Summary:
Call Transaction::MultiGet from TestMultiGet() in db_stress. We add some Puts/Merges/Deletes into the transaction in order to exercise MultiGetFromBatchAndDB. There is no data verification on read, just check status. There is currently no read data verification in db_stress as it requires synchronization with writes. It needs to be tackled separately.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6227
Test Plan: make crash_test_with_txn
Differential Revision: D19204611
Pulled By: anand1976
fbshipit-source-id: 770d0e30d002e88626c264c58103f1d709bb060c
Summary:
Recently db_stress starts to use a special Env that keeps all manifest files. This should not apply to checkpoint directory and causes test failure like this:
Verification failed: Checkpoint gave inconsistent state. Status is IO error: While mkdir: /dev/shm/rocksdb/rocksdb_crashtest_whitebox/.checkpoint27.tmp: File exists
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6233
Test Plan: Run crash_test with high chance of checkpoint and make sure it doesn't reproduce.
Differential Revision: D19207250
fbshipit-source-id: 12a931379e2e0572bb84aa658b6d03770c8551d4
Summary:
Listners are one source of bugs because we frequently release some mutex to invoke them, which introduce race conditions. Implement all callback functions in db_stress's listener class, and randomly sleep.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6197
Test Plan: Run crash_test for a while and see no obvious problem.
Differential Revision: D19134015
fbshipit-source-id: b9ea8be9366e4501759119520cd4f204943538f6
Summary:
db_stress to execute DB::GetApproximateSizes() with randomized keys and options. Return value is not validated but error will be reported.
Two ways to generate the range keys: (1) two random keys; (2) a small range.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6213
Test Plan: (1) run "make crash_test" for a while; (2) hack the code to ingest some errors to see it is reported.
Differential Revision: D19204665
fbshipit-source-id: 652db36f13bcb5a3bd8fe4a10c0aa22a77a0bce2
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:
1. Cover SeekToFirst() and SeekToLast().
2. Try to record the history of iterator operations.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6166
Test Plan: Do some manual changes in the code to cover the failure cases and see the error printing is correct and SeekToFirst() and SeekToLast() sometimes show up.
Differential Revision: D19047079
fbshipit-source-id: 1ed616f919fe4d32c0a021fc37932a7bd3063bcd
Summary:
There are no API changes ;-)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6218
Differential Revision: D19200373
Pulled By: pdillinger
fbshipit-source-id: 58d34b01ea53b75a1eccbd72f8b14d6256a7380f
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:
As title. We can run non-cf-consistency stress tests with verify_db_one_in>0,
thus remove the check added previously.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6231
Test Plan:
```
make crash_test
```
Differential Revision: D19198295
Pulled By: riversand963
fbshipit-source-id: e874c701bb03ab76eaab00f059dd4032bb2f537f
Summary:
The patch adds support for BlobDB to `db_stress`. Note that BlobDB currently does
not support (amongst other features) Column Families or the `SingleDelete` API,
so for now, those should be disabled on the command line when running `db_stress` in
BlobDB mode (using `-column_families=1` and `-nooverwritepercent=0`,
respectively). Also, some BlobDB features that do not go well with the verification logic
in `db_stress` like TTL and FIFO eviction are not supported currently.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6230
Test Plan:
```
./db_stress -max_key=100000 -use_blob_db -column_families=1 -nooverwritepercent=0 -reopen=1 -blob_db_file_size=1000000 -target_file_size_base=1000000 -blob_db_enable_gc -blob_db_gc_cutoff=0.1 -blob_db_min_blob_size=10 -blob_db_bytes_per_sync=16384
```
Differential Revision: D19191476
Pulled By: ltamasi
fbshipit-source-id: 35840452af8c5e6095249c7fd9a53a119a0985fc
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:
BlobDB currently only supports using the default column family. The earlier
code enforces this by comparing the `ColumnFamilyHandle` passed to the
`Get`/`Put`/etc. call with the handle returned by `DefaultColumnFamily`
(which, at the end of the day, comes from `DBImpl::default_cf_handle_`).
Since other `ColumnFamilyHandle`s can also point to the default column
family, this can reject legitimate requests as well. (As an example,
with the earlier code, the handle returned by `BlobDB::Open` cannot
actually be used in API calls.) The patch fixes this by comparing only
the IDs of the column family handles instead of the pointers themselves.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6226
Test Plan: `make check`
Differential Revision: D19187461
Pulled By: ltamasi
fbshipit-source-id: 54ce2e12ebb1f07e6d1e70e3b1e0213dfa94bda2
Summary:
The new Python syntax check could fail if external entities
were cloned or symlinked to a subdir in a rocksdb git clone. (E.g.
