Commit graph

124 commits

Author SHA1 Message Date
Yu Zhang 44aceb88d0 Add a OnManualFlushScheduled callback in event listener (#12631)
Summary:
As titled. Also added the newest user-defined timestamp into the `MemTableInfo`. This can be a useful info in the callback.

Added some unit tests as examples for how users can use two separate approaches to allow manual flush / manual compactions to go through when the user-defined timestamps in memtable only feature is enabled. One approach relies on selectively increase cutoff timestamp in `OnMemtableSeal` callback when it's initiated by a manual flush. Another approach is to increase cutoff timestamp in `OnManualFlushScheduled` callback. The caveats of the approaches are also documented in the unit test.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12631

Reviewed By: ajkr

Differential Revision: D58260528

Pulled By: jowlyzhang

fbshipit-source-id: bf446d7140affdf124744095e0a179fa6e427532
2024-06-06 17:29:01 -07:00
Yu Zhang fc59d8f9c6 Add public API WriteWithCallback to support custom callbacks (#12603)
Summary:
This PR adds a `DB::WriteWithCallback` API that does the same things as `DB::Write` while takes an argument `UserWriteCallback` to execute custom callback functions during the write.

We currently support two types of callback functions: `OnWriteEnqueued` and `OnWalWriteFinish`. The former is invoked   after the write is enqueued, and the later is invoked after WAL write finishes when applicable.

These callback functions are intended for users to use to improve synchronization between concurrent writes, their execution is on the write's critical path so it will impact the write's latency if not used properly. The documentation for the callback interface mentioned this and suggest user to keep these callback functions' implementation minimum.

Although transaction interfaces' writes doesn't yet allow user to specify such a user write callback argument, the `DBImpl::Write*` type of APIs do not differentiate between regular DB writes or writes coming from the transaction layer when it comes to supporting this `UserWriteCallback`. These callbacks works for all the write modes including: default write mode, Options.two_write_queues, Options.unordered_write, Options.enable_pipelined_write

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12603

Test Plan: Added unit test in ./write_callback_test

Reviewed By: anand1976

Differential Revision: D58044638

Pulled By: jowlyzhang

fbshipit-source-id: 87a84a0221df8f589ec8fc4d74597e72ce97e4cd
2024-05-31 19:30:19 -07:00
Rulin Huang 20777b96cb Optimizations in notify-one (#12545)
Summary:
We tested on icelake server (vcpu=160). The default configuration is allow_concurrent_memtable_write=1, thread number =activate core number. With our optimizations, the improvement can reach up to 184% in fillseq case. op/s is as the performance indicator in db_bench, and the following are performance improvements in some cases in db_bench.
| case name          | optimized/original  |
|-------------------:|--------------------:|
| fillrandom         | 182%                |
| fillseq            | 184%                |
| fillsync           | 136%                |
| overwrite          | 179%                |
| randomreplacekeys  | 180%                |
| randomtransaction  | 161%                |
| updaterandom       | 163%                |
| xorupdaterandom    | 165%                |

With analysis, we find that although the process of writing memtable is processed in parallel, the process of waking up the writers is not processed in parallel, which means that only one writers is responsible for the sequential waking up other writers. The following is our method to optimize this process.

Assume that there are currently n threads in total, we parallelize SetState in LaunchParallelMemTableWriters. To wake up each writer to write its own memtable, the leader writer first wakes up the (n^0.5-1) caller writers, and then those callers and the leader will wake up n/x separately to write to the memtable. This reduces the number for the leader's to SetState n-1 writers to 2*(n^0.5) writers in turn.

A reproduction script:
./db_bench --benchmarks="fillrandom"  --threads ${number of all activate vcpu}  --seed 1708494134896523  --duration 60

![image](https://github.com/facebook/rocksdb/assets/22110918/c5eca02f-93b3-4434-bba2-5155fc892a97)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12545

Reviewed By: ajkr

Differential Revision: D57422827

Pulled By: cbi42

fbshipit-source-id: 94127937c0c61e4241720bd902c82c607b7b2431
2024-05-30 09:10:44 -07:00
Changyu Bi af3be5255a Fail DeleteRange() early when row_cache is configured (#12710)
Summary:
https://github.com/facebook/rocksdb/issues/12512 added the sanity check for this incompatible combination. However, it does the check during memtable insertion which can turn the DB into read-only mode. This PR moves the check earlier so that this write failure will not turn the DB into read-only mode and affect other DB operations.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12710

Test Plan: * updated unit test `DBRangeDelTest.RowCache` to write to DB after a failed DeleteRange(). The test fails before this PR.

Reviewed By: ajkr

Differential Revision: D57925188

Pulled By: cbi42

fbshipit-source-id: 8bf001bd3fcf05635411ba28bc4a037321942879
2024-05-29 15:03:15 -07:00
Peter Dillinger d89ab23bec Disallow memtable flush and sst ingest while WAL is locked (#12652)
Summary:
We recently noticed that some memtable flushed and file
ingestions could proceed during LockWAL, in violation of its stated
contract. (Note: we aren't 100% sure its actually needed by MySQL, but
we want it to be in a clean state nonetheless.)

Despite earlier skepticism that this could be done safely (https://github.com/facebook/rocksdb/issues/12666), I
found a place to wait to wait for LockWAL to be cleared before allowing
these operations to proceed: WaitForPendingWrites()

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12652

Test Plan:
Added to unit tests. Extended how db_stress validates LockWAL
and re-enabled combination of ingestion and LockWAL in crash test, in
follow-up to https://github.com/facebook/rocksdb/issues/12642

Ran blackbox_crash_test for a long while with relevant features
amplified.

Suggested follow-up: fix FaultInjectionTestFS to report file sizes
consistent with what the user has requested to be flushed.

Reviewed By: jowlyzhang

Differential Revision: D57622142

Pulled By: pdillinger

fbshipit-source-id: aef265fce69465618974b4ec47f4636257c676ce
2024-05-21 10:17:34 -07:00
Peter Dillinger b75438f986 Allow disableWAL+recycle with WritePreparedTxnDB internals (#12639)
Summary:
Follow-up from https://github.com/facebook/rocksdb/issues/12403

The crash test was periodically failing with the
"disableWAL option is not supported if recycle_log_file_num > 0" failure, despite not setting the disableWAL from the user side.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12639

Test Plan: db_stress reproducer now passes. Added WAL recycling to txn DB unit tests, which is generally more difficult for correctness. Many tests now cover this change and pass.

Reviewed By: anand1976

Differential Revision: D57227617

Pulled By: pdillinger

fbshipit-source-id: db9abefeb505bce624b45bc64009694d2a5baed9
2024-05-10 17:56:40 -07:00
anand76 63a105a481 Enable recycle_log_file_num option for point in time recovery (#12403)
Summary:
This option was previously disabled due to a bug in the recovery logic. The recovery code in `DBImpl::RecoverLogFiles` couldn't tell if an EoF reported by the log reader was really an EoF or a possible corruption that made a record look like an old log record. To fix this, the log reader now explicitly reports when it encounters what looks like an old record. The recovery code treats it as a possible corruption, and uses the next sequence number in the WAL to determine if it should continue replaying the WAL.

This PR also fixes a couple of bugs that log file recycling exposed in the backup and checkpoint path.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12403

Test Plan:
1. Add new unit tests to verify behavior upon corruption
2. Re-enable disabled tests for verifying recycling behavior

Reviewed By: ajkr

Differential Revision: D54544824

Pulled By: anand1976

fbshipit-source-id: 12f5ce39bd6bc0d63b0bc6432dc4db510e0e802a
2024-03-21 12:29:35 -07:00
yuzhangyu@fb.com 1cfdece85d Run internal cpp modernizer on RocksDB repo (#12398)
Summary:
When internal cpp modernizer attempts to format rocksdb code, it will replace macro `ROCKSDB_NAMESPACE`  with its default definition `rocksdb` when collapsing nested namespace. We filed a feedback for the tool T180254030 and the team filed a bug for this: https://github.com/llvm/llvm-project/issues/83452. At the same time, they suggested us to run the modernizer tool ourselves so future auto codemod attempts will be smaller. This diff contains:

Running
`xplat/scripts/codemod_service/cpp_modernizer.sh`
in fbcode/internal_repo_rocksdb/repo (excluding some directories in utilities/transactions/lock/range/range_tree/lib that has a non meta copyright comment)
without swapping out the namespace macro `ROCKSDB_NAMESPACE`

Followed by RocksDB's own
`make format`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/12398

Test Plan: Auto tests

Reviewed By: hx235

Differential Revision: D54382532

Pulled By: jowlyzhang

fbshipit-source-id: e7d5b40f9b113b60e5a503558c181f080b9d02fa
2024-03-04 10:08:32 -08:00
Changyu Bi 4aed229fa7 Add write_memtable_time to perf level kEnableWait (#12394)
Summary:
.. so write time can be measured under the new perf level for single-threaded writes.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12394

Test Plan: * add a new UT `PerfContextTest.WriteMemtableTimePerfLevel`

Reviewed By: anand1976

Differential Revision: D54326263

Pulled By: cbi42

fbshipit-source-id: d0e334d9581851ba6cf53c776c0bd876365d1e00
2024-02-29 15:08:26 -08:00
anand76 d9c0d44dab Add a perf level for measuring user thread block time (#12368)
Summary:
Enabling time PerfCounter stats in RocksDB is currently very expensive, as it enables all sorts of relatively uninteresting stats, such as iteration, point lookup breakdown etc. This PR adds a new perf level between `kEnableCount` and `kEnableTimeExceptForMutex` to enable stats for time spent by user (i.e a RocksDB user) threads blocked by other RocksDB threads or events, such as a write group leader, write delay or stalls etc. It does not include time spent waiting to acquire mutexes, or waiting for IO.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12368

Test Plan: Add a unit test for write_thread_wait_nanos

Reviewed By: ajkr

Differential Revision: D54021583

Pulled By: anand1976

fbshipit-source-id: 3f6fcf71010132ffffca0391a5565f3b59fddd48
2024-02-22 12:14:53 -08:00
Chdy fc48af33f5 fix some perf statistic in write (#12285)
Summary:
### Summary:  perf context lack statistics in some write steps
```
rocksdb::get_perf_context()->write_wal_time);
rocksdb::get_perf_context()->write_memtable_time);
rocksdb::get_perf_context()->write_pre_and_post_process_time);
```

#### case 1:
when the unordered_write is true, the `write_memtable_time` is 0
```
write_wal_time : 13.7012
write_memtable_time : 0
write_pre_and_post_process_time : 142.037
```

Reason: `DBImpl::UnorderedWriteMemtable` function has no statistical `write_memtable_time` during insert memtable,

```c++
Status DBImpl::UnorderedWriteMemtable(const WriteOptions& write_options,
                                      WriteBatch* my_batch,
                                      WriteCallback* callback, uint64_t log_ref,
                                      SequenceNumber seq,
                                      const size_t sub_batch_cnt) {
	...
  if (w.CheckCallback(this) && w.ShouldWriteToMemtable()) {

    // need calculate write_memtable_time
    ColumnFamilyMemTablesImpl column_family_memtables(
        versions_->GetColumnFamilySet());
    w.status = WriteBatchInternal::InsertInto(
        &w, w.sequence, &column_family_memtables, &flush_scheduler_,
        &trim_history_scheduler_, write_options.ignore_missing_column_families,
        0 /*log_number*/, this, true /*concurrent_memtable_writes*/,
        seq_per_batch_, sub_batch_cnt, true /*batch_per_txn*/,
        write_options.memtable_insert_hint_per_batch);
    if (write_options.disableWAL) {
      has_unpersisted_data_.store(true, std::memory_order_relaxed);
    }
  }
	...
}
```
Fix: add perf function
```
write_wal_time : 14.3991
write_memtable_time : 19.3367
write_pre_and_post_process_time : 130.441
```

