Summary:
Cover paranoid_file_checks in crash test.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7489
Test Plan: Run crash tests for hours and didn't see any failure.
Reviewed By: ajkr
Differential Revision: D24063868
fbshipit-source-id: 7b48b110e66ce78ae5d0c99a9f32af86edd34c1e
Summary:
It's important to make sure no false positive is reported when options.paranoid_file_checks is used. Add it to stress test and a place holder in crash test. It is disabled in crash test as there appears to be a bug causing false positive.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7473
Test Plan: Run crash test
Reviewed By: ajkr
Differential Revision: D24026939
fbshipit-source-id: 89102acb45cf041776775ce44a4eef4b0f3a380c
Summary:
(1) Skip check on specific key if restoring an old backup
(small minority of cases) because it can fail in those cases. (2) Remove
an old assertion about number of column families and number of keys
passed in, which is broken by atomic flush (cf_consistency) test. Like
other code (for better or worse) assume a single key and iterate over
column families. (3) Apply mock_direct_io to NewSequentialFile so that
db_stress backup works on /dev/shm.
Also add more context to output in case of backup/restore db_stress
failure.
Also a minor fix to BackupEngine to report first failure status in
creating new backup, and drop another clue about the potential
source of a "Backup failed" status.
Reverts "Disable backup/restore stress test (https://github.com/facebook/rocksdb/issues/7350)"
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7357
Test Plan:
Using backup_one_in=10000,
"USE_CLANG=1 make crash_test_with_atomic_flush" for 30+ minutes
"USE_CLANG=1 make blackbox_crash_test" for 30+ minutes
And with use_direct_reads with TEST_TMPDIR=/dev/shm/rocksdb
Reviewed By: riversand963
Differential Revision: D23567244
Pulled By: pdillinger
fbshipit-source-id: e77171c2e8394d173917e36898c02dead1c40b77
Summary:
This change has the crash test randomly select from a few file
checksum implementations, or nullptr, for DB file_checksum_gen_factory.
For compatibility across runs on same DB, each non-null factory can
understand all the other functions, but the default changes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7343
Test Plan:
'make blackbox_crash_test' for a while, including with some
debug output to ensure code is being exercised.
Reviewed By: zhichao-cao
Differential Revision: D23494580
Pulled By: pdillinger
fbshipit-source-id: 73bbc7ca32c1adaf619134c0c830f12894880b8a
Summary:
Although added to db_stress, testing of backup/restore
was never integrated into the crash test, originally concerned about
performance. I've enabled it now and to address the peformance concern,
testing backup/restore is always skipped once the db exceeds a certain
size threshold, default 100MB. This should provide sufficient
opportunity for testing BackupEngine without bogging down everything
else with heavier and heavier operations.
Also fixed backup/restore in db_stress by making sure PurgeOldBackups
can remove manifest files, which are normally kept around for db_stress.
Added more coverage of backup options, and up to three backups being
saved in one backup directory (in some cases).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7348
Test Plan:
ran 'make blackbox_crash_test' for a while, with heightened
probabilitly of taking backups (1/10k). Also confirmed with some debug
output that the code is being covered, TestBackupRestore only takes
a few seconds to complete when triggered, and even at 1/10k and ~50MB
database, there's <,~ 1 thread testing backups at any time.
Reviewed By: ajkr
Differential Revision: D23510835
Pulled By: pdillinger
fbshipit-source-id: b6b8735591808141f81f10773ac31634cf03b6c0
Summary:
The mechanism to mark files for compaction is most commonly used in
delete-triggered compaction. This PR adds an option to exercise the
marking mechanism on random files created by db_stress. This PR also
enables that option in db_crashtest.py on its db_stress runs at random.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7231
Test Plan:
- ran some minified crash tests; verified they succeed and we see `"compaction_reason": "FilesMarkedForCompaction"` regularly in the logs.
```
$ TEST_TMPDIR=/dev/shm python tools/db_crashtest.py blackbox --duration=600 --interval=30 --max_key=10000000 --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --value_size_mult=33
$ TEST_TMPDIR=/dev/shm python tools/db_crashtest.py whitebox --duration=600 --interval=30 --max_key=1000000 --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --value_size_mult=33 --random_kill_odd=8887
```
Reviewed By: anand1976
Differential Revision: D23025156
Pulled By: ajkr
fbshipit-source-id: a404c467ebc12afa94dae35956ea9b372f592a96
Summary:
SstFileManager is already supported in the stress test as of https://github.com/facebook/rocksdb/issues/6454. This
PR enables the SstFileManager in some of the crash test runs.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6993
Reviewed By: riversand963
Differential Revision: D22084406
Pulled By: ajkr
fbshipit-source-id: 78b8642682e7570ff6ec3a1c3ccd9940f4362289
Summary:
New experimental option BBTO::optimize_filters_for_memory builds
filters that maximize their use of "usable size" from malloc_usable_size,
which is also used to compute block cache charges.
Rather than always "rounding up," we track state in the
BloomFilterPolicy object to mix essentially "rounding down" and
"rounding up" so that the average FP rate of all generated filters is
the same as without the option. (YMMV as heavily accessed filters might
be unluckily lower accuracy.)
Thus, the option near-minimizes what the block cache considers as
"memory used" for a given target Bloom filter false positive rate and
Bloom filter implementation. There are no forward or backward
compatibility issues with this change, though it only works on the
format_version=5 Bloom filter.
With Jemalloc, we see about 10% reduction in memory footprint (and block
cache charge) for Bloom filters, but 1-2% increase in storage footprint,
due to encoding efficiency losses (FP rate is non-linear with bits/key).
Why not weighted random round up/down rather than state tracking? By
only requiring malloc_usable_size, we don't actually know what the next
larger and next smaller usable sizes for the allocator are. We pick a
requested size, accept and use whatever usable size it has, and use the
difference to inform our next choice. This allows us to narrow in on the
right balance without tracking/predicting usable sizes.
