7.2.2 (2022-04-28)

Bug Fixes

• Fixed a bug in async_io path where incorrect length of data is read by FilePrefetchBuffer if data is consumed from two populated buffers and request for more data is sent.

7.2.1 (2022-04-26)

Bug Fixes

• Fixed a bug where RocksDB could corrupt DBs with avoid_flush_during_recovery == true by removing valid WALs, leading to Status::Corruption with message like "SST file is ahead of WALs" when attempting to reopen.
• RocksDB calls FileSystem::Poll API during FilePrefetchBuffer destruction which impacts performance as it waits for read requets completion which is not needed anymore. Calling FileSystem::AbortIO to abort those requests instead fixes that performance issue.

7.2.0 (2022-04-15)

Bug Fixes

• Fixed bug which caused rocksdb failure in the situation when rocksdb was accessible using UNC path
• Fixed a race condition when 2PC is disabled and WAL tracking in the MANIFEST is enabled. The race condition is between two background flush threads trying to install flush results, causing a WAL deletion not tracked in the MANIFEST. A future DB open may fail.
• Fixed a heap use-after-free race with DropColumnFamily.
• Fixed a bug that rocksdb.read.block.compaction.micros cannot track compaction stats (#9722).
• Fixed file_type, relative_filename and directory fields returned by GetLiveFilesMetaData(), which were added in inheriting from FileStorageInfo.
• Fixed a bug affecting track_and_verify_wals_in_manifest. Without the fix, application may see "open error: Corruption: Missing WAL with log number" while trying to open the db. The corruption is a false alarm but prevents DB open (#9766).
• Fix segfault in FilePrefetchBuffer with async_io as it doesn't wait for pending jobs to complete on destruction.
• Fix ERROR_HANDLER_AUTORESUME_RETRY_COUNT stat whose value was set wrong in portal.h
• Fixed a bug for non-TransactionDB with avoid_flush_during_recovery = true and TransactionDB where in case of crash, min_log_number_to_keep may not change on recovery and persisting a new MANIFEST with advanced log_numbers for some column families, results in "column family inconsistency" error on second recovery. As a solution the corrupted WALs whose numbers are larger than the corrupted wal and smaller than the new WAL will be moved to archive folder.
• Fixed a bug in RocksDB DB::Open() which may creates and writes to two new MANIFEST files even before recovery succeeds. Now writes to MANIFEST are persisted only after recovery is successful.

New Features

• For db_bench when --seed=0 or --seed is not set then it uses the current time as the seed value. Previously it used the value 1000.
• For db_bench when --benchmark lists multiple tests and each test uses a seed for a RNG then the seeds across tests will no longer be repeated.
• Added an option to dynamically charge an updating estimated memory usage of block-based table reader to block cache if block cache available. To enable this feature, set BlockBasedTableOptions::reserve_table_reader_memory = true.
• Add new stat ASYNC_READ_BYTES that calculates number of bytes read during async read call and users can check if async code path is being called by RocksDB internal automatic prefetching for sequential reads.
• Enable async prefetching if ReadOptions.readahead_size is set along with ReadOptions.async_io in FilePrefetchBuffer.
• Add event listener support on remote compaction compactor side.
• Added a dedicated integer DB property rocksdb.live-blob-file-garbage-size that exposes the total amount of garbage in the blob files in the current version.
• RocksDB does internal auto prefetching if it notices sequential reads. It starts with readahead size initial_auto_readahead_size which now can be configured through BlockBasedTableOptions.
• Add a merge operator that allows users to register specific aggregation function so that they can does aggregation using different aggregation types for different keys. See comments in include/rocksdb/utilities/agg_merge.h for actual usage. The feature is experimental and the format is subject to change and we won't provide a migration tool.
• Meta-internal / Experimental: Improve CPU performance by replacing many uses of std::unordered_map with folly::F14FastMap when RocksDB is compiled together with Folly.
• Experimental: Add CompressedSecondaryCache, a concrete implementation of rocksdb::SecondaryCache, that integrates with compression libraries (e.g. LZ4) to hold compressed blocks.

Behavior changes

• Disallow usage of commit-time-write-batch for write-prepared/write-unprepared transactions if TransactionOptions::use_only_the_last_commit_time_batch_for_recovery is false to prevent two (or more) uncommitted versions of the same key in the database. Otherwise, bottommost compaction may violate the internal key uniqueness invariant of SSTs if the sequence numbers of both internal keys are zeroed out (#9794).
• Make DB::GetUpdatesSince() return NotSupported early for write-prepared/write-unprepared transactions, as the API contract indicates.