#### case 2:
when the enable_pipelined_write is true, the `write_memtable_time` is small
```
write_wal_time : 11.2986
write_memtable_time : 1.0205
write_pre_and_post_process_time : 140.131
```

Fix: `DBImpl::UnorderedWriteMemtable` function has no statistical `write_memtable_time` when `w.state == WriteThread::STATE_PARALLEL_MEMTABLE_WRITER`
```c++
Status DBImpl::PipelinedWriteImpl(const WriteOptions& write_options,
                                  WriteBatch* my_batch, WriteCallback* callback,
                                  uint64_t* log_used, uint64_t log_ref,
                                  bool disable_memtable, uint64_t* seq_used) {
  ...
  if (w.state == WriteThread::STATE_PARALLEL_MEMTABLE_WRITER) {
    // need calculate write_memtable_time

    assert(w.ShouldWriteToMemtable());
    ColumnFamilyMemTablesImpl column_family_memtables(
        versions_->GetColumnFamilySet());
    w.status = WriteBatchInternal::InsertInto(
        &w, w.sequence, &column_family_memtables, &flush_scheduler_,
        &trim_history_scheduler_, write_options.ignore_missing_column_families,
        0 /*log_number*/, this, true /*concurrent_memtable_writes*/,
        false /*seq_per_batch*/, 0 /*batch_cnt*/, true /*batch_per_txn*/,
        write_options.memtable_insert_hint_per_batch);

    if (write_thread_.CompleteParallelMemTableWriter(&w)) {
      MemTableInsertStatusCheck(w.status);
      versions_->SetLastSequence(w.write_group->last_sequence);
      write_thread_.ExitAsMemTableWriter(&w, *w.write_group);
    }
  }
  if (seq_used != nullptr) {
    *seq_used = w.sequence;
  }

  assert(w.state == WriteThread::STATE_COMPLETED);
  return w.FinalStatus();
}
```
FIx: add perf function
```
write_wal_time : 10.5201
write_memtable_time : 17.1048
write_pre_and_post_process_time : 114.313
```

#### case3:
`DBImpl::WriteImplWALOnly` function has no statistical `write_delay_time`
```c++
Status DBImpl::WriteImplWALOnly(
    WriteThread* write_thread, const WriteOptions& write_options,
    WriteBatch* my_batch, WriteCallback* callback, uint64_t* log_used,
    const uint64_t log_ref, uint64_t* seq_used, const size_t sub_batch_cnt,
    PreReleaseCallback* pre_release_callback, const AssignOrder assign_order,
    const PublishLastSeq publish_last_seq, const bool disable_memtable) {
 ...
  if (publish_last_seq == kDoPublishLastSeq) {

  } else {
    // need calculate write_delay_time
    InstrumentedMutexLock lock(&mutex_);
    Status status =
        DelayWrite(/*num_bytes=*/0ull, *write_thread, write_options);
    if (!status.ok()) {
      WriteThread::WriteGroup write_group;
      write_thread->EnterAsBatchGroupLeader(&w, &write_group);
      write_thread->ExitAsBatchGroupLeader(write_group, status);
      return status;
    }
  }
}
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12285

Reviewed By: ajkr

Differential Revision: D53191765

Pulled By: cbi42

fbshipit-source-id: f78d5b280bea6a777f077c89c3e0b8fe98d3c860
2024-01-29 12:31:11 -08:00
Hui Xiao 06e593376c Group SST write in flush, compaction and db open with new stats (#11910)
Summary:
## Context/Summary
Similar to https://github.com/facebook/rocksdb/pull/11288, https://github.com/facebook/rocksdb/pull/11444, categorizing SST/blob file write according to different io activities allows more insight into the activity.

For that, this PR does the following:
- Tag different write IOs by passing down and converting WriteOptions to IOOptions
- Add new SST_WRITE_MICROS histogram in WritableFileWriter::Append() and breakdown FILE_WRITE_{FLUSH|COMPACTION|DB_OPEN}_MICROS

Some related code refactory to make implementation cleaner:
- Blob stats
   - Replace high-level write measurement with low-level WritableFileWriter::Append() measurement for BLOB_DB_BLOB_FILE_WRITE_MICROS. This is to make FILE_WRITE_{FLUSH|COMPACTION|DB_OPEN}_MICROS  include blob file. As a consequence, this introduces some behavioral changes on it, see HISTORY and db bench test plan below for more info.
   - Fix bugs where BLOB_DB_BLOB_FILE_SYNCED/BLOB_DB_BLOB_FILE_BYTES_WRITTEN include file failed to sync and bytes failed to write.
- Refactor WriteOptions constructor for easier construction with io_activity and rate_limiter_priority
- Refactor DBImpl::~DBImpl()/BlobDBImpl::Close() to bypass thread op verification
- Build table
   - TableBuilderOptions now includes Read/WriteOpitons so BuildTable() do not need to take these two variables
   - Replace the io_priority passed into BuildTable() with TableBuilderOptions::WriteOpitons::rate_limiter_priority. Similar for BlobFileBuilder.
This parameter is used for dynamically changing file io priority for flush, see  https://github.com/facebook/rocksdb/pull/9988?fbclid=IwAR1DtKel6c-bRJAdesGo0jsbztRtciByNlvokbxkV6h_L-AE9MACzqRTT5s for more
   - Update ThreadStatus::FLUSH_BYTES_WRITTEN to use io_activity to track flush IO in flush job and db open instead of io_priority

## Test
### db bench

Flush
```
./db_bench --statistics=1 --benchmarks=fillseq --num=100000 --write_buffer_size=100

rocksdb.sst.write.micros P50 : 1.830863 P95 : 4.094720 P99 : 6.578947 P100 : 26.000000 COUNT : 7875 SUM : 20377
rocksdb.file.write.flush.micros P50 : 1.830863 P95 : 4.094720 P99 : 6.578947 P100 : 26.000000 COUNT : 7875 SUM : 20377
rocksdb.file.write.compaction.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0
rocksdb.file.write.db.open.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0
```

compaction, db oopen
```
Setup: ./db_bench --statistics=1 --benchmarks=fillseq --num=10000 --disable_auto_compactions=1 -write_buffer_size=100 --db=../db_bench

Run:./db_bench --statistics=1 --benchmarks=compact  --db=../db_bench --use_existing_db=1

rocksdb.sst.write.micros P50 : 2.675325 P95 : 9.578788 P99 : 18.780000 P100 : 314.000000 COUNT : 638 SUM : 3279
rocksdb.file.write.flush.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0
rocksdb.file.write.compaction.micros P50 : 2.757353 P95 : 9.610687 P99 : 19.316667 P100 : 314.000000 COUNT : 615 SUM : 3213
rocksdb.file.write.db.open.micros P50 : 2.055556 P95 : 3.925000 P99 : 9.000000 P100 : 9.000000 COUNT : 23 SUM : 66
```

blob stats - just to make sure they aren't broken by this PR
```
Integrated Blob DB

Setup: ./db_bench --enable_blob_files=1 --statistics=1 --benchmarks=fillseq --num=10000 --disable_auto_compactions=1 -write_buffer_size=100 --db=../db_bench

Run:./db_bench --enable_blob_files=1 --statistics=1 --benchmarks=compact  --db=../db_bench --use_existing_db=1

pre-PR:
rocksdb.blobdb.blob.file.write.micros P50 : 7.298246 P95 : 9.771930 P99 : 9.991813 P100 : 16.000000 COUNT : 235 SUM : 1600
rocksdb.blobdb.blob.file.synced COUNT : 1
rocksdb.blobdb.blob.file.bytes.written COUNT : 34842

post-PR:
rocksdb.blobdb.blob.file.write.micros P50 : 2.000000 P95 : 2.829360 P99 : 2.993779 P100 : 9.000000 COUNT : 707 SUM : 1614
- COUNT is higher and values are smaller as it includes header and footer write
- COUNT is 3X higher due to each Append() count as one post-PR, while in pre-PR, 3 Append()s counts as one. See https://github.com/facebook/rocksdb/pull/11910/files#diff-32b811c0a1c000768cfb2532052b44dc0b3bf82253f3eab078e15ff201a0dabfL157-L164

rocksdb.blobdb.blob.file.synced COUNT : 1 (stay the same)
rocksdb.blobdb.blob.file.bytes.written COUNT : 34842 (stay the same)
```

```
Stacked Blob DB

Run: ./db_bench --use_blob_db=1 --statistics=1 --benchmarks=fillseq --num=10000 --disable_auto_compactions=1 -write_buffer_size=100 --db=../db_bench

pre-PR:
rocksdb.blobdb.blob.file.write.micros P50 : 12.808042 P95 : 19.674497 P99 : 28.539683 P100 : 51.000000 COUNT : 10000 SUM : 140876
rocksdb.blobdb.blob.file.synced COUNT : 8
rocksdb.blobdb.blob.file.bytes.written COUNT : 1043445

post-PR:
rocksdb.blobdb.blob.file.write.micros P50 : 1.657370 P95 : 2.952175 P99 : 3.877519 P100 : 24.000000 COUNT : 30001 SUM : 67924
- COUNT is higher and values are smaller as it includes header and footer write
- COUNT is 3X higher due to each Append() count as one post-PR, while in pre-PR, 3 Append()s counts as one. See https://github.com/facebook/rocksdb/pull/11910/files#diff-32b811c0a1c000768cfb2532052b44dc0b3bf82253f3eab078e15ff201a0dabfL157-L164

rocksdb.blobdb.blob.file.synced COUNT : 8 (stay the same)
rocksdb.blobdb.blob.file.bytes.written COUNT : 1043445 (stay the same)
```

###  Rehearsal CI stress test
Trigger 3 full runs of all our CI stress tests

###  Performance

Flush
```
TEST_TMPDIR=/dev/shm ./db_basic_bench_pre_pr --benchmark_filter=ManualFlush/key_num:524288/per_key_size:256 --benchmark_repetitions=1000
-- default: 1 thread is used to run benchmark; enable_statistics = true

Pre-pr: avg 507515519.3 ns
497686074,499444327,500862543,501389862,502994471,503744435,504142123,504224056,505724198,506610393,506837742,506955122,507695561,507929036,508307733,508312691,508999120,509963561,510142147,510698091,510743096,510769317,510957074,511053311,511371367,511409911,511432960,511642385,511691964,511730908,

Post-pr: avg 511971266.5 ns, regressed 0.88%
502744835,506502498,507735420,507929724,508313335,509548582,509994942,510107257,510715603,511046955,511352639,511458478,512117521,512317380,512766303,512972652,513059586,513804934,513808980,514059409,514187369,514389494,514447762,514616464,514622882,514641763,514666265,514716377,514990179,515502408,
```

Compaction
```
TEST_TMPDIR=/dev/shm ./db_basic_bench_{pre|post}_pr --benchmark_filter=ManualCompaction/comp_style:0/max_data:134217728/per_key_size:256/enable_statistics:1  --benchmark_repetitions=1000
-- default: 1 thread is used to run benchmark

Pre-pr: avg 495346098.30 ns
492118301,493203526,494201411,494336607,495269217,495404950,496402598,497012157,497358370,498153846

Post-pr: avg 504528077.20, regressed 1.85%. "ManualCompaction" include flush so the isolated regression for compaction should be around 1.85-0.88 = 0.97%
502465338,502485945,502541789,502909283,503438601,504143885,506113087,506629423,507160414,507393007
```

Put with WAL (in case passing WriteOptions slows down this path even without collecting SST write stats)
```
TEST_TMPDIR=/dev/shm ./db_basic_bench_pre_pr --benchmark_filter=DBPut/comp_style:0/max_data:107374182400/per_key_size:256/enable_statistics:1/wal:1  --benchmark_repetitions=1000
-- default: 1 thread is used to run benchmark

