Summary:
**Context:**
`EventListenerTest.MultiCF` occasionally failed on TSAN data race as below:
```
WARNING: ThreadSanitizer: data race (pid=2047633)
Read of size 8 at 0x7b6000001440 by main thread:
#0 std::vector<rocksdb::DB*, std::allocator<rocksdb::DB*> >::size() const /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_vector.h:916:40 (listener_test+0x52337c)
https://github.com/facebook/rocksdb/issues/1 rocksdb::EventListenerTest_MultiCF_Test::TestBody() /home/circleci/project/db/listener_test.cc:384:7 (listener_test+0x52337c)
Previous write of size 8 at 0x7b6000001440 by thread T2:
#0 void std::vector<rocksdb::DB*, std::allocator<rocksdb::DB*> >::_M_realloc_insert<rocksdb::DB* const&>(__gnu_cxx::__normal_iterator<rocksdb::DB**, std::vector<rocksdb::DB*, std::allocator<rocksdb::DB*> > >, rocksdb::DB* const&) /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/vector.tcc:503:31 (listener_test+0x550654)
https://github.com/facebook/rocksdb/issues/1 std::vector<rocksdb::DB*, std::allocator<rocksdb::DB*> >::push_back(rocksdb::DB* const&) /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_vector.h:1195:4 (listener_test+0x550654)
https://github.com/facebook/rocksdb/issues/2 rocksdb::TestFlushListener::OnFlushCompleted(rocksdb::DB*, rocksdb::FlushJobInfo const&) /home/circleci/project/db/listener_test.cc:255:18 (listener_test+0x550654)
```
After investigation, it is due to the following:
(1) `ASSERT_OK(Flush(i));` before the read `std::vector::size()` is supposed to be [blocked on `DB::Impl::bg_cv_` for memtable flush to finish](320d9a8e8a/db/db_impl/db_impl_compaction_flush.cc (L2319)) and get signaled [at the end of background flush ](320d9a8e8a/db/db_impl/db_impl_compaction_flush.cc (L2830)), which happens after the write `std::vector::push_back()` . So the sequence of execution should have been synchronized as `call flush() -> write -> return from flush() -> read` and would not cause any TSAN data race.
- The subsequent `ASSERT_OK(dbfull()->TEST_WaitForFlushMemTable());` serves a similar purpose based on [the previous attempt to deflake the test.](https://github.com/facebook/rocksdb/pull/9084)
(2) However, there are multiple places in the code can signal this `DB::Impl::bg_cv_` and mistakenly wake up `ASSERT_OK(Flush(i));` (or `ASSERT_OK(dbfull()->TEST_WaitForFlushMemTable());`) too early (and with the lock available to them), resulting in non-synchronized read and write thus a TSAN data race.
- Reproduced by the following, suggested by ajkr:
```
diff --git a/db/db_impl/db_impl_compaction_flush.cc b/db/db_impl/db_impl_compaction_flush.cc
index 4ff87c1e4..52492e9cf 100644
--- a/db/db_impl/db_impl_compaction_flush.cc
+++ b/db/db_impl/db_impl_compaction_flush.cc
@@ -22,7 +22,7 @@
#include "test_util/sync_point.h"
#include "util/cast_util.h"
#include "util/concurrent_task_limiter_impl.h"
namespace ROCKSDB_NAMESPACE {
bool DBImpl::EnoughRoomForCompaction(
@@ -855,6 +855,7 @@ void DBImpl::NotifyOnFlushCompleted(
mutable_cf_options.level0_stop_writes_trigger);
// release lock while notifying events
mutex_.Unlock();
+ bg_cv_.SignalAll();
```
**Summary:**
- Added synchornization between read and write by ` ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency()` mechanism
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9528
Test Plan:
`./listener_test --gtest_filter=EventListenerTest.MultiCF --gtest_repeat=10`
- pre-fix:
```
Repeating all tests (iteration 3)
Note: Google Test filter = EventListenerTest.MultiCF
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from EventListenerTest
[ RUN ] EventListenerTest.MultiCF
==================
WARNING: ThreadSanitizer: data race (pid=3377137)
Read of size 8 at 0x7b6000000840 by main thread:
#0 std::vector<rocksdb::DB*, std::allocator<rocksdb::DB*> >::size()
https://github.com/facebook/rocksdb/issues/1 rocksdb::EventListenerTest_MultiCF_Test::TestBody() db/listener_test.cc:384 (listener_test+0x4bb300)
Previous write of size 8 at 0x7b6000000840 by thread T2:
#0 void std::vector<rocksdb::DB*, std::allocator<rocksdb::DB*> >::_M_realloc_insert<rocksdb::DB* const&>(__gnu_cxx::__normal_iterator<rocksdb::DB**, std::vector<rocksdb::DB*, std::allocator<rocksdb::DB*> > >, rocksdb::DB* const&)
https://github.com/facebook/rocksdb/issues/1 std::vector<rocksdb::DB*, std::allocator<rocksdb::DB*> >::push_back(rocksdb::DB* const&)
https://github.com/facebook/rocksdb/issues/2 rocksdb::TestFlushListener::OnFlushCompleted(rocksdb::DB*, rocksdb::FlushJobInfo const&) db/listener_test.cc:255 (listener_test+0x4e820f)
```
- post-fix: `All passed`
Reviewed By: ajkr
Differential Revision: D34085791
Pulled By: hx235
fbshipit-source-id: f877aa687ea1d5cb6f31ef8c4772625d22868e8b
Summary:
The patch replaces `std::map` with a sorted `std::vector` for
`VersionStorageInfo::blob_files_` and preallocates the space
for the `vector` before saving the `BlobFileMetaData` into the
new `VersionStorageInfo` in `VersionBuilder::Rep::SaveBlobFilesTo`.
These changes reduce the time the DB mutex is held while
saving new `Version`s, and using a sorted `vector` also makes
lookups faster thanks to better memory locality.
