Summary:
Periodic compactions ensure that even SSTs that do not get picked up
otherwise eventually go through compaction; used in conjunction with
BlobDB's garbage collection, they enable BlobDB to reclaim space when
old blob files are used by such straggling SSTs.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6172
Test Plan: Ran `make check` and used the BlobDB mode of `db_bench`.
Differential Revision: D19045045
Pulled By: ltamasi
fbshipit-source-id: 04636ecc4b6cfe8d495bf656faa65d54a5eb1a93
Summary:
The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc.
This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO.
The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before.
This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection.
The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761
Differential Revision: D18868376
Pulled By: anand1976
fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
Summary:
The patch adds logic that relocates live blobs from the oldest N non-TTL
blob files as they are encountered during compaction (assuming the BlobDB
configuration option `enable_garbage_collection` is `true`), where N is defined
as the number of immutable non-TTL blob files multiplied by the value of
a new BlobDB configuration option called `garbage_collection_cutoff`.
(The default value of this parameter is 0.25, that is, by default the valid blobs
residing in the oldest 25% of immutable non-TTL blob files are relocated.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6121
Test Plan: Added unit test and tested using the BlobDB mode of `db_bench`.
Differential Revision: D18785357
Pulled By: ltamasi
fbshipit-source-id: 8c21c512a18fba777ec28765c88682bb1a5e694e
Summary:
**NOTE**: this also needs to be back-ported to 6.4.6 and possibly older branches if further releases from them is envisaged.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6081
Differential Revision: D18710107
Pulled By: zhichao-cao
fbshipit-source-id: 03260f9316566e2bfc12c7d702d6338bb7941e01
Summary:
This patch factors out the logic that reads a (potentially compressed) blob
from a file into a separate helper method `GetRawBlobFromFile`, and cleans
up the code a bit. Also, errors during decompression are now logged/propagated
to the user by returning a `Status` code of `Corruption`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6093
Test Plan: `make check`
Differential Revision: D18716673
Pulled By: ltamasi
fbshipit-source-id: 44144bc064cab616862d5643f34384f2bae6eb78
Summary:
The patch refactors and cleans up the logic around creating new blob files
by moving the common code of `SelectBlobFile` and `SelectBlobFileTTL`
to a new helper method `CreateBlobFileAndWriter`, bringing the implementation
of `SelectBlobFile` and `SelectBlobFileTTL` into sync, and increasing encapsulation
by adding new constructors for `BlobFile` and `BlobLogHeader`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6066
Test Plan:
Ran `make check` and used the BlobDB mode of `db_bench` to sanity test both
the TTL and the non-TTL code paths.
Differential Revision: D18646921
Pulled By: ltamasi
fbshipit-source-id: e5705a84807932e31dccab4f49b3e64369cea26d
Summary:
This change ignores the value of BackupableDBOptions::max_valid_backups_to_open when a BackupEngine is not read-only.
Issue: https://github.com/facebook/rocksdb/issues/4997
Note on tests: I had to remove test case WriteOnlyEngine of BackupableDBTest because it was not consistent with the new semantic of BackupableDBOptions::max_valid_backups_to_open. Maybe, we should think about adding a new interface for append-only BackupEngines. On the other hand, I changed LimitBackupsOpened test case to use a read-only BackupEngine, and I added a new specific test case for the change.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6072
Reviewed By: pdillinger
Differential Revision: D18687364
Pulled By: sebastianopeluso
fbshipit-source-id: 77bc1f927d623964d59137a93de123bbd719da4e
Summary:
The patch adds logic to mark no longer needed blob files obsolete upon database open
and whenever a flush or compaction completes. Unneeded blob files are detected by
iterating through live immutable non-TTL blob files starting from the lowest-numbered one,
and stopping when a blob file used by any SSTs or potentially used by memtables is found.
(The latter is determined by comparing the sequence number at which the blob file
became immutable with the largest sequence number received in flush notifications.)