Why not weight history of generated filter false positive rates by
number of keys? This could lead to excess skew in small filters after
generating a large filter.
Results from filter_bench with jemalloc (irrelevant details omitted):
(normal keys/filter, but high variance)
$ ./filter_bench -quick -impl=2 -average_keys_per_filter=30000 -vary_key_count_ratio=0.9
Build avg ns/key: 29.6278
Number of filters: 5516
Total size (MB): 200.046
Reported total allocated memory (MB): 220.597
Reported internal fragmentation: 10.2732%
Bits/key stored: 10.0097
Average FP rate %: 0.965228
$ ./filter_bench -quick -impl=2 -average_keys_per_filter=30000 -vary_key_count_ratio=0.9 -optimize_filters_for_memory
Build avg ns/key: 30.5104
Number of filters: 5464
Total size (MB): 200.015
Reported total allocated memory (MB): 200.322
Reported internal fragmentation: 0.153709%
Bits/key stored: 10.1011
Average FP rate %: 0.966313
(very few keys / filter, optimization not as effective due to ~59 byte
internal fragmentation in blocked Bloom filter representation)
$ ./filter_bench -quick -impl=2 -average_keys_per_filter=1000 -vary_key_count_ratio=0.9
Build avg ns/key: 29.5649
Number of filters: 162950
Total size (MB): 200.001
Reported total allocated memory (MB): 224.624
Reported internal fragmentation: 12.3117%
Bits/key stored: 10.2951
Average FP rate %: 0.821534
$ ./filter_bench -quick -impl=2 -average_keys_per_filter=1000 -vary_key_count_ratio=0.9 -optimize_filters_for_memory
Build avg ns/key: 31.8057
Number of filters: 159849
Total size (MB): 200
Reported total allocated memory (MB): 208.846
Reported internal fragmentation: 4.42297%
Bits/key stored: 10.4948
Average FP rate %: 0.811006
(high keys/filter)
$ ./filter_bench -quick -impl=2 -average_keys_per_filter=1000000 -vary_key_count_ratio=0.9
Build avg ns/key: 29.7017
Number of filters: 164
Total size (MB): 200.352
Reported total allocated memory (MB): 221.5
Reported internal fragmentation: 10.5552%
Bits/key stored: 10.0003
Average FP rate %: 0.969358
$ ./filter_bench -quick -impl=2 -average_keys_per_filter=1000000 -vary_key_count_ratio=0.9 -optimize_filters_for_memory
Build avg ns/key: 30.7131
Number of filters: 160
Total size (MB): 200.928
Reported total allocated memory (MB): 200.938
Reported internal fragmentation: 0.00448054%
Bits/key stored: 10.1852
Average FP rate %: 0.963387
And from db_bench (block cache) with jemalloc:
$ ./db_bench -db=/dev/shm/dbbench.no_optimize -benchmarks=fillrandom -format_version=5 -value_size=90 -bloom_bits=10 -num=2000000 -threads=8 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=false
$ ./db_bench -db=/dev/shm/dbbench -benchmarks=fillrandom -format_version=5 -value_size=90 -bloom_bits=10 -num=2000000 -threads=8 -optimize_filters_for_memory -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=false
$ (for FILE in /dev/shm/dbbench.no_optimize/*.sst; do ./sst_dump --file=$FILE --show_properties | grep 'filter block' ; done) | awk '{ t += $4; } END { print t; }'
17063835
$ (for FILE in /dev/shm/dbbench/*.sst; do ./sst_dump --file=$FILE --show_properties | grep 'filter block' ; done) | awk '{ t += $4; } END { print t; }'
17430747
$ #^ 2.1% additional filter storage
$ ./db_bench -db=/dev/shm/dbbench.no_optimize -use_existing_db -benchmarks=readrandom,stats -statistics -bloom_bits=10 -num=2000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=false -duration=10 -cache_index_and_filter_blocks -cache_size=1000000000
rocksdb.block.cache.index.add COUNT : 33
rocksdb.block.cache.index.bytes.insert COUNT : 8440400
rocksdb.block.cache.filter.add COUNT : 33
rocksdb.block.cache.filter.bytes.insert COUNT : 21087528
rocksdb.bloom.filter.useful COUNT : 4963889
rocksdb.bloom.filter.full.positive COUNT : 1214081
rocksdb.bloom.filter.full.true.positive COUNT : 1161999
$ #^ 1.04 % observed FP rate
$ ./db_bench -db=/dev/shm/dbbench -use_existing_db -benchmarks=readrandom,stats -statistics -bloom_bits=10 -num=2000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=false -optimize_filters_for_memory -duration=10 -cache_index_and_filter_blocks -cache_size=1000000000
rocksdb.block.cache.index.add COUNT : 33
rocksdb.block.cache.index.bytes.insert COUNT : 8448592
rocksdb.block.cache.filter.add COUNT : 33
rocksdb.block.cache.filter.bytes.insert COUNT : 18220328
rocksdb.bloom.filter.useful COUNT : 5360933
rocksdb.bloom.filter.full.positive COUNT : 1321315
rocksdb.bloom.filter.full.true.positive COUNT : 1262999
$ #^ 1.08 % observed FP rate, 13.6% less memory usage for filters
(Due to specific key density, this example tends to generate filters that are "worse than average" for internal fragmentation. "Better than average" cases can show little or no improvement.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6427
Test Plan: unit test added, 'make check' with gcc, clang and valgrind
Reviewed By: siying
Differential Revision: D22124374
Pulled By: pdillinger
fbshipit-source-id: f3e3aa152f9043ddf4fae25799e76341d0d8714e
Summary:
Avoid using `cf_consistency` together with `enable_compaction_filter` as
the former heavily uses snapshots while the latter is incompatible with
snapshots.