Public API changes

• Exposed APIs to examine results of block cache stats collections in a structured way. In particular, users of GetMapProperty() with property kBlockCacheEntryStats can now use the functions in BlockCacheEntryStatsMapKeys to find stats in the map.
• Add fail_if_not_bottommost_level to IngestExternalFileOptions so that ingestion will fail if the file(s) cannot be ingested to the bottommost level.
• Add output parameter is_in_sec_cache to SecondaryCache::Lookup(). It is to indicate whether the handle is possibly erased from the secondary cache after the Lookup.

7.1.2 (2022-04-19)

Bug Fixes

• Fixed bug which caused rocksdb failure in the situation when rocksdb was accessible using UNC path
• Fixed a race condition when 2PC is disabled and WAL tracking in the MANIFEST is enabled. The race condition is between two background flush threads trying to install flush results, causing a WAL deletion not tracked in the MANIFEST. A future DB open may fail.
• Fixed a heap use-after-free race with DropColumnFamily.
• Fixed a bug that rocksdb.read.block.compaction.micros cannot track compaction stats (#9722).
• Fixed file_type, relative_filename and directory fields returned by GetLiveFilesMetaData(), which were added in inheriting from FileStorageInfo.
• Fixed a bug affecting track_and_verify_wals_in_manifest. Without the fix, application may see "open error: Corruption: Missing WAL with log number" while trying to open the db. The corruption is a false alarm but prevents DB open (#9766).

7.1.1 (2022-04-07)

Bug Fixes

• Fix segfault in FilePrefetchBuffer with async_io as it doesn't wait for pending jobs to complete on destruction.

7.1.0 (2022-03-23)

New Features

• Allow WriteBatchWithIndex to index a WriteBatch that includes keys with user-defined timestamps. The index itself does not have timestamp.
• Add support for user-defined timestamps to write-committed transaction without API change. The TransactionDB layer APIs do not allow timestamps because we require that all user-defined-timestamps-aware operations go through the Transaction APIs.
• Added BlobDB options to ldb
• BlockBasedTableOptions::detect_filter_construct_corruption can now be dynamically configured using DB::SetOptions.
• Automatically recover from retryable read IO errors during backgorund flush/compaction.
• Experimental support for preserving file Temperatures through backup and restore, and for updating DB metadata for outside changes to file Temperature (UpdateManifestForFilesState or ldb update_manifest --update_temperatures).
• Experimental support for async_io in ReadOptions which is used by FilePrefetchBuffer to prefetch some of the data asynchronously, if reads are sequential and auto readahead is enabled by rocksdb internally.

Bug Fixes

• Fixed a major performance bug in which Bloom filters generated by pre-7.0 releases are not read by early 7.0.x releases (and vice-versa) due to changes to FilterPolicy::Name() in #9590. This can severely impact read performance and read I/O on upgrade or downgrade with existing DB, but not data correctness.
• Fixed a data race on versions_ between DBImpl::ResumeImpl() and threads waiting for recovery to complete (#9496)
• Fixed a bug caused by race among flush, incoming writes and taking snapshots. Queries to snapshots created with these race condition can return incorrect result, e.g. resurfacing deleted data.
• Fixed a bug that DB flush uses options.compression even options.compression_per_level is set.
• Fixed a bug that DisableManualCompaction may assert when disable an unscheduled manual compaction.
• Fix a race condition when cancel manual compaction with DisableManualCompaction. Also DB close can cancel the manual compaction thread.
• Fixed a potential timer crash when open close DB concurrently.
• Fixed a race condition for alive_log_files_ in non-two-write-queues mode. The race is between the write_thread_ in WriteToWAL() and another thread executing FindObsoleteFiles(). The race condition will be caught if __glibcxx_requires_nonempty is enabled.
• Fixed a bug that Iterator::Refresh() reads stale keys after DeleteRange() performed.
• Fixed a race condition when disable and re-enable manual compaction.
• Fixed automatic error recovery failure in atomic flush.
• Fixed a race condition when mmaping a WritableFile on POSIX.

Public API changes

• Added pure virtual FilterPolicy::CompatibilityName(), which is needed for fixing major performance bug involving FilterPolicy naming in SST metadata without affecting Customizable aspect of FilterPolicy. This change only affects those with their own custom or wrapper FilterPolicy classes.
• options.compression_per_level is dynamically changeable with SetOptions().
• Added WriteOptions::rate_limiter_priority. When set to something other than Env::IO_TOTAL, the internal rate limiter (DBOptions::rate_limiter) will be charged at the specified priority for writes associated with the API to which the WriteOptions was provided. Currently the support covers automatic WAL flushes, which happen during live updates (Put(), Write(), Delete(), etc.) when WriteOptions::disableWAL == false and DBOptions::manual_wal_flush == false.
• Add DB::OpenAndTrimHistory API. This API will open DB and trim data to the timestamp specified by trim_ts (The data with timestamp larger than specified trim bound will be removed). This API should only be used at a timestamp-enabled column families recovery. If the column family doesn't have timestamp enabled, this API won't trim any data on that column family. This API is not compatible with avoid_flush_during_recovery option.
• Remove BlockBasedTableOptions.hash_index_allow_collision which already takes no effect.