In addition, the patch cleans up the logic around closing and obsoleting blob files and
enforces invariants around this area (blob files are now guaranteed to go through the
stages mutable-non-obsolete, immutable-non-obsolete, and immutable-obsolete in this
order).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6032
Test Plan: Extended unit tests and tested using the BlobDB mode of `db_bench`.
Differential Revision: D18495610
Pulled By: ltamasi
fbshipit-source-id: 11825b84af74f3f4abfd9bcae04e80870ae58961
Summary:
SmallestUnCommittedSeq sometimes takes too long when run under Valgrind. The patch disables it when the tests are run under Valgrind.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6035
Differential Revision: D18509198
Pulled By: maysamyabandeh
fbshipit-source-id: 1191443b9fedb6b9c50d6b76f5c92371f5030230
Summary:
Production:
* Fixes GarbageCollect (and auto-GC triggered by PurgeOldBackups, DeleteBackup, or CreateNewBackup) to clean up backup directory independent of current settings (except max_valid_backups_to_open; see issue https://github.com/facebook/rocksdb/issues/4997) and prior settings used with same backup directory.
* Fixes GarbageCollect (and auto-GC) not to attempt to remove "." and ".." entries from directories.
* Clarifies contract with users in modifying BackupEngine operations. In short, leftovers from any incomplete operation are cleaned up by any subsequent call to that same kind of operation (PurgeOldBackups and DeleteBackup considered the same kind of operation). GarbageCollect is available to clean up after all kinds. (NB: right now PurgeOldBackups and DeleteBackup will clean up after incomplete CreateNewBackup, but we aren't promising to continue that behavior.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6023
Test Plan:
* Refactors open parameters to use an option enum, for readability, etc. (Also fixes an unused parameter bug in the redundant OpenDBAndBackupEngineShareWithChecksum.)
* Fixes an apparent bug in ShareTableFilesWithChecksumsTransition in which old backup data was destroyed in the transition to be tested. That test is now augmented to ensure GarbageCollect (or auto-GC) does not remove shared files when BackupEngine is opened with share_table_files=false.
* Augments DeleteTmpFiles test to ensure that CreateNewBackup does auto-GC when an incompletely created backup is detected.
Differential Revision: D18453559
Pulled By: pdillinger
fbshipit-source-id: 5e54e7b08d711b161bc9c656181012b69a8feac4
Summary:
Add a new API that allows a user to call MultiGet specifying multiple keys belonging to different column families. This is mainly useful for users who want to do a consistent read of keys across column families, with the added performance benefits of batching and returning values using PinnableSlice.
As part of this change, the code in the original multi-column family MultiGet for acquiring the super versions has been refactored into a separate function that can be used by both, the batching and the non-batching versions of MultiGet.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5816
Test Plan:
make check
make asan_check
asan_crash_test
Differential Revision: D18408676
Pulled By: anand1976
fbshipit-source-id: 933e7bec91dd70e7b633be4ff623a1116cc28c8d
Summary:
The patch adds logic to BlobDB to maintain the mapping between blob files
and SSTs for which the blob file in question is the oldest blob file referenced
by the SST file. The mapping is initialized during database open based on the
information retrieved using `GetLiveFilesMetaData`, and updated after
flushes/compactions based on the information received through the `EventListener`
interface (or, in the case of manual compactions issued through the `CompactFiles`
API, the `CompactionJobInfo` object).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6020
Test Plan: Added a unit test; also tested using the BlobDB mode of `db_bench`.
Differential Revision: D18410508
Pulled By: ltamasi
fbshipit-source-id: dd9e778af781cfdb0d7056298c54ba9cebdd54a5
Summary:
Only if there is a crash, power failure, or I/O error in
DeleteBackup, shared or private files from the backup might be left
behind that are not cleaned up by PurgeOldBackups or DeleteBackup-- only
by GarbageCollect. This makes the BackupEngine API "leaky by default."
