipit-source-id: 9623e400f3752577c0ecf977e6d0915562cf9968
Summary:
Add a new Option "allow_data_in_errors". When it's set by users, it allows them to opt-in to get error messages containing corrupted keys/values. Corrupt keys, values will be logged in the messages, logs, status etc. that will help users with the useful information regarding affected data.
By default value is set false to prevent users data to be exposed in the messages.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7420
Test Plan:
1. make check -j64
2. Add a new test case
Reviewed By: ajkr
Differential Revision: D23835028
Pulled By: akankshamahajan15
fbshipit-source-id: 8d2eba8fb898e79fcf1fccc07295065a75eb59b1
Summary:
The assertion checks that there is no overlap in sequence numbers across levels in universal compaction. However, this assumption doesn't hold when there is a delete triggered compaction or a trivial move, as they operate on a subset of a level.
Tests -
make check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7421
Reviewed By: ajkr
Differential Revision: D23872672
Pulled By: anand1976
fbshipit-source-id: c386deab8e01a5746ca996ff1f4ebcae3b15b7d2
Summary:
Add db_basic_test status check list. Some of the warnings are suppressed. It is possible that some of them are due to real bugs.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7452
Test Plan: See CI tests pass.
Reviewed By: zhichao-cao
Differential Revision: D23979764
fbshipit-source-id: 6151570c2a9b931b0fbb3fe939a94b2bd1583cbe
Summary:
A generic algorithm in progress depends on a templatized
version of fastrange, so this change generalizes it and renames
it to fit our style guidelines, FastRange32, FastRange64, and now
FastRangeGeneric.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7436
Test Plan: added a few more test cases
Reviewed By: jay-zhuang
Differential Revision: D23958153
Pulled By: pdillinger
fbshipit-source-id: 8c3b76101653417804997e5f076623a25586f3e8
Summary:
Possible fix for a TSAN issue reported in EnableFileDeletions.
disable_delete_obsolete_files_ should only be accessed holding the db
mutex, but for logging it was being accessed outside holding the mutex,
now fixed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7435
Test Plan: existing tests, watch for recurrence
Reviewed By: ltamasi
Differential Revision: D23917578
Pulled By: pdillinger
fbshipit-source-id: 8573025bca3f6fe169b24b87bbfc4ce9667b0482
Summary:
Add a method `CheckWals` in `WalSet` to check the logs on disk. See `CheckWals`'s comments.
This method will be used to check consistency of WALs during DB recovery.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7236
Test Plan: a set of tests are added to wal_edit_test.cc.
Reviewed By: riversand963
Differential Revision: D23036505
Pulled By: cheng-chang
fbshipit-source-id: 5b1d6857ac173429b00f950c32c4a5b8d063a732
Summary:
Fix few test cases and add them in ASSERT_STATUS_CHECKED build.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7427
Test Plan:
1. ASSERT_STATUS_CHECKED=1 make -j48 check,
2. travis build for ASSERT_STATUS_CHECKED,
3. Without ASSERT_STATUS_CHECKED: make check -j64, CircleCI build and travis build
Reviewed By: pdillinger
Differential Revision: D23909983
Pulled By: akankshamahajan15
fbshipit-source-id: 42d7e4aea972acb9fcddb7ca73fcb82f93272434
Summary:
Implement a parsing tool io_tracer_parser that takes IO trace file (binary file) with command line argument --io_trace_file and output file with --output_file and dumps the IO trace records in outputfile in human readable form.
Also added unit test cases that generates IO trace records and calls io_tracer_parse to parse those records.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7333
Test Plan:
make check -j64,
Add unit test cases.
Reviewed By: anand1976
Differential Revision: D23772360
Pulled By: akankshamahajan15
fbshipit-source-id: 9c20519c189362e6663352d08863326f3e496271
Summary:
This option is apparently used by some teams within Facebook
(internal ref T75998621)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7431
Test Plan: USE_CLANG=1 make check before (fails) and after
Reviewed By: jay-zhuang
Differential Revision: D23876584
Pulled By: pdillinger
fbshipit-source-id: abb8b67a1f1aac75327944d266e284b2b6727191
Summary:
There are some tricky behaviors related to WAL sync:
- When creating a WAL, the WAL might not be synced, if the WAL directory is not synced, the WAL file's metadata may not even be synced to disk, so during recovery, when listing the WAL directory, the WAL may not even show up.
