Summary:
`BeginWriteStall()` removes no_slowdown write from the write
list and updates `link_newer`, which makes `CreateMissingNewerLinks()`
thought all write list has valid `link_newer` and failed to create link
for all writers.
It caused flaky test and SegFault for release build.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7508
Test Plan: Add unittest to reproduce the issue.
Reviewed By: anand1976
Differential Revision: D24126601
Pulled By: jay-zhuang
fbshipit-source-id: f8ac5dba653f7ee1b0950296427d4f5f8ee34a06
Summary:
This PR schedules a background thread (shared across all DB instances)
to flush info log every ten seconds. This improves debuggability in case
of RocksDB hanging since it ensures the log messages leading up to the hang
will eventually become visible in the log.
The bulk of this PR is moving monitoring/stats_dump_scheduler* to db/periodic_work_scheduler*
and making the corresponding name changes since now the scheduler handles info
log flushing, not just stats dumping.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7488
Reviewed By: riversand963
Differential Revision: D24065165
Pulled By: ajkr
fbshipit-source-id: 339c47a0ff43b79fdbd055fbd9fefbb6f9d8d3b5
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:
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:
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:
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:
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:
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:
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:
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:
More tests now pass. When in doubt, I added a TODO comment to check what should happen with an ignored error.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7305
Reviewed By: akankshamahajan15
Differential Revision: D23301262
Pulled By: ajkr
fbshipit-source-id: 5f120edc7393560aefc0633250277bbc7e8de9e6
Summary:
When a memtable is trimmed in MemTableListVersion, the memtable
is only added to delete list if it is
the last reference. However it is not the last reference as it is held
by the super version. But the super version would not be switched if the
delete list is empty. So the memtable is never destroyed and memory
usage increases beyond write_buffer_size +
max_write_buffer_size_to_maintain.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7296
Test Plan:
1. ./db_bench -benchmarks=randomtransaction
-optimistic_transaction_db=1 -statistics -stats_interval_seconds=1
-duration=90 -num=500000 --max_write_buffer_size_to_maintain=16000000
--transaction_set_snapshot
Reviewed By: ltamasi
Differential Revision: D23267395
Pulled By: akankshamahajan15
fbshipit-source-id: 3a8d437fe9f4015f851ff84c0e29528aa946b650
Summary:
This test uses database functionality and required more extensive work to get it to pass than the other tests. The DB functionality required for this test now passes the check.
When it was unclear what the proper behavior was for unchecked status codes, a TODO was added.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7283
Reviewed By: akankshamahajan15
Differential Revision: D23251497
Pulled By: ajkr
fbshipit-source-id: 52b79629bdafa0a58de8ead1d1d66f141b331523
Summary:
This diff contains following changes:
1. Replace `FSSequentialFile` pointer with `FSSequentialFilePtr` object that wraps `FSSequentialFile` pointer in `SequenceFileReader`.
Objective: If tracing is enabled, `FSSequentialFilePtr` returns `FSSequentialFileTracingWrapper` 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. `FSSequentialFilePtr` wrapper class is added to bypass the `FSSequentialFileTracingWrapper` when tracing is disabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7190
Test Plan:
make check -j64
COMPILE_WITH_TSAN=1 make check -j64
Reviewed By: anand1976
Differential Revision: D23059616
Pulled By: akankshamahajan15
fbshipit-source-id: 1564b94dd1297cd0fbfe2ed5c9cc3e20f7395301
Summary:
After https://github.com/facebook/rocksdb/pull/7036, we still see extra DBTest that can timeout when running 10 or 20 in parallel. Expand skip-fsync mode in whole DBTest. Still preserve other tests from doing this mode to be conservative.
This commit reinstates https://github.com/facebook/rocksdb/issues/7049, whose un-revert was lost in an automatic
infrastructure mis-merge.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7274
Test Plan: Run all existing files.
Reviewed By: pdillinger
Differential Revision: D23177444
fbshipit-source-id: 1f61690b2ac6333c3b2c87176fef6b2cba086b33
Summary:
The two features are naturally incompatible. WAL recycling expects the recovery to succeed upon encountering a corrupt record at the point where new data ends and recycled data remains at the tail. However, `WALRecoveryMode::kTolerateCorruptedTailRecords` must fail upon encountering any such corrupt record, as it cannot differentiate between this and a real corruption, which would cause committed updates to be truncated.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7271
Reviewed By: riversand963
Differential Revision: D23169923
Pulled By: ajkr
fbshipit-source-id: 2cf8a3bcd2c9a0ecb0055a84725047a10fd4db50
Summary:
There is potential data race related CompactRange() with level refitting. After the compaction step and refitting step, some automatic compaction could put data to the destination level and cause the DB to be corrupted. Fix the bug by checking the target level to be empty.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7261
Test Plan: Add a unit test, which would fail with "Corruption: L1 have overlapping ranges '666F6F' seq:6, type:1 vs. '626172' seq:2, type:1", and now it succeeds.