Even if it means a modest performance hit, I think we should make
Delete and Purge do as they say, with ongoing best effort: i.e. future
calls will attempt to finish any incomplete work from earlier calls.
This change does that by having DeleteBackup and PurgeOldBackups do a
GarbageCollect, unless (to minimize performance hit) this BackupEngine
has already done a GarbageCollect and there have been no
deletion-related I/O errors in that GarbageCollect or since then.
Rejected alternative 1: remove meta file last instead of first. This would in theory turn partially deleted backups into corrupted backups, but code changes would be needed to allow the missing files and consider it acceptably corrupt, rather than failing to open the BackupEngine. This might be a reasonable choice, but I mostly rejected it because it doesn't solve the legacy problem of cleaning up existing lingering files.
Rejected alternative 2: use a deletion marker file. If deletion started with creating a file that marks a backup as flagged for deletion, then we could reliably detect partially deleted backups and efficiently finish removing them. In addition to not solving the legacy problem, this could be precarious if there's a disk full situation, and we try to create a new file in order to delete some files. Ugh.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6015
Test Plan: Updated unit tests
Differential Revision: D18401333
Pulled By: pdillinger
fbshipit-source-id: 12944e372ce6809f3f5a4c416c3b321a8927d925
Summary:
The patch exposes the file numbers of the SSTs as well as the oldest blob
files they contain a reference to through the GetColumnFamilyMetaData/
GetLiveFilesMetaData interface.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6011
Test Plan:
Fixed and extended the existing unit tests. (The earlier ColumnFamilyMetaDataTest
wasn't really testing anything because the generated memtables were never
flushed, so the metadata structure was essentially empty.)
Differential Revision: D18361697
Pulled By: ltamasi
fbshipit-source-id: d5ed1d94ac70858b84393c48711441ddfe1251e9
Summary:
According to
https://github.com/facebook/rocksdb/wiki/Rocksdb-BlockBasedTable-Format,
the block read by BlockBasedTable::ReadMetaBlock is actually the meta index
block. Therefore, it is better to rename the function to ReadMetaIndexBlock.
This PR also applies some format change to existing code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6009
Test Plan: make check
Differential Revision: D18333238
Pulled By: riversand963
fbshipit-source-id: 2c4340a29b3edba53d19c132cbfd04caf6242aed
Summary:
For MDEV-19670: MyRocks: key lookups into deleted data are very slow
BaseDeltaIterator remembers iterate_upper_bound and will not let delta_iterator_
walk above the iterate_upper_bound if base_iterator_ is not valid
anymore.
== Rationale ==
The most straightforward way would be to make the delta_iterator
(which is a rocksdb::WBWIIterator) to support iterator bounds. But
checking for bounds has an extra CPU overhead.
So we put the check into BaseDeltaIterator, and only make it when
base_iterator_ is not valid.
(note: We could take it even further, and move the check a few lines
down, and only check iterator bounds ourselves if base_iterator_ is
not valid AND delta_iterator_ hit a tombstone).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5403
Differential Revision: D15863092
Pulled By: maysamyabandeh
fbshipit-source-id: 8da458e7b9af95ff49356666f69664b4a6ccf49b
Summary:
MaxCatchupWithNewSnapshot tests that the snapshot sequence number will be larger than the max sequence number when the snapshot was taken. However since the test does not have access to the max sequence number when the snapshot was taken, it uses max sequence number after that, which could have advanced the snapshot by then, thus making the test flaky.
The fix is to compare with max sequence number before the snapshot was taken, which is a lower bound for the value when the snapshot was taken.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5850
Test Plan: ~/gtest-parallel/gtest-parallel --repeat=12800 ./write_prepared_transaction_test --gtest_filter="*MaxCatchupWithNewSnapshot*"
Differential Revision: D17608926
Pulled By: maysamyabandeh
fbshipit-source-id: b122ae5a27f982b290bd60da852e28d3c5eb0136
Summary:
- Periodic compactions are auto-enabled if a compaction filter or a compaction filter factory is set, in Level Compaction.