Also fix a clang-analyze error for a write to a variable that is never
read.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7006
Reviewed By: zhichao-cao
Differential Revision: D22141679
Pulled By: ajkr
fbshipit-source-id: 1840ae238168818a9ab5973f90fd78c067399447
Summary:
Added a `CompactionFilter` that is aware of the stress test's expected state. It only drops key versions that are already covered according to the expected state. It is incompatible with snapshots (same as all `CompactionFilter`s), so disables all snapshot-related features when used in the crash test.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6988
Test Plan:
running a minified blackbox crash test
```
$ TEST_TMPDIR=/dev/shm python tools/db_crashtest.py blackbox --max_key=1000000 -write_buffer_size=1048576 -max_bytes_for_level_base=4194304 -target_file_size_base=1048576 -value_size_mult=33 --interval=10 --duration=3600
```
Reviewed By: anand1976
Differential Revision: D22072888
Pulled By: ajkr
fbshipit-source-id: 727b9d7a90d5eab18be0ec6cd5a810712ac13320
Summary:
Add crash test for the case of best-efforts recovery.
After a certain amount of time, we kill the db_stress process, randomly delete some certain table files and restart db_stress. Given the randomness of file deletion, it is difficult to verify against a reference for data correctness. Therefore, we just check that the db can restart successfully.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6819
Test Plan:
```
./db_stress -best_efforts_recovery=true -disable_wal=1 -reopen=0
./db_stress -best_efforts_recovery=true -disable_wal=0 -skip_verifydb=1 -verify_db_one_in=0 -continuous_verification_interval=0
make crash_test_with_best_efforts_recovery
```
Reviewed By: anand1976
Differential Revision: D21436753
Pulled By: riversand963
fbshipit-source-id: 0b3605c922a16c37ed17d5ab6682ca4240e47926
Summary:
RocksDB Makefile was assuming existence of 'python' command,
which is not present in CentOS 8. We avoid using 'python' if 'python3' is available.
Also added fancy logic to format-diff.sh to make clang-format-diff.py for Python2 work even with Python3 only (as some CentOS 8 FB machines come equipped)
Also, now use just 'python3' for PYTHON if not found so that an informative
"command not found" error will result rather than something weird.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6883
Test Plan: manually tried some variants, 'make check' on a fresh CentOS 8 machine without 'python' executable or Python2 but with clang-format-diff.py for Python2.
Reviewed By: gg814
Differential Revision: D21767029
Pulled By: pdillinger
fbshipit-source-id: 54761b376b140a3922407bdc462f3572f461d0e9
Summary:
"compressio_parallel_threads" caused several test failure tests. To keep crash test clean, disable it for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6816
Test Plan: "make crash_test" to make sure the python script doesn't break
Reviewed By: zhichao-cao
Differential Revision: D21462112
fbshipit-source-id: 9eecc764800da82cd19665dc8b167eacead3310b
Summary:
This commit adds an `compression_parallel_threads` option in
db_stress. It also fixes the naming of parallel compression
option in db_bench to keep it aligned with others.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6722
Reviewed By: pdillinger
Differential Revision: D21091385
fbshipit-source-id: c9ba8c4e5cc327ff9e6094a6dc6a15fcff70f100
Summary:
In crash test, the db directory might be set to /dev/shm or /tmp, in certain environments such as internal testing infrastructure, neither of these directories support direct IO, so direct IO is never enabled in crash test.
This PR sets up SyncPoints in direct IO related code paths to disable O_DIRECT flag in calls to `open`, so the direct IO code paths will be executed, all direct IO related assertions will be checked, but no real direct IO request will be issued to the file system.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6727
Test Plan:
export CRASH_TEST_EXT_ARGS="--use_direct_reads=1 --mmap_read=0"
make -j24 crash_test
Reviewed By: zhichao-cao
Differential Revision: D21139250
Pulled By: cheng-chang
fbshipit-source-id: db9adfe78d91aa4759835b1af91c5db7b27b62ee
Summary:
Recently index_type kBinarySearchWithFirstKey is improved so that the API guarantee is exactly the same as other types and it is ready for wide production. We should cover it in crash tst.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6721
Test Plan: Run crash_test
Reviewed By: anand1976
Differential Revision: D21099781
fbshipit-source-id: fda91eba831d9eacbb140c703e9768bb1701f935
Summary:
RocksDB behavior is different while max_open_files is small or large. Add the coverage to small max_open_files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6719
Test Plan: Run crash_test
Reviewed By: pdillinger
Differential Revision: D21081021
fbshipit-source-id: e3e211761a9bd25d93d19a61c1f7b62d48cf5e3c
Summary:
Options.avoid_flush_during_recovery is uncovered in crash_test. Add the coverage with a chance of 1/8, as it is a less frequently used options.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6712
Test Plan: Run crash_test and see the option can be used or not used by chance.
Reviewed By: ltamasi
Differential Revision: D21056566
fbshipit-source-id: c3b1521517cfc204786e6ef8c6acd7fffda64793
Summary:
Add env_fault_injection argument to db_stress. When enabled,
FaultInjectionTestEnv will be used instead. Currently this
option does not support running with other env setting.