In addition, the patch introduces helper methods
`VersionStorageInfo::GetBlobFileMetaData` and
`VersionStorageInfo::GetBlobFileMetaDataLB` that can be used by
clients to perform lookups in the `vector`, and does some general
cleanup in the parts of code where blob file metadata are used.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9526
Test Plan:
Ran `make check` and the crash test script for a while.
Performance was tested using a load-optimized benchmark (`fillseq` with vector memtable, no WAL) and small file sizes so that a significant number of files are produced:
```
numactl --interleave=all ./db_bench --benchmarks=fillseq --allow_concurrent_memtable_write=false --level0_file_num_compaction_trigger=4 --level0_slowdown_writes_trigger=20 --level0_stop_writes_trigger=30 --max_background_jobs=8 --max_write_buffer_number=8 --db=/data/ltamasi-dbbench --wal_dir=/data/ltamasi-dbbench --num=800000000 --num_levels=8 --key_size=20 --value_size=400 --block_size=8192 --cache_size=51539607552 --cache_numshardbits=6 --compression_max_dict_bytes=0 --compression_ratio=0.5 --compression_type=lz4 --bytes_per_sync=8388608 --cache_index_and_filter_blocks=1 --cache_high_pri_pool_ratio=0.5 --benchmark_write_rate_limit=0 --write_buffer_size=16777216 --target_file_size_base=16777216 --max_bytes_for_level_base=67108864 --verify_checksum=1 --delete_obsolete_files_period_micros=62914560 --max_bytes_for_level_multiplier=8 --statistics=0 --stats_per_interval=1 --stats_interval_seconds=20 --histogram=1 --memtablerep=skip_list --bloom_bits=10 --open_files=-1 --subcompactions=1 --compaction_style=0 --min_level_to_compress=3 --level_compaction_dynamic_level_bytes=true --pin_l0_filter_and_index_blocks_in_cache=1 --soft_pending_compaction_bytes_limit=167503724544 --hard_pending_compaction_bytes_limit=335007449088 --min_level_to_compress=0 --use_existing_db=0 --sync=0 --threads=1 --memtablerep=vector --allow_concurrent_memtable_write=false --disable_wal=1 --enable_blob_files=1 --blob_file_size=16777216 --min_blob_size=0 --blob_compression_type=lz4 --enable_blob_garbage_collection=1 --seed=<some value>
```
Final statistics before the patch:
```
Cumulative writes: 0 writes, 700M keys, 0 commit groups, 0.0 writes per commit group, ingest: 284.62 GB, 121.27 MB/s
Interval writes: 0 writes, 334K keys, 0 commit groups, 0.0 writes per commit group, ingest: 139.28 MB, 72.46 MB/s
```
With the patch:
```
Cumulative writes: 0 writes, 760M keys, 0 commit groups, 0.0 writes per commit group, ingest: 308.66 GB, 131.52 MB/s
Interval writes: 0 writes, 445K keys, 0 commit groups, 0.0 writes per commit group, ingest: 185.35 MB, 93.15 MB/s
```
Total time to complete the benchmark is 2611 seconds with the patch, down from 2986 secs.
Reviewed By: riversand963
Differential Revision: D34082728
Pulled By: ltamasi
fbshipit-source-id: fc598abf676dce436734d06bb9d2d99a26a004fc
Summary:
* Add more micro-benchmark tests
* Expose an API in DBImpl for waiting for compactions (still not visible to the user)
* Add argument name for ribbon_bench
* remove benchmark run from CI, as it runs too long.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9436
Test Plan: CI
Reviewed By: riversand963
Differential Revision: D33777836
Pulled By: jay-zhuang
fbshipit-source-id: c05de3bc082cc05b5d019f00b324e774bf4bbd96
Summary:
Fix https://github.com/facebook/rocksdb/issues/8046 : FlushMemTable return ok but memtable does not synchronize flush. The way to fix it is to expose RecoveryError.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8173
Reviewed By: ajkr
Differential Revision: D31674552
Pulled By: jay-zhuang
fbshipit-source-id: 9d16b69ba12a196bb429332ec8224754de97773d
Summary:
As (https://github.com/facebook/rocksdb/issues/9210) discussed, the **full_history_ts_low** is a member of CompactRangeOptions currently, which means a CF's fullHistoryTsLow is advanced only when users submit a CompactRange request.
However, users may want to advance the fllHistoryTsLow without an immediate compact.
This merge make IncreaseFullHistoryTsLow to a public API so users can advance each CF's fullHistoryTsLow seperately.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9221
Reviewed By: akankshamahajan15
Differential Revision: D33201106
Pulled By: riversand963
fbshipit-source-id: 9cb1d013ba93260f72e16353e693ffee167b47ee
Summary:
Fix a bug that causes file temperature not preserved after DB is restarted, or options.max_manifest_file_size is hit.
Also, pass temperature information to NewRandomAccessFile() to allow users to hack a solution where they don't preserve tiering information.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9242
Test Plan: Add a unit test that would fail without the fix.
Reviewed By: jay-zhuang
Differential Revision: D32818150
fbshipit-source-id: 36aa3f148c60107f7b8e9d65b63b039f9e1a1eec
Summary:
After RocksDB 6.19 and before this PR, RocksDB FlushJob may pick more memtables to flush beyond synced WALs.
This can be problematic if there are multiple column families, since it can prematurely advance the flushed column
family's log_number. Should subsequent attempts fail to sync the latest WALs and the database goes
through a recovery, it may detect corrupted WAL number below the flushed column family's log number
and complain about column family inconsistency.
To fix, we record the maximum memtable ID of the column family being flushed. Then we call SyncClosedLogs()
so that all closed WALs at the time when memtable ID is recorded will be synced.