- During each DB::Write, the WriteOption can control whether the WAL should be synced, so a WAL previously not synced on creation can be synced during Write.
For each `SyncWAL`, we'll track the synced status and the current WAL size. Previously, we only track the WAL size on closing.
During recovery, we check that the on-disk WAL size is >= the last synced size.
So this PR introduces `synced_size` and `closed` to `WalMetadata` for the above design update.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7414
Test Plan:
- updated wal_edit_test
- updated version_edit_test
Reviewed By: riversand963
Differential Revision: D23796127
Pulled By: cheng-chang
fbshipit-source-id: 5498ab80f537c48a10157e71a4745716aef5cf30
Summary:
Current implementation holds db mutex while calling
`GetAggregatedIntProperty()`. For property kEstimateTableReadersMem,
this can be expensive, especially if the number of table readers is
high.
We can release and re-acquire db mutex if
property_info.need_out_of_mutex is true.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7412
Test Plan:
make check
COMPILE_WITH_ASAN=1 make check
COMPILE_WITH_TSAN=1 make check
Also test internally on a shadow host. Used bpf to verify the
excessively long db mutex holding no longer exists when applications
call GetApproximateMemoryUsageByType().
Reviewed By: jay-zhuang
Differential Revision: D23794824
Pulled By: riversand963
fbshipit-source-id: 6bc02a59fd25613d343a62cf817467c7122c9721
Summary:
Make the test robust to spurious wakeups on condition variable,
and clear sync points to ensure no use-after-free.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7418
Test Plan: repeated runs on updated test, watch CircleCI for recurrence
Reviewed By: jay-zhuang
Differential Revision: D23828823
Pulled By: pdillinger
fbshipit-source-id: af85117d9c02602541a90252840e0e5a6996de5b
Summary:
Fix the flaky test failure in error_handler_fs_test. Add the sync point, solve the dependency.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7415
Test Plan: make asan_check, ~/gtest-parallel/gtest-parallel -r 100 ./error_handler_fs_test
Reviewed By: siying
Differential Revision: D23804330
Pulled By: zhichao-cao
fbshipit-source-id: 5175108651f7652e47e15978f2a9c1669ef59d80
Summary:
In the current implementation, any retryable IO error happens during Flush is mapped to a hard error. In this case, DB is stopped and write is stalled unless the background error is cleaned. In this PR, if WAL is DISABLED, the retryable IO error during FLush is mapped to a soft error. Such that, the memtable can continue receive the writes. At the same time, if auto resume is triggered, SwtichMemtable will not be called during Flush when resuming the DB to avoid to many small memtables. Testing cases are added.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7310
Test Plan: adding new unit test, pass make check.
Reviewed By: anand1976
Differential Revision: D23710892
Pulled By: zhichao-cao
fbshipit-source-id: bc4ca50d11c6b23b60d2c0cb171d86d542b038e9
Summary:
Prior to 6.12, backup files using share_files_with_checksum had
the file size encoded in the file name, after the last '\_' and before
the last '.'. We considered this an implementation detail subject to
change, and indeed removed this information from the file name (with an
option to use old behavior) because it was considered
ineffective/inefficient for file name uniqueness. However, some
downstream RocksDB users were relying on this information since the file
size is not explicitly in the backup manifest file.
This primary purpose of this change is "retrofitting" the 6.12 release
(not yet a public release) to simultaneously support the benefits of the
new naming scheme (I/O performance and data correctness at scale) and
preserve the file size information, both as default behaviors. With this
change, we are essentially making the file size information encoded in
the file name an official, though obscure, extension of the backup meta
file format.
We preserve an option (kLegacyCrc32cAndFileSize) to use the original
"legacy" naming scheme, with its caveats, and make it easy to omit the
file size information (no kFlagIncludeFileSize), for more compact file
names. But note that changing the naming scheme used on an existing db
and backup directory can lead to transient space amplification, as some
files will be stored under two names in the shared_checksum directory.