This will allow
us to later manually produce error when running db_crashtest.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6687
Test Plan:
make db_stress -j32
./db_stress --env_fault_injection
./db_stress --env_fault_injection --hdfs // expect error message
Reviewed By: ajkr
Differential Revision: D21014683
Pulled By: yhchiang
fbshipit-source-id: 0724aeac37efd57adb72a37defe6dbd3bfa8106a
Summary:
This was causing db_crashtest.py to wrongly assume an error by parsing the output. Hopefully this will stabilize the crash tests.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6705
Test Plan: make blackbox_crash_test
Reviewed By: ltamasi
Differential Revision: D21043335
Pulled By: anand1976
fbshipit-source-id: 5cddd112b124d4e2ebd11724a17d4ef0f50c1cf8
Summary:
This PR implements a fault injection mechanism for injecting errors in reads in db_stress. The FaultInjectionTestFS is used for this purpose. A thread local structure is used to track the errors, so that each db_stress thread can independently enable/disable error injection and verify observed errors against expected errors. This is initially enabled only for Get and MultiGet, but can be extended to iterator as well once its proven stable.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6538
Test Plan:
crash_test
make check
Reviewed By: riversand963
Differential Revision: D20714347
Pulled By: anand1976
fbshipit-source-id: d7598321d4a2d72bda0ced57411a337a91d87dc7
Summary:
Currently, `db_stress` tests a randomly picked one of `GetLiveFiles`,
`GetSortedWalFiles`, and `GetCurrentWalFile` with a 1/N chance when the
command line parameter `get_live_files_and_wal_files_one_in` is specified.
The problem is that `GetSortedWalFiles` and `GetCurrentWalFile` are unreliable
in the sense that they can return errors if another thread removes a WAL file
while they are executing (which is a perfectly plausible and legitimate scenario).
The patch splits this command line parameter into three (one for each API),
and changes the crash test script so that only `GetLiveFiles` is tested during
our continuous crash test runs.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6491
Test Plan:
```
make check
python tools/db_crashtest.py whitebox
```
Reviewed By: siying
Differential Revision: D20312200
Pulled By: ltamasi
fbshipit-source-id: e7c3481eddfe3bd3d5349476e34abc9eee5b7dc8
Summary:
This reverts commit 8e309b35bb.
The stress tests are failing . Revert it until we figure the root cause.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6327
Differential Revision: D19537657
Pulled By: maysamyabandeh
fbshipit-source-id: bf34a5dd720825957729e136e9a5a729a240e61a
Summary:
kHashSearch is incompatible with larger than 1 values for index_block_restart_interval. Setting it to 1 in stress tests would avoid confusion about the test parameters.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6324
Differential Revision: D19525669
Pulled By: maysamyabandeh
fbshipit-source-id: fbf3a797e0ebcebb4d32eba3728cf3583906fc8a
Summary:
Block-based table has index has been disabled in crash test due to bugs. We fixed a bug and re-enable it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6310
Test Plan: Finish one round of "crash_test_with_atomic_flush" test successfully while exclusively running has index. Another run also ran for several hours without failure.
Differential Revision: D19455856
fbshipit-source-id: 1192752d2c1e81ed7e5c5c7a9481c841582d5274
Summary:
A previous change meant to make db_stress to run on sync=1 mode for 1/20 of the time in crash_test, but a bug caused to to always run on sync=1 mode. Fix it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6304
Test Plan: Start and kill "python -u tools/db_crashtest.py --simple whitebox" multiple times and observe that most times sync=0 is used while some times sync=1 is used.
Differential Revision: D19433000
fbshipit-source-id: 7a0adba39b17a1b3acbbd791bb0cdb743b91fa95
Summary:
This commit is suspected in some crash test failures such as
Verification failed for column family 0 key 78438077: Value not found: NotFound:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6243
Test Plan: 'make check' and start 'make crash_test'
Differential Revision: D19220495
Pulled By: pdillinger
fbshipit-source-id: 6c4709cee80ab4344e06ce360f51e947d79fb3fa
Summary:
Currently, db_stress generates fixed length keys of 8 bytes. This patch adds the ability to generate variable length keys. Most of the db_stress code continues to work with a numeric key randomly generated, and the numeric key also acts as an index into the values_ array. The numeric key is mapped to a variable length string key in a deterministic way. Furthermore, the ordering is preserved.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6165
Test Plan: run make crash_test
Differential Revision: D19204646
Pulled By: anand1976
fbshipit-source-id: d2d46a96615b4832a8be2a981f5913905f0e1ca7
Summary:
Several improvements to crash_test/stress_test:
(1) Stress_test to support an parameter of bottommost compression
(2) Rename those FLAGS_* variables that are not gflags to avoid confusion
(3) Crash_test to randomly generate compression type for bottommost compression with half the chance.
(4) Stress_test to sanitize unsupported compression type to snappy, so that crash_test to cover all possible compression types and people don't need to worry about they don't support all comrpession types in their environment.
(5) In crash_test, when generating db_stress command, sort arguments in alphabeta order, so that it is easier to find value for a specific argument.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6215
Test Plan: Run "make crash_test" for a while and see the botommost option shown in LOG files.
Differential Revision: D19171255
fbshipit-source-id: d7001e246c4ff9ee5760776eea0be97738650735
Summary:
Add the verification in operateDB to verify GetLiveFiles, GetSortedWalFiles and GetCurrentWalFile. The test will be called every 1 out of N, N is decided by get_live_files_and_wal_files_one_i, whose default is 1000000.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6224
Test Plan: pass db_stress default run.
Differential Revision: D19183358
Pulled By: zhichao-cao
fbshipit-source-id: 20073cf72ede77a3e0d3cf5f28304f1f605d2b1a
Summary:
Currently, db_stress performs verification by calling `VerifyDb()` at the end of test and optionally before tests start. In case of corruption or incorrect result, it will be too late. This PR adds more verification in two ways.
1. For cf consistency test, each test thread takes a snapshot and verifies every N ops. N is configurable via `-verify_db_one_in`. This option is not supported in other stress tests.
2. For cf consistency test, we use another background thread in which a secondary instance periodically tails the primary (interval is configurable). We verify the secondary. Once an error is detected, we terminate the test and report. This does not affect other stress tests.
