Summary:
DB::OpenForReadOnly will not write anything to the file system (i.e., create directories or files for the DB) unless create_if_missing is true.
This change also fixes some subcommands of ldb, which write to the file system even if the purpose is for readonly.
Two tests for this updated behavior of DB::OpenForReadOnly are also added.
Other minor changes:
1. Updated HISTORY.md to include this API change of DB::OpenForReadOnly;
2. Updated the help information for the put and batchput subcommands of ldb with the option [--create_if_missing];
3. Updated the comment of Env::DeleteDir to emphasize that it returns OK only if the directory to be deleted is empty.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6900
Test Plan: passed make check; also manually tested a few ldb subcommands
Reviewed By: pdillinger
Differential Revision: D21822188
Pulled By: gg814
fbshipit-source-id: 604cc0f0d0326a937ee25a32cdc2b512f9a3be6e
Summary:
This reverts commit 8d87e9cea1.
Based on offline discussions, it's too early to upgrade to gtest 1.10, as it prevents some developers from using an older version of gtest to integrate to some other systems. Revert it for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6923
Reviewed By: pdillinger
Differential Revision: D21864799
fbshipit-source-id: d0726b1ff649fc911b9378f1763316200bd363fc
Summary:
Currently there is no check for whether BlockBasedTableBuilder will expose
compression error status if compression fails during the table building.
This commit adds fake faulting compressors and a unit test to test such
cases.
This check finds 5 bugs, and this commit also fixes them:
1. Not handling compression failure well in
BlockBasedTableBuilder::BGWorkWriteRawBlock.
2. verify_compression failing in BlockBasedTableBuilder when used with ZSTD.
3. Wrongly passing the same reference of block contents to
BlockBasedTableBuilder::CompressAndVerifyBlock in parallel compression.
4. Wrongly setting block_rep->first_key_in_next_block to nullptr in
BlockBasedTableBuilder::EnterUnbuffered when there are still incoming data
blocks.
5. Not maintaining variables for compression ratio estimation and first_block
in BlockBasedTableBuilder::EnterUnbuffered.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6709
Reviewed By: ajkr
Differential Revision: D21236254
fbshipit-source-id: 101f6e62b2bac2b7be72be198adf93cd32a1ff46
Summary:
We are swallowing some file consistency checking failures. This is not expected. We are fixing two cases: DB reopen and manifest dump.
More places are not fixed and need follow-up.
Error from CheckConsistencyForDeletes() is also swallowed, which is not fixed in this PR.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6793
Test Plan: Add a unit test to cover the reopen case.
Reviewed By: riversand963
Differential Revision: D21366525
fbshipit-source-id: eb438a322237814e8d5125f916a3c6de97f39ded
Summary:
This PR adds support for pipelined & parallel compression optimization for `BlockBasedTableBuilder`. This optimization makes block building, block compression and block appending a pipeline, and uses multiple threads to accelerate block compression. Users can set `CompressionOptions::parallel_threads` greater than 1 to enable compression parallelism.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6262
Reviewed By: ajkr
Differential Revision: D20651306
fbshipit-source-id: 62125590a9c15b6d9071def9dc72589c1696a4cb
Summary:
In CompactRange, if there is no key in memtable falling in the specified range, then flush is skipped.
This PR extends this skipping logic to SST file levels: it starts compaction from the highest level (starting from L0) that has files with key falling in the specified range, instead of always starts from L0.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6482
Test Plan:
A new test ManualCompactionTest::SkipLevel is added.
Also updated a test related to statistics of index block cache hit in db_test2, the index cache hit is increased by 1 in this PR because when checking overlap for the key range in L0, OverlapWithLevelIterator will do a seek in the table cache iterator, which will read from the cached index.
Also updated db_compaction_test and db_test to use correct range for full compaction.
Differential Revision: D20251149
Pulled By: cheng-chang
fbshipit-source-id: f822157cf4796972bd5035d9d7178d8dfb7af08b
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433
Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.
Differential Revision: D19977691
fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
Summary:
DBTest2.ChangePrefixExtractor fails in LITE build because LITE build doesn't support adaptive build. Fix it by removing the stats check but only check correctness.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6356
Test Plan: Run the test with both of LITE and non-LITE build.
Differential Revision: D19669537
fbshipit-source-id: 6d7dd6c8a79f18e80ca1636864b9c71922030d8e
Summary:
Add a unit test for prefix extractor change, including a check that fails due to a bug.