7.0.4 (2022-03-29)

Bug Fixes

• Fixed a race condition when disable and re-enable manual compaction.
• Fixed a race condition for alive_log_files_ in non-two-write-queues mode. The race is between the write_thread_ in WriteToWAL() and another thread executing FindObsoleteFiles(). The race condition will be caught if __glibcxx_requires_nonempty is enabled.
• Fixed a race condition when mmaping a WritableFile on POSIX.
• Fixed a race condition when 2PC is disabled and WAL tracking in the MANIFEST is enabled. The race condition is between two background flush threads trying to install flush results, causing a WAL deletion not tracked in the MANIFEST. A future DB open may fail.
• Fixed a heap use-after-free race with DropColumnFamily.
• Fixed a bug that rocksdb.read.block.compaction.micros cannot track compaction stats (#9722).

6.29.5 (2022-03-29)

Bug Fixes

• Fixed a race condition for alive_log_files_ in non-two-write-queues mode. The race is between the write_thread_ in WriteToWAL() and another thread executing FindObsoleteFiles(). The race condition will be caught if __glibcxx_requires_nonempty is enabled.
• Fixed a race condition when mmaping a WritableFile on POSIX.
• Fixed a race condition when 2PC is disabled and WAL tracking in the MANIFEST is enabled. The race condition is between two background flush threads trying to install flush results, causing a WAL deletion not tracked in the MANIFEST. A future DB open may fail.
• Fixed a heap use-after-free race with DropColumnFamily.
• Fixed a bug that rocksdb.read.block.compaction.micros cannot track compaction stats (#9722).

7.0.3 (2022-03-25)

Bug Fixes

• Fixed a major performance bug in which Bloom filters generated by pre-7.0 releases are not read by early 7.0.x releases (and vice-versa) due to changes to FilterPolicy::Name() in #9590. This can severely impact read performance and read I/O on upgrade or downgrade with existing DB, but not data correctness.
• Fixed a bug that Iterator::Refresh() reads stale keys after DeleteRange() performed.

Public API changes

• Added pure virtual FilterPolicy::CompatibilityName(), which is needed for fixing major performance bug involving FilterPolicy naming in SST metadata without affecting Customizable aspect of FilterPolicy. For source code, this change only affects those with their own custom or wrapper FilterPolicy classes, but does break compiled library binary compatibility in a patch release.
• Since RocksDB 7, RocksJava now requires Java 8 (previously Java 7).

6.29.4 (2022-03-22)

Bug Fixes

• Fixed a bug caused by race among flush, incoming writes and taking snapshots. Queries to snapshots created with these race condition can return incorrect result, e.g. resurfacing deleted data.
• Fixed a bug that DisableManualCompaction may assert when disable an unscheduled manual compaction.
• Fixed a bug that Iterator::Refresh() reads stale keys after DeleteRange() performed.
• Fixed a race condition when disable and re-enable manual compaction.
• Fix a race condition when cancel manual compaction with DisableManualCompaction. Also DB close can cancel the manual compaction thread.
• Fixed a data race on versions_ between DBImpl::ResumeImpl() and threads waiting for recovery to complete (#9496)
• Fixed a read-after-free bug in DB::GetMergeOperands().
• Fixed NUM_INDEX_AND_FILTER_BLOCKS_READ_PER_LEVEL, NUM_DATA_BLOCKS_READ_PER_LEVEL, and NUM_SST_READ_PER_LEVEL stats to be reported once per MultiGet batch per level.

Rocksdb Change Log

7.0.2 (2022-03-12)

• Fixed a bug that DisableManualCompaction may assert when disable an unscheduled manual compaction.

Rocksdb Change Log

7.0.1 (2022-03-02)

Bug Fixes

• Fix a race condition when cancel manual compaction with DisableManualCompaction. Also DB close can cancel the manual compaction thread.
• Fixed a data race on versions_ between DBImpl::ResumeImpl() and threads waiting for recovery to complete (#9496)
• Fixed a bug caused by race among flush, incoming writes and taking snapshots. Queries to snapshots created with these race condition can return incorrect result, e.g. resurfacing deleted data.