Test plan (devserver)
```
$./db_stress -test_cf_consistency -verify_db_one_in=0 -ops_per_thread=100000 -continuous_verification_interval=100
$./db_stress -test_cf_consistency -verify_db_one_in=1000 -ops_per_thread=10000 -continuous_verification_interval=0
$make crash_test
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6173
Differential Revision: D19047367
Pulled By: riversand963
fbshipit-source-id: aeed584ad71f9310c111445f34975e5ab47a0615
Summary:
This reverts commit 54f9092b0c.
It making our daily stress tests fail. Revert it until the issues are fixed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6220
Differential Revision: D19179881
Pulled By: maysamyabandeh
fbshipit-source-id: 99de0eaf776567fa81110b9ad2608234a16083ce
Summary:
We're seeing assertion violations like this in crash test:
db_stress: table/block_based/block_based_table_reader.cc:4129: virtual uint64_t rocksdb::BlockBasedTable::ApproximateSize(const rocksdb::Slice&, const rocksdb::Slice&, rocksdb::TableReaderCaller): Assertion `end_offset >= start_offset' failed.***
And ApproximateSize appears only to be called with the level_compaction_dynamic_level_bytes option.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6217
Test Plan:
temporarily put an assert(false) in ApproximateSize and
briefly run 'make crash_test'
Differential Revision: D19179174
Pulled By: pdillinger
fbshipit-source-id: 506e6549aea0da19b363a1a6da04373c364d92e4
Summary:
Beside extending index_type to kHashSearch, it clarifies in the code base that this feature is incompatible with index_block_restart_interval > 1.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6210
Test Plan:
```
make -j32 crash_test
Differential Revision: D19166567
Pulled By: maysamyabandeh
fbshipit-source-id: 3aaf75a70a8b462d372d43aac69dbd10df303ec7
Summary:
Add an option to db_stress, verify_checksum_one_in, to call DB::VerifyChecksum() once every N ops.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6203
Differential Revision: D19145753
Pulled By: anand1976
fbshipit-source-id: d09edf21f309ad53aa40dd25b7a563d50665fd8b
Summary:
Fix two crash test issues:
1. sync mode should not run with disable_wal=true
2. disable "compaction_readahead_size" for now. With it on, some block checksum verification failure will happen in compaction paths. Not sure why, but disable it for now to keep the test clean.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6200
Test Plan: Run "make crash_test" and "make crash_test_with_atomic_flush" and see it runs way longer than before the fix without failing.
Differential Revision: D19143493
fbshipit-source-id: 438fad52fbda60aafd142e1b65578addbe7d72b1
Summary:
Several options are trivially added to crash test and random values are picked.
Made simple test run non-dynamic level and normal test run dynamic level.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6176
Test Plan: Run crash_test and watch the printing
Differential Revision: D19053955
fbshipit-source-id: 958cb43c968541ebd87ed4d91e778bd1d40e7502
Summary:
Current implementation holds on to 10% of snapshots for 10x longer, and 1% of snapshots 100x longer.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6171
Test Plan:
```
make -j32 crash_test
Differential Revision: D19038399
Pulled By: maysamyabandeh
fbshipit-source-id: 75da2dbb5c47a0b3f37d299b8719e392b73b42c0
Summary:
With WritePrepared transactions configured with two_write_queues, unordered_write will offer the same guarantees as vanilla rocksdb and thus can be enabled in stress tests.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6164
Test Plan:
```
make -j32 crash_test_with_txn
Differential Revision: D18991899
Pulled By: maysamyabandeh
fbshipit-source-id: eece5e96b4169b67d7931e5c0afca88540a113e1
Summary:
Currently the default txn write policy in crash tests is WRITE_PREPARED. The patch randomly picks the write policy at the start of the crash test.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6158
Test Plan:
```
make -j32 crash_test_with_txn
```
Differential Revision: D18946307
Pulled By: maysamyabandeh
fbshipit-source-id: f77d7a94f99a08791ef9626da153d284bf521950
Summary:
Especially with non-integral bits/key now supported,
db_crashtest should vary the bloom_bits configuration. The probabilities
look like this:
1/2 chance of a uniform int from 0 to 19. This includes overall 1/40
chance of 0 which disables the bloom filter.
1/2 chance of a float from a lognormal distribution with a median of 10.
This always produces positive values but with a decent chance of < 1
(overall ~1/40) or > 100 (overall ~1/40), the enforced/coerced
implementation limits.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6103
Test Plan:
start 'make blackbox_crash_test' several times and look at
configuration output
Differential Revision: D18734877
Pulled By: pdillinger
fbshipit-source-id: 4a38cb057d3b3fc1327f93199f65b9a9ffbd7316
Summary:
format_version=5 enables new Bloom filter. Using 2/5
probability for "latest and greatest" rather than naive 1/4.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6102
Test Plan: start 'make blackbox_crash_test'
Differential Revision: D18735685
Pulled By: pdillinger
fbshipit-source-id: e81529c8a3f53560d246086ee5f92ee7d79a2eab
Summary:
Right now, crash_test always uses 16KB max_manifest_file_size value. It is good to cover logic of manifest file switch. However, information stored in manifest files might be useful in debugging failures. Switch to only use small manifest file size in 1/15 of the time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6034
Test Plan: Observe command generated by db_crash_test.py multiple times and see the --max_manifest_file_size value distribution.
Differential Revision: D18513824
fbshipit-source-id: 7b3ae6dbe521a0918df41064e3fa5ecbf2466e04
Summary:
A recent commit make periodic compaction option valid in FIFO, which means TTL. But we fail to disable it in crash test, causing assert failure. Fix it by having it disabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5993
Test Plan: Restart "make crash_test" many times and make sure --periodic_compaction_seconds=0 is always the case when --compaction_style=2
Differential Revision: D18263223
fbshipit-source-id: c91a802017d83ae89ac43827d1b0012861933814
Summary:
Recently, pipelined write is enabled even if atomic flush is enabled, which causing sanitizing failure in db_stress. Revert this change.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5986
Test Plan: Run "make crash_test_with_atomic_flush" and see it to run for some while so that the old sanitizing error (which showed up quickly) doesn't show up.