Reviewed By: ajkr
Differential Revision: D23142269
fbshipit-source-id: 28bc14d5ac934c192260b23a4ce3f10a95e3ee91
Summary:
Looks like somebody simply missed initializing a member variable. The column family ID, cf_id, is not set during OnCompactionBegin. But it is set properly in the next function for OnCompactionCompleted. Need this cf_id for tracking progress of a Stardog optimize since there may be multiple compactions required for a given column family.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6938
Reviewed By: siying
Differential Revision: D23153235
Pulled By: ajkr
fbshipit-source-id: 932938de3a4ebbc7ac89702f655583862587d251
Summary:
Have a global StatsDumpScheduler for all DB instance stats dumping, including `DumpStats()` and `PersistStats()`. Before this, there're 2 dedicate threads for every DB instance, one for DumpStats() one for PersistStats(), which could create lots of threads if there're hundreds DB instances.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7223
Reviewed By: riversand963
Differential Revision: D23056737
Pulled By: jay-zhuang
fbshipit-source-id: 0faa2311142a73433ebb3317361db7cbf43faeba
Summary:
If user-defined timestamp is enabled, current implementation can expose
newer data to queries even if an older sequence number is specified via
read_options.snapshot. This PR makes Get() respect sequence-number-based
snapshot.
Solution is simple. Besides using <ukey, ts, seq> to search the index for the key,
we also verify that the candidate result's seq is smaller than or equal to seq. This
requires passing a seq via `GetContext`, which results in the majority of code
change caused by this PR.
Also added a few unit tests to demonstrate standard visibility during point lookup
and range scan when timestamp and snapshot are both present.
Test plan (devserver):
```
make check
$./db_bench --benchmarks=fillseq,readrandom -cache_size=$[64*1024*1024]
```
Result
this PR: readrandom : 4.827 micros/op 207180 ops/sec; 22.9 MB/s (1000000 of 1000000 found)
master: readrandom : 4.936 micros/op 202610 ops/sec; 22.4 MB/s (1000000 of 1000000 found)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7227
Reviewed By: ltamasi
Differential Revision: D23015242
Pulled By: riversand963
fbshipit-source-id: ea7b85a728654553ba357d2e6a207b5e40f7376a
Summary:
Manual compaction with `CompactRangeOptions::change_levels` set could
refit to a level targeted by another manual compaction. If
force_consistency_checks were disabled, it could be possible for
overlapping files to be written at that target level.
This PR prevents the possibility by calling `DisableManualCompaction()`
prior to `ReFitLevel()`. It also improves the manual compaction disabling
mechanism to wait for pending manual compactions to complete before
returning, and support disabling from multiple threads.
Fixes https://github.com/facebook/rocksdb/issues/6432.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7250
Test Plan:
crash test command that repro'd the bug reliably:
```
$ TEST_TMPDIR=/dev/shm python tools/db_crashtest.py blackbox --simple -target_file_size_base=524288 -write_buffer_size=1048576 -clear_column_family_one_in=0 -reopen=0 -max_key=10000000 -column_families=1 -max_background_compactions=8 -compact_range_one_in=100000 -compression_type=none -compaction_style=1 -num_levels=5 -universal_min_merge_width=4 -universal_max_merge_width=8 -level0_file_num_compaction_trigger=12 -rate_limiter_bytes_per_sec=1048576000 -universal_max_size_amplification_percent=100 --duration=3600 --interval=60 --use_direct_io_for_flush_and_compaction=0 --use_direct_reads=0 --enable_compaction_filter=0
```
Reviewed By: ltamasi
Differential Revision: D23090800
Pulled By: ajkr
fbshipit-source-id: afcbcd51b42ce76789fdb907d8b9ada790709c13
Summary:
As part of the IOTracing project, this PR
1. Caches "FileSystemPtr" object(wrapper class that returns file system pointer based on tracing enabled) instead of "FileSystem" pointer.
2. FileSystemPtr object is created using FileSystem pointer and IOTracer
pointer.