Also comment out the partitioned filter case which will fail the test too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6323
Test Plan: Run the test and it passes (and fails if the SeekForPrev() part is uncommented)
Differential Revision: D19509744
fbshipit-source-id: 678202ca97b5503e9de73b54b90de9e5ba822b72
Summary:
DBTest2.AutoPrefixMode1 doesn't pass because auto prefix mode is not supported there.
Fix it by disabling the test.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6346
Test Plan: Run DBTest2.AutoPrefixMode1 in lite mode
Differential Revision: D19627486
fbshipit-source-id: fbde75260aeecb7e6fc406e09c19a71a95aa5f08
Summary:
Add a new option ReadOptions.auto_prefix_mode. When set to true, iterator should return the same result as total order seek, but may choose to do prefix seek internally, based on iterator upper bounds. Also fix two previous bugs when handling prefix extrator changes: (1) reverse iterator should not rely on upper bound to determine prefix. Fix it with skipping prefix check. (2) block-based filter is not handled properly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6314
Test Plan: (1) add a unit test; (2) add the check to stress test and run see whether it can pass at least one run.
Differential Revision: D19458717
fbshipit-source-id: 51c1bcc5cdd826c2469af201979a39600e779bce
Summary:
Recent bug fix related to hash index introduced a new bug: hash index can return NotFound but it is not handled by BlockBasedTable::Get(). The end result is that Get() stops being executed too early. Fix it by ignoring NotFound code in Get().
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6305
Test Plan: A problematic DB used to return NotFound incorrectly, and now able to return correct result. Will try to construct a unit test too.0
Differential Revision: D19438925
fbshipit-source-id: e751afa8c13728d56511cfeb1bc811ecb99f3217
Summary:
Recent fix to Prefix Hash https://github.com/facebook/rocksdb/pull/6292 caused a bug that the newly created NotFound status in hash index is never reset. This causes reseek or implict reseek to return wrong results sometimes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6302
Test Plan:
Add a unit test that would fail. Not fix.
crash test with hash test would fail in several seconds. With the fix, it will run about several minutes before failing with another failure.
Differential Revision: D19424572
fbshipit-source-id: c5276f36a95fd0e2837e30190476d2fe21ed8566
Summary:
When prefix is enabled the expected behavior when the prefix of the target does not exist is for Seek is to seek to any key larger than target and SeekToPrev to any key less than the target.
Currently. the prefix index (kHashSearch) returns OK status but sets Invalid() to indicate two cases: a prefix of the searched key does not exist, ii) the key is beyond the range of the keys in SST file. The SeekForPrev implementation in BlockBasedTable thus does not have enough information to know when it should set the index key to first (to return a key smaller than target). The patch fixes that by returning NotFound status for cases that the prefix does not exist. SeekForPrev in BlockBasedTable accordingly SeekToFirst instead of SeekToLast on the index iterator.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6297
Test Plan: SeekForPrev of non-exsiting prefix is added to block_test.cc, and a test case is added in db_test2, which fails without the fix.
Differential Revision: D19404695
fbshipit-source-id: cafbbf95f8f60ff9ede9ccc99d25bfa1cf6fcdc3
Summary:
A recent commit adds a unit test that uses a function not available in LITE build. Fix it by avoiding the call
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6295
Test Plan: Run the test in LITE build and see it passes.
Differential Revision: D19395678
fbshipit-source-id: 37b42835bae02511630d80f7cafb1179401bc033
Summary:
The fractional cascading index is not correctly generated when two files at the same level contains the same smallest or largest user key.
The result would be that it would hit an assertion in debug mode and lower level files might be skipped.
This might cause wrong results when the same user keys are of merge operands and Get() is called using the exact user key. In that case, the lower files would need to further checked.
The fix is to fix the fractional cascading index.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6285
Test Plan: Add a unit test which would cause the assertion which would be fixed.
Differential Revision: D19358426
fbshipit-source-id: 39b2b1558075fd95e99491d462a67f9f2298c48e
Summary:
unordered_write is incompatible with non-zero max_successive_merges. Although we check this at runtime, we currently don't prevent the user from setting this combination in options. This has led to stress tests to fail with this combination is tried in ::SetOptions.