I also disabled a unit test temporarily due to reasons described in https://github.com/facebook/rocksdb/issues/9151
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9142
Test Plan: make check
Reviewed By: ajkr
Differential Revision: D32299956
Pulled By: riversand963
fbshipit-source-id: 0da75888177d91905cf8c9d00605b73afb5970a7
Summary:
- Fixed bug where bottom-pri manual compactions were counting towards `bg_compaction_scheduled_` instead of `bg_bottom_compaction_scheduled_`. It seems to have no negative effect.
- Fixed bug where automatic compaction scheduling did not consider `bg_bottom_compaction_scheduled_`. Now automatic compactions cannot be scheduled that exceed the per-DB compaction concurrency limit (`max_compactions`) when some existing compactions are bottommost.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9179
Test Plan: new unit test for manual/automatic. Also verified the existing automatic/automatic test ("ConcurrentBottomPriLowPriCompactions") hanged until changing it to explicitly enable concurrency.
Reviewed By: riversand963
Differential Revision: D32488048
Pulled By: ajkr
fbshipit-source-id: 20c4c0693678e81e43f85ed3cc3402fcf26e3310
Summary:
Track per-SST user-defined timestamp information in MANIFEST https://github.com/facebook/rocksdb/issues/8957
Rockdb has supported user-defined timestamp feature. Application can specify a timestamp
when writing each k-v pair. When data flush from memory to disk file called SST files, file
creation activity will commit to MANIFEST. This commit is for tracking timestamp info in the
MANIFEST for each file. The changes involved are as follows:
1) Track max/min timestamp in FileMetaData, and fix invoved codes.
2) Add NewFileCustomTag::kMinTimestamp and NewFileCustomTag::kMinTimestamp in
NewFileCustomTag ( in the kNewFile4 part ), and support invoved codes such as
VersionEdit Encode and Decode etc.
3) Add unit test code for VersionEdit EncodeDecodeNewFile4, and fix invoved test codes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9092
Reviewed By: ajkr, akankshamahajan15
Differential Revision: D32252323
Pulled By: riversand963
fbshipit-source-id: d2642898d6e3ad1fef0eb866b98045408bd4e162
Summary:
Directory fsync might be expensive on btrfs and it may not be needed.
Here are 4 directory fsync cases:
1. creating a new file: dir-fsync is not needed on btrfs, as long as the
new file itself is synced.
2. renaming a file: dir-fsync is not needed if the renamed file is
synced. So an API `FsyncAfterFileRename(filename, ...)` is provided
to sync the file on btrfs. By default, it just calls dir-fsync.
3. deleting files: dir-fsync is forced by set
`IOOptions.force_dir_fsync = true`
4. renaming multiple files (like backup and checkpoint): dir-fsync is
forced, the same as above.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8903
Test Plan: run tests on btrfs and non btrfs
Reviewed By: ajkr
Differential Revision: D30885059
Pulled By: jay-zhuang
fbshipit-source-id: dd2730b31580b0bcaedffc318a762d7dbf25de4a
Summary:
currently histogram `NUM_FILES_IN_SINGLE_COMPACTION` just counted files in first level of compaction input, this fix counts files in all levels of compaction input.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9026
Reviewed By: ajkr
Differential Revision: D31668241
Pulled By: jay-zhuang
fbshipit-source-id: c02f6c4a5df9fbf0b7510036594811152e8738af
Summary:
The bug can impact the following scenario. There must be two `CompactRange()`s, call them A and B. Compaction A must have `change_level=true`. Compactions A and B must run in parallel, and new data must be added while they run as well.
Now, on to the details of the race condition. Compaction A must reach the refitting phase while B's next step is to trivial move new data (i.e., data that has been inserted behind A) down to the same level that A's refit targets (`CompactRangeOptions::target_level`). B must be unregistered (i.e., has not yet called `AddManualCompaction()` for the current `RunManualCompaction()`) while A invokes `DisableManualCompaction()`s to prepare for refitting. In the old code, B could still proceed to register a manual compaction, while A had disabled manual compaction.
The next part of the race condition is B picks and schedules a trivial move while A has released the lock in refitting phase in order to persist the LSM state change (i.e., the log phase of `LogAndApply()`). That way, B does not see the refitted data when picking a trivial-move compaction. So it is susceptible to picking one that overlaps.
Finally, B executes the picked trivial-move compaction. Trivial-move compactions are special in that they never check whether manual compaction is disabled. So the picked compaction causing overlap ends up being applied, leading to LSM corruption if `force_consistency_checks=false`, or entering read-only mode with `Status::Corruption` if `force_consistency_checks=true` (the default).
The fix is just to prevent B from registering itself in `RunManualCompaction()` while manual compactions are disabled, consequently preventing any trivial move or other compaction from being picked/scheduled.
Thanks to siying for finding the bug.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9077
Test Plan: The test does not go all the way in exposing the bug because it requires a compaction to be picked/scheduled while logging LSM state change for RefitLevel(). But the fix is to make such a compaction not picked/scheduled in the first place, so any repro of that scenario would end up hanging RefitLevel() logging. So instead I just verified no such compaction is registered in the scenario where `RefitLevel()` disables manual compactions.
Reviewed By: siying
Differential Revision: D31921908
Pulled By: ajkr
fbshipit-source-id: 9bb5d0e847ad428211227f40830c685c209fbecb
Summary:
In atomic flush, concurrent background flush threads will commit to the MANIFEST
one by one, in the order of the IDs of their picked memtables for all included column
families. Each time, a background flush thread decides whether to wait based on two
criteria:
- Is db stopped? If so, don't wait.
- Am I the one to commit the currently earliest memtable? If so, don't wait and ready to go.
When atomic flush was implemented, error writing to or syncing the MANIFEST would
cause the db to be stopped. Therefore, this background thread does not have to check
for the background error while waiting. If there has been such an error, `DBStopped()`
would have been true, and this thread will **not** wait forever.