Facebook internal LITE build.) Only look for Python files in specific
subdirs
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6225
Test Plan: python tools/check_all_python.py (still 34 files checked)
Reviewed By: gfosco
Differential Revision: D19186110
Pulled By: pdillinger
fbshipit-source-id: 1fefa54e36b32cd5d96d3d1a43e8a2a694c22ea5
Summary:
Right now BlockBasedTable::ApproximateSize() uses default setting about whether to use total order seek. There is no reason for that. There is no reason to do any filtering for approximate size boundary key, and it may introduce bugs. Disable it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6222
Test Plan: Run existing tests
Differential Revision: D19184787
fbshipit-source-id: 64180660bd2800914fff75104172b61c06f0b1c9
Summary:
Complete some refactoring called for in https://github.com/facebook/rocksdb/issues/6148. Somehow I got some 'make format' in here for files I didn't change, but that should be OK. (I'm not sure why "hide whitespace changes" doesn't seem to help in review.)
Not addressed in this PR: some operations simply print to stdout rather than failing on discovering a bad status or inconsistency.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6195
Differential Revision: D19131067
Pulled By: pdillinger
fbshipit-source-id: 4f416e6b792023989ef119f385fe122426cb825d
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:
Adds a python script to syntax check all python files in the
repository and report any errors.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6209
Test Plan:
'make check' with and without seeded syntax errors. Also look
for "No syntax errors in 34 .py files" on success, and in java_test CI output
Differential Revision: D19166756
Pulled By: pdillinger
fbshipit-source-id: 537df464b767260d66810b4cf4c9808a026c58a4
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:
The patch makes it possible to set the BlobDB configuration option
`garbage_collection_cutoff` on the command line. In addition, it changes
the `db_bench` code so that the default values of BlobDB related
parameters are taken from the defaults of the actual BlobDB
configuration options (note: this changes the the default of
`blob_db_bytes_per_sync`).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6211
Test Plan: Ran `db_bench` with various values of the new parameter.
Differential Revision: D19166895
Pulled By: ltamasi
fbshipit-source-id: 305ccdf0123b9db032b744715810babdc3e3b7d5
Summary:
level passed into ColumnFamilyData::CalculateSSTWriteHint() can be smaller than base_level in current version, which would cause overflow.
We see ubsan complains:
db/compaction/compaction_job.cc:1511:39: runtime error: load of value 4294967295, which is not a valid value for type 'Env::WriteLifeTimeHint'
and I hope this commit fixes it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6212
Test Plan: Run existing tests and see them to pass.
Differential Revision: D19168442
fbshipit-source-id: bf8fd86f85478ecfa7556db46dc3242de8c83dc9
Summary:
Should fix Travis build error that randomly showed up upon
using Java 13 version of javadoc.
AdvancedColumnFamilyOptionsInterface.java:257: error:
unexpected heading used: <H2>, compared to implicit preceding heading: <H3>
According to this reference https://bugs.openjdk.java.net/browse/JDK-8220379
it should work to start at h4, but that didn't work, so avoiding
headings should be fine.
Also fix Java EnvironmentTest for JDK13.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6208
Test Plan: Travis run on PR (don't have Java 13 handy)
Differential Revision: D19163105
Pulled By: pdillinger
fbshipit-source-id: 4a9419cbe7ef780fba771b8a1508e1ea80d17b3e
Summary:
Right now, sometimes file prefetching is still on when mmap is enabled. This causes bug of reading wrong data. In this commit, we remove all those possible paths.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6206
Test Plan: make crash_test with compaction_readahead_size, which used to fail. RUn all existing tests.
Differential Revision: D19149429
fbshipit-source-id: 9e18ea8c566e416aac9647bdd05afe596634791b
Summary:
buf_offset does not need to get the value from req.len for othe final block. It can cause test fail for clan_analyze. Remove it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6204
Test Plan: pass make asan_check
Differential Revision: D19145335
Pulled By: zhichao-cao
fbshipit-source-id: 8f6e74565746381b5c5ef598b97d746517b36e5b
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:
The bad code was:
```
mutex.Lock(); // `mutex` protects `container`
for (auto& x : container) {
mutex.Unlock();
// do stuff to x
mutex.Lock();
}
```
It's incorrect because both `x` and the iterator may become invalid if another thread modifies the container while this thread is not holding the mutex.
Broken by https://github.com/facebook/rocksdb/pull/5796 - it replaced a `while (!container.empty())` loop with a `for (auto x : container)`.