The patch fixes that and also reverts the changes performed by https://github.com/facebook/rocksdb/pull/6254, in which max_successive_merges was mistakenly declared incompatible with unordered_write.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6284
Differential Revision: D19356115
Pulled By: maysamyabandeh
fbshipit-source-id: f06dadec777622bd75f267361c022735cf8cecb6
Summary:
Currently, the recently-added test DBTest2.SwitchMemtableRaceWithNewManifest
fails in LITE mode since SetOptions() returns "Not supported". I do not want to
put `#ifndef ROCKSDB_LITE` because it reduces test coverage. Instead, just
trigger compaction on a different column family. The bg compaction thread
calling LogAndApply() may race with thread calling SwitchMemtable().
Test Plan (dev server):
make check
OPT=-DROCKSDB_LITE make check
or run DBTest2.SwitchMemtableRaceWithNewManifest 100 times.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6267
Differential Revision: D19301309
Pulled By: riversand963
fbshipit-source-id: 88cedcca2f985968ed3bb234d324ffa2aa04ca50
Summary:
allow_concurrent_memtable_write is incompatible with non-zero max_successive_merges. Although we check this at runtime, we currently don't prevent the user from setting this combination in options. This has led to stress tests to fail with this combination is tried in ::SetOptions. The patch fixes that.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6254
Differential Revision: D19265819
Pulled By: maysamyabandeh
fbshipit-source-id: 47f2e2dc26fe0972c7152f4da15dadb9703f1179
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:
Recent change https://github.com/facebook/rocksdb/pull/5861 mistakely use "prefix_extractor_ != nullptr" as the condition to determine whehter prefix bloom filter isused. It fails to consider read_options.total_order_seek, so it is wrong. The result is that an optimization for non-total-order seek is mistakely applied to total order seek, and introduces a bug in following corner case:
Because of RangeDelete(), a file's largest key is extended. Seek key falls into the range deleted file, so level iterator seeks into the previous file without getting any key. The correct behavior is to place the iterator to the first key of the next file. However, an optimization is triggered and invalidates the iterator because it is out of the prefix range, causing wrong results. This behavior is reproduced in the unit test added.
Fix the bug by setting prefix_extractor to be null if total order seek is used.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6028
Test Plan: Add a unit test which fails without the fix.
Differential Revision: D18479063
fbshipit-source-id: ac075f013029fcf69eb3a598f14c98cce3e810b3
Summary:
A bug occasionally shows up in crash test, and https://github.com/facebook/rocksdb/issues/5851 reproduces it.
The bug can surface in the following way.
1. Database has multiple column families.
2. Between one DB restart, the last log file is corrupted in the middle (not the tail)
3. During restart, DB crashes between flushing between two column families.
Then DB will fail to be opened again with error "SST file is ahead of WALs".
Solution is to update the log number associated with each column family altogether after flushing all column families' memtables. The version edits should be written to a new MANIFEST. Only after writing to all these version edits succeed does RocksDB (atomically) points the CURRENT file to the new MANIFEST.
Test plan (on devserver):
```
$make all && make check
```
Specifically
```
$make db_test2
$./db_test2 --gtest_filter=DBTest2.CrashInRecoveryMultipleCF
```
Also checked for compatibility as follows.
Use this branch, run DBTest2.CrashInRecoveryMultipleCF and preserve the db directory.
Then checkout 5.4, build ldb, and dump the MANIFEST.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5856
Differential Revision: D17620818
Pulled By: riversand963
fbshipit-source-id: b52ce5969c9a8052cacec2bd805fcfb373589039
Summary:
Right now, when LevelIterator::Seek() is called, when a file is filtered out by prefix bloom filter, the position is put to the beginning of the next file. This is a confusing internal interface because many keys in the levels are skipped. Avoid this behavior by checking the key of the next file against the seek key, and invalidate the whole iterator if the prefix doesn't match.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5861
Test Plan: Add a new unit test to validate the behavior; run all exsiting tests; run crash_test
Differential Revision: D17918213
fbshipit-source-id: f06b47d937c7cc8919001f18dcc3af5b28c9cdac
Summary:
Since we do not evict a file's blocks from block cache before that file
is deleted, we require a file's cache ID prefix is both unique and
non-reusable. However, the Windows functionality we were relying on only
guaranteed uniqueness. That meant a newly created file could be assigned
the same cache ID prefix as a deleted file. If the newly created file
had block offsets matching the deleted file, full cache keys could be
exactly the same, resulting in obsolete data blocks returned from cache
when trying to read from the new file.