After we improved error handling, RocksDB may map an IOError while writing to MANIFEST
to a soft error, if there is no WAL. This requires the background threads to check for
background error while waiting. Otherwise, a background flush thread may wait forever.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9034
Test Plan: make check
Reviewed By: zhichao-cao
Differential Revision: D31639225
Pulled By: riversand963
fbshipit-source-id: e9ab07c4d8f2eade238adeefe3e42dd9a5a3ebbd
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8991
Test Plan: the new test hangs forever without this fix and passes with this fix.
Reviewed By: hx235
Differential Revision: D31456419
Pulled By: ajkr
fbshipit-source-id: a82c0e5560b6e6153089dccd8e46163c61b07bff
Summary:
This header file was including everything and the kitchen sink when it did not need to. This resulted in many places including this header when they needed other pieces instead.
Cleaned up this header to only include what was needed and fixed up the remaining code to include what was now missing.
Hopefully, this sort of code hygiene cleanup will speed up the builds...
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8930
Reviewed By: pdillinger
Differential Revision: D31142788
Pulled By: mrambacher
fbshipit-source-id: 6b45de3f300750c79f751f6227dece9cfd44085d
Summary:
1. Extend FlushJobInfo and CompactionJobInfo with information about the blob files generated by flush/compaction jobs. This PR add two structures BlobFileInfo and BlobFileGarbageInfo that contains the required information of blob files.
2. Notify the creation and deletion of blob files through OnBlobFileCreationStarted, OnBlobFileCreated, and OnBlobFileDeleted.
3. Test OnFile*Finish operations notifications with Blob Files.
4. Log the blob file creation/deletion events through EventLogger in Log file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8675
Test Plan: Add new unit tests in listener_test
Reviewed By: ltamasi
Differential Revision: D30412613
Pulled By: akankshamahajan15
fbshipit-source-id: ca51b63c6e8c8d0485a38c503572bc5a82bd5d07
Summary:
Pass BlobFileCompletionCallback in case of atomic flush and
compaction job which is currently nullptr(default parameter).
BlobFileCompletionCallback is used in case of IntegratedBlobDB to report new blob files to
SstFileManager.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8681
Test Plan: CircleCI jobs
Reviewed By: ltamasi
Differential Revision: D30445998
Pulled By: akankshamahajan15
fbshipit-source-id: ba48093843864faec57f1f365cce7b5a569c4021
Summary:
Previously, when a `FlushJob` was redirected to a MemPurge, the function `DBImpl::NotifyOnFlushComplete` was called, which created a series of issues because the JobInfo was not correctly collected from the memtables.
This diff aims at correcting these two issues (`FlushJobInfo` collection in `FlushJob::MemPurge` , no call to `DBImpl::NotifyOnFlushComplete` after successful mempurge).
Event listeners were added to the unit tests to handle these situations.
Surprisingly none of the crashtests caught this issue, I will try to add event listeners to crash tests in the future.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8672
Reviewed By: akankshamahajan15
Differential Revision: D30383109
Pulled By: bjlemaire
fbshipit-source-id: 35a8d4295886923ee4049a6447f00022cb221c73
Summary:
Changes the API of the MemPurge process: the `bool experimental_allow_mempurge` and `experimental_mempurge_policy` flags have been replaced by a `double experimental_mempurge_threshold` option.
This change of API reflects another major change introduced in this PR: the MemPurgeDecider() function now works by sampling the memtables being flushed to estimate the overall amount of useful payload (payload minus the garbage), and then compare this useful payload estimate with the `double experimental_mempurge_threshold` value.
Therefore, when the value of this flag is `0.0` (default value), mempurge is simply deactivated. On the other hand, a value of `DBL_MAX` would be equivalent to always going through a mempurge regardless of the garbage ratio estimate.
At the moment, a `double experimental_mempurge_threshold` value else than 0.0 or `DBL_MAX` is opnly supported`with the `SkipList` memtable representation.
Regarding the sampling, this PR includes the introduction of a `MemTable::UniqueRandomSample` function that collects (approximately) random entries from the memtable by using the new `SkipList::Iterator::RandomSeek()` under the hood, or by iterating through each memtable entry, depending on the target sample size and the total number of entries.
The unit tests have been readapted to support this new API.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8628
Reviewed By: pdillinger
Differential Revision: D30149315
Pulled By: bjlemaire
fbshipit-source-id: 1feef5390c95db6f4480ab4434716533d3947f27
Summary:
PR https://github.com/facebook/rocksdb/issues/5908 added `flush_jobs_info_` to `FlushJob` to make sure
`OnFlushCompleted()` is called after committing flush results to
MANIFEST. However, `flush_jobs_info_` is not updated in atomic
flush, causing `NotifyOnFlushCompleted()` to skip `OnFlushCompleted()`.
This PR fixes this, in a similar way to https://github.com/facebook/rocksdb/issues/5908 that handles regular flush.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8585
Test Plan: make check
Reviewed By: jay-zhuang
Differential Revision: D29913720
Pulled By: riversand963
fbshipit-source-id: 4ff023c98372fa2c93188d4a5c8a4e9ffa0f4dda
Summary:
The `ColumnFamilyData::UnrefAndTryDelete` code currently on the trunk
unlocks the DB mutex before destroying the `ThreadLocalPtr` holding
the per-thread `SuperVersion` pointers when the only remaining reference
is the back reference from `super_version_`. The idea behind this was to
break the circular dependency between `ColumnFamilyData` and `SuperVersion`:
when the penultimate reference goes away, `ColumnFamilyData` can clean up
the `SuperVersion`, which can in turn clean up `ColumnFamilyData`. (Assuming there
is a `SuperVersion` and it is not referenced by anything else.) However,
unlocking the mutex throws a wrench in this plan by making it possible for another thread
to jump in and take another reference to the `ColumnFamilyData`, keeping the
object alive in a zombie `ThreadLocalPtr`-less state. This can cause issues like
https://github.com/facebook/rocksdb/issues/8440 ,
https://github.com/facebook/rocksdb/issues/8382 ,
and might also explain the `was_last_ref` assertion failures from the `ColumnFamilySet`
destructor we sometimes observe during close in our stress tests.