Differential Revision: D18228278
fbshipit-source-id: 27fdf2f8e3e77068c9725a838b9bef4ab25a2553
Summary:
In pipeline writing mode, memtable switching needs to wait for memtable writing to finish to make sure that when memtables are made immutable, inserts are not going to them. This is currently done in DBImpl::SwitchMemtable(). This is done after flush_scheduler_.TakeNextColumnFamily() is called to fetch the list of column families to switch. The function flush_scheduler_.TakeNextColumnFamily() itself, however, is not thread-safe when being called together with flush_scheduler_.ScheduleFlush().
This change provides a fix, which moves the waiting logic before flush_scheduler_.TakeNextColumnFamily(). WaitForPendingWrites() is a natural place where the logic can happen.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5716
Test Plan: Run all tests with ASAN and TSAN.
Differential Revision: D18217658
fbshipit-source-id: b9c5e765c9989645bf10afda7c5c726c3f82f6c3
Summary:
This is the 2nd attempt after the revert of https://github.com/facebook/rocksdb/pull/4020
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5895
Test Plan:
```
./tools/db_crashtest.py blackbox --simple --interval=10 --max_key=10000000
```
Differential Revision: D17822137
Pulled By: maysamyabandeh
fbshipit-source-id: 3d148c0d8cc129080410ff859c04b544223c8ea3
Summary:
For now, crash_test is not able to report any failure for the logic related to iterator upper, lower bounds or iterators, or reseek. These are features prone to errors. Improve db_stress in several ways:
(1) For each iterator run, reseek up to 3 times.
(2) For every iterator, create control iterator with upper or lower bound, with total order seek. Compare the results with the iterator.
(3) Make simple crash test to avoid prefix size to have more coverage.
(4) make prefix_size = 0 a valid size and -1 to indicate disabling prefix extractor.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5846
Test Plan: Manually hack the code to create wrong results and see they are caught by the tool.
Differential Revision: D17631760
fbshipit-source-id: acd460a177bd2124a5ffd7fff490702dba63030b
Summary:
PR https://github.com/facebook/rocksdb/issues/4020 enabled partitioned indexes/filters in stress tests; however,
this causes assertion failures in BatchedOpsStressTest. This patch
disables them until we can root cause the failures.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5811
Test Plan: Ran the script and made sure it only uses the binary search index.
Differential Revision: D17399366
Pulled By: ltamasi
fbshipit-source-id: adb116e6297f9c6ccd7ac15b6a16c9aa91f21ac5
Summary:
PR https://github.com/facebook/rocksdb/issues/4020 implicitly enabled the hash index as well in stress/crash
tests, resulting in assertion failures in Block. This patch disables
the hash index until we can pinpoint the root cause of these issues.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5792
Test Plan:
Ran tools/db_crashtest.py and made sure it only uses index types 0 and 2
(binary search and partitioned index).
Differential Revision: D17346777
Pulled By: ltamasi
fbshipit-source-id: b4318f37f1fda3ee1bbff4ef2c2f556ca9e6b551
Summary:
- In `db_stress`, support choosing index type and whether to enable filter partitioning, and randomly set those options in crash test
- When partitioned filter is enabled by crash test, force partitioned index to also be enabled since it's a prerequisite
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4020
Test Plan:
currently this is blocked on fixing the bug that crash test caught:
```
$ TEST_TMPDIR=/data/compaction_bench python ./tools/db_crashtest.py blackbox --simple --interval=10 --max_key=10000000
...
Verification failed for column family 0 key 937501: Value not found: NotFound:
Crash-recovery verification failed :(
```
Differential Revision: D8508683
Pulled By: maysamyabandeh
fbshipit-source-id: 0337e5d0558bcef26b1f3699f47265a2c1e99629
Summary:
https://github.com/facebook/rocksdb/pull/5741 added compaction TTL to crash test, but it causes assertion fails for FIFO compaction. Disable this combination for now while we debug the assertion failure.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5749
Test Plan: Run crash test and observe that when compaction_style=2, compaction_ttl is always 0.
Differential Revision: D17078292
fbshipit-source-id: 446821a3b9739956094d5e4f9be1251a15b57f5d
Summary:
Covering periodic compaction and compaction TTL can help us expose potential issues. Add it there.
Randomly select value for these two options.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5741
Test Plan: Run crash_test and see the perameters generated.
Differential Revision: D17059515
fbshipit-source-id: 8213974846a0b6a22fc13be705825c9054d1d097
Summary:
AtomicFlushStressTest is a powerful test, but right now we only run it for atomic_flush=true + disable_wal=true. We further extend it to the case where atomic_flush=false + disable_wal = false. All the workload generation and validation can stay the same.
Atomic flush crash test is also changed to switch between the two test scenarios. It makes the name "atomic flush crash test" out of sync from what it really does. We leave it as it is to avoid troubles with continous test set-up.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5729
Test Plan: Run "CRASH_TEST_KILL_ODD=188 TEST_TMPDIR=/dev/shm/ USE_CLANG=1 make whitebox_crash_test_with_atomic_flush", observe the settings used and see it passed.
Differential Revision: D16969791
fbshipit-source-id: 56e37487000ae631e31b0100acd7bdc441c04163
Summary:
Atomic white box test's kill odd is the same as normal test. However, in the scenario that only WritableFileWriter::Append() is blacklisted, WritableFileWriter::Flush() dominates the killing odds. Normally, most of WritableFileWriter::Flush() are called in WAL writes, where every write triggers a WAL flush. In atomic test, WAL is disabled, so the kill happens less frequently than we antipated. In some rare cases, the kill didn't end up with happening (for reasons I still don't fully understand) and cause the stress test timeout.