- The default value of `periodic_compaction_seconds` is changed to UINT64_MAX, which lets RocksDB auto-tune periodic compactions as needed. An explicit value of 0 will still work as before ie. to disable periodic compactions completely. For now, on seeing a compaction filter along with a UINT64_MAX value for `periodic_compaction_seconds`, RocksDB will make SST files older than 30 days to go through periodic copmactions.
Some RocksDB users make use of compaction filters to control when their data can be deleted, usually with a custom TTL logic. But it is occasionally possible that the compactions get delayed by considerable time due to factors like low writes to a key range, data reaching bottom level, etc before the TTL expiry. Periodic Compactions feature was originally built to help such cases. Now periodic compactions are auto enabled by default when compaction filters or compaction filter factories are used, as it is generally helpful to all cases to collect garbage.
`periodic_compaction_seconds` is set to a large value, 30 days, in `SanitizeOptions` when RocksDB sees that a `compaction_filter` or `compaction_filter_factory` is used.
This is done only for Level Compaction style.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5865
Test Plan:
- Added a new test `DBCompactionTest.LevelPeriodicCompactionWithCompactionFilters` to make sure that `periodic_compaction_seconds` is set if either `compaction_filter` or `compaction_filter_factory` options are set.
- `COMPILE_WITH_ASAN=1 make check`
Differential Revision: D17659180
Pulled By: sagar0
fbshipit-source-id: 4887b9cf2e53cf2dc93a7b658c6b15e1181217ee
Summary:
- Updated our included xxhash implementation to version 0.7.2 (== the latest dev version as of 2019-10-09).
- Using XXH_NAMESPACE (like other fb projects) to avoid potential name collisions.
- Added fastrange64, and unit tests for it and fastrange32. These are faster alternatives to hash % range.
- Use preview version of XXH3 instead of MurmurHash64A for NPHash64
-- Had to update cache_test to increase probability of passing for any given hash function.
- Use fastrange64 instead of % with uses of NPHash64
-- Had to fix WritePreparedTransactionTest.CommitOfDelayedPrepared to avoid deadlock apparently caused by new hash collision.
- Set default seed for NPHash64 because specifying a seed rarely makes sense for it.
- Removed unnecessary include xxhash.h in a popular .h file
- Rename preview version of XXH3 to XXH3p for clarity and to ease backward compatibility in case final version of XXH3 is integrated.
Relying on existing unit tests for NPHash64-related changes. Each new implementation of fastrange64 passed unit tests when manipulating my local build to select it. I haven't done any integration performance tests, but I consider the improved performance of the pieces being swapped in to be well established.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5909
Differential Revision: D18125196
Pulled By: pdillinger
fbshipit-source-id: f6bf83d49d20cbb2549926adf454fd035f0ecc0d
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 PR eliminates repeated lookups in associative or ordered containers when a single lookup suffices.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5875
Differential Revision: D17753172
Pulled By: anand1976
fbshipit-source-id: 796b02b760082521d8c42a1cb65a76bf0e6c1b8e
Summary:
Further apply formatter to more recent commits.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5830
Test Plan: Run all existing tests.
Differential Revision: D17488031
fbshipit-source-id: 137458fd94d56dd271b8b40c522b03036943a2ab
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:
clang-analyzer has uncovered a bunch of places where the code is relying
on pointers being valid and one case (in VectorIterator) where a moved-from
object is being used:
In file included from db/range_tombstone_fragmenter.cc:17:
./util/vector_iterator.h:23:18: warning: Method called on moved-from object 'keys' of type 'std::vector'
current_(keys.size()) {
^~~~~~~~~~~
1 warning generated.