3. IOTracer shared_ptr is created in DBImpl and it is passed to different classes through constructor.
4. When tracing is enabled through DB::StartIOTrace, FileSystemPtr
returns FileSystemTracingWrapper pointer for tracing purpose and when
it is disabled underlying FileSystem pointer is returned.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7180
Test Plan:
make check -j64
COMPILE_WITH_TSAN=1 make check -j64
Reviewed By: anand1976
Differential Revision: D22987117
Pulled By: akankshamahajan15
fbshipit-source-id: 6073617e4c2d5bc363914f3a1f55ae3b0a58fbf1
Summary:
Introduce io_timeout in ReadOptions and enabled deadline/io_timeout for
Iterators.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7161
Test Plan: New unit tests in db_basic_test
Reviewed By: riversand963
Differential Revision: D22687352
Pulled By: anand1976
fbshipit-source-id: 67bbb0e6d7ae80b256589244468494292538c6ec
Summary:
Pointed out by https://github.com/facebook/rocksdb/issues/7197 , there is a double lock in WriteImplWALOnly.
Also find another deadlock in UnorderedWriteMemtable. Move the check after switch_all_.notify_all().
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7199
Test Plan: pass make check
Reviewed By: anand1976
Differential Revision: D22961714
Pulled By: zhichao-cao
fbshipit-source-id: 0707922dc50d28ea141a15a8cdcbd1c8993ea0d8
Summary:
A colon will be added after 'msg' automatically when invoke function Status(Code _code, const Slice& msg, const Slice& msg2),
it's not needed to append a colon explicitly to 'msg'.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7041
Reviewed By: ajkr
Differential Revision: D22292801
fbshipit-source-id: 8f2d69065bb779d2613468bf9fc9169f32c3f1ec
Summary:
Previously, a `ReadOptions` object was stored in every `BlockBasedTableIterator`
and every `LevelIterator`. This redundancy consumes extra memory,
resulting in the `Arena` making more allocations, and iteration
observing worse cache performance.
This PR migrates callers of `NewInternalIterator()` and
`MakeInputIterator()` to provide a `ReadOptions` object guaranteed to
outlive the returned iterator. When the iterator's lifetime will be managed by the
user, this lifetime guarantee is achieved by storing the `ReadOptions`
value in `ArenaWrappedDBIter`. Then, sub-iterators of `NewInternalIterator()` and
`MakeInputIterator()` can hold a reference-to-const `ReadOptions`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7210
Test Plan:
- `make check` under ASAN and valgrind
- benchmark: on a DB with 2 L0 files and 3 L1+ levels, this PR reduced `Arena` allocation 4792 -> 4160 bytes.
Reviewed By: anand1976
Differential Revision: D22861323
Pulled By: ajkr
fbshipit-source-id: 54aebb3e89c872eeab0f5793b4b6e42878d093ce
Summary:
Make (most of) the env*_test pass when ASSERT_STATUS_CHECKED is enabled.
One test that opens a database is currently disabled in this mode, as there are many errors that need revisited for DB tests and status checks.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7176
Reviewed By: cheng-chang
Differential Revision: D22799278
Pulled By: ajkr
fbshipit-source-id: 16d8a02eaeecd6df1060249b6a5811292801f2ed
Summary:
Previously when running `db_bench` with large value for `num_multi_dbs` and enabled `Options::dump_malloc_stats`, we would see most CPU spent in jemalloc locking. After this PR that no longer shows up at the top of the profile.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7145
Reviewed By: riversand963
Differential Revision: D22593031
Pulled By: ajkr
fbshipit-source-id: 3b3fc91f93249c6afee53f59f34c487c3fc5add6
Summary:
In current codebase, in write path, if Retryable IO Error happens, SetBGError is called. The retryable IO Error is converted to hard error and DB is in read only mode. User or application needs to resume it. In this PR, if Retryable IO Error happens in one DB, SetBGError will create a new thread to call Resume (auto resume). otpions.max_bgerror_resume_count controls if auto resume is enabled or not (if max_bgerror_resume_count<=0, auto resume will not be enabled). options.bgerror_resume_retry_interval controls the time interval to call Resume again if the previous resume fails due to the Retryable IO Error. If non-retryable error happens during resume, auto resume will terminate.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6765
Test Plan: Added the unit test cases in error_handler_fs_test and pass make asan_check
Reviewed By: anand1976
Differential Revision: D21916789
Pulled By: zhichao-cao
fbshipit-source-id: acb8b5e5dc3167adfa9425a5b7fc104f6b95cb0b