Because some backups were saved using the original 6.12 naming scheme,
we offer two ways of dealing with those files: SST files generated by
older 6.12 versions can either use the default naming scheme in effect
when the SST files were generated (kFlagMatchInterimNaming, default, no
transient space amplification) or can use a new naming scheme (no
kFlagMatchInterimNaming, potential space amplification because some
already stored files getting a new name).
We don't have a natural way to detect which files were generated by
previous 6.12 versions, but this change hacks one in by changing DB
session ids to now use a more concise encoding, reducing file name
length, saving ~dozen bytes from SST files, and making them visually
distinct from DB ids so that they are less likely to be mixed up.
Two final auxiliary notes:
Recognizing that the backup file names have become a de facto part of
the backup meta schema, this change makes them easier to parse and
extend by putting a distinct marker, 's', before DB session ids embedded
in the name. When we extend this to allow custom checksums in the name,
they can get their own marker to ensure safe parsing. For backward
compatibility, file size does not get a marker but is assumed for
`_[0-9]+[.]`
Another change from initial 6.12 default behavior is never including
file custom checksum in the file name. Looking ahead to 6.13, we do not
want the default behavior to cause backup space amplification for
someone turning on file custom checksum checking in BackupEngine; we
want that to be an easy decision. When implemented, including file
custom checksums in backup file names will be a non-default option.
Actual file name patterns and priorities, as regexes:
kLegacyCrc32cAndFileSize OR pre-6.12 SST file ->
[0-9]+_[0-9]+_[0-9]+[.]sst
kFlagMatchInterimNaming set (default) AND early 6.12 SST file ->
[0-9]+_[0-9a-fA-F-]+[.]sst
kUseDbSessionId AND NOT kFlagIncludeFileSize ->
[0-9]+_s[0-9A-Z]{20}[.]sst
kUseDbSessionId AND kFlagIncludeFileSize (default) ->
[0-9]+_s[0-9A-Z]{20}_[0-9]+[.]sst
We might add opt-in options for more '\_' separated data in the name,
but embedded file size, if present, will always be after last '\_' and
before '.sst'.
This change was originally applied to version 6.12. (See https://github.com/facebook/rocksdb/issues/7390)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7400
Test Plan:
unit tests included. Sync point callbacks are used to mimic
previous version SST files.
Reviewed By: ajkr
Differential Revision: D23759587
Pulled By: pdillinger
fbshipit-source-id: f62d8af4e0978de0a34f26288cfbe66049b70025
Summary:
`IntraL0CompactionAfterFlushCheckConsistencyFail` was flaky by sometimes failing due to no intra-L0 compactions happening. I was able to repro it by putting a `sleep(1)` in the compaction thread before it grabs the lock and picks a compaction. This also showed other intra-L0 tests are affected too, although some of them exhibit hanging forever rather than failing.
The problem was that all the flushes/ingestions could finish before any compaction got picked, so it would end up simply picking all the files that the test generates for L0->L1. But, these tests intend only the first few files to be picked for L0->L1, and the subsequent files to be picked for intra-L0. This PR adjusts the sync points of all the intra-L0 tests to enforce this.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7382
Test Plan: run all the `db_compaction_test`s with and without the artificial `sleep()`
Reviewed By: jay-zhuang
Differential Revision: D23684985
Pulled By: ajkr
fbshipit-source-id: 6508399030dddec7738e9853a7b3dc53ef77a584
Summary:
The patch adds support for extracting large values into blob files when
performing a flush during recovery (when `avoid_flush_during_recovery` is
`false`). Blob files are built and added to the `Version` similarly to flush.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7388
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D23709912
Pulled By: ltamasi
fbshipit-source-id: ce48b4227849cf25429ae98574e72b0e1cb9c67d
Summary:
Cleaned up the public API to use the EncryptedEnv. This change will allow providers to be developed and added to the system easier in the future. It will also allow better integration in the future with the OPTIONS file.
- The internal classes were moved out of the public API into an internal "env_encryption_ctr.h" header. Short-cut constructors were added to provide the original API functionality.