utilities/persistent_cache/block_cache_tier_file.cc:39:14: warning: Called C++ object pointer is null
Status s = env->NewRandomAccessFile(filepath, file, opt);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
utilities/persistent_cache/block_cache_tier_file.cc:47:19: warning: Called C++ object pointer is null
Status status = env_->GetFileSize(Path(), size);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
utilities/persistent_cache/block_cache_tier_file.cc:290:14: warning: Called C++ object pointer is null
Status s = env_->FileExists(Path());
^~~~~~~~~~~~~~~~~~~~~~~~
utilities/persistent_cache/block_cache_tier_file.cc:363:35: warning: Called C++ object pointer is null
CacheWriteBuffer* const buf = alloc_->Allocate();
^~~~~~~~~~~~~~~~~~
utilities/persistent_cache/block_cache_tier_file.cc:399:41: warning: Called C++ object pointer is null
const uint64_t file_off = buf_doff_ * alloc_->BufferSize();
^~~~~~~~~~~~~~~~~~~~
utilities/persistent_cache/block_cache_tier_file.cc:463:33: warning: Called C++ object pointer is null
size_t start_idx = lba.off_ / alloc_->BufferSize();
^~~~~~~~~~~~~~~~~~~~
utilities/persistent_cache/block_cache_tier_file.cc:515:5: warning: Called C++ object pointer is null
alloc_->Deallocate(bufs_[i]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~
7 warnings generated.
ar: creating librocksdb_debug.a
utilities/memory/memory_test.cc:68:25: warning: Called C++ object pointer is null
cache_set->insert(db->GetDBOptions().row_cache.get());
^~~~~~~~~~~~~~~~~~
1 warning generated.
The patch fixes these by adding assertions and explicitly passing in zero
when initializing VectorIterator::current_ (which preserves the existing
behavior).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5821
Test Plan: Ran make check and make analyze to make sure the warnings have disappeared.
Differential Revision: D17455949
Pulled By: ltamasi
fbshipit-source-id: 363619618ea649a0674287f9f3b3393e390571ee
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:
file_reader_writer.h and .cc contain several files and helper function, and it's hard to navigate. Separate it to multiple files and put them under file/
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5803
Test Plan: Build whole project using make and cmake.
Differential Revision: D17374550
fbshipit-source-id: 10efca907721e7a78ed25bbf74dc5410dea05987
Summary:
Move definition and implementation for ArenaWrappedDBIter into its own .h/.cc files. Also, change inlining of functions to better comply with the Google C++ style guide.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5801
Test Plan: make check
Differential Revision: D17371012
Pulled By: anand1976
fbshipit-source-id: c1361abc2851575111e357a63d88be3b3d6cb341
Summary:
Use delete to disable automatic generated methods instead of private, and put the constructor together for more clear.This modification cause the unused field warning, so add unused attribute to disable this warning.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5009
Differential Revision: D17288733
fbshipit-source-id: 8a767ce096f185f1db01bd28fc88fef1cdd921f3
Summary:
ReadYourOwnWriteStress occasionally times out on some platforms. The patch splits it to three.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5776
Differential Revision: D17231743
Pulled By: maysamyabandeh
fbshipit-source-id: d42eeaf22f61a48d50f9c404d98b1081ae8dac94
Summary:
This avoids rehashing the key in TrackKey() in case the key is not already
in the map of tracked keys, which will happen at least once per key used in a
transaction.
Additionally fix two typos.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5696
Differential Revision: D17210178
Pulled By: lth
fbshipit-source-id: 7e2c28e9e505c1d1c1535d435250cf2b191a6fdf
Summary:
Iterators reseek to the target key after iterating over max_sequential_skip_in_iterations invalid values. The logic is susceptible to an infinite loop bug, which has been present with WritePrepared Transactions up until 6.2 release. Although the bug is not present on master, the patch adds a unit test to prevent it from resurfacing again.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5727
Differential Revision: D16952759
Pulled By: maysamyabandeh
fbshipit-source-id: d0d973dddc8dfabd5a794931232aa4c862c74f51
Summary:
MyRocks currently sets `max_write_buffer_number_to_maintain` in order to maintain enough history for transaction conflict checking. The effectiveness of this approach depends on the size of memtables. When memtables are small, it may not keep enough history; when memtables are large, this may consume too much memory.