We noticed this when running on FAT32 where compaction was writing out
of order keys due to reading obsolete blocks from its input files. The
functionality is documented as behaving the same on NTFS, although I
wasn't able to repro it there.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5844
Test Plan:
we had a reliable repro of out-of-order keys on FAT32 that
was fixed by this change
Differential Revision: D17752442
fbshipit-source-id: 95d983f9196cf415f269e19293b97341edbf7e00
Summary:
This is a bug occaionally shows up in crash test, and this unit test is to reproduce it. The bug is following:
1. Database has multiple CFs.
2. Between one DB restart, the last log file is corrupted in the middle (not the tail)
3. During restart, DB crashes between flushes between two CFs.
The DB will fail to be opened again with error "SST file is ahead of WALs"
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5851
Test Plan: Run the test itself.
Differential Revision: D17614721
fbshipit-source-id: 1b0abce49b203a76a039e38e76bc940429975f20
Summary:
Some recent commits might not have passed through the formatter. I formatted recent 45 commits. The script hangs for more commits so I stopped there.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5827
Test Plan: Run all existing tests.
Differential Revision: D17483727
fbshipit-source-id: af23113ee63015d8a43d89a3bc2c1056189afe8f
Summary:
We are seeing a bug of wrong results with merging iterator's reseek avoidence feature and prefix extractor. Disable this optimization for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5815
Test Plan: Validated the same MyRocks case was fixed; run all existing tests.
Differential Revision: D17430776
fbshipit-source-id: aef664277ba0ab8a2e68331ff0db6ae682535371
Summary:
Manual compaction may bring in very high load because sometime the amount of data involved in a compaction could be large, which may affect online service. So it would be good if the running compaction making the server busy can be stopped immediately. In this implementation, stopping manual compaction condition is only checked in slow process. We let deletion compaction and trivial move go through.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3971
Test Plan: add tests at more spots.
Differential Revision: D17369043
fbshipit-source-id: 575a624fb992ce0bb07d9443eb209e547740043c
Summary:
For our default block cache, each additional entry has extra memory overhead. It include LRUHandle (72 bytes currently) and the cache key (two varint64, file id and offset). The usage is not negligible. For example for block_size=4k, the overhead accounts for an extra 2% memory usage for the cache. The patch charging the cache for the extra usage, reducing untracked memory usage outside block cache. The feature is enabled by default and can be disabled by passing kDontChargeCacheMetadata to the cache constructor.
This PR builds up on https://github.com/facebook/rocksdb/issues/4258
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5797
Test Plan:
- Existing tests are updated to either disable the feature when the test has too much dependency on the old way of accounting the usage or increasing the cache capacity to account for the additional charge of metadata.
- The Usage tests in cache_test.cc are augmented to test the cache usage under kFullChargeCacheMetadata.
Differential Revision: D17396833
Pulled By: maysamyabandeh
fbshipit-source-id: 7684ccb9f8a40ca595e4f5efcdb03623afea0c6f
Summary:
Most existing RocksDB unit tests run on `Env::Default()`. It will be useful to port the unit tests to non-default environments, e.g. `HdfsEnv`, etc.
This pull request is one step towards this goal. If RocksDB unit tests are built with a static library exposing a function `RegisterCustomObjects()`, then it is possible to implement custom object registrar logic in the library. RocksDB unit test can call `RegisterCustomObjects()` at the beginning.
By default, `ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS` is not defined, thus this PR has no impact on existing RocksDB because `RegisterCustomObjects()` is a noop.
Test plan (on devserver):
```
$make clean && COMPILE_WITH_ASAN=1 make -j32 all
$make check
```
All unit tests must pass.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5676
Differential Revision: D16679157
Pulled By: riversand963
fbshipit-source-id: aca571af3fd0525277cdc674248d0fe06e060f9d
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
Summary:
Right now, users cannot take advantage of row cache, unless no snapshot is used, or Get() is repeated for the same snapshots. This limits the usage of row cache.
This change eliminate this restriction in some cases. If the snapshot used is newer than the largest sequence number in the file, and write callback function is not registered, the same row cache key is used as no snapshot is given. We still need the callback function restriction for now because the callback function may filter out different keys for different snapshots even if the snapshots are new.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5600
Test Plan: Add a unit test.
