Summary:
This option causes trace records to be written in the serialized write thread. That way, the write records in the trace must follow the same order as writes that are logged to WAL and writes that are applied to the DB.
By default I left it disabled to match existing behavior. I enabled it in `db_stress`, though, as that use case requires order of write records in trace matches the order in WAL.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9334
Test Plan:
- See if below unsynced data loss crash test can run for 24h straight. It used to crash after a few hours when reaching an unlucky trace ordering.
```
DEBUG_LEVEL=0 TEST_TMPDIR=/dev/shm /usr/local/bin/python3 -u tools/db_crashtest.py blackbox --interval=10 --max_key=100000 --write_buffer_size=524288 --target_file_size_base=524288 --max_bytes_for_level_base=2097152 --value_size_mult=33 --sync_fault_injection=1 --test_batches_snapshots=0 --duration=86400
```
Reviewed By: zhichao-cao
Differential Revision: D33301990
Pulled By: ajkr
fbshipit-source-id: 82d97559727adb4462a7af69758449c8725b22d3
Summary:
`db_stress` traces are used for tracking unsynced changes. For that purpose, we
only need to track writes and not reads. Currently `TraceOptions` only
supports excluding `Get()`s from the trace, so this PR only excludes
`Get()`s. In the future it would be good to exclude `MultiGet()`s and
iterator operations too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9315
Test Plan:
- trace-heavy `db_stress` command elapsed time reduced 37%
Benchmark:
```
TEST_TMPDIR=/dev/shm /usr/bin/time ./db_stress -ops_per_thread=100000 -sync_fault_injection=1 -expected_values_dir=/dev/shm/dbstress_expected --clear_column_family_one_in=0
```
- replay-heavy `db_stress` command elapsed time reduced 38%
Setup:
```
TEST_TMPDIR=/dev/shm /usr/bin/time ./db_stress -ops_per_thread=100000000 -sync_fault_injection=1 -expected_values_dir=/dev/shm/dbstress_expected --clear_column_family_one_in=0 & sleep 120; pkill -9 db_stress
```
Benchmark:
```
TEST_TMPDIR=/dev/shm /usr/bin/time ./db_stress -ops_per_thread=1 -reopen=0 -expected_values_dir=/dev/shm/dbstress_expected --clear_column_family_one_in=0 --destroy_db_initially=0
```
Reviewed By: zhichao-cao
Differential Revision: D33229900
Pulled By: ajkr
fbshipit-source-id: 0e4251c674d236ddbc4548e9bbfdd608bf3cdc93
Summary:
I saw the following error when running crash test for a while with
unsynced data loss:
```
Error restoring historical expected values: Corruption: Corrupted trace file.
```
The trace file turned out to have an incomplete tail record. This is
normal considering blackbox kills `db_stress` while trace can be
ongoing.
In the case where the trace file is not otherwise corrupted, there
should be enough records already seen to sync up the expected state with
the recovered DB. This PR ignores any `Status::Corruption` the
`Replayer` returns when that happens.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9316
Reviewed By: jay-zhuang
Differential Revision: D33230579
Pulled By: ajkr
fbshipit-source-id: 9814af4e39e57f00d85be7404363211762f9b41b
Summary:
This fixes two bugs in the recently committed DB verification following
crash-recovery with unsynced data loss (https://github.com/facebook/rocksdb/issues/8966):
The first bug was in crash test runs involving mixed values for
`-test_batches_snapshots`. The problem was we were neither restoring
expected values nor enabling tracing when `-test_batches_snapshots=1`.
This caused a future `-test_batches_snapshots=0` run to not find enough
trace data to restore expected values. The fix is to restore expected
values at the start of `-test_batches_snapshots=1` runs, but still leave
tracing disabled as we do not need to track those KVs.
The second bug was in `db_stress` runs that restore the expected values
file and use compaction filter. The compaction filter was initialized to use
the pre-restore expected values, which would be `munmap()`'d during
`FileExpectedStateManager::Restore()`. Then compaction filter would run
into a segfault. The fix is just to reorder compaction filter init after expected
values restore.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9302
Test Plan:
- To verify the first problem, the below sequence used to fail; now it passes.
```
$ ./db_stress --db=./test-db/ --expected_values_dir=./test-db-expected/ --max_key=100000 --ops_per_thread=1000 --sync_fault_injection=1 --clear_column_family_one_in=0 --destroy_db_initially=0 -reopen=0 -test_batches_snapshots=0
$ ./db_stress --db=./test-db/ --expected_values_dir=./test-db-expected/ --max_key=100000 --ops_per_thread=1000 --sync_fault_injection=1 --clear_column_family_one_in=0 --destroy_db_initially=0 -reopen=0 -test_batches_snapshots=1
$ ./db_stress --db=./test-db/ --expected_values_dir=./test-db-expected/ --max_key=100000 --ops_per_thread=1000 --sync_fault_injection=1 --clear_column_family_one_in=0 --destroy_db_initially=0 -reopen=0 -test_batches_snapshots=0
```
- The second problem occurred rarely in the form of a SIGSEGV on a file that was `munmap()`d. I have not seen it after this PR though this doesn't prove much.