Pre-pr: avg 3848.10 ns
3814,3838,3839,3848,3854,3854,3854,3860,3860,3860

Post-pr: avg 3874.20 ns, regressed 0.68%
3863,3867,3871,3874,3875,3877,3877,3877,3880,3881
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11910

Reviewed By: ajkr

Differential Revision: D49788060

Pulled By: hx235

fbshipit-source-id: 79e73699cda5be3b66461687e5147c2484fc5eff
2023-12-29 15:29:23 -08:00
Peter Dillinger a771a47a1b Fix leak or crash on failure in automatic atomic flush (#12176)
Summary:
Through code inspection in debugging an apparent leak of ColumnFamilyData in the crash test, I found a case where too few UnrefAndTryDelete() could be called on a cfd. This fixes that case, which would fail like this in the new unit test:

```
db_flush_test: db/column_family.cc:1648:
rocksdb::ColumnFamilySet::~ColumnFamilySet(): Assertion `last_ref' failed.
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12176

Test Plan: unit test added

Reviewed By: cbi42

Differential Revision: D52417071

Pulled By: pdillinger

fbshipit-source-id: 4ee33c918409cf9c1968f138e273d3347a6cc8e5
2023-12-26 11:04:25 -08:00
Akanksha Mahajan cd577f6059 Fix WRITE_STALL start_time (#12147)
Summary:
`Delayed` is set true in two cases. One is when `delay` is specified. Other one is in the `while` loop - cd21e4e69d/db/db_impl/db_impl_write.cc (L1876)
However start_time is not initialized in second case, resulting in time_delayed = immutable_db_options_.clock->NowMicros() - 0(start_time);

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12147

Test Plan: Existing CircleCI

Reviewed By: cbi42

Differential Revision: D52173481

Pulled By: akankshamahajan15

fbshipit-source-id: fb9183b24c191d287a1d715346467bee66190f98
2023-12-14 13:45:06 -08:00
Kevin Mingtarja 44fd914128 Fix double counting of BYTES_WRITTEN ticker (#12111)
Summary:
Fixes https://github.com/facebook/rocksdb/issues/12061.

We were double counting the `BYTES_WRITTEN` ticker when doing writes with transactions. During transactions, after writing, a client can call `Prepare()`, which writes the values to WAL but not to the Memtable. After that, they can call `Commit()`, which writes a commit marker to the WAL and the values to Memtable.

The cause of this bug is previously during writes, we didn't take into account `writer->ShouldWriteToMemtable()` before adding to `total_byte_size`, so it is still added to during the `Prepare()` phase even though we're not writing to the Memtable, which was why we saw the value to be double of what's written to WAL.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12111

Test Plan: Added a test in `db/db_statistics_test.cc` that tests writes with and without transactions, by comparing the values of `BYTES_WRITTEN` and `WAL_FILE_BYTES` after doing writes.

Reviewed By: jaykorean

Differential Revision: D51954327

Pulled By: jowlyzhang

fbshipit-source-id: 57a0986a14e5b94eb5188715d819212529110d2c
2023-12-08 17:12:11 -08:00
leipeng b3ffca0e29 DBImpl::DelayWrite: Remove bad WRITE_STALL histogram (#12067)
Summary:
When delay didn't happen, histogram WRITE_STALL is still recorded, and ticker STALL_MICROS is not recorded.

This is a bug, neither WRITE_STALL or STALL_MICROS should not be recorded when delay did not happen.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12067

Reviewed By: cbi42

Differential Revision: D51263133

Pulled By: ajkr

fbshipit-source-id: bd82d8328fe088d613991966e83854afdabc6a25
2023-11-13 12:48:44 -08:00
Jay Huh 2adef5367a AttributeGroups - PutEntity Implementation (#11977)
Summary:
Write Path for AttributeGroup Support. The new `PutEntity()` API uses `WriteBatch` and atomically writes WideColumns entities in multiple Column Families.

Combined the release note from PR https://github.com/facebook/rocksdb/issues/11925

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11977

Test Plan:
- `DBWideBasicTest::MultiCFMultiGetEntityAsPinnableAttributeGroups` updated
- `WriteBatchTest::AttributeGroupTest` added
- `WriteBatchTest::AttributeGroupSavePointTest` added

Reviewed By: ltamasi

Differential Revision: D50457122

Pulled By: jaykorean

fbshipit-source-id: 4997b265e415588ce077933082dcd1ac3eeae2cd
2023-11-06 16:52:51 -08:00
Myth 0ff7665c95 Fix low priority write may cause crash when it is rate limited (#11932)
Summary:
Fixed https://github.com/facebook/rocksdb/issues/11902

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11932

Reviewed By: akankshamahajan15

Differential Revision: D50573356

Pulled By: hx235

fbshipit-source-id: adeb1abdc43b523b0357746055ce4a2eabde56a1
2023-10-24 14:41:46 -07:00
Changyu Bi f3aef8cad7 Add write operation to tracer only after successful callback (#11954)
Summary:
We saw optimistic transaction stress test failures like the following:
```
Verification failed for column family 0 key 000000000001E9AF000000000000012B00000000000000B5 (12535491): value_from_db: 010000000504070609080B0A0D0C0F0E111013121514171619181B1A1D1C1F1E212023222524272629282B2A2D2C2F2E313033323534373639383B3A3D3C3F3E, value_from_expected: , msg: Iterator verification: Unexpected value found```
```
With ajkr's repro (see test plan), I found that we record duplicated writes to tracer when an optimistic transaction conflict checking fails. This PR fixes it by checking callback status before record a write operation to tracer.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11954

Test Plan:
this reproduces the failure consistently
```
#!/bin/bash
db=/dev/shm/rocksdb_crashtest_blackbox exp=/dev/shm/rocksdb_crashtest_expected
rm -rf $db $exp && mkdir -p $exp && while ./db_stress \
        --atomic_flush=1 \
        --clear_column_family_one_in=0 \
        --db=$db \
        --db_write_buffer_size=2097152 \
        --delpercent=0 \
        --delrangepercent=0 \
        --destroy_db_initially=0 \
        --disable_wal=1 \
        --expected_values_dir=$exp \
        --iterpercent=0 \
        --max_bytes_for_level_base=2097152 \
        --max_key=250000 \
        --memtable_prefix_bloom_size_ratio=0.5 \
        --memtable_whole_key_filtering=1 \
        --occ_lock_bucket_count=100 \
        --occ_validation_policy=0 \
        --ops_per_thread=10 \
        --prefixpercent=0 \
        --readpercent=0 \
        --reopen=0 \
        --target_file_size_base=524288 \
        --test_batches_snapshots=0 \
        --use_optimistic_txn=1 \
        --use_txn=1 \
        --value_size_mult=32 \
        --write_buffer_size=524288 \
        --writepercent=100 ; do : ; done
```

Reviewed By: akankshamahajan15

Differential Revision: D50284976

Pulled By: cbi42

fbshipit-source-id: 793e3cee186c8b4f406b29166efd8d9028695206
2023-10-14 12:00:31 -07:00
Andrew Kryczka 8a9cfd5292 Make stopped writes block on recovery (#11879)
Summary:
Relaxed the constraints for blocking when writes are stopped. When a recovery is already being attempted, we might as well let `!no_slowdown` writes wait on it in case it succeeds. This makes the user-visible behavior consistent across recovery flush and non-recovery flush.

This enables `db_stress` to inject retryable (soft) flush read errors without having to handle user write failures. I changed `db_stress` a bit to permit injected errors in much more foreground operations as more admin operations (like `GetLiveFiles()`) can fail on a retryable error during flush.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11879

Reviewed By: anand1976

Differential Revision: D49571196

Pulled By: ajkr

fbshipit-source-id: 5d516d6faf20d2c6bfe0594ab4f2706bca6d69b0
2023-10-10 06:29:01 -07:00
Yu Zhang 39a4ff2cab Track full_history_ts_low per SuperVersion (#11784)
Summary:
As discussed in https://github.com/facebook/rocksdb/issues/11730 , this PR tracks the effective `full_history_ts_low` per SuperVersion and update existing sanity checks for `ReadOptions.timestamp >= full_history_ts_low` to use this per SuperVersion `full_history_ts_low` instead. This also means the check is moved to happen after acquiring SuperVersion.

There are two motivations for this: 1) Each time `full_history_ts_low` really come into effect to collapse history, a new SuperVersion is always installed, because it would involve either a Flush or Compaction, both of which change the LSM tree shape. We can take advantage of this to ensure that as long as this sanity check is passed, even if `full_history_ts_low` can be concurrently increased and collapse some history above the requested `ReadOptions.timestamp`, a read request won’t have visibility to that part of history through this SuperVersion that it already acquired.  2) the existing sanity check uses `ColumnFamilyData::GetFullHistoryTsLow` without locking the db mutex, which is the mutex all `IncreaseFullHistoryTsLow` operation is using when mutating this field. So there is a race condition. This also solve the race condition on the read path.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11784

Test Plan:
`make all check`

// Checks success scenario really provide the read consistency attribute as mentioned above.
`./db_with_timestamp_basic_test --gtest_filter=*FullHistoryTsLowSanityCheckPassReadIsConsistent*`

// Checks failure scenario cleans up SuperVersion properly.
`./db_with_timestamp_basic_test --gtest_filter=*FullHistoryTsLowSanityCheckFail*`
`./db_secondary_test --gtest_filter=*FullHistoryTsLowSanityCheckFail*`
`./db_readonly_with_timestamp_test --gtest_filter=*FullHistoryTsLowSanitchCheckFail*`

Reviewed By: ltamasi

Differential Revision: D48894795

Pulled By: jowlyzhang

fbshipit-source-id: 1f801fe8e1bc8e63ca76c03cbdbd0974e5ff5bf6
2023-09-13 16:34:18 -07:00
Yu Zhang 56ca9e3106 Logging timestamp size record in WAL and use it during recovery (#11471)
Summary:
Start logging the timestamp size record in WAL and use the record during recovery.  Currently, user comparator cannot be different from what was used to create a column family, so the timestamp size record is just used to confirm it's consistent with the timestamp size the running user comparator indicates.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11471

Test Plan:
```
make all check
./db_secondary_test
./db_wal_test --gtest_filter="*WithTimestamp*"
./repair_test --gtest_filter="*WithTimestamp*"
```

Reviewed By: ltamasi

Differential Revision: D46236769

Pulled By: jowlyzhang

fbshipit-source-id: f6c60b5c8defdb05021c63df302ccc0be1275ad0
2023-05-30 19:32:00 -07:00
Hui Xiao 151242ce46 Group rocksdb.sst.read.micros stat by IOActivity flush and compaction (#11288)
Summary:
**Context:**
The existing stat rocksdb.sst.read.micros does not reflect each of compaction and flush cases but aggregate them, which is not so helpful for us to understand IO read behavior of each of them.

**Summary**
- Update `StopWatch` and `RandomAccessFileReader` to record `rocksdb.sst.read.micros` and `rocksdb.file.{flush/compaction}.read.micros`
   - Fixed the default histogram in `RandomAccessFileReader`
- New field `ReadOptions/IOOptions::io_activity`; Pass `ReadOptions` through paths under db open, flush and compaction to where we can prepare `IOOptions` and pass it to `RandomAccessFileReader`
- Use `thread_status_util` for assertion in `DbStressFSWrapper` for continuous testing on we are passing correct `io_activity` under db open, flush and compaction

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11288

Test Plan:
- **Stress test**
- **Db bench 1: rocksdb.sst.read.micros COUNT ≈ sum of rocksdb.file.read.flush.micros's and rocksdb.file.read.compaction.micros's.**  (without blob)
     - May not be exactly the same due to `HistogramStat::Add` only guarantees atomic not accuracy across threads.
```
./db_bench -db=/dev/shm/testdb/ -statistics=true -benchmarks="fillseq" -key_size=32 -value_size=512 -num=50000 -write_buffer_size=655 -target_file_size_base=655 -disable_auto_compactions=false -compression_type=none -bloom_bits=3 (-use_plain_table=1 -prefix_size=10)
```
```
// BlockBasedTable
rocksdb.sst.read.micros P50 : 2.009374 P95 : 4.968548 P99 : 8.110362 P100 : 43.000000 COUNT : 40456 SUM : 114805
rocksdb.file.read.flush.micros P50 : 1.871841 P95 : 3.872407 P99 : 5.540541 P100 : 43.000000 COUNT : 2250 SUM : 6116
rocksdb.file.read.compaction.micros P50 : 2.023109 P95 : 5.029149 P99 : 8.196910 P100 : 26.000000 COUNT : 38206 SUM : 108689