If WAL is disabled, make the odds 5x likely to trigger.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5717
Test Plan: Run whitebox_crash_test_with_atomic_flush and whitebox_crash_test and observe the kill odds printed out.
Differential Revision: D16897237
fbshipit-source-id: cbf5d96f6fc0e980523d0f1f94bf4e72cdb82d1c
Summary:
Atomic flush test started to fail after https://github.com/facebook/rocksdb/issues/5099. Then https://github.com/facebook/rocksdb/issues/5278 provided a fix after
which the same error occurred much less frequently. However it still occur
occasionally. Not sure what the root cause is. This PR disables the feature of
snapshot list refresh, and we should keep an eye on the failure in the future.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5581
Differential Revision: D16295985
Pulled By: riversand963
fbshipit-source-id: c9e62e65133c52c21b07097de359632ca62571e4
Summary:
The tsan crash tests are failing with a data race compliant with pipelined write option. Temporarily disable it until its concurrency issue are fixed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5445
Differential Revision: D15783824
Pulled By: maysamyabandeh
fbshipit-source-id: 413a0c3230b86f524fc7eeea2cf8e8375406e65b
Summary:
This PR fixes a couple of bugs in FilePickerMultiGet that were causing db_stress test failures. The failures were caused by -
1. Improper handling of a key that matches the user key portion of an L0 file's largest key. In this case, the curr_index_in_curr_level file index in L0 for that key was getting incremented, but batch_iter_ was not advanced. By design, all keys in a batch are supposed to be checked against an L0 file before advancing to the next L0 file. Not advancing to the next key in the batch was causing a double increment of curr_index_in_curr_level due to the same key being processed again
2. Improper handling of a key that matches the user key portion of the largest key in the last file of L1 and higher. This was resulting in a premature end to the processing of the batch for that level when the next key in the batch is a duplicate. Typically, the keys in MultiGet will not be duplicates, but its good to handle that case correctly
Test -
asan_crash
make check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5292
Differential Revision: D15282530
Pulled By: anand1976
fbshipit-source-id: d1a6a86e0af273169c3632db22a44d79c66a581f
Summary:
Disable it for now until we can get stress tests to pass consistently.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5284
Differential Revision: D15230727
Pulled By: anand1976
fbshipit-source-id: 239baacdb3c4cd4fb7c4447f7582b9042501d752
Summary:
Part of compaction cpu goes to processing snapshot list, the larger the list the bigger the overhead. Although the lifetime of most of the snapshots is much shorter than the lifetime of compactions, the compaction conservatively operates on the list of snapshots that it initially obtained. This patch allows the snapshot list to be updated via a callback if the compaction is taking long. This should let the compaction to continue more efficiently with much smaller snapshot list.
For simplicity, to avoid the feature is disabled in two cases: i) When more than one sub-compaction are sharing the same snapshot list, ii) when Range Delete is used in which the range delete aggregator has its own copy of snapshot list.
This fixes the reverted https://github.com/facebook/rocksdb/pull/5099 issue with range deletes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5278
Differential Revision: D15203291
Pulled By: maysamyabandeh
fbshipit-source-id: fa645611e606aa222c7ce53176dc5bb6f259c258
Summary:
The new option will pick a batch size randomly in the range 1-64. It will then space the keys in the batch by random intervals.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5264
Differential Revision: D15175522
Pulled By: anand1976
fbshipit-source-id: c16baa69d0f1ff4cf53c55c813ddd82c8aeb58fc
Summary:
At least one of the meta-block loading functions (`ReadRangeDelBlock`)
uses the same block reading function (`NewDataBlockIterator`) as data
block reads, which means it uses the dictionary handle. However, the
dictionary handle was uninitialized while reading meta-blocks, causing
readers to receive an error. This situation was only noticed when
`cache_index_and_filter_blocks=true`.
This PR initializes the handle to null while reading meta-blocks to
prevent the error. It also adds support to `db_stress` /
`db_crashtest.py` for `cache_index_and_filter_blocks`.