Differential Revision: D16386616
fbshipit-source-id: 6b7d214bd215d191b03ccf55926ad4b703ec2e53
Summary:
Fix flaky DBTest2.PresetCompressionDict test.
This PR fixes two issues with the test:
1. Replaces `GetSstFiles` with `TotalSize`, which is based on `DB::GetColumnFamilyMetaData` so that only the size of the live SST files is taken into consideration when computing the total size of all sst files. Earlier, with `GetSstFiles`, even obsolete files were getting picked up.
1. In ZSTD compression, it is sometimes possible that using a trained dictionary is not better than using an untrained one. Using a trained dictionary performs well in 99% of the cases, but still in the remaining ~1% of the cases (out of 10000 runs) using an untrained dictionary gets better compression results.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5378
Differential Revision: D15559100
Pulled By: sagar0
fbshipit-source-id: c35adbf13871f520a2cec48f8bad9ff27ff7a0b4
Summary:
Sometimes, users might make mistake of not releasing snapshots before closing the DB. This is undocumented use of RocksDB and the behavior is unknown. We return DB::Close() to provide a way to check it for the users. Aborted() will be returned to users when they call DB::Close().
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5272
Differential Revision: D15159713
Pulled By: siying
fbshipit-source-id: 39369def612398d9f239d83d396b5a28e5af65cd
Summary:
Depending on the config, manual compaction (leveled compaction style) does following compactions:
L0->L1
L1->L2
...
Ln-1 -> Ln
Ln -> Ln
The final Ln -> Ln compaction is partly unnecessary as it recompacts all the files that were just generated by the Ln-1 -> Ln. We should avoid recompacting such files. This rule should be applied to Lmax only.
Resolves issue https://github.com/facebook/rocksdb/issues/4995
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5138
Differential Revision: D14940106
Pulled By: miasantreble
fbshipit-source-id: 8d3cf5507a17e76f3333cfd4bac5256d005636e5
Summary:
Dummy cache size of 1MB is too large for small block sizes. Our GetDefaultCacheShardBits() use min_shard_size = 512L * 1024L to determine number of shards, so 1MB will excceeds the size of the whole shard and make the cache excceeds the budget.
Change it to 256KB accordingly.
There shouldn't be obvious performance impact, since inserting a cache entry every 256KB of memtable inserts is still infrequently enough.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5175
Differential Revision: D14954289
Pulled By: siying
fbshipit-source-id: 2c275255c1ac3992174e06529e44c55538325c94
Summary:
Since Statistics::measureTime() is deprecated, StatisticsImpl::measureTime() is not implemented. We realized that users might have a wrapped Statistics implementation in which measureTime() is implemented as forwarded to StatisticsImpl, and causes assert failure. In order to make the change less intrusive, we implement StatisticsImpl::measureTime(). We will revisit whether we need to remove it after several releases.
Also, add a test to make sure that a Statistics implementation using the old interface still works.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5181
Differential Revision: D14907089
Pulled By: siying
fbshipit-source-id: 29b6202fd04e30ed6f6adcaeb1000e87f10d1e1a
Summary:
Change the behavior of OptimizeForSmallDb() so that it is less likely to go out of memory.
Change the behavior of OptimizeForPointLookup() to take advantage of the new memtable whole key filter, and move away from prefix extractor as well as hash-based indexing, as they are prone to misuse.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5165
Differential Revision: D14880709
Pulled By: siying
fbshipit-source-id: 9af30e3c9e151eceea6d6b38701a58f1f9fb692d
Summary:
Although user should first call StartTrace to begin the RocksDB tracing function and call EndTrace to stop the tracing process, user can accidentally call EndTrace first. It will cause segment fault and crash the DB instance. The issue is fixed by checking the pointer first.
Test case added in db_test2.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5130
Differential Revision: D14691420
Pulled By: zhichao-cao
fbshipit-source-id: 3be13d2f944bc453728ef8eef67b68d7ad0939c8
Summary:
WriteUnPrepared adds a virtual function, MaxUnpreparedSequenceNumber, to ReadCallback, which returns 0 unless WriteUnPrepared is enabled and the transaction has uncommitted data written to the DB. Together with snapshot sequence number, this determines the last sequence that is visible to reads.
The patch clarifies the guarantees of the GetIterator API in WriteUnPrepared transactions and make use of that to statically initialize the read callback and thus avoid the virtual call.