// PlainTable
Does not apply
```
- **Db bench 2: performance**

**Read**

SETUP: db with 900 files
```
./db_bench -db=/dev/shm/testdb/ -benchmarks="fillseq" -key_size=32 -value_size=512 -num=50000 -write_buffer_size=655  -disable_auto_compactions=true -target_file_size_base=655 -compression_type=none
```run till convergence
```
./db_bench -seed=1678564177044286 -use_existing_db=true -db=/dev/shm/testdb -benchmarks=readrandom[-X60] -statistics=true -num=1000000 -disable_auto_compactions=true -compression_type=none -bloom_bits=3
```
Pre-change
`readrandom [AVG 60 runs] : 21568 (± 248) ops/sec`
Post-change (no regression, -0.3%)
`readrandom [AVG 60 runs] : 21486 (± 236) ops/sec`

**Compaction/Flush**run till convergence
```
./db_bench -db=/dev/shm/testdb2/ -seed=1678564177044286 -benchmarks="fillseq[-X60]" -key_size=32 -value_size=512 -num=50000 -write_buffer_size=655  -disable_auto_compactions=false -target_file_size_base=655 -compression_type=none

rocksdb.sst.read.micros  COUNT : 33820
rocksdb.sst.read.flush.micros COUNT : 1800
rocksdb.sst.read.compaction.micros COUNT : 32020
```
Pre-change
`fillseq [AVG 46 runs] : 1391 (± 214) ops/sec;    0.7 (± 0.1) MB/sec`

Post-change (no regression, ~-0.4%)
`fillseq [AVG 46 runs] : 1385 (± 216) ops/sec;    0.7 (± 0.1) MB/sec`

Reviewed By: ajkr

Differential Revision: D44007011

Pulled By: hx235

fbshipit-source-id: a54c89e4846dfc9a135389edf3f3eedfea257132
2023-04-21 09:07:18 -07:00
Hui Xiao cb58477185 New stat rocksdb.{cf|db}-write-stall-stats exposed in a structural way (#11300)
Summary:
**Context/Summary:**
Users are interested in figuring out what has caused write stall.
- Refactor write stall related stats from property `kCFStats` into its own db property `rocksdb.cf-write-stall-stats` as a map or string. For now, this only contains count of different combination of (CF-scope `WriteStallCause`) + (`WriteStallCondition`)
- Add new `WriteStallCause::kWriteBufferManagerLimit` to reflect write stall caused by write buffer manager
- Add new `rocksdb.db-write-stall-stats`. For now, this only contains `WriteStallCause::kWriteBufferManagerLimit` + `WriteStallCondition::kStopped`

- Expose functions in new class `WriteStallStatsMapKeys` for examining the above two properties returned as map
- Misc: rename/comment some write stall InternalStats for clarity

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11300

Test Plan:
- New UT
- Stress test
`python3 tools/db_crashtest.py blackbox --simple --get_property_one_in=1`
- Perf test: Both converge very slowly at similar rates but post-change has higher average ops/sec than pre-change even though they are run at the same time.
```
./db_bench -seed=1679014417652004 -db=/dev/shm/testdb/ -statistics=false -benchmarks="fillseq[-X60]" -key_size=32 -value_size=512 -num=100000 -db_write_buffer_size=655 -target_file_size_base=655 -disable_auto_compactions=false -compression_type=none -bloom_bits=3
```
pre-change:
```
fillseq [AVG 15 runs] : 1176 (± 732) ops/sec;    0.6 (± 0.4) MB/sec
fillseq      :    1052.671 micros/op 949 ops/sec 105.267 seconds 100000 operations;    0.5 MB/s
fillseq [AVG 16 runs] : 1162 (± 685) ops/sec;    0.6 (± 0.4) MB/sec
fillseq      :    1387.330 micros/op 720 ops/sec 138.733 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 17 runs] : 1136 (± 646) ops/sec;    0.6 (± 0.3) MB/sec
fillseq      :    1232.011 micros/op 811 ops/sec 123.201 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 18 runs] : 1118 (± 610) ops/sec;    0.6 (± 0.3) MB/sec
fillseq      :    1282.567 micros/op 779 ops/sec 128.257 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 19 runs] : 1100 (± 578) ops/sec;    0.6 (± 0.3) MB/sec
fillseq      :    1914.336 micros/op 522 ops/sec 191.434 seconds 100000 operations;    0.3 MB/s
fillseq [AVG 20 runs] : 1071 (± 551) ops/sec;    0.6 (± 0.3) MB/sec
fillseq      :    1227.510 micros/op 814 ops/sec 122.751 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 21 runs] : 1059 (± 525) ops/sec;    0.5 (± 0.3) MB/sec
```
post-change:
```
fillseq [AVG 15 runs] : 1226 (± 732) ops/sec;    0.6 (± 0.4) MB/sec
fillseq      :    1323.825 micros/op 755 ops/sec 132.383 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 16 runs] : 1196 (± 687) ops/sec;    0.6 (± 0.4) MB/sec
fillseq      :    1223.905 micros/op 817 ops/sec 122.391 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 17 runs] : 1174 (± 647) ops/sec;    0.6 (± 0.3) MB/sec
fillseq      :    1168.996 micros/op 855 ops/sec 116.900 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 18 runs] : 1156 (± 611) ops/sec;    0.6 (± 0.3) MB/sec
fillseq      :    1348.729 micros/op 741 ops/sec 134.873 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 19 runs] : 1134 (± 579) ops/sec;    0.6 (± 0.3) MB/sec
fillseq      :    1196.887 micros/op 835 ops/sec 119.689 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 20 runs] : 1119 (± 550) ops/sec;    0.6 (± 0.3) MB/sec
fillseq      :    1193.697 micros/op 837 ops/sec 119.370 seconds 100000 operations;    0.4 MB/s
fillseq [AVG 21 runs] : 1106 (± 524) ops/sec;    0.6 (± 0.3) MB/sec
```

Reviewed By: ajkr

Differential Revision: D44159541

Pulled By: hx235

fbshipit-source-id: 8d29efb70001fdc52d34535eeb3364fc3e71e40b
2023-03-18 09:51:58 -07:00
Hui Xiao 11cb6af6e5 Fix bug of prematurely excluded CF in atomic flush contains unflushed data that should've been included in the atomic flush (#11148)
Summary:
**Context:**
Atomic flush should guarantee recoverability of all data of seqno up to the max seqno of the flush. It achieves this by ensuring all such data are flushed by the time this atomic flush finishes through `SelectColumnFamiliesForAtomicFlush()`. However, our crash test exposed the following case where an excluded CF from an atomic flush contains unflushed data of seqno less than the max seqno of that atomic flush and loses its data with `WriteOptions::DisableWAL=true` in face of a crash right after the atomic flush finishes .
```
./db_stress --preserve_unverified_changes=1 --reopen=0 --acquire_snapshot_one_in=0 --adaptive_readahead=1 --allow_data_in_errors=True --async_io=1 --atomic_flush=1 --avoid_flush_during_recovery=0 --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=0 --batch_protection_bytes_per_key=0 --block_size=16384 --bloom_bits=15 --bottommost_compression_type=none --bytes_per_sync=262144 --cache_index_and_filter_blocks=0 --cache_size=8388608 --cache_type=lru_cache --charge_compression_dictionary_building_buffer=0 --charge_file_metadata=1 --charge_filter_construction=0 --charge_table_reader=0 --checkpoint_one_in=0 --checksum_type=kXXH3 --clear_column_family_one_in=0 --compact_files_one_in=0 --compact_range_one_in=0 --compaction_pri=1 --compaction_ttl=100 --compression_max_dict_buffer_bytes=134217727 --compression_max_dict_bytes=16384 --compression_parallel_threads=1 --compression_type=lz4hc --compression_use_zstd_dict_trainer=0 --compression_zstd_max_train_bytes=0 --continuous_verification_interval=0 --data_block_index_type=0 --db=$db --db_write_buffer_size=1048576 --delpercent=4 --delrangepercent=1 --destroy_db_initially=0 --detect_filter_construct_corruption=0 --disable_wal=1 --enable_compaction_filter=0 --enable_pipelined_write=0 --expected_values_dir=$exp --fail_if_options_file_error=0 --fifo_allow_compaction=0 --file_checksum_impl=none --flush_one_in=0 --format_version=5 --get_current_wal_file_one_in=0 --get_live_files_one_in=100 --get_property_one_in=0 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=2 --index_type=0 --ingest_external_file_one_in=0 --initial_auto_readahead_size=524288 --iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True --long_running_snapshots=1 --manual_wal_flush_one_in=100 --mark_for_compaction_one_file_in=0 --max_auto_readahead_size=0 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=10000 --max_key_len=3 --max_manifest_file_size=1073741824 --max_write_batch_group_size_bytes=64 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=0 --memtable_prefix_bloom_size_ratio=0.01 --memtable_protection_bytes_per_key=4 --memtable_whole_key_filtering=0 --memtablerep=skip_list --min_write_buffer_number_to_merge=2 --mmap_read=1 --mock_direct_io=False --nooverwritepercent=1 --num_file_reads_for_auto_readahead=0 --open_files=-1 --open_metadata_write_fault_one_in=0 --open_read_fault_one_in=0 --open_write_fault_one_in=0 --ops_per_thread=100000000 --optimize_filters_for_memory=1 --paranoid_file_checks=1 --partition_filters=0 --partition_pinning=3 --pause_background_one_in=0 --periodic_compaction_seconds=100 --prefix_size=8 --prefixpercent=5 --prepopulate_block_cache=0 --preserve_internal_time_seconds=3600 --progress_reports=0 --read_fault_one_in=32 --readahead_size=16384 --readpercent=50 --recycle_log_file_num=0 --ribbon_starting_level=6 --secondary_cache_fault_one_in=0 --set_options_one_in=10000 --snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=104857600 --sst_file_manager_bytes_per_truncate=1048576 --stats_dump_period_sec=10 --subcompactions=1 --sync=0 --sync_fault_injection=0 --target_file_size_base=524288 --target_file_size_multiplier=2 --test_batches_snapshots=0 --top_level_index_pinning=0 --unpartitioned_pinning=1 --use_direct_io_for_flush_and_compaction=0 --use_direct_reads=0 --use_full_merge_v1=0 --use_merge=0 --use_multiget=1 --use_put_entity_one_in=0 --user_timestamp_size=0 --value_size_mult=32 --verify_checksum=1 --verify_checksum_one_in=0 --verify_db_one_in=1000 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=524288 --wal_compression=none --write_buffer_size=524288 --write_dbid_to_manifest=1 --write_fault_one_in=0 --writepercent=30 &
    pid=$!
    sleep 0.2
    sleep 10
    kill $pid
    sleep 0.2
./db_stress --ops_per_thread=1 --preserve_unverified_changes=1 --reopen=0 --acquire_snapshot_one_in=0 --adaptive_readahead=1 --allow_data_in_errors=True --async_io=1 --atomic_flush=1 --avoid_flush_during_recovery=0 --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=0 --batch_protection_bytes_per_key=0 --block_size=16384 --bloom_bits=15 --bottommost_compression_type=none --bytes_per_sync=262144 --cache_index_and_filter_blocks=0 --cache_size=8388608 --cache_type=lru_cache --charge_compression_dictionary_building_buffer=0 --charge_file_metadata=1 --charge_filter_construction=0 --charge_table_reader=0 --checkpoint_one_in=0 --checksum_type=kXXH3 --clear_column_family_one_in=0 --compact_files_one_in=0 --compact_range_one_in=0 --compaction_pri=1 --compaction_ttl=100 --compression_max_dict_buffer_bytes=134217727 --compression_max_dict_bytes=16384 --compression_parallel_threads=1 --compression_type=lz4hc --compression_use_zstd_dict_trainer=0 --compression_zstd_max_train_bytes=0 --continuous_verification_interval=0 --data_block_index_type=0 --db=$db --db_write_buffer_size=1048576 --delpercent=4 --delrangepercent=1 --destroy_db_initially=0 --detect_filter_construct_corruption=0 --disable_wal=1 --enable_compaction_filter=0 --enable_pipelined_write=0 --expected_values_dir=$exp --fail_if_options_file_error=0 --fifo_allow_compaction=0 --file_checksum_impl=none --flush_one_in=0 --format_version=5 --get_current_wal_file_one_in=0 --get_live_files_one_in=100 --get_property_one_in=0 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=2 --index_type=0 --ingest_external_file_one_in=0 --initial_auto_readahead_size=524288 --iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True --long_running_snapshots=1 --manual_wal_flush_one_in=100 --mark_for_compaction_one_file_in=0 --max_auto_readahead_size=0 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=10000 --max_key_len=3 --max_manifest_file_size=1073741824 --max_write_batch_group_size_bytes=64 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=0 --memtable_prefix_bloom_size_ratio=0.01 --memtable_protection_bytes_per_key=4 --memtable_whole_key_filtering=0 --memtablerep=skip_list --min_write_buffer_number_to_merge=2 --mmap_read=1 --mock_direct_io=False --nooverwritepercent=1 --num_file_reads_for_auto_readahead=0 --open_files=-1 --open_metadata_write_fault_one_in=0 --open_read_fault_one_in=0 --open_write_fault_one_in=0 --ops_per_thread=100000000 --optimize_filters_for_memory=1 --paranoid_file_checks=1 --partition_filters=0 --partition_pinning=3 --pause_background_one_in=0 --periodic_compaction_seconds=100 --prefix_size=8 --prefixpercent=5 --prepopulate_block_cache=0 --preserve_internal_time_seconds=3600 --progress_reports=0 --read_fault_one_in=32 --readahead_size=16384 --readpercent=50 --recycle_log_file_num=0 --ribbon_starting_level=6 --secondary_cache_fault_one_in=0 --set_options_one_in=10000 --snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=104857600 --sst_file_manager_bytes_per_truncate=1048576 --stats_dump_period_sec=10 --subcompactions=1 --sync=0 --sync_fault_injection=0 --target_file_size_base=524288 --target_file_size_multiplier=2 --test_batches_snapshots=0 --top_level_index_pinning=0 --unpartitioned_pinning=1 --use_direct_io_for_flush_and_compaction=0 --use_direct_reads=0 --use_full_merge_v1=0 --use_merge=0 --use_multiget=1 --use_put_entity_one_in=0 --user_timestamp_size=0 --value_size_mult=32 --verify_checksum=1 --verify_checksum_one_in=0 --verify_db_one_in=1000 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=524288 --wal_compression=none --write_buffer_size=524288 --write_dbid_to_manifest=1 --write_fault_one_in=0 --writepercent=30 &
    pid=$!
    sleep 0.2
    sleep 40
    kill $pid
    sleep 0.2