Digging through the archives, this unlocking goes way back to 2014 (or earlier). The original
rationale was that `SuperVersionUnrefHandle` used to lock the mutex so it can call
`SuperVersion::Cleanup`; however, this logic turned out to be deadlock-prone.
https://github.com/facebook/rocksdb/pull/3510 fixed the deadlock but left the
unlocking in place. https://github.com/facebook/rocksdb/pull/6147 then introduced
the circular dependency and associated cleanup logic described above (in order
to enable iterators to keep the `ColumnFamilyData` for dropped column families alive),
and moved the unlocking-relocking snippet to its present location in `UnrefAndTryDelete`.
Finally, https://github.com/facebook/rocksdb/pull/7749 fixed a memory leak but
apparently exacerbated the race by (otherwise correctly) switching to `UnrefAndTryDelete`
in `SuperVersion::Cleanup`.
The patch simply eliminates the unlocking and relocking, which has been unnecessary
ever since https://github.com/facebook/rocksdb/issues/3510 made `SuperVersionUnrefHandle` lock-free.
This closes the window during which another thread could increase the reference count,
and hopefully fixes the issues above.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8605
Test Plan: Ran `make check` and stress tests locally.
Reviewed By: pdillinger
Differential Revision: D30051035
Pulled By: ltamasi
fbshipit-source-id: 8fe559e4b4ad69fc142579f8bc393ef525918528
Summary:
Rare TSAN and valgrind failures are caused by unnecessary
reading of a field on the TaskLimiterToken::limiter_ for an assertion
after the token has been released and the limiter destroyed. To simplify
we can simply destroy the token before triggering DB shutdown
(potentially destroying the limiter). This makes the ReleaseOnce logic
unnecessary.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8567
Test Plan: watch for more failures in CI
Reviewed By: ajkr
Differential Revision: D29811795
Pulled By: pdillinger
fbshipit-source-id: 135549ebb98fe4f176d1542ed85d5bd6350a40b3
Summary:
In this PR, `mempurge` is made compatible with the Write Ahead Log: in case of recovery, the DB is now capable of recovering the data that was "mempurged" and kept in the `imm()` list of immutable memtables.
The twist was to add a uint64_t to the `memtable` struct to store the number of the earliest log file containing entries from the `memtable`. When a `Flush` operation is replaced with a `MemPurge`, the `VersionEdit` (which usually contains the new min log file number to pick up for recovery and the level 0 file path of the newly created SST file) is no longer appended to the manifest log, and every time the `deleteWal` method is called, a check is made on the list of immutable memtables.
This PR also includes a unit test that verifies that no data is lost upon Reopening of the database when the mempurge feature is activated. This extensive unit test includes two column families, with valid data contained in the imm() at time of "crash"/reopening (recovery).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8528
Reviewed By: pdillinger
Differential Revision: D29701097
Pulled By: bjlemaire
fbshipit-source-id: 072a900fb6ccc1edcf5eef6caf88f3060238edf9
Summary:
In https://github.com/facebook/rocksdb/issues/8454, I introduced a new process baptized `MemPurge` (memtable garbage collection). This new PR is built upon this past mempurge prototype.
In this PR, I made the `mempurge` process a background task, which provides superior performance since the mempurge process does not cling on the db_mutex anymore, and addresses severe restrictions from the past iteration (including a scenario where the past mempurge was failling, when a memtable was mempurged but was still referred to by an iterator/snapshot/...).
Now the mempurge process ressembles an in-memory compaction process: the stack of immutable memtables is filtered out, and the useful payload is used to populate an output memtable. If the output memtable is filled at more than 60% capacity (arbitrary heuristic) the mempurge process is aborted and a regular flush process takes place, else the output memtable is kept in the immutable memtable stack. Note that adding this output memtable to the `imm()` memtable stack does not trigger another flush process, so that the flush thread can go to sleep at the end of a successful mempurge.
MemPurge is activated by making the `experimental_allow_mempurge` flag `true`. When activated, the `MemPurge` process will always happen when the flush reason is `kWriteBufferFull`.
The 3 unit tests confirm that this process supports `Put`, `Get`, `Delete`, `DeleteRange` operators and is compatible with `Iterators` and `CompactionFilters`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8505
Reviewed By: pdillinger
Differential Revision: D29619283
Pulled By: bjlemaire
fbshipit-source-id: 8a99bee76b63a8211bff1a00e0ae32360aaece95
Summary:
Implement an experimental feature called "MemPurge", which consists in purging "garbage" bytes out of a memtable and reuse the memtable struct instead of making it immutable and eventually flushing its content to storage.
The prototype is by default deactivated and is not intended for use. It is intended for correctness and validation testing. At the moment, the "MemPurge" feature can be switched on by using the `options.experimental_allow_mempurge` flag. For this early stage, when the allow_mempurge flag is set to `true`, all the flush operations will be rerouted to perform a MemPurge. This is a temporary design decision that will give us the time to explore meaningful heuristics to use MemPurge at the right time for relevant workloads . Moreover, the current MemPurge operation only supports `Puts`, `Deletes`, `DeleteRange` operations, and handles `Iterators` as well as `CompactionFilter`s that are invoked at flush time .
Three unit tests are added to `db_flush_test.cc` to test if MemPurge works correctly (and checks that the previously mentioned operations are fully supported thoroughly tested).