- The APIs to the constructors were changed to take shared_ptr, rather than raw pointers or references to allow better memory management and alternative implementations.
- CreateFromString methods were added to allow future expansion to other provider and cipher implementations through a standard API.
Additionally, there was a code duplication in the NewXXXFile methods. This common code was moved under a templatized function.
A first-pass at structuring the code was made to potentially allow multiple EncryptionProviders in a single EncryptedEnv. The idea was that different providers may use different cipher keys or different versions/algorithms. The EncryptedEnv should have some means of picking different providers based on information. The groundwork was started for this (the use of the provider_ member variable was localized) but the work has not been completed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7279
Reviewed By: jay-zhuang
Differential Revision: D23709440
Pulled By: zhichao-cao
fbshipit-source-id: 0e845fff0e03a52603eb9672b4ade32d063ff2f2
Summary:
The patch adds support for writing blob files during flush by integrating
`BlobFileBuilder` with the flush logic, most importantly, `BuildTable` and
`CompactionIterator`. If `enable_blob_files` is set, large values are extracted
to blob files and replaced with references. The resulting blob files are then
logged to the MANIFEST as part of the flush job's `VersionEdit` and
added to the `Version`, similarly to table files. Errors related to writing
blob files fail the flush, and any blob files written by such jobs are immediately
deleted (again, similarly to how SST files are handled). In addition, the patch
extends the logging and statistics around flushes to account for the presence
of blob files (e.g. `InternalStats::CompactionStats::bytes_written`, which is
used for calculating write amplification, now considers the blob files as well).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7345
Test Plan: Tested using `make check` and `db_bench`.
Reviewed By: riversand963
Differential Revision: D23506369
Pulled By: ltamasi
fbshipit-source-id: 646885f22dfbe063f650d38a1fedc132f499a159
Summary:
This PR merges the functionality of making the ColumnFamilyOptions, TableFactory, and DBOptions into Configurable into a single PR, resolving any merge conflicts
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5753
Reviewed By: ajkr
Differential Revision: D23385030
Pulled By: zhichao-cao
fbshipit-source-id: 8b977a7731556230b9b8c5a081b98e49ee4f160a
Summary:
In a distributed file system, directory ownership is enforced by fencing
off the previous owner once they've been preempted by a new owner. This
PR adds a IOStatus subcode for ```StatusCode::IOError``` to indicate this.
Once this error is returned for a file write, the DB is put in read-only
mode and not allowed to resume in read-write mode.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7374
Test Plan: Add new unit tests in ```error_handler_fs_test```
Reviewed By: riversand963
Differential Revision: D23687777
Pulled By: anand1976
fbshipit-source-id: bef948642089dc0af399057864d9a8ca339e8b2f
Summary:
During bottommost compaction, RocksDB cannot simply drop a tombstone if
this tombstone is not in the earliest snapshot. The current behavior is: RocksDB
skips other internal keys (of the same user key) in the same snapshot range. In
the meantime, RocksDB should check for the `shutting_down` flag. Otherwise, it
is possible for a bottommost compaction that has already started running to take
a long time to finish, even if the application has tried to cancel all background jobs.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7356
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D23663241
Pulled By: riversand963
fbshipit-source-id: 25f8e9b51bc3bfa3353cdf87557800f9d90ee0b5
Summary:
We've seen some segfaults in db_write_test, with at least one
suggesting corruption of a write group linked list. Adding an assertion
to have this fail in a more specific way if that is the broken
invariant.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7375
Test Plan: make check
Reviewed By: jay-zhuang
Differential Revision: D23638477
Pulled By: pdillinger
fbshipit-source-id: a76fd677cad60a3a516bd363947bfd9ce418edc1
Summary:
https://github.com/facebook/rocksdb/issues/3341 guaranteed that upon return of `GetSortedWalFiles` after
`DisableFileDeletions`, all pending purges of previously obsolete WAL
files will have finished. However, the addition of
avoid_unnecessary_blocking_io in https://github.com/facebook/rocksdb/issues/5043 opened a hole in the code making
that assurance, which can lead to files to be copied for checkpoint or
backup going missing before being copied, with that option enabled.