Fixes#5263.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5267
Differential Revision: D15149264
Pulled By: maysamyabandeh
fbshipit-source-id: 991d38a306c62db5976778bfb050fa3cd4a0671b
Summary:
Since currently pipelined write allows one thread to perform memtable writes
while another thread is traversing the `flush_scheduler_`, it will cause an
assertion failure in `FlushScheduler::Clear`. To unblock crash recoery tests,
we temporarily disable pipelined write when atomic flush is enabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5266
Differential Revision: D15142285
Pulled By: riversand963
fbshipit-source-id: a0c20fe4ac543e08feaed602414f982054df7831
Summary:
Since this feature affects the WAL behavior, it seems important our crash-recovery tests cover it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5070
Differential Revision: D14470085
Pulled By: miasantreble
fbshipit-source-id: 9b9682a718a926d57d055e0a5ec867efbd2eb9c1
Summary:
Previously `finalize_and_sanitize` function was always zeroing out `compression_zstd_max_train_bytes`. It was only supposed to do that when non-ZSTD compression was used. But since `--compression_type` was an unknown argument (i.e., one that `db_crashtest.py` does not recognize and blindly forwards to `db_stress`), `finalize_and_sanitize` could not tell whether ZSTD was used. This PR fixes it simply by making `--compression_type` a known argument with snappy as default (same as `db_stress`).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4957
Differential Revision: D13994302
Pulled By: ajkr
fbshipit-source-id: 1b0baea7331397822830970d3698642eb7a7df65
Summary:
Separate flag for enabling option from flag for enabling dedicated atomic stress test. I have found setting the former without setting the latter can detect different problems.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4781
Differential Revision: D13463211
Pulled By: ajkr
fbshipit-source-id: 054f777885b2dc7d5ea99faafa21d6537eee45fd
Summary:
The default for index_block_restart_interval is 1 but some use 16 in production. The patch extends crash test to test both values.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4383
Differential Revision: D9887304
Pulled By: maysamyabandeh
fbshipit-source-id: a8d00fea974a79ad563f9f4d9d7b069e9f746a8f
Summary:
- Add `--compression_max_dict_bytes` and `--compression_zstd_max_train_bytes` flags to stress test
- Randomly enable/disable the above flags in crash test
- Set `--compression_type=zstd` in FB-specific crash test runs
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4234
Differential Revision: D9187207
Pulled By: ajkr
fbshipit-source-id: 8d78cf8d8e1165f2cd1c32e069b73726b5bc1fd2
Summary:
db_stress doesn't cover upper or lower bound in iterators. Try to cover it by randomly assigning a random one. Also in prefix scan tests, with 50% of the chance, set next prefix as the upper bound.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4162
Differential Revision: D8953507
Pulled By: siying
fbshipit-source-id: f0f04e9cb6c07cbebbb82b892ca23e0daeea708b
Summary:
Add the `backup_one_in` and `checkpoint_one_in` options to periodically trigger backups and checkpoints. The directory names contain thread ID to avoid clashing with parallel backups/checkpoints. Enable checkpoint in crash test so our CI runs will use it. Didn't enable backup in crash test since it copies all the files which is too slow.
Closes https://github.com/facebook/rocksdb/pull/4005
Differential Revision: D8472275
Pulled By: ajkr
fbshipit-source-id: ff91bdc37caac4ffd97aea8df96b3983313ac1d5
Summary:
Fixed bug where `db_stress` output a line with a warning followed by a line with an error, and `db_crashtest.py` considered that a success. For example:
```
WARNING: prefix_size is non-zero but memtablerep != prefix_hash
open error: Corruption: SST file is ahead of WALs
```
Closes https://github.com/facebook/rocksdb/pull/4006
Differential Revision: D8473463
Pulled By: ajkr
fbshipit-source-id: 60461bdd7491d9d26c63f7d4ee522a0f88ba3de7
Summary:
format_version=3 changes the format of SST index. This is however not being tested currently since tests only work with the default format_version which is currently 2. The patch extends the most related tests to also test for format_version=3.
Closes https://github.com/facebook/rocksdb/pull/3942
Differential Revision: D8238413
Pulled By: maysamyabandeh
fbshipit-source-id: 915725f55753dd8e9188e802bf471c23645ad035
Summary:
We need to keep the DB directory around since the direct IO check in "db_crashtest.py" relies on it existing. This PR fixes an issue where it was removed after each stress test run during the second half of whitebox crash testing.
Closes https://github.com/facebook/rocksdb/pull/3946
Differential Revision: D8247998
Pulled By: ajkr
fbshipit-source-id: 4e7cffbdab9b40df125e7842d0d59916e76261d3
Summary:
Previously `db_stress` attempted to configure direct I/O dynamically in `SetOptions()` which had multiple problems (ummm must've never been tested):
- It's a DB option so SetDBOptions should've been called instead
- It's not a dynamic option so even SetDBOptions would fail
- It required enabling SyncPoint to mask O_DIRECT since it had no way to detect whether the DB directory was in tmpfs or not. This required locking that consumed ~80% of db_stress CPU.
In this PR I delete the broken dynamic config and instead configure it statically, only enabling it if the DB directory truly supports O_DIRECT.
Closes https://github.com/facebook/rocksdb/pull/3939
Differential Revision: D8238120
Pulled By: ajkr
fbshipit-source-id: 60bb2deebe6c9b54a3f788079261715b4a229279
Summary:
- Any options unknown to `db_crashtest.py` are now passed directly to `db_stress`. This way, we won't need to update `db_crashtest.py` every time `db_stress` gets a new option.
- Remove `db_crashtest.py` redundant arguments where the value is the same as `db_stress`'s default
- Remove `db_crashtest.py` redundant arguments where the value is the same in a previously applied options map. For example, default_params are always applied before whitebox_default_params, so if they require the same value for an argument, that value only needs to be provided in default_params.
- Made the simple option maps applied in addition to the regular option maps. Previously they were exclusive which led to lots of duplication
Closes https://github.com/facebook/rocksdb/pull/3809
Differential Revision: D7885779
Pulled By: ajkr
fbshipit-source-id: 3a3243b55724d6d5bff36e939b582b9b62c538a8
Summary:
- Original commit: a4fb1f8c04
- Revert commit (we reverted as a quick fix to get crash tests passing): 6afe22db2e
This PR includes the contents of the original commit plus two bug fixes, which are:
- In whitebox crash test, only set `--expected_values_path` for `db_stress` runs in the first half of the crash test's duration. In the second half, a fresh DB is created for each `db_stress` run, so we cannot maintain expected state across `db_stress` runs.
- Made `Exists()` return true for `UNKNOWN_SENTINEL` values. I previously had an assert in `Exists()` that value was not `UNKNOWN_SENTINEL`. But it is possible for post-crash-recovery expected values to be `UNKNOWN_SENTINEL` (i.e., if the crash happens in the middle of an update), in which case this assertion would be tripped. The effect of returning true in this case is there may be cases where a `SingleDelete` deletes no data. But if we had returned false, the effect would be calling `SingleDelete` on a key with multiple older versions, which is not supported.
Closes https://github.com/facebook/rocksdb/pull/3793
Differential Revision: D7811671
Pulled By: ajkr
fbshipit-source-id: 67e0295bfb1695ff9674837f2e05bb29c50efc30