(RocksDB code does a lot of such unlocking+re-locking of mutexes, and this type of bugs comes up a lot :/ )
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6193
Test Plan: Ran some logdevice integration tests that were crashing without this fix.
Differential Revision: D19116874
Pulled By: al13n321
fbshipit-source-id: 9672bc4227c1b68f46f7436db2b96811adb8c703
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:
Cuts about 30-60 seconds to from each Travis Linux build, and about 15 minutes from each macOS build
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6181
Differential Revision: D19098357
Pulled By: pdillinger
fbshipit-source-id: 863dd1ab09076ad9b03c2b7914908359628315ae
Summary:
I found that CleanupSuperVersion() may block Get() for 30ms+ （per MemTable is 256MB）.
Then I found "delete sv" in ~SuperVersion() takes the time.
The backtrace looks like this
DBImpl::GetImpl() -> DBImpl::ReturnAndCleanupSuperVersion() ->
DBImpl::CleanupSuperVersion() : delete sv; -> ~SuperVersion()
I think it's better to delete in a background thread, please review it。
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6146
Differential Revision: D18972066
fbshipit-source-id: 0f7b0b70b9bb1e27ad6fc1c8a408fbbf237ae08c
Summary:
With https://github.com/facebook/rocksdb/pull/6121, errors returned by `PrepareBlobValue`
result in `CompactionIterator::status_` being set to `Corruption` or `IOError`
as appropriate, however, `valid_` is not set to `false`. The error is eventually propagated in
`CompactionJob::ProcessKeyValueCompaction` but only after the main loop completes.
Setting `valid_` to `false` upon errors enables us to terminate the loop early and fail the
compaction sooner.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6170
Test Plan:
Ran `make check` and used `db_bench` in BlobDB mode.
fbshipit-source-id: a2ca88a3ca71115e2605bd34a4c795d8a28bef27
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/6192
Test Plan:
Add a unit test that fails without the fix and passes now
make check
Differential Revision: D19124781
Pulled By: anand1976
fbshipit-source-id: 8c8cb6fa16c3fc23ec011e168561a13f76bbd783
Summary:
As title. Previous assumption was that the underlying lib can always return
a shared_ptr<Env>. This is too strong. Therefore, we use Env::LoadEnv to relax
it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6196
Test Plan: make check
Differential Revision: D19133199
Pulled By: riversand963
fbshipit-source-id: c83a0c02a42610d077054f2de1acfc45126b3a75
Summary:
In https://github.com/facebook/rocksdb/issues/6174 we fixed the stress test to respect the CancelAllBackgroundWork + Close order for WritePrepared transactions. The fix missed to take into account that some invocation of CancelAllBackgroundWork are with wait=false parameter which essentially breaks the order.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6191
Differential Revision: D19102709
Pulled By: maysamyabandeh
fbshipit-source-id: f4e7b5fdae47ff1c1ac284ba1cf67d5d3f3d03eb
Summary:
In the current MultiGet, if the KV-pairs do not belong to the data blocks in the block cache, multiple blocks are read from a SST. It will trigger one block read for each block request and read them in parallel. In some cases, if some data blocks are adjacent in the SST, the reads for these blocks can be combined to a single large read, which can reduce the system calls and reduce the read latency if possible.
Considering to fill the block cache, if multiple data blocks are in the same memory buffer, we need to copy them to the heap separately. Therefore, only in the case that 1) data block compression is enabled, and 2) compressed block cache is null, we can do combined read. Otherwise, extra memory copy is needed, which may cause extra overhead. In the current case, data blocks will be uncompressed to a new memory space.
Also, in the case that 1) data block compression is enabled, and 2) compressed block cache is null, it is possible the data block is actually not compressed. In the current logic, these data blocks will not be added to the uncompressed_cache. So if memory buffer is shared and the data block is not compressed, the data block are copied to the head and fill the cache.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6089
Test Plan: Added test case to ParallelIO.MultiGet. Pass make asan_check
Differential Revision: D18734668
Pulled By: zhichao-cao
fbshipit-source-id: 67c5615ed373e51e42635fd74b36f8f3a66d5da4
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:
compaction history is stored in manifest files. Preserve all of them in db_stress would help debugging.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6142
Test Plan: Run db_stress and observe that manifest files are preserved. Run whole crash_test and see how DB directory looks like.