One noticeable design decision is the timing of the MemPurge operation in the memtable workflow: for this prototype, the mempurge happens when the memtable is switched (and usually made immutable). This is an inefficient process because it implies that the entirety of the MemPurge operation happens while holding the db_mutex. Future commits will make the MemPurge operation a background task (akin to the regular flush operation) and aim at drastically enhancing the performance of this operation. The MemPurge is also not fully "WAL-compatible" yet, but when the WAL is full, or when the regular MemPurge operation fails (or when the purged memtable still needs to be flushed), a regular flush operation takes place. Later commits will also correct these behaviors.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8454
Reviewed By: anand1976
Differential Revision: D29433971
Pulled By: bjlemaire
fbshipit-source-id: 6af48213554e35048a7e03816955100a80a26dc5
Summary:
This is the next part of the ImmutableOptions cleanup. After changing the use of ImmutableCFOptions to ImmutableOptions, there were places in the code that had did something like "ImmutableOptions* immutable_cf_options", where "cf" referred to the "old" type.
This change simply renames the variables to match the current type. No new functionality is introduced.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8409
Reviewed By: pdillinger
Differential Revision: D29166248
Pulled By: mrambacher
fbshipit-source-id: 96de97f8e743f5c5160f02246e3ed8269556dc6f
Summary:
Added the ability to cancel an in-progress range compaction by storing to an atomic "canceled" variable pointed to within the CompactRangeOptions structure.
Tested via two tests added to db_tests2.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8351
Reviewed By: ajkr
Differential Revision: D28808894
Pulled By: ddevec
fbshipit-source-id: cb321361c9e23b084b188bb203f11c375a22c2dd
Summary:
Previously the shutdown process did not properly wait for all
`compaction_thread_limiter` tokens to be released before proceeding to
delete the DB's C++ objects. When this happened, we saw tests like
"DBCompactionTest.CompactionLimiter" flake with the following error:
```
virtual
rocksdb::ConcurrentTaskLimiterImpl::~ConcurrentTaskLimiterImpl():
Assertion `outstanding_tasks_ == 0' failed.
```
There is a case where a token can still be alive even after the shutdown
process has waited for BG work to complete. In particular, this happens
because the shutdown process only waits for flush/compaction scheduled/unscheduled counters to all
reach zero. These counters are decremented in `BackgroundCallCompaction()`
functions. However, tokens are released in `BGWork*Compaction()` functions, which
actually wrap the `BackgroundCallCompaction()` function.
A simple sleep could repro the race condition:
```
$ diff --git a/db/db_impl/db_impl_compaction_flush.cc
b/db/db_impl/db_impl_compaction_flush.cc
index 806bc548a..ba59efa89 100644
--- a/db/db_impl/db_impl_compaction_flush.cc
+++ b/db/db_impl/db_impl_compaction_flush.cc
@@ -2442,6 +2442,7 @@ void DBImpl::BGWorkCompaction(void* arg) {
static_cast<PrepickedCompaction*>(ca.prepicked_compaction);
static_cast_with_check<DBImpl>(ca.db)->BackgroundCallCompaction(
prepicked_compaction, Env::Priority::LOW);
+ sleep(1);
delete prepicked_compaction;
}
$ ./db_compaction_test --gtest_filter=DBCompactionTest.CompactionLimiter
db_compaction_test: util/concurrent_task_limiter_impl.cc:24: virtual rocksdb::ConcurrentTaskLimiterImpl::~ConcurrentTaskLimiterImpl(): Assertion `outstanding_tasks_ == 0' failed.
Received signal 6 (Aborted)
#0 /usr/local/fbcode/platform007/lib/libc.so.6(gsignal+0xcf) [0x7f02673c30ff] ?? ??:0
https://github.com/facebook/rocksdb/issues/1 /usr/local/fbcode/platform007/lib/libc.so.6(abort+0x134) [0x7f02673ac934] ?? ??:0
...
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8253
Test Plan: sleeps to expose race conditions
Reviewed By: akankshamahajan15
Differential Revision: D28168064
Pulled By: ajkr
fbshipit-source-id: 9e5167c74398d323e7975980c5cc00f450631160
Summary:
In current RocksDB, in recover the information form WAL, we do the consistency check for each column family when one WAL file is corrupted and PointInTimeRecovery is set. However, it will report a false positive alert on "SST file is ahead of WALs" when one of the CF current log number is greater than the corrupted WAL number (CF contains the data beyond the corrupted WAl) due to a new column family creation during flush. In this case, a new WAL is created (it is empty) during a flush. Also, due to some reason (e.g., storage issue or crash happens before SyncCloseLog is called), the old WAL is corrupted. The new CF has no data, therefore, it does not have the consistency issue.
Fix: when checking cfd->GetLogNumber() > corrupted_wal_number also check cfd->GetLiveSstFilesSize() > 0. So the CFs with no SST file data will skip the check here.
Note potential ignored inconsistency caused due to fix: empty CF can also be caused by write+delete. In this case, after flush, there is no SST files being generated. However, this CF still have the log in the WAL. When the WAL is corrupted, the DB might be inconsistent.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8207
Test Plan: added unit test, make crash_test
Reviewed By: riversand963
Differential Revision: D27898839
Pulled By: zhichao-cao
fbshipit-source-id: 931fc2d8b92dd00b4169bf84b94e712fd688a83e
Summary:
Add comment to DisableManualCompaction() which was missing.
Also explictly return from DBImpl::CompactRange() to avoid memtable flush when manual compaction is disabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8186
Test Plan: Run existing unit tests.
Reviewed By: jay-zhuang
Differential Revision: D27744517
fbshipit-source-id: 449548a48905903b888dc9612bd17480f6596a71
Summary:
In DBImpl::CloseHelper, we wait for bg_compaction_scheduled_
and bg_flush_scheduled_ to drop to 0. Unschedule is called prior
to cancel any unscheduled flushes/compactions. It is assumed that
anything in the high priority is a flush, and anything in the low
priority pool is a compaction. This assumption, however, is broken when
the high-pri pool is full.
As a result, bg_compaction_scheduled_ can go < 0 and bg_flush_scheduled_
will remain > 0 and DB can be in hang state.