Verification failed for column family 6 key 0000000000000239000000000000012B0000000000000138 (56622): value_from_db: , value_from_expected: 4A6331754E4F4C4D42434041464744455A5B58595E5F5C5D5253505156575455, msg: Value not found: NotFound:
Crash-recovery verification failed :(
No writes or ops?
Verification failed :(
```

The bug is due to the following:
- When atomic flush is used, an empty CF is legally [excluded](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_filesnapshot.cc#L39) in `SelectColumnFamiliesForAtomicFlush` as the first step of `DBImpl::FlushForGetLiveFiles` before [passing](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_filesnapshot.cc#L42) the included CFDs to `AtomicFlushMemTables`.
- But [later](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_impl/db_impl_compaction_flush.cc#L2133) in `AtomicFlushMemTables`, `WaitUntilFlushWouldNotStallWrites` will [release the db mutex](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_impl/db_impl_compaction_flush.cc#L2403), during which data@seqno N can be inserted into the excluded CF and data@seqno M can be inserted into one of the included CFs, where M > N.
- However, data@seqno N in an already-excluded CF is thus excluded from this atomic flush while we seqno N is less than seqno M.

**Summary:**
- Replace `SelectColumnFamiliesForAtomicFlush()`-before-`AtomicFlushMemTables()` with `SelectColumnFamiliesForAtomicFlush()`-after-wait-within-`AtomicFlushMemTables()` so we ensure no write affecting the recoverability of this atomic job (i.e, change to max seqno of this atomic flush or insertion of data with less seqno than the max seqno of the atomic flush to excluded CF) can happen after calling `SelectColumnFamiliesForAtomicFlush()`.
- For above, refactored and clarified comments on `SelectColumnFamiliesForAtomicFlush()` and `AtomicFlushMemTables()` for clearer semantics of passed-in CFDs to atomic-flush

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11148

Test Plan:
- New unit test failed before the fix and passes after
- Make check
- Rehearsal stress test

Reviewed By: ajkr

Differential Revision: D42799871

Pulled By: hx235

fbshipit-source-id: 13636b63e9c25c5895857afc36ea580d57f6d644
2023-03-14 16:53:20 -07:00
Peter Dillinger 390cc0b156 Ensure LockWAL() stall cleared for UnlockWAL() return (#11172)
Summary:
Fixes https://github.com/facebook/rocksdb/issues/11160

By counting the number of stalls placed on a write queue, we can check in UnlockWAL() whether the stall present at the start of UnlockWAL() has been cleared by the end, or wait until it's cleared.

More details in code comments and new unit test.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11172

Test Plan: unit test added. Yes, it uses sleep to amplify failure on buggy behavior if present, but using a sync point to only allow new behavior would fail with the old code only because it doesn't contain the new sync point. Basically, using a sync point in UnlockWAL() could easily mask a regression by artificially limiting key behaviors. The test would only check that UnlockWAL() invokes code that *should* do the right thing, without checking that it *does* the right thing.

Reviewed By: ajkr

Differential Revision: D42894341

Pulled By: pdillinger

fbshipit-source-id: 15c9da0ca383e6aec845b29f5447d76cecbf46c3
2023-02-03 12:08:37 -08:00
sdong 4720ba4391 Remove RocksDB LITE (#11147)
Summary:
We haven't been actively mantaining RocksDB LITE recently and the size must have been gone up significantly. We are removing the support.

Most of changes were done through following comments:

unifdef -m -UROCKSDB_LITE `git grep -l ROCKSDB_LITE | egrep '[.](cc|h)'`

by Peter Dillinger. Others changes were manually applied to build scripts, CircleCI manifests, ROCKSDB_LITE is used in an expression and file db_stress_test_base.cc.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11147

Test Plan: See CI

Reviewed By: pdillinger

Differential Revision: D42796341

fbshipit-source-id: 4920e15fc2060c2cd2221330a6d0e5e65d4b7fe2
2023-01-27 13:14:19 -08:00
Peter Dillinger 546e213c4f Fix DelayWrite() calls for two_write_queues (#11130)
Summary:
PR https://github.com/facebook/rocksdb/issues/11020 fixed a case where it was easy to deadlock the DB with LockWAL() but introduced a bug showing up as a rare assertion failure in the stress test. Specifically, `assert(w->state == STATE_INIT)` in `WriteThread::LinkOne()` called from `BeginWriteStall()`, `DelayWrite()`, `WriteImplWALOnly()`. I haven't been about to generate a unit test that reproduces this failure but I believe the root cause is that DelayWrite() was never meant to be re-entrant, only called from the DB's write_thread_ leader. https://github.com/facebook/rocksdb/issues/11020 introduced a call to DelayWrite() from the nonmem_write_thread_ group leader.

This fix is to make DelayWrite() apply to the specific write queue that it is being called from (inject a dummy write stall entry to the head of the appropriate write queue). WriteController is re-entrant, based on polling and state changes signalled with bg_cv_, so can manage stalling two queues. The only anticipated complication (called out by Andrew in previous PR) is that we don't want timed write delays being injected in parallel for the two queues, because that dimishes the intended throttling effect. Thus, we only allow timed delays for the primary write queue.

HISTORY not updated because this is intended for the same release where the bug was introduced.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11130

Test Plan:
Although I was not able to reproduce the assertion failure, I was able to reproduce a distinct flaw with what I believe is the same root cause: a kind of deadlock if both write queues need to wake up from stopped writes. Only one will be waiting on bg_cv_ (the other waiting in `LinkOne()` for the write queue to open up), so a single SignalAll() will only unblock one of the queues, with the other re-instating the stop until another signal on bg_cv_. A simple unit test is added for this case.

Will also run crash_test_with_multiops_wc_txn for a while looking for issues.

Reviewed By: ajkr

Differential Revision: D42749330

Pulled By: pdillinger

fbshipit-source-id: 4317dd899a93d57c26fd5af7143038f82d4d4d1b
2023-01-25 14:18:27 -08:00
Hui Xiao 86fa2592be Fix data race on ColumnFamilyData::flush_reason by letting FlushRequest/Job owns flush_reason instead of CFD (#11111)
Summary:
**Context:**
Concurrent flushes on the same CF can set on `ColumnFamilyData::flush_reason` before each other flush finishes. An symptom is one CF has different flush_reason with others though all of them are in an atomic flush  `db_stress: db/db_impl/db_impl_compaction_flush.cc:423: rocksdb::Status rocksdb::DBImpl::AtomicFlushMemTablesToOutputFiles(const rocksdb::autovector<rocksdb::DBImpl::BGFlushArg>&, bool*, rocksdb::JobContext*, rocksdb::LogBuffer*, rocksdb::Env::Priority): Assertion cfd->GetFlushReason() == cfds[0]->GetFlushReason() failed. `

**Summary:**
Suggested by ltamasi, we now refactor and let FlushRequest/Job to own flush_reason as there is no good way to define `ColumnFamilyData::flush_reason` in face of concurrent flushes on the same CF (which wasn't the case a long time ago when `ColumnFamilyData::flush_reason ` first introduced`)

**Tets:**
- new unit test
- make check
- aggressive crash test rehearsal

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11111

Reviewed By: ajkr

Differential Revision: D42644600

Pulled By: hx235

fbshipit-source-id: 8589c8184869d3415e5b780c887f877818a5ebaf
2023-01-24 09:54:04 -08:00
Yanqin Jin c93ba7db5d Revise LockWAL/UnlockWAL implementation (#11020)
Summary:
RocksDB has two public APIs: `DB::LockWAL()`/`DB::UnlockWAL()`. The current implementation acquires and
releases the internal `DBImpl::log_write_mutex_`.

According to the comment on `DBImpl::log_write_mutex_`: https://github.com/facebook/rocksdb/blob/7.8.fb/db/db_impl/db_impl.h#L2287:L2288
> Note: to avoid dealock, if needed to acquire both log_write_mutex_ and mutex_, the order should be first mutex_ and then log_write_mutex_.

This puts limitations on how applications can use the `LockWAL()` API. After `LockWAL()` returns ok, then application
should not perform any operation that acquires `mutex_`. Currently, the use case of `LockWAL()` is MyRocks implementing
the MySQL storage engine handlerton `lock_hton_log` interface. The operation that MyRocks performs after `LockWAL()`
is `GetSortedWalFiless()` which not only acquires mutex_, but also `log_write_mutex_`.

There are two issues:
1. Applications using these two APIs may hang if one thread calls `GetSortedWalFiles()` after
calling `LockWAL()` because log_write_mutex is not recursive.
2. Two threads may dead lock due to lock order inversion.

To fix these issues, we can modify the implementation of LockWAL so that it does not keep
`log_write_mutex_` held until UnlockWAL. To achieve the goal of locking the WAL, we can
instead manually inject a write stall so that all future writes will be stopped.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11020

Test Plan: make check

Reviewed By: ajkr

Differential Revision: D41785203

Pulled By: riversand963

fbshipit-source-id: 5ccb7a9c6eb9a2c3fa80fd2c399cc2568b8f89ce
2022-12-13 21:45:00 -08:00
Yanqin Jin 7d26e4c5a3 Basic Support for Merge with user-defined timestamp (#10819)
Summary:
This PR implements the originally disabled `Merge()` APIs when user-defined timestamp is enabled.

Simplest usage:
```cpp
// assume string append merge op is used with '.' as delimiter.
// ts1 < ts2
db->Put(WriteOptions(), "key", ts1, "v0");
db->Merge(WriteOptions(), "key", ts2, "1");
ReadOptions ro;
ro.timestamp = &ts2;
db->Get(ro, "key", &value);
ASSERT_EQ("v0.1", value);
```

Some code comments are added for clarity.

Note: support for timestamp in `DB::GetMergeOperands()` will be done in a follow-up PR.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10819

Test Plan: make check

Reviewed By: ltamasi

Differential Revision: D40603195

Pulled By: riversand963

fbshipit-source-id: f96d6f183258f3392d80377025529f7660503013
2022-10-31 22:28:58 -07:00
Qingping Wang a45e6878f3 fix issue 10751 (#10765)
Summary:
Fix https://github.com/facebook/rocksdb/issues/10751 where a stalled write could be blocked forever when DB shutdown.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10765

Reviewed By: ajkr

Differential Revision: D40110069

Pulled By: ajkr

fbshipit-source-id: 598c05777db9be85913a0a85e421b3295ecdff5e
2022-10-10 09:46:09 -07:00
Yanqin Jin edda219fc3 Manual flush with wait=false should not stall when writes stopped (#10001)
Summary:
When `FlushOptions::wait` is set to false, manual flush should not stall forever.

If the database has already stopped writes, then the thread calling `DB::Flush()` with
`FlushOptions::wait=false` should not enter the `DBImpl::write_thread_`.

To prevent this, we should do a check at the beginning and return `TryAgain()`

Resolves: https://github.com/facebook/rocksdb/issues/9892

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10001

Reviewed By: siying

Differential Revision: D36422303

Pulled By: siying

fbshipit-source-id: 723bd3065e8edc4f17c82449d0d6b95a2381ac0a
2022-10-04 16:43:01 -07:00
Changyu Bi 9f2363f4c4 User-defined timestamp support for DeleteRange() (#10661)
Summary:
Add user-defined timestamp support for range deletion. The new API is `DeleteRange(opt, cf, begin_key, end_key, ts)`. Most of the change is to update the comparator to compare without timestamp. Other than that, major changes are
- internal range tombstone data structures (`FragmentedRangeTombstoneList`, `RangeTombstone`, etc.) to store timestamps.
- Garbage collection of range tombstones and range tombstone covered keys during compaction.
- Get()/MultiGet() to return the timestamp of a range tombstone when needed.
- Get/Iterator with range tombstones bounded by readoptions.timestamp.
- timestamp crash test now issues DeleteRange by default.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10661

Test Plan:
- Added unit test: `make check`
- Stress test: `python3 tools/db_crashtest.py --enable_ts whitebox --readpercent=57 --prefixpercent=4 --writepercent=25 -delpercent=5 --iterpercent=5 --delrangepercent=4`
- Ran `db_bench` to measure regression when timestamp is not enabled. The tests are for write (with some range deletion) and iterate with DB fitting in memory: `./db_bench--benchmarks=fillrandom,seekrandom --writes_per_range_tombstone=200 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=500000 --reads=500000 --seek_nexts=10 --disable_auto_compactions -disable_wal=true --max_num_range_tombstones=1000`.  Did not see consistent regression in no timestamp case.

| micros/op | fillrandom | seekrandom |
| --- | --- | --- |
|main| 2.58 |10.96|
|PR 10661| 2.68 |10.63|

Reviewed By: riversand963

Differential Revision: D39441192

Pulled By: cbi42

fbshipit-source-id: f05aca3c41605caf110daf0ff405919f300ddec2
2022-09-30 16:13:03 -07:00
Hui Xiao e484b81eee Sync dir containing CURRENT after RenameFile on CURRENT as much as possible (#10573)
Summary:
**Context:**
Below crash test revealed a bug that directory containing CURRENT file (short for `dir_contains_current_file` below) was not always get synced after a new CURRENT is created and being called with `RenameFile` as part of the creation.

This bug exposes a risk that such un-synced directory containing the updated CURRENT can’t survive a host crash (e.g, power loss) hence get corrupted. This then will be followed by a recovery from a corrupted CURRENT that we don't want.

The root-cause is that a nullptr `FSDirectory* dir_contains_current_file` sometimes gets passed-down to `SetCurrentFile()` hence in those case `dir_contains_current_file->FSDirectory::FsyncWithDirOptions()` will be skipped  (which otherwise will internally call`Env/FS::SyncDic()` )
```
./db_stress --acquire_snapshot_one_in=10000 --adaptive_readahead=1 --allow_data_in_errors=True --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=100000 --batch_protection_bytes_per_key=8 --block_size=16384 --bloom_bits=134.8015470676662 --bottommost_compression_type=disable --cache_size=8388608 --checkpoint_one_in=1000000 --checksum_type=kCRC32c --clear_column_family_one_in=0 --compact_files_one_in=1000000 --compact_range_one_in=1000000 --compaction_pri=2 --compaction_ttl=100 --compression_max_dict_buffer_bytes=511 --compression_max_dict_bytes=16384 --compression_type=zstd --compression_use_zstd_dict_trainer=1 --compression_zstd_max_train_bytes=65536 --continuous_verification_interval=0 --data_block_index_type=0 --db=$db --db_write_buffer_size=1048576 --delpercent=5 --delrangepercent=0 --destroy_db_initially=0 --disable_wal=0 --enable_compaction_filter=0 --enable_pipelined_write=1 --expected_values_dir=$exp --fail_if_options_file_error=1 --file_checksum_impl=none --flush_one_in=1000000 --get_current_wal_file_one_in=0 --get_live_files_one_in=1000000 --get_property_one_in=1000000 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=4 --ingest_external_file_one_in=0 --iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True --mark_for_compaction_one_file_in=10 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=10000 --max_key_len=3 --max_manifest_file_size=16384 --max_write_batch_group_size_bytes=64 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=0 --memtable_prefix_bloom_size_ratio=0.001 --memtable_protection_bytes_per_key=1 --memtable_whole_key_filtering=1 --mmap_read=1 --nooverwritepercent=1 --open_metadata_write_fault_one_in=0 --open_read_fault_one_in=0 --open_write_fault_one_in=0 --ops_per_thread=100000000 --optimize_filters_for_memory=1 --paranoid_file_checks=1 --partition_pinning=2 --pause_background_one_in=1000000 --periodic_compaction_seconds=0 --prefix_size=5 --prefixpercent=5 --prepopulate_block_cache=1 --progress_reports=0 --read_fault_one_in=1000 --readpercent=45 --recycle_log_file_num=0 --reopen=0 --ribbon_starting_level=999 --secondary_cache_fault_one_in=32 --secondary_cache_uri=compressed_secondary_cache://capacity=8388608 --set_options_one_in=10000 --snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=0 --sst_file_manager_bytes_per_truncate=0 --subcompactions=3 --sync_fault_injection=1 --target_file_size_base=2097 --target_file_size_multiplier=2 --test_batches_snapshots=1 --top_level_index_pinning=1 --use_full_merge_v1=1 --use_merge=1 --value_size_mult=32 --verify_checksum=1 --verify_checksum_one_in=1000000 --verify_db_one_in=100000 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=524288 --write_buffer_size=4194 --writepercent=35
```