We are proposing a new way to configure memtable list history: by limiting the memory usage of immutable memtables. The new option is `max_write_buffer_size_to_maintain` and it will take precedence over the old `max_write_buffer_number_to_maintain` if they are both set to non-zero values. The new option accounts for the total memory usage of flushed immutable memtables and mutable memtable. When the total usage exceeds the limit, RocksDB may start dropping immutable memtables (which is also called trimming history), starting from the oldest one.
The semantics of the old option actually works both as an upper bound and lower bound. History trimming will start if number of immutable memtables exceeds the limit, but it will never go below (limit-1) due to history trimming.
In order the mimic the behavior with the new option, history trimming will stop if dropping the next immutable memtable causes the total memory usage go below the size limit. For example, assuming the size limit is set to 64MB, and there are 3 immutable memtables with sizes of 20, 30, 30. Although the total memory usage is 80MB > 64MB, dropping the oldest memtable will reduce the memory usage to 60MB < 64MB, so in this case no memtable will be dropped.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5022
Differential Revision: D14394062
Pulled By: miasantreble
fbshipit-source-id: 60457a509c6af89d0993f988c9b5c2aa9e45f5c5
Summary:
In valgrind_test, TransactionTest.GetWithoutSnapshot ran 2 hours and still didn't finish. Black list from valgrind_test to prevent timeout.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5715
Test Plan: run "make valgrind_test" and see whether the test is still generated.
Differential Revision: D16866009
fbshipit-source-id: 92c78049b0bc1c2b9a0dfc1b7c8a9206b36f02f0
Summary:
Fix a bug in write unprepared savepoints. When flushing the write batch according to savepoint boundaries, we were forgetting to flush the last write batch after the last savepoint, meaning that some data was not written to DB.
Also, add a small optimization where we avoid flushing empty batches.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5703
Differential Revision: D16811996
Pulled By: lth
fbshipit-source-id: 600c7e0e520ad7a8fad32d77e11d932453e68e3f
Summary:
Some accesses to blob_files_ and open_ttl_files_ in BlobDBImpl, as well
as to expiration_range_ in BlobFile were not properly synchronized.
The patch fixes this and also makes sure the invariant that obsolete_files_
is a subset of blob_files_ holds even when an attempt to delete an obsolete
blob file fails.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5698
Test Plan:
COMPILE_WITH_TSAN=1 make blob_db_test
gtest-parallel --repeat=1000 ./blob_db_test --gtest_filter="*ShutdownWait*"
The test fails with TSAN errors ~20 times out of 1000 without the patch but
completes successfully 1000 out of 1000 times with the fix.
Differential Revision: D16793235
Pulled By: ltamasi
fbshipit-source-id: 8034b987598d4fdc9f15098d4589cc49cde484e9
Summary:
In MyRocks, there are cases where we write while iterating through keys. This currently breaks WBWIIterator, because if a write batch flushes during iteration, the delta iterator would point to invalid memory.
For now, fix by disallowing flush if there are active iterators. In the future, we will loop through all the iterators on a transaction, and refresh the iterators when a write batch is flushed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5699
Differential Revision: D16794157
Pulled By: lth
fbshipit-source-id: 5d5bf70688bd68fe58e8a766475ae88fd1be3190
Summary:
Fix the following clang analyze failures:
```
In file included from utilities/transactions/transaction_test.cc:8:
./utilities/transactions/transaction_test.h:174:14: warning: Attempt to delete released memory
delete root_db;
^
```
The destructor of StackableDB already deletes the root db and there is no need to delete the db separately.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5700
Test Plan: USE_CLANG=1 TEST_TMPDIR=/dev/shm/rocksdb OPT=-g make -j24 analyze
Differential Revision: D16800579
Pulled By: maysamyabandeh
fbshipit-source-id: 64c2d70f23e07e6a15242add97c744902ea33be5
Summary:
Currently, if a write is done without a snapshot, then `largest_validated_seq_` is set to `kMaxSequenceNumber`. This is too aggressive, because an iterator with a snapshot created after this write should be valid.