7.0.0 (2022-02-20)

Bug Fixes

• Fixed a major bug in which batched MultiGet could return old values for keys deleted by DeleteRange when memtable Bloom filter is enabled (memtable_prefix_bloom_size_ratio > 0). (The fix includes a substantial MultiGet performance improvement in the unusual case of both memtable_whole_key_filtering and prefix_extractor.)
• Fixed more cases of EventListener::OnTableFileCreated called with OK status, file_size==0, and no SST file kept. Now the status is Aborted.
• Fixed a read-after-free bug in DB::GetMergeOperands().
• Fix a data loss bug for 2PC write-committed transaction caused by concurrent transaction commit and memtable switch (#9571).
• Fixed NUM_INDEX_AND_FILTER_BLOCKS_READ_PER_LEVEL, NUM_DATA_BLOCKS_READ_PER_LEVEL, and NUM_SST_READ_PER_LEVEL stats to be reported once per MultiGet batch per level.

Performance Improvements

• Mitigated the overhead of building the file location hash table used by the online LSM tree consistency checks, which can improve performance for certain workloads (see #9351).
• Switched to using a sorted std::vector instead of std::map for storing the metadata objects for blob files, which can improve performance for certain workloads, especially when the number of blob files is high.
• DisableManualCompaction() doesn't have to wait scheduled manual compaction to be executed in thread-pool to cancel the job.