```
stderr:
WARNING: prefix_size is non-zero but memtablerep != prefix_hash
db_stress: utilities/fault_injection_fs.cc:748: virtual rocksdb::IOStatus rocksdb::FaultInjectionTestFS::RenameFile(const std::string &, const std::string &, const rocksdb::IOOptions &, rocksdb::IODebugContext *): Assertion `tlist.find(tdn.second) == tlist.end()' failed.`
```

**Summary:**
The PR ensured the non-test path pass down a non-null dir containing CURRENT (which is by current RocksDB assumption just db_dir) by doing the following:
- Renamed `directory_to_fsync` as `dir_contains_current_file` in `SetCurrentFile()` to tighten the association between this directory and CURRENT file
- Changed `SetCurrentFile()` API to require `dir_contains_current_file` being passed-in, instead of making it by default nullptr.
    -  Because `SetCurrentFile()`'s `dir_contains_current_file` is passed down from `VersionSet::LogAndApply()` then `VersionSet::ProcessManifestWrites()` (i.e, think about this as a chain of 3 functions related to MANIFEST update), these 2 functions also got refactored to require `dir_contains_current_file`
- Updated the non-test-path callers of these 3 functions to obtain and pass in non-nullptr `dir_contains_current_file`, which by current assumption of RocksDB, is the `FSDirectory* db_dir`.
    - `db_impl` path will obtain `DBImpl::directories_.getDbDir()` while others with no access to such `directories_` are obtained on the fly by creating such object `FileSystem::NewDirectory(..)` and manage it by unique pointers to ensure short life time.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10573

Test Plan:
- `make check`
- Passed the repro db_stress command
- For future improvement, since we currently don't assert dir containing CURRENT to be non-nullptr due to https://github.com/facebook/rocksdb/pull/10573#pullrequestreview-1087698899, there is still chances that future developers mistakenly pass down nullptr dir containing CURRENT thus resulting skipped sync dir and cause the bug again. Therefore a smarter test (e.g, such as quoted from ajkr  "(make) unsynced data loss to be dropping files corresponding to unsynced directory entries") is still needed.

Reviewed By: ajkr

Differential Revision: D39005886

Pulled By: hx235

fbshipit-source-id: 336fb9090d0cfa6ca3dd580db86268007dde7f5a
2022-08-29 17:35:21 -07:00
Andrew Kryczka 91166012c8 Prevent a case of WriteBufferManager flush thrashing (#6364)
Summary:
Previously, the flushes triggered by `WriteBufferManager` could affect
the same CF repeatedly if it happens to get consecutive writes. Such
flushes are not particularly useful for reducing memory usage since
they switch nearly-empty memtables to immutable while they've just begun
filling their first arena block. In fact they may not even reduce the
mutable memory count if they involve replacing one mutable memtable containing
one arena block with a new mutable memtable containing one arena block.
Further, if such switches happen even a few times before a flush finishes,
the immutable memtable limit will be reached and writes will stall.

This PR adds a heuristic to not switch memtables to immutable for CFs
that already have one or more immutable memtables awaiting flush. There
is a memory usage regression if the user continues writing to the same
CF, that DB does not have any CFs eligible for switching, flushes
are not finishing, and the `WriteBufferManager` was constructed with
`allow_stall=false`. Before, it would grow by switching nearly empty
memtables until writes stall. Now, it would grow by filling memtables
until writes stall. This feels like an acceptable behavior change because
users who prefer to stall over violate the memory limit should be using
`allow_stall=true`, which is unaffected by this PR.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/6364

Test Plan:
- Command:

`rm -rf /dev/shm/dbbench/ && TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -num_multi_db=8 -num_column_families=2 -write_buffer_size=4194304 -db_write_buffer_size=16777216 -compression_type=none -statistics=true -target_file_size_base=4194304 -max_bytes_for_level_base=16777216`

- `rocksdb.db.write.stall` count before this PR: 175
- `rocksdb.db.write.stall` count after this PR: 0

Reviewed By: jay-zhuang

Differential Revision: D20167197

Pulled By: ajkr

fbshipit-source-id: 4a64064e9bc33d57c0a35f15547542d0191d0cb7
2022-08-17 15:53:40 -07:00
sdong 911c0208b9 WritableFileWriter tries to skip operations after failure (#10489)
Summary:
A flag in WritableFileWriter is introduced to remember error has happened. Subsequent operations will fail with an assertion. Those operations, except Close() are not supposed to be called anyway. This change will help catch bug in tests and stress tests and limit damage of a potential bug of continue writing to a file after a failure.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10489

Test Plan: Fix existing unit tests and watch crash tests for a while.

Reviewed By: anand1976

Differential Revision: D38473277

fbshipit-source-id: 09aafb971e56cfd7f9ef92ad15b883f54acf1366
2022-08-10 10:19:20 -07:00
Changyu Bi 9d77bf8f7b Fragment memtable range tombstone in the write path (#10380)
Summary:
- Right now each read fragments the memtable range tombstones https://github.com/facebook/rocksdb/issues/4808. This PR explores the idea of fragmenting memtable range tombstones in the write path and reads can just read this cached fragmented tombstone without any fragmenting cost. This PR only does the caching for immutable memtable, and does so right before a memtable is added to an immutable memtable list. The fragmentation is done without holding mutex to minimize its performance impact.
- db_bench is updated to print out the number of range deletions executed if there is any.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10380

Test Plan:
- CI, added asserts in various places to check whether a fragmented range tombstone list should have been constructed.
- Benchmark: as this PR only optimizes immutable memtable path, the number of writes in the benchmark is chosen such  an immutable memtable is created and range tombstones are in that memtable.