Differential Revision: D19047026
fbshipit-source-id: f83c3e0bb5332b1b4768be5dcee56a24f9b760a9
Summary:
In the current db_stress, all the keys are generated randomly and follows the uniform distribution. In order to test some corner cases that some key are always updated or read, we need to generate the key based on other distributions. In this PR, the key is generated based on Zipfian distribution and the skewness can be controlled by setting hot_key_alpha (0.8 to 1.5 is suggested). The larger hot_key_alpha is, the more skewed will be. Not that, usually, if hot_key_alpha is larger than 2, there might be only 1 or 2 keys that are generated. If hot_key_alpha is 0, it generate the key follows uniform distribution (random key)
Testing plan: pass the db_stress and printed the keys to make sure it follows the distribution.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6163
Differential Revision: D18978480
Pulled By: zhichao-cao
fbshipit-source-id: e123b4865477f7478e83fb581f9576bada334680
Summary:
https://github.com/facebook/rocksdb/pull/6177 introduced a data race
involving `MemTableList::InstallNewVersion` and `MemTableList::NumFlushed`.
The patch fixes this by caching whether the current version has any
memtable history (i.e. flushed memtables that are kept around for
transaction conflict checking) in an `std::atomic<bool>` member called
`current_has_history_`, similarly to how `current_memory_usage_excluding_last_`
is handled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6187
Test Plan:
```
make clean
COMPILE_WITH_TSAN=1 make db_test -j24
./db_test
```
Differential Revision: D19084059
Pulled By: ltamasi
fbshipit-source-id: 327a5af9700fb7102baea2cc8903c085f69543b9
Summary:
The filter bits builder collects all the hashes to add in memory before adding them (because the number of keys is not known until we've walked over all the keys). Existing code uses a std::vector for this, which can mean up to 2x than necessary space allocated (and not freed) and up to ~2x write amplification in memory. Using std::deque uses close to minimal space (for large filters, the only time it matters), no write amplification, frees memory while building, and no need for large contiguous memory area. The only cost is more calls to allocator, which does not appear to matter, at least in benchmark test.
For now, this change only applies to the new (format_version=5) Bloom filter implementation, to ease before-and-after comparison downstream.
Temporary memory use during build is about the only way the new Bloom filter could regress vs. the old (because of upgrade to 64-bit hash) and that should only matter for full filters. This change should largely mitigate that potential regression.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6175
Test Plan:
Using filter_bench with -new_builder option and 6M keys per filter is like large full filter (improvement). 10k keys and no -new_builder is like partitioned filters (about the same). (Corresponding configurations run simultaneously on devserver.)
std::vector impl (before)
$ /usr/bin/time -v ./filter_bench -impl=2 -quick -new_builder -working_mem_size_mb=1000 -
average_keys_per_filter=6000000
Build avg ns/key: 52.2027
Maximum resident set size (kbytes): 1105016
$ /usr/bin/time -v ./filter_bench -impl=2 -quick -working_mem_size_mb=1000 -
average_keys_per_filter=10000
Build avg ns/key: 30.5694
Maximum resident set size (kbytes): 1208152
std::deque impl (after)
$ /usr/bin/time -v ./filter_bench -impl=2 -quick -new_builder -working_mem_size_mb=1000 -
average_keys_per_filter=6000000
Build avg ns/key: 39.0697
Maximum resident set size (kbytes): 1087196
$ /usr/bin/time -v ./filter_bench -impl=2 -quick -working_mem_size_mb=1000 -
average_keys_per_filter=10000
Build avg ns/key: 30.9348
Maximum resident set size (kbytes): 1207980
Differential Revision: D19053431
Pulled By: pdillinger
fbshipit-source-id: 2888e748723a19d9ea40403934f13cbb8483430c
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:
We have observed an increase in CPU load caused by frequent calls to
`ColumnFamilyData::InstallSuperVersion` from `DBImpl::TrimMemtableHistory`
when using `max_write_buffer_size_to_maintain` to limit the amount of
memtable history maintained for transaction conflict checking. Part of the issue
is that trimming can potentially be scheduled even if there is no memtable
history. The patch adds a check that fixes this.
See also https://github.com/facebook/rocksdb/pull/6169.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6177
Test Plan:
Compared `perf` output for
```
./db_bench -benchmarks=randomtransaction -optimistic_transaction_db=1 -statistics -stats_interval_seconds=1 -duration=90 -num=500000 --max_write_buffer_size_to_maintain=16000000 --transaction_set_snapshot=1 --threads=32
```
before and after the change. There is a significant reduction for the call chain
`rocksdb::DBImpl::TrimMemtableHistory` -> `rocksdb::ColumnFamilyData::InstallSuperVersion` ->
`rocksdb::ThreadLocalPtr::StaticMeta::Scrape` even without https://github.com/facebook/rocksdb/pull/6169.
Differential Revision: D19057445
Pulled By: ltamasi
fbshipit-source-id: dff81882d7b280e17eda7d9b072a2d4882c50f79
Peter Dillinger