Set `largest_validated_seq_` to `GetLastPublishedSequence` instead. The variable means that no keys in the current tracked key set has changed by other transactions since `largest_validated_seq_`.
Also, do some extra cleanup in Clear() for safety.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5697
Differential Revision: D16788613
Pulled By: lth
fbshipit-source-id: f2aa40b8b12e0c0cf9e38c940fecc8f1cc0d2385
Summary:
With changes made in https://github.com/facebook/rocksdb/pull/5664 we meant to pass snap_released parameter of ::IsInSnapshot from the read callbacks. Although the variable was defined, passing it to the callback in WritePreparedTxnReadCallback was missing, which is fixed in this PR.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5691
Differential Revision: D16767310
Pulled By: maysamyabandeh
fbshipit-source-id: 3bf53f5964a2756a66ceef7c8f6b3ac75f102f48
Summary:
The changes transaction_test to set `txn_db_options.default_write_batch_flush_threshold = 1` in order to give better test coverage for WriteUnprepared.
As part of the change, some tests had to be updated.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5658
Differential Revision: D16740468
Pulled By: lth
fbshipit-source-id: 3821eec20baf13917c8c1fab444332f75a509de9
Summary:
SmallestUnCommittedSeq reads two data structures, prepared_txns_ and delayed_prepared_. These two are updated in CheckPreparedAgainstMax when max_evicted_seq_ advances some prepared entires. To avoid the cost of acquiring a mutex, the read from them in SmallestUnCommittedSeq is not atomic. This creates a potential race condition.
The fix is to read the two data structures in the reverse order of their update. CheckPreparedAgainstMax copies the prepared entry to delayed_prepared_ before removing it from prepared_txns_ and SmallestUnCommittedSeq looks into prepared_txns_ before reading delayed_prepared_.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5683
Differential Revision: D16744699
Pulled By: maysamyabandeh
fbshipit-source-id: b1bdb134018beb0b9de58827f512662bea35cad0
Summary:
This PR adds four more eviction policies.
- OPT [1]
- Hyperbolic caching [2]
- ARC [3]
- GreedyDualSize [4]
[1] L. A. Belady. 1966. A Study of Replacement Algorithms for a Virtual-storage Computer. IBM Syst. J. 5, 2 (June 1966), 78-101. DOI=http://dx.doi.org/10.1147/sj.52.0078
[2] Aaron Blankstein, Siddhartha Sen, and Michael J. Freedman. 2017. Hyperbolic caching: flexible caching for web applications. In Proceedings of the 2017 USENIX Conference on Usenix Annual Technical Conference (USENIX ATC '17). USENIX Association, Berkeley, CA, USA, 499-511.
[3] Nimrod Megiddo and Dharmendra S. Modha. 2003. ARC: A Self-Tuning, Low Overhead Replacement Cache. In Proceedings of the 2nd USENIX Conference on File and Storage Technologies (FAST '03). USENIX Association, Berkeley, CA, USA, 115-130.
[4] N. Young. The k-server dual and loose competitiveness for paging. Algorithmica, June 1994, vol. 11,(no.6):525-41. Rewritten version of ''On-line caching as cache size varies'', in The 2nd Annual ACM-SIAM Symposium on Discrete Algorithms, 241-250, 1991.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5644
Differential Revision: D16548817
Pulled By: HaoyuHuang
fbshipit-source-id: 838f76db9179f07911abaab46c97e1c929cfcd63
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
Levi Tamasi