```
single thread:
./db_bench --benchmarks=fillrandom,readrandom --writes_per_range_tombstone=1 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=500000 --reads=100000 --max_num_range_tombstones=100

multi_thread
./db_bench --benchmarks=fillrandom,readrandom --writes_per_range_tombstone=1 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=15000 --reads=20000 --threads=32 --max_num_range_tombstones=100
```
Commit 99cdf16464 is included in benchmark result. It was an earlier attempt where tombstones are fragmented for each write operation. Reader threads share it using a shared_ptr which would slow down multi-thread read performance as seen in benchmark results.
Results are averaged over 5 runs.

Single thread result:
| Max # tombstones  | main fillrandom micros/op | 99cdf16464 | Post PR | main readrandom micros/op |  99cdf16464 | Post PR |
| ------------- | ------------- |------------- |------------- |------------- |------------- |------------- |
| 0    |6.68     |6.57     |6.72     |4.72     |4.79     |4.54     |
| 1    |6.67     |6.58     |6.62     |5.41     |4.74     |4.72     |
| 10   |6.59     |6.5      |6.56     |7.83     |4.69     |4.59     |
| 100  |6.62     |6.75     |6.58     |29.57    |5.04     |5.09     |
| 1000 |6.54     |6.82     |6.61     |320.33   |5.22     |5.21     |

32-thread result: note that "Max # tombstones" is per thread.
| Max # tombstones  | main fillrandom micros/op | 99cdf16464 | Post PR | main readrandom micros/op |  99cdf16464 | Post PR |
| ------------- | ------------- |------------- |------------- |------------- |------------- |------------- |
| 0    |234.52   |260.25   |239.42   |5.06     |5.38     |5.09     |
| 1    |236.46   |262.0    |231.1    |19.57    |22.14    |5.45     |
| 10   |236.95   |263.84   |251.49   |151.73   |21.61    |5.73     |
| 100  |268.16   |296.8    |280.13   |2308.52  |22.27    |6.57     |

Reviewed By: ajkr

Differential Revision: D37916564

Pulled By: cbi42

fbshipit-source-id: 05d6d2e16df26c374c57ddcca13a5bfe9d5b731e
2022-08-05 12:02:33 -07:00
Wallace 1e9bf25f61 Do not hold mutex when write keys if not necessary (#7516)
Summary:
## Problem Summary
RocksDB will acquire the global mutex of db instance for every time when user calls `Write`.  When RocksDB schedules a lot of compaction jobs,   it will compete the mutex with write thread and it will hurt the write performance.

## Problem Solution:
I want to use log_write_mutex to replace the global mutex in most case so that we do not acquire it in write-thread unless there is a write-stall event or a write-buffer-full event occur.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7516

Test Plan:
1. make check
2. CI
3. COMPILE_WITH_TSAN=1 make db_stress
make crash_test
make crash_test_with_multiops_wp_txn
make crash_test_with_multiops_wc_txn
make crash_test_with_atomic_flush

Reviewed By: siying

Differential Revision: D36908702

Pulled By: riversand963

fbshipit-source-id: 59b13881f4f5c0a58fd3ca79128a396d9cd98efe
2022-07-21 13:35:36 -07:00
Levi Tamasi c73d2a9d18 Add API for writing wide-column entities (#10242)
Summary:
The patch builds on https://github.com/facebook/rocksdb/pull/9915 and adds
a new API called `PutEntity` that can be used to write a wide-column entity
to the database. The new API is added to both `DB` and `WriteBatch`. Note
that currently there is no way to retrieve these entities; more precisely, all
read APIs (`Get`, `MultiGet`, and iterator) return `NotSupported` when they
encounter a wide-column entity that is required to answer a query. Read-side
support (as well as other missing functionality like `Merge`, compaction filter,
and timestamp support) will be added in later PRs.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10242

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D37369748

Pulled By: ltamasi

fbshipit-source-id: 7f5e412359ed7a400fd80b897dae5599dbcd685d
2022-06-25 15:30:47 -07:00
Andrew Kryczka d5d8920f2c Fix race condition with WAL tracking and FlushWAL(true /* sync */) (#10185)
Summary:
`FlushWAL(true /* sync */)` is used internally and for manual WAL sync. It had a bug when used together with `track_and_verify_wals_in_manifest` where the synced size tracked in MANIFEST was larger than the number of bytes actually synced.

The bug could be repro'd almost immediately with the following crash test command: `python3 tools/db_crashtest.py blackbox --simple --write_buffer_size=524288 --max_bytes_for_level_base=2097152 --target_file_size_base=524288 --duration=3600 --interval=10 --sync_fault_injection=1 --disable_wal=0 --checkpoint_one_in=1000 --max_key=10000 --value_size_mult=33`.

An example error message produced by the above command is shown below. The error sometimes arose from the checkpoint and other times arose from the main stress test DB.

```
Corruption: Size mismatch: WAL (log number: 119) in MANIFEST is 27938 bytes , but actually is 27859 bytes on disk.
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10185

Test Plan:
- repro unit test
- the above crash test command no longer finds the error. It does find a different error after a while longer such as "Corruption: WAL file 481 required by manifest but not in directory list"

Reviewed By: riversand963

Differential Revision: D37200993

Pulled By: ajkr

fbshipit-source-id: 98e0071c1a89f4d009888512ed89f9219779ae5f
2022-06-17 16:45:28 -07:00
Andrew Kryczka 5d6005c780 Add WriteOptions::protection_bytes_per_key (#10037)
Summary:
Added an option, `WriteOptions::protection_bytes_per_key`, that controls how many bytes per key we use for integrity protection in `WriteBatch`. It takes effect when `WriteBatch::GetProtectionBytesPerKey() == 0`.

Currently the only supported value is eight. Invoking a user API with it set to any other nonzero value will result in `Status::NotSupported` returned to the user.

There is also a bug fix for integrity protection with `inplace_callback`, where we forgot to take into account the possible change in varint length when calculating KV checksum for the final encoded buffer.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10037

Test Plan:
- Manual
  - Set default value of `WriteOptions::protection_bytes_per_key` to eight and ran `make check -j24`
  - Enabled in MyShadow for 1+ week
- Automated
  - Unit tests have a `WriteMode` that enables the integrity protection via `WriteOptions`
  - Crash test - in most cases, use `WriteOptions::protection_bytes_per_key` to enable integrity protection

Reviewed By: cbi42

Differential Revision: D36614569

Pulled By: ajkr

fbshipit-source-id: 8650087ceac9b61b560f1e5fafe5e1baf9c725fb
2022-06-16 23:10:07 -07:00
Changyu Bi 9882652b0e Verify write batch checksum before WAL (#10114)
Summary:
Context: WriteBatch can have key-value checksums when it was created `with protection_bytes_per_key > 0`.
This PR added checksum verification for write batches before they are written to WAL.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10114

Test Plan:
- Added new unit tests to db_kv_checksum_test.cc: `make check -j32`
- benchmark on performance regression: `./db_bench --benchmarks=fillrandom[-X20] -db=/dev/shm/test_rocksdb -write_batch_protection_bytes_per_key=8`
  - Pre-PR:
`
fillrandom [AVG    20 runs] : 198875 (± 3006) ops/sec;   22.0 (± 0.3) MB/sec
`
  - Post-PR:
`
fillrandom [AVG    20 runs] : 196487 (± 2279) ops/sec;   21.7 (± 0.3) MB/sec
`
  Mean regressed about 1% (198875 -> 196487 ops/sec).

Reviewed By: ajkr

Differential Revision: D36917464

Pulled By: cbi42

fbshipit-source-id: 29beb74edf65f04b1a890b4f650d873dc7ed790d
2022-06-15 13:43:58 -07:00
Yanqin Jin 1777e5f7e9 Snapshots with user-specified timestamps (#9879)
Summary:
In RocksDB, keys are associated with (internal) sequence numbers which denote when the keys are written
to the database. Sequence numbers in different RocksDB instances are unrelated, thus not comparable.

It is nice if we can associate sequence numbers with their corresponding actual timestamps. One thing we can
do is to support user-defined timestamp, which allows the applications to specify the format of custom timestamps
and encode a timestamp with each key. More details can be found at https://github.com/facebook/rocksdb/wiki/User-defined-Timestamp-%28Experimental%29.

This PR provides a different but complementary approach. We can associate rocksdb snapshots (defined in
https://github.com/facebook/rocksdb/blob/7.2.fb/include/rocksdb/snapshot.h#L20) with **user-specified** timestamps.
Since a snapshot is essentially an object representing a sequence number, this PR establishes a bi-directional mapping between sequence numbers and timestamps.

In the past, snapshots are usually taken by readers. The current super-version is grabbed, and a `rocksdb::Snapshot`
object is created with the last published sequence number of the super-version. You can see that the reader actually
has no good idea of what timestamp to assign to this snapshot, because by the time the `GetSnapshot()` is called,
an arbitrarily long period of time may have already elapsed since the last write, which is when the last published
sequence number is written.

This observation motivates the creation of "timestamped" snapshots on the write path. Currently, this functionality is
exposed only to the layer of `TransactionDB`. Application can tell RocksDB to create a snapshot when a transaction
commits, effectively associating the last sequence number with a timestamp. It is also assumed that application will
ensure any two snapshots with timestamps should satisfy the following:
```
snapshot1.seq < snapshot2.seq iff. snapshot1.ts < snapshot2.ts
```

If the application can guarantee that when a reader takes a timestamped snapshot, there is no active writes going on
in the database, then we also allow the user to use a new API `TransactionDB::CreateTimestampedSnapshot()` to create
a snapshot with associated timestamp.