Reviewed By: jay-zhuang
Differential Revision: D33155283
Pulled By: ajkr
fbshipit-source-id: 66fd0f0edf34015a010c30015f14f104734e964e
Summary:
When a previous run left behind historical state/trace files (implying it was run with --sync_fault_injection set), this PR uses them to restore the expected state according to the DB's recovered sequence number. That way, a tail of latest unsynced operations are permitted to be dropped, as is the case when data in page cache or certain `Env`s is lost. The point of the verification in this scenario is just to ensure there is no hole in the recovered data.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8966
Test Plan:
- ran it a while, made sure it is restoring expected values using the historical state/trace files:
```
$ rm -rf ./tmp-db/ ./exp/ && mkdir -p ./tmp-db/ ./exp/ && while ./db_stress -compression_type=none -clear_column_family_one_in=0 -expected_values_dir=./exp -sync_fault_injection=1 -destroy_db_initially=0 -db=./tmp-db -max_key=1000000 -ops_per_thread=10000 -reopen=0 -threads=32 ; do : ; done
```
Reviewed By: pdillinger
Differential Revision: D31219445
Pulled By: ajkr
fbshipit-source-id: f0e1d51fe5b35465b00565c33331190ea38ba0ad
Summary:
Context/Summary:
Uninitialized variable `SequenceNumber old_saved_seqno` causes asan related compilation error/warning below:
```
db_stress_tool/expected_state.cc:308:55: error: ‘old_saved_seqno’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
308 | if (s.ok() && old_saved_seqno != kMaxSequenceNumber &&
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
```
Fix it by initializing to 0.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9265
Test Plan:
- make clean && COMPILE_WITH_ASAN=1 make -j48 db_stress_tool/expected_state.o
- monitor if same error happens again after merging
Reviewed By: ajkr
Differential Revision: D32939630
Pulled By: hx235
fbshipit-source-id: 41697515fd11ada8427f606b5dceb4e58d12cb80
Summary:
When `--sync_fault_injection` is set, this PR takes a snapshot of the expected values and starts an operation trace when the DB is opened. These files are stored in `--expected_values_dir`. They will be used for recovering the expected state of the DB following a crash where a suffix of unsynced operations are allowed to be lost.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8960
Test Plan: injected crashed at various points in `FileExpectedStateManager` and verified the next run recovers the state/trace file with highest seqno and removes all older/temporary files. Note we don't use sync_fault_injection in CI crash tests yet.
Reviewed By: pdillinger
Differential Revision: D31194941
Pulled By: ajkr
fbshipit-source-id: b0f935a529a0186c5a9c7709fcaa8829de8a84cf
Summary:
This is a precursor refactoring to enable an upcoming feature: persistence failure correctness testing.
- Changed `--expected_values_path` to `--expected_values_dir` and migrated "db_crashtest.py" to use the new flag. For persistence failure correctness testing there are multiple possible correct states since unsynced data is allowed to be dropped. Making it possible to restore all these possible correct states will eventually involve files containing snapshots of expected values and DB trace files.
- The expected values directory is managed by an `ExpectedStateManager` instance. Managing expected state files is separated out of `SharedState` to prevent `SharedState` from becoming too complex when the new files and features (snapshotting, tracing, and restoring) are introduced.
- Migrated expected values file access/management out of `SharedState` into a separate class called `ExpectedState`. This is not exposed directly to the test but rather the `ExpectedState` for the latest values file is accessed via a pass-through API on `ExpectedStateManager`. This forces the test to always access the single latest `ExpectedState`.
- Changed the initialization of the latest expected values file to use a tempfile followed by rename, and also add cleanup logic for possible stranded tempfiles.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8913
Test Plan:
run in several ways; try to make sure it's not obviously broken.
- crashtest blackbox without TEST_TMPDIR
```
$ python3 tools/db_crashtest.py blackbox --simple --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --duration=120 --interval=10 --compression_type=none --blob_compression_type=none
```
- crashtest blackbox with TEST_TMPDIR
```
$ TEST_TMPDIR=/dev/shm python3 tools/db_crashtest.py blackbox --simple --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --duration=120 --interval=10 --compression_type=none --blob_compression_type=none
```
- crashtest whitebox with TEST_TMPDIR
```
$ TEST_TMPDIR=/dev/shm python3 tools/db_crashtest.py whitebox --simple --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --duration=120 --interval=10 --compression_type=none --blob_compression_type=none --random_kill_odd=88887
```
- db_stress without expected_values_dir
```
$ ./db_stress --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --ops_per_thread=10000 --clear_column_family_one_in=0 --destroy_db_initially=true
```
- db_stress with expected_values_dir and manual corruption
```
$ ./db_stress --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --ops_per_thread=10000 --clear_column_family_one_in=0 --destroy_db_initially=true --expected_values_dir=./
// modify one byte in "./LATEST.state"
$ ./db_stress --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --ops_per_thread=10000 --clear_column_family_one_in=0 --destroy_db_initially=false --expected_values_dir=./
...
Verification failed for column family 0 key 0000000000000000 (0): Value not found: NotFound:
...
```
Reviewed By: riversand963
Differential Revision: D30921951
Pulled By: ajkr
fbshipit-source-id: babfe218062e55d018c9b046536c0289fb78f41c