Furthermore it increases the minimum value for min_uncommitted from 0 to 1 as seq 0 is used only for last level keys that are committed in all snapshots.
The following benchmark shows +0.26% higher throughput in seekrandom benchmark.
Benchmark:
./db_bench --benchmarks=fillrandom --use_existing_db=0 --num=1000000 --db=/dev/shm/dbbench
./db_bench --benchmarks=seekrandom[X10] --use_existing_db=1 --db=/dev/shm/dbbench --num=1000000 --duration=60 --seek_nexts=100
seekrandom [AVG 10 runs] : 20355 ops/sec; 225.2 MB/sec
seekrandom [MEDIAN 10 runs] : 20425 ops/sec; 225.9 MB/sec
./db_bench_lessvirtual3 --benchmarks=seekrandom[X10] --use_existing_db=1 --db=/dev/shm/dbbench --num=1000000 --duration=60 --seek_nexts=100
seekrandom [AVG 10 runs] : 20409 ops/sec; 225.8 MB/sec
seekrandom [MEDIAN 10 runs] : 20487 ops/sec; 226.6 MB/sec
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5049
Differential Revision: D14366459
Pulled By: maysamyabandeh
fbshipit-source-id: ebaff8908332a5ae9af7defeadabcb624be660ef
Summary:
Introduce CPU timers for iterator seek and next operations. Seek
counter includes SeekToFirst, SeekToLast and SeekForPrev, w/ the
caveat that SeekToLast timer doesn't include some post processing
time if upper bound is defined.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5076
Differential Revision: D14525218
Pulled By: fredfsh
fbshipit-source-id: 03ba25df3b22b06c072621e4de0eacfa1445f0d9
Summary:
Add an option to filter out READ or WRITE operations while tracing.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5082
Differential Revision: D14515083
Pulled By: mrmiywj
fbshipit-source-id: 2504c89a9abf1dd629cad44b4104092702d77610
Summary:
The read path includes a callback function, ReadCallback, which would eventually calls IsInSnapshot to figure if a particular seq is in the reading snapshot or not. This callback is virtual, which adds the cost of multiple virtual function call to each read. The first few checks in IsInSnapshot, however, are quite trivial and take care of majority of the cases. The patch moves those to a non-virtual function in the the parent class, ReadCallback, to lower the virtual callback cost.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5018
Differential Revision: D14226562
Pulled By: maysamyabandeh
fbshipit-source-id: 6feed5b34f3b082e52092c5ef143e29b49c46b44
Summary:
Our previous approach was to train one compression dictionary per compaction, using the first output SST to train a dictionary, and then applying it on subsequent SSTs in the same compaction. While this was great for minimizing CPU/memory/I/O overhead, it did not achieve good compression ratios in practice. In our most promising potential use case, moderate reductions in a dictionary's scope make a major difference on compression ratio.
So, this PR changes compression dictionary to be scoped per-SST. It accepts the tradeoff during table building to use more memory and CPU. Important changes include:
- The `BlockBasedTableBuilder` has a new state when dictionary compression is in-use: `kBuffered`. In that state it accumulates uncompressed data in-memory whenever `Add` is called.
- After accumulating target file size bytes or calling `BlockBasedTableBuilder::Finish`, a `BlockBasedTableBuilder` moves to the `kUnbuffered` state. The transition (`EnterUnbuffered()`) involves sampling the buffered data, training a dictionary, and compressing/writing out all buffered data. In the `kUnbuffered` state, a `BlockBasedTableBuilder` behaves the same as before -- blocks are compressed/written out as soon as they fill up.
- Samples are now whole uncompressed data blocks, except the final sample may be a partial data block so we don't breach the user's configured `max_dict_bytes` or `zstd_max_train_bytes`. The dictionary trainer is supposed to work better when we pass it real units of compression. Previously we were passing 64-byte KV samples which was not realistic.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4952
Differential Revision: D13967980
Pulled By: ajkr
fbshipit-source-id: 82bea6f7537e1529c7a1a4cdee84585f5949300f
Summary:
Implement trace sampling to allow user to specify the sampling frequency, i.e. save one per how many requests, so that a user does not need to log all if he/she is interested in only a sampled set.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4963
Differential Revision: D14011190
Pulled By: tang-jianfeng
fbshipit-source-id: 078b631d9319b67cb089dd2c30e21d0df8dc406a
Zitan Chen