Code example
```cpp
// Create a timestamped snapshot when committing transaction.
txn->SetCommitTimestamp(100);
txn->SetSnapshotOnNextOperation();
txn->Commit();

// A wrapper API for convenience
Status Transaction::CommitAndTryCreateSnapshot(
    std::shared_ptr<TransactionNotifier> notifier,
    TxnTimestamp ts,
    std::shared_ptr<const Snapshot>* ret);

// Create a timestamped snapshot if caller guarantees no concurrent writes
std::pair<Status, std::shared_ptr<const Snapshot>> snapshot = txn_db->CreateTimestampedSnapshot(100);
```

The snapshots created in this way will be managed by RocksDB with ref-counting and potentially shared with
other readers. We provide the following APIs for readers to retrieve a snapshot given a timestamp.
```cpp
// Return the timestamped snapshot correponding to given timestamp. If ts is
// kMaxTxnTimestamp, then we return the latest timestamped snapshot if present.
// Othersise, we return the snapshot whose timestamp is equal to `ts`. If no
// such snapshot exists, then we return null.
std::shared_ptr<const Snapshot> TransactionDB::GetTimestampedSnapshot(TxnTimestamp ts) const;
// Return the latest timestamped snapshot if present.
std::shared_ptr<const Snapshot> TransactionDB::GetLatestTimestampedSnapshot() const;
```

We also provide two additional APIs for stats collection and reporting purposes.

```cpp
Status TransactionDB::GetAllTimestampedSnapshots(
    std::vector<std::shared_ptr<const Snapshot>>& snapshots) const;
// Return timestamped snapshots whose timestamps fall in [ts_lb, ts_ub) and store them in `snapshots`.
Status TransactionDB::GetTimestampedSnapshots(
    TxnTimestamp ts_lb,
    TxnTimestamp ts_ub,
    std::vector<std::shared_ptr<const Snapshot>>& snapshots) const;
```

To prevent the number of timestamped snapshots from growing infinitely, we provide the following API to release
timestamped snapshots whose timestamps are older than or equal to a given threshold.
```cpp
void TransactionDB::ReleaseTimestampedSnapshotsOlderThan(TxnTimestamp ts);
```

Before shutdown, RocksDB will release all timestamped snapshots.

Comparison with user-defined timestamp and how they can be combined:
User-defined timestamp persists every key with a timestamp, while timestamped snapshots maintain a volatile
mapping between snapshots (sequence numbers) and timestamps.
Different internal keys with the same user key but different timestamps will be treated as different by compaction,
thus a newer version will not hide older versions (with smaller timestamps) unless they are eligible for garbage collection.
In contrast, taking a timestamped snapshot at a certain sequence number and timestamp prevents all the keys visible in
this snapshot from been dropped by compaction. Here, visible means (seq < snapshot and most recent).
The timestamped snapshot supports the semantics of reading at an exact point in time.

Timestamped snapshots can also be used with user-defined timestamp.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9879

Test Plan:
```
make check
TEST_TMPDIR=/dev/shm make crash_test_with_txn
```

Reviewed By: siying

Differential Revision: D35783919

Pulled By: riversand963

fbshipit-source-id: 586ad905e169189e19d3bfc0cb0177a7239d1bd4
2022-06-10 16:07:03 -07:00
Yu Zhang a101c9de60 Return "invalid argument" when read timestamp is too old (#10109)
Summary:
With this change, when a given read timestamp is smaller than the column-family's full_history_ts_low, Get(), MultiGet() and iterators APIs will return Status::InValidArgument().
Test plan
```
$COMPILE_WITH_ASAN=1 make -j24 all
$./db_with_timestamp_basic_test --gtest_filter=DBBasicTestWithTimestamp.UpdateFullHistoryTsLow
$ make -j24 check
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10109

Reviewed By: riversand963

Differential Revision: D36901126

Pulled By: jowlyzhang

fbshipit-source-id: 255feb1a66195351f06c1d0e42acb1ff74527f86
2022-06-06 14:36:22 -07:00
Jay Zhuang 5864900cf4 Get current LogFileNumberSize the same as log_writer (#10086)
Summary:
`db_impl.alive_log_files_` is used to track the WAL size in `db_impl.logs_`.
Get the `LogFileNumberSize` obj in `alive_log_files_` the same time as `log_writer` to keep them consistent.
For this issue, it's not safe to do `deque::reverse_iterator::operator*` and `deque::pop_front()` concurrently,
so remove the tail cache.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10086

Test Plan:
```
# on Windows
gtest-parallel ./db_test --gtest_filter=DBTest.FileCreationRandomFailure -r 1000 -w 100
```

Reviewed By: riversand963

Differential Revision: D36822373

Pulled By: jay-zhuang

fbshipit-source-id: 5e738051dfc7bcf6a15d85ba25e6365df6b6a6af
2022-06-01 15:33:22 -07:00
Yanqin Jin 7c8c803938 Remove unused variable single_column_family_mode_ (#10078)
Summary:
This variable is actually not being used for anything meaningful, thus remove it.

This can make https://github.com/facebook/rocksdb/issues/7516 slightly simpler by reducing the amount of state that must be made lock-free.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10078

Test Plan: make check

Reviewed By: ajkr

Differential Revision: D36779817

Pulled By: riversand963

fbshipit-source-id: ffb0d9ad6149616917ae5e02bb28102cb90fc406
2022-05-31 13:03:37 -07:00
Yanqin Jin de9df6e818 Do not release and re-acquire dbmutex on memtable-switch if no listener (#9758)
Summary:
There is no need to release-and-acquire immediately when no listener is registered. This is
what we have been doing for `NotifyOnFlushBegin()`, `NotifyOnFlushCompleted()`, `NotifyOnCompactionBegin()`,
`NotifyOnCompactionCompleted()`, and some other `NotifyOnXX` methods in event_helpers.cc.
Do the same for `NotifyOnMemTableSealed ()`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9758

Test Plan: make check

Reviewed By: jay-zhuang

Differential Revision: D35159552

Pulled By: riversand963

fbshipit-source-id: 6e0aac50bd5c8f506d809b6638c33a7a28d1e87f
2022-03-30 20:48:23 -07:00
Yanqin Jin 29bec740f5 Return invalid argument if batch is null (#9744)
Summary:
Originally, a corruption will be returned by `DBImpl::WriteImpl(batch...)` if batch is
null. This is inaccurate since there is no data corruption.
Return `Status::InvalidArgument()` instead.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9744

Test Plan: make check

Reviewed By: ltamasi

Differential Revision: D35086268

Pulled By: riversand963

fbshipit-source-id: 677397b007a53bc25210eac0178d49c9797b5951
2022-03-23 14:28:13 -07:00
Yanqin Jin b2aacaf923 Fix assertion error by doing comparison with mutex (#9717)
Summary:
On CircleCI MacOS instances, we have been seeing the following assertion error:
```
Assertion failed: (alive_log_files_tail_ == alive_log_files_.rbegin()), function WriteToWAL, file /Users/distiller/project/db/db_impl/db_impl_write.cc, line 1213.
Received signal 6 (Abort trap: 6)
#0   0x1
https://github.com/facebook/rocksdb/issues/1   abort (in libsystem_c.dylib) + 120
https://github.com/facebook/rocksdb/issues/2   err (in libsystem_c.dylib) + 0
https://github.com/facebook/rocksdb/issues/3   rocksdb::DBImpl::WriteToWAL(rocksdb::WriteBatch const&, rocksdb::log::Writer*, unsigned long long*, unsigned long long*, rocksdb::Env::IOPriority, bool, bool) (in librocksdb.7.0.0.dylib) (db_impl_write.cc:1213)
https://github.com/facebook/rocksdb/issues/4   rocksdb::DBImpl::WriteToWAL(rocksdb::WriteThread::WriteGroup const&, rocksdb::log::Writer*, unsigned long long*, bool, bool, unsigned long long) (in librocksdb.7.0.0.dylib) (db_impl_write.cc:1251)
https://github.com/facebook/rocksdb/issues/5   rocksdb::DBImpl::WriteImpl(rocksdb::WriteOptions const&, rocksdb::WriteBatch*, rocksdb::WriteCallback*, unsigned long long*, unsigned long long, bool, unsigned long long*, unsigned long, rocksdb::PreReleaseCallback*) (in librocksdb.7.0.0.dylib) (db_impl_	rite.cc:421)
https://github.com/facebook/rocksdb/issues/6   rocksdb::DBImpl::Write(rocksdb::WriteOptions const&, rocksdb::WriteBatch*) (in librocksdb.7.0.0.dylib) (db_impl_write.cc:109)
https://github.com/facebook/rocksdb/issues/7   rocksdb::DB::Put(rocksdb::WriteOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::Slice const&, rocksdb::Slice const&) (in librocksdb.7.0.0.dylib) (db_impl_write.cc:2159)
https://github.com/facebook/rocksdb/issues/8   rocksdb::DBImpl::Put(rocksdb::WriteOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::Slice const&, rocksdb::Slice const&) (in librocksdb.7.0.0.dylib) (db_impl_write.cc:37)
https://github.com/facebook/rocksdb/issues/9   rocksdb::DB::Put(rocksdb::WriteOptions const&, rocksdb::Slice const&, rocksdb::Slice const&, rocksdb::Slice const&) (in librocksdb.7.0.0.dylib) (db.h:382)
https://github.com/facebook/rocksdb/issues/10  rocksdb::DBBasicTestWithTimestampPrefixSeek_IterateWithPrefix_Test::TestBody() (in db_with_timestamp_basic_test) (db_with_timestamp_basic_test.cc:2926)
https://github.com/facebook/rocksdb/issues/11  void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) (in db_with_timestamp_basic_test) (gtest-all.cc:3899)
https://github.com/facebook/rocksdb/issues/12  void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) (in db_with_timestamp_basic_test) (gtest-all.cc:3935)
https://github.com/facebook/rocksdb/issues/13  testing::Test::Run() (in db_with_timestamp_basic_test) (gtest-all.cc:3980)
https://github.com/facebook/rocksdb/issues/14  testing::TestInfo::Run() (in db_with_timestamp_basic_test) (gtest-all.cc:4153)
https://github.com/facebook/rocksdb/issues/15  testing::TestCase::Run() (in db_with_timestamp_basic_test) (gtest-all.cc:4266)
https://github.com/facebook/rocksdb/issues/16  testing::internal::UnitTestImpl::RunAllTests() (in db_with_timestamp_basic_test) (gtest-all.cc:6632)
https://github.com/facebook/rocksdb/issues/17  bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) (in db_with_timestamp_basic_test) (gtest-all.cc:3899)
https://github.com/facebook/rocksdb/issues/18  bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) (in db_with_timestamp_basic_test) (gtest-all.cc:3935)
https://github.com/facebook/rocksdb/issues/19  testing::UnitTest::Run() (in db_with_timestamp_basic_test) (gtest-all.cc:6242)
https://github.com/facebook/rocksdb/issues/20  RUN_ALL_TESTS() (in db_with_timestamp_basic_test) (gtest.h:22110)
https://github.com/facebook/rocksdb/issues/21  main (in db_with_timestamp_basic_test) (db_with_timestamp_basic_test.cc:3150)
https://github.com/facebook/rocksdb/issues/22  start (in libdyld.dylib) + 1
```

It's likely caused by concurrent, unprotected access to the deque, even though `back()` is never popped,
and we are comparing `rbegin()` with a cached `riterator`. To be safe, do the comparison only if we have mutex.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9717

Test Plan:
One example
Ssh to one CircleCI MacOS instance.
```
gtest-parallel -r 1000 -w 8 ./db_test --gtest_filter=DBTest.FlushesInParallelWithCompactRange
```

Reviewed By: pdillinger

Differential Revision: D34990696

Pulled By: riversand963

fbshipit-source-id: 62dd48ae6fedbda53d0a64d73de9b948b4c26eee
2022-03-18 13:11:57 -07:00