The fix is, we decrement the `bg_{flush,compaction,bottom_compaction}_scheduled_`
inside the `Unschedule{Flush,Compaction,BottomCompaction}Callback()`s. DB
`mutex_` will make the counts atomic in `Unschedule`.
Related discussion: https://github.com/facebook/rocksdb/issues/7928
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8125
Test Plan: Added new test case which hangs without the fix.
Reviewed By: jay-zhuang
Differential Revision: D27390043
Pulled By: ajkr
fbshipit-source-id: 78a367fba9a59ac5607ad24bd1c46dc16d5ec110
Summary:
There is bug in the current code base introduced in https://github.com/facebook/rocksdb/issues/8049 , we still set the SST file write IO Error only case as hard error. Fix it by removing the logic.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8107
Test Plan: make check, error_handler_fs_test
Reviewed By: anand1976
Differential Revision: D27321422
Pulled By: zhichao-cao
fbshipit-source-id: c014afc1553ca66b655e3bbf9d0bf6eb417ccf94
Summary:
In previous codebase, if WAL is used, all the retryable IO Error will be treated as hard error. So write is stalled. In this PR, the retryable IO error from WAL sync is separated from SST file flush io error. If WAL Sync is ok and retryable IO Error only happens during SST flush, the error is mapped to soft error. So user can continue insert to Memtable and append to WAL.
Resolve the bug that if WAL sync fails, the memtable status does not roll back due to calling PickMemtable early than calling and checking SyncClosedLog.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8049
Test Plan: added new unit test, make check
Reviewed By: anand1976
Differential Revision: D26965529
Pulled By: zhichao-cao
fbshipit-source-id: f5fecb66602212523c92ee49d7edcb6065982410
Summary:
Extend support to track blob files in SST File manager.
This PR notifies SstFileManager whenever a new blob file is created,
via OnAddFile and an obsolete blob file deleted via OnDeleteFile
and delete file via ScheduleFileDeletion.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8037
Test Plan: Add new unit tests
Reviewed By: ltamasi
Differential Revision: D26891237
Pulled By: akankshamahajan15
fbshipit-source-id: 04c69ccfda2a73782fd5c51982dae58dd11979b6
Summary:
For performance purposes, the lower level routines were changed to use a SystemClock* instead of a std::shared_ptr<SystemClock>. The shared ptr has some performance degradation on certain hardware classes.
For most of the system, there is no risk of the pointer being deleted/invalid because the shared_ptr will be stored elsewhere. For example, the ImmutableDBOptions stores the Env which has a std::shared_ptr<SystemClock> in it. The SystemClock* within the ImmutableDBOptions is essentially a "short cut" to gain access to this constant resource.
There were a few classes (PeriodicWorkScheduler?) where the "short cut" property did not hold. In those cases, the shared pointer was preserved.
Using db_bench readrandom perf_level=3 on my EC2 box, this change performed as well or better than 6.17:
6.17: readrandom : 28.046 micros/op 854902 ops/sec; 61.3 MB/s (355999 of 355999 found)
6.18: readrandom : 32.615 micros/op 735306 ops/sec; 52.7 MB/s (290999 of 290999 found)
PR: readrandom : 27.500 micros/op 871909 ops/sec; 62.5 MB/s (367999 of 367999 found)
(Note that the times for 6.18 are prior to revert of the SystemClock).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8033
Reviewed By: pdillinger
Differential Revision: D27014563
Pulled By: mrambacher
fbshipit-source-id: ad0459eba03182e454391b5926bf5cdd45657b67
Summary:
## 1. Bug description:
When RocksDB Checkpoint, it may be stuck in `WaitUntilFlushWouldNotStallWrites` method.
## 2. Simple analysis of the reasons:
### 2.1 Configuration parameters:
```yaml
Compaction Style : Universal
max_write_buffer_number : 4
min_write_buffer_number_to_merge : 3
```
Checkpoint is usually very fast. When the Checkpoint is executed, `WaitUntilFlushWouldNotStallWrites` is called. If there are 2 Immutable MemTables, which are less than `min_write_buffer_number_to_merge`, they will not be flushed. But will enter this code.
```c++
// method: GetWriteStallConditionAndCause
if (mutable_cf_options.max_write_buffer_number> 3 &&
num_unflushed_memtables >=
mutable_cf_options.max_write_buffer_number-1) {
return {WriteStallCondition::kDelayed, WriteStallCause::kMemtableLimit};
}
```
code link: fbed72f03c/db/column_family.cc (L847)
Checkpoint thought there was a FlushJob, but it didn't. So will always wait.
### 2.2 solution:
Increase the restriction: the `number of Immutable MemTable` >= `min_write_buffer_number_to_merge will wait`.
If there are other better solutions, you can correct me.
### 2.3 Code that can reproduce the problem:
https://github.com/1996fanrui/fanrui-learning/blob/flink-1.12/module-java/src/main/java/com/dream/rocksdb/RocksDBCheckpointStuck.java
## 3. Interesting point
This bug will be triggered only when `the number of sorted runs >= level0_file_num_compaction_trigger`.
Because there is a break in WaitUntilFlushWouldNotStallWrites.
```c++
if (cfd->imm()->NumNotFlushed() <
cfd->ioptions()->min_write_buffer_number_to_merge &&
vstorage->l0_delay_trigger_count() <
mutable_cf_options.level0_file_num_compaction_trigger) {
break;
}
```
code link: fbed72f03c/db/db_impl/db_impl_compaction_flush.cc (L1974)
Universal may have `l0_delay_trigger_count() >= level0_file_num_compaction_trigger`, so this bug is triggered.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7921
Reviewed By: jay-zhuang
Differential Revision: D26900559
Pulled By: ajkr
fbshipit-source-id: 133c1252dad7393753f04a47590b68c7d8e670df
Summary:
Introduces and uses a SystemClock class to RocksDB. This class contains the time-related functions of an Env and these functions can be redirected from the Env to the SystemClock.