This change patches the hole.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7369
Test Plan:
apparent fix to backups in crash test observed. Will work
on a unit test for another commit
Reviewed By: ajkr
Differential Revision: D23620258
Pulled By: pdillinger
fbshipit-source-id: bea36b461a5b719c3e3ef802f967bc3e8ae71614
Summary:
When multiple background jobs are generating blob files in parallel, it is actually
possible for a blob file to be added with a file number that is lower than the
highest one in the base version. (This is a harmless race condition.) The patch
fixes the handling of this case and adds a unit test.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7349
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D23542453
Pulled By: ltamasi
fbshipit-source-id: 4ff6f3654bc58c391d10b9870e1cc40b5e3fa8e4
Summary:
Replace FSRandomRWFile pointer with FSRandomRWFilePtr object in the rocksdb internal code.
This new object wraps FSRandomRWFile pointer.
Objective: If tracing is enabled, FSRandomRWFile object returns FSRandomRWFileTracingWrapper pointer that includes all necessary information in IORecord and calls underlying FileSystem and invokes IOTracer to dump that record in a binary file. If tracing is disabled then, underlying FileSystem pointer is returned directly.
FSRandomRWFilePtr wrapper class is added to bypass the FSRandomRWFileWrapper when
tracing is disabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7198
Test Plan: make check -j64
Reviewed By: anand1976
Differential Revision: D23421116
Pulled By: akankshamahajan15
fbshipit-source-id: 8a5ba0e7d9c1ba34c3a6f29829b107c5f09ab6a3
Summary:
Replace FSWritableFile pointer with FSWritableFilePtr
object in WritableFileWriter.
This new object wraps FSWritableFile pointer.
Objective: If tracing is enabled, FSWritableFile Ptr returns
FSWritableFileTracingWrapper pointer that includes all necessary
information in IORecord and calls underlying FileSystem and invokes
IOTracer to dump that record in a binary file. If tracing is disabled
then, underlying FileSystem pointer is returned directly.
FSWritableFilePtr wrapper class is added to bypass the
FSWritableFileWrapper when
tracing is disabled.
Test Plan: make check -j64
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7193
Reviewed By: anand1976
Differential Revision: D23355915
Pulled By: akankshamahajan15
fbshipit-source-id: e62a27a13c1fd77e36a6dbafc7006d969bed25cf
Summary:
The patch cleans up a few things in `CompactionJob::SubcompactionState`:
* Instead of using both the member initializer list and in-class initializers (and
sometimes both at the same time for the same member), the struct now uniformly
uses the latter to initialize integer members.
* The default parameter value for the constructor parameter `size` is removed.
* The explicitly deleted copy operations are removed, since they are implicitly deleted
anyways because of the `unique_ptr` members.
* The handwritten move operations, which did not move the member `c_iter` and
were not declared `nothrow`, are removed. Note that with the user-declared copy
operations gone (see the previous item), we can rely on the compiler to (correctly)
generate these methods.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7322
Test Plan: `make check`
Reviewed By: siying
Differential Revision: D23382408
Pulled By: ltamasi
fbshipit-source-id: a4ae5af150161c50ff7bdc07fa145482d0150bfe
Summary:
Currently, application may pass a statistics object to db but later
wants to reduce stats tracking overhead by setting stats level to
kExceptHistogramOrTimers (the current lowest level). Tickers will still
be incremented, causing up to 1% CPU. We can add a new lowest stats
level `kExceptTickers` to disable ticker incrementing as well, thus
reducing CPU cycles spent on tickers.
Test Plan (devserver):
```
make check
make clean
DEBUG_LEVEL=0 make db_bench
./db_bench -perf_level=1 -stats_level=0 -statistics -benchmarks=fillseq,readrandom -duration=120
```
Measure CPU util (%) before and after change:
CPU util by rocksdb::RecordTick: 1.1 vs (<0.1)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7329
Reviewed By: pdillinger
Differential Revision: D23434014
Pulled By: riversand963
fbshipit-source-id: 72ff0f02a192ac476d4b0044b9f37fd4a22ff0d4
Levi Tamasi