Many of the places that used an Env (Timer, PerfStepTimer, RepeatableThread, RateLimiter, WriteController) for time-related functions have been changed to use SystemClock instead. There are likely more places that can be changed, but this is a start to show what can/should be done. Over time it would be nice to migrate most (if not all) of the uses of the time functions from the Env to the SystemClock.
There are several Env classes that implement these functions. Most of these have not been converted yet to SystemClock implementations; that will come in a subsequent PR. It would be good to unify many of the Mock Timer implementations, so that they behave similarly and be tested similarly (some override Sleep, some use a MockSleep, etc).
Additionally, this change will allow new methods to be introduced to the SystemClock (like https://github.com/facebook/rocksdb/issues/7101 WaitFor) in a consistent manner across a smaller number of classes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7858
Reviewed By: pdillinger
Differential Revision: D26006406
Pulled By: mrambacher
fbshipit-source-id: ed10a8abbdab7ff2e23d69d85bd25b3e7e899e90
Summary:
The returned Status is ignored here as some stress tests are failing, presumably when attempting to add an empty file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7826
Reviewed By: jay-zhuang
Differential Revision: D25742931
fbshipit-source-id: a1fcd620d9472993a009929306dfc421f93eb43b
Summary:
Added "no-elide-constructors to the ASSERT_STATUS_CHECK builds. This flag gives more errors/warnings for some of the Status checks where an inner class checks a Status and later returns it. In this case, without the elide check on, the returned status may not have been checked in the caller, thereby bypassing the checked code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7798
Reviewed By: jay-zhuang
Differential Revision: D25680451
Pulled By: pdillinger
fbshipit-source-id: c3f14ed9e2a13f0a8c54d839d5fb4d1fc1e93917
Summary:
When ConcurrentTaskLimiter is enabled and there are too many outstanding compactions, BackgroundCompaction returns Status::Busy(), which shouldn't be treat as compaction failure.
This caused performance issue when outstanding compactions reached the limit.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7739
Reviewed By: cheng-chang
Differential Revision: D25508319
Pulled By: ltamasi
fbshipit-source-id: 3b181b16ada0ca3393cfa3a7412985764e79c719
Summary:
This change eliminates the need for a lot of the PermitUncheckedError calls on return from ErrorHandler methods. The calls are no longer needed as the status is returned as a reference rather than a copy. Additionally, this means that the originating status (recovery_error_, bg_error_) is not cleared implicitly as a result of calling one of these methods.
For this class, I do not know if the proper behavior should be to call PermitUncheckedError in the destructor or if the checked state should be cleared when the status is cleared. I did tests both ways. Without the code in the destructor, the status will need to be cleared in at least some of the places where it is set to OK. When running tests, I found no instances where this class was destructed with a non-OK, non-checked Status.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7539
Reviewed By: anand1976
Differential Revision: D25340565
Pulled By: pdillinger
fbshipit-source-id: 1730c035c81a475875ea745226112030ec25136c
Summary:
Following https://github.com/facebook/rocksdb/issues/7655 and https://github.com/facebook/rocksdb/issues/7657, this PR adds `full_history_ts_low_` to `ColumnFamilyData`.
`ColumnFamilyData::full_history_ts_low_` will be used to create `FlushJob` and `CompactionJob`.
`ColumnFamilyData::full_history_ts_low` is persisted to the MANIFEST file. An application can only
increase its value. Consider the following case:
>
> The database has a key at ts=950. `full_history_ts_low` is first set to 1000, and then a GC is triggered
> and cleans up all data older than 1000. If the application sets `full_history_ts_low` to 900 afterwards,
> and tries to read at ts=960, the key at 950 is not seen. From the perspective of the read, the result
> is hard to reason. For simplicity, we just do now allow decreasing full_history_ts_low for now.
>
During recovery, the value of `full_history_ts_low` is restored for each column family if applicable. Note that
version edits in the MANIFEST file for the same column family may have `full_history_ts_low` unsorted due
to the potential interleaving of `LogAndApply` calls. Only the max will be used to restore the state of the
column family.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7740
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D25296217
Pulled By: riversand963
fbshipit-source-id: 24acda1df8262cd7cfdc6ce7b0ec56438abe242a
Summary:
In current code base, in FlushMemtable, when `(Flush_reason == FlushReason::kErrorRecoveryRetryFlush && (!cfd->mem()->IsEmpty() || !cached_recoverable_state_empty_.load()))`, we assert that cfd->imm()->NumNotFlushed() > 0. However, there are some corner cases that can fail this assert: 1) if there are multiple CFs, some CF has immutable memtable, some CFs don't. In ResumeImpl, all CFs will call FlushMemtable, which will hit the assert. 2) Regular flush is scheduled and running, the resume thread is waiting. New KVs are inserted and SchedulePendingFlush is called. Regular flush will continue call MaybeScheduleFlushAndCompaction until all the immutable memtables are flushed. When regular flush ends and auto resume thread starts to schedule new flushes, cfd->imm()->NumNotFlushed() can be 0.
Remove the assert and added the comments.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7744
Test Plan: make check and pass the stress test
Reviewed By: riversand963
Differential Revision: D25340573
Pulled By: zhichao-cao
fbshipit-source-id: eac357bdace660247c197f01a9ff6857e3c97672
Summary:
When 2 phase commit is enabled, if there are prepared data in a WAL, the WAL should be kept, the minimum log number for such a WAL is written to MANIFEST during flush. In atomic flush, such information is not written to MANIFEST.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7570
Test Plan: Added a new unit test `DBAtomicFlushTest.ManualFlushUnder2PC`, this test fails in atomic flush without this PR, after this PR, it succeeds.
Reviewed By: riversand963
Differential Revision: D24394222
Pulled By: cheng-chang
fbshipit-source-id: 60ce74b21b704804943be40c8de01b41269cf116