Public API changes

• Require C++17 compatible compiler (GCC >= 7, Clang >= 5, Visual Studio >= 2017) for compiling RocksDB and any code using RocksDB headers (previously required C++11). See #9388.
• Require Java 8 for compiling RocksJava (previously Java 7). See #9541
• Removed deprecated automatic finalization of RocksJava RocksObjects, the user must explicitly call close() on their RocksJava objects. See #9523.
• Added ReadOptions::rate_limiter_priority. When set to something other than Env::IO_TOTAL, the internal rate limiter (DBOptions::rate_limiter) will be charged at the specified priority for file reads associated with the API to which the ReadOptions was provided.
• Remove HDFS support from main repo.
• Remove librados support from main repo.
• Remove obsolete backupable_db.h and type alias BackupableDBOptions. Use backup_engine.h and BackupEngineOptions. Similar renamings are in the C and Java APIs.
• Removed obsolete utility_db.h and UtilityDB::OpenTtlDB. Use db_ttl.h and DBWithTTL::Open.
• Remove deprecated API DB::AddFile from main repo.
• Remove deprecated API ObjectLibrary::Register() and the (now obsolete) Regex public API. Use ObjectLibrary::AddFactory() with PatternEntry instead.
• Remove deprecated option DBOption::table_cache_remove_scan_count_limit.
• Remove deprecated API AdvancedColumnFamilyOptions::soft_rate_limit.
• Remove deprecated API AdvancedColumnFamilyOptions::hard_rate_limit.
• Remove deprecated API DBOption::base_background_compactions.
• Remove deprecated API DBOptions::purge_redundant_kvs_while_flush.
• Remove deprecated overloads of API DB::CompactRange.
• Remove deprecated option DBOptions::skip_log_error_on_recovery.
• Remove ReadOptions::iter_start_seqnum which has been deprecated.
• Remove DBOptions::preserved_deletes and DB::SetPreserveDeletesSequenceNumber().
• Remove deprecated API AdvancedColumnFamilyOptions::rate_limit_delay_max_milliseconds.
• Removed timestamp from WriteOptions. Accordingly, added to DB APIs Put, Delete, SingleDelete, etc. accepting an additional argument 'timestamp'. Added Put, Delete, SingleDelete, etc to WriteBatch accepting an additional argument 'timestamp'. Removed WriteBatch::AssignTimestamps(vector) API. Renamed WriteBatch::AssignTimestamp() to WriteBatch::UpdateTimestamps() with clarified comments.
• Changed type of cache buffer passed to Cache::CreateCallback from void* to const void*.
• Significant updates to FilterPolicy-related APIs and configuration:
  • Remove public API support for deprecated, inefficient block-based filter (use_block_based_builder=true).
    • Old code and configuration strings that would enable it now quietly enable full filters instead, though any built-in FilterPolicy can still read block-based filters. This includes changing the longstanding default behavior of the Java API.
    • Remove deprecated FilterPolicy::CreateFilter() and FilterPolicy::KeyMayMatch()
    • Remove rocksdb_filterpolicy_create() from C API, as the only C API support for custom filter policies is now obsolete.
    • If temporary memory usage in full filter creation is a problem, consider using partitioned filters, smaller SST files, or setting reserve_table_builder_memory=true.
  • Remove support for "filter_policy=experimental_ribbon" configuration
    string. Use something like "filter_policy=ribbonfilter:10" instead.
  • Allow configuration string like "filter_policy=bloomfilter:10" without
    bool, to minimize acknowledgement of obsolete block-based filter.
  • Made FilterPolicy Customizable. Configuration of filter_policy is now accurately saved in OPTIONS file and can be loaded with LoadOptionsFromFile. (Loading an OPTIONS file generated by a previous version only enables reading and using existing filters, not generating new filters. Previously, no filter_policy would be configured from a saved OPTIONS file.)
  • Change meaning of nullptr return from GetBuilderWithContext() from "use
    block-based filter" to "generate no filter in this case."
    • Also, when user specifies bits_per_key < 0.5, we now round this down
      to "no filter" because we expect a filter with >= 80% FP rate is
      unlikely to be worth the CPU cost of accessing it (esp with
      cache_index_and_filter_blocks=1 or partition_filters=1).
    • bits_per_key >= 0.5 and < 1.0 is still rounded up to 1.0 (for 62% FP
      rate)
  • Remove class definitions for FilterBitsBuilder and FilterBitsReader from
    public API, so these can evolve more easily as implementation details.
    Custom FilterPolicy can still decide what kind of built-in filter to use
    under what conditions.
  • Also removed deprecated functions
    • FilterPolicy::GetFilterBitsBuilder()
    • NewExperimentalRibbonFilterPolicy()
  • Remove default implementations of
    • FilterPolicy::GetBuilderWithContext()
• Remove default implementation of Name() from FileSystemWrapper.
• Rename SizeApproximationOptions.include_memtabtles to SizeApproximationOptions.include_memtables.
• Remove deprecated option DBOptions::max_mem_compaction_level.
• Return Status::InvalidArgument from ObjectRegistry::NewObject if a factory exists but the object ould not be created (returns NotFound if the factory is missing).
• Remove deprecated overloads of API DB::GetApproximateSizes.
• Remove deprecated option DBOptions::new_table_reader_for_compaction_inputs.
• Add Transaction::SetReadTimestampForValidation() and Transaction::SetCommitTimestamp(). Default impl returns NotSupported().
• Add support for decimal patterns to ObjectLibrary::PatternEntry
• Remove deprecated remote compaction APIs CompactionService::Start() and CompactionService::WaitForComplete(). Please use CompactionService::StartV2(), CompactionService::WaitForCompleteV2() instead, which provides the same information plus extra data like priority, db_id, etc.
• ColumnFamilyOptions::OldDefaults and DBOptions::OldDefaults are marked deprecated, as they are no longer maintained.
• Add subcompaction callback APIs: OnSubcompactionBegin() and OnSubcompactionCompleted().
• Add file Temperature information to FileOperationInfo in event listener API.
• Change the type of SizeApproximationFlags from enum to enum class. Also update the signature of DB::GetApproximateSizes API from uint8_t to SizeApproximationFlags.
• Add Temperature hints information from RocksDB in API NewSequentialFile(). backup and checkpoint operations need to open the source files with NewSequentialFile(), which will have the temperature hints. Other operations are not covered.

Behavior Changes

• Disallow the combination of DBOptions.use_direct_io_for_flush_and_compaction == true and DBOptions.writable_file_max_buffer_size == 0. This combination can cause WritableFileWriter::Append() to loop forever, and it does not make much sense in direct IO.
• ReadOptions::total_order_seek no longer affects DB::Get(). The original motivation for this interaction has been obsolete since RocksDB has been able to detect whether the current prefix extractor is compatible with that used to generate table files, probably RocksDB 5.14.0.

New Features

• Introduced an option BlockBasedTableOptions::detect_filter_construct_corruption for detecting corruption during Bloom Filter (format_version >= 5) and Ribbon Filter construction.
• Improved the SstDumpTool to read the comparator from table properties and use it to read the SST File.
• Extended the column family statistics in the info log so the total amount of garbage in the blob files and the blob file space amplification factor are also logged. Also exposed the blob file space amp via the rocksdb.blob-stats DB property.
• Introduced the API rocksdb_create_dir_if_missing in c.h that calls underlying file system's CreateDirIfMissing API to create the directory.
• Added last level and non-last level read statistics: LAST_LEVEL_READ_*, NON_LAST_LEVEL_READ_*.
• Experimental: Add support for new APIs ReadAsync in ...

Rocksdb Change Log

6.29.3 (2022-02-17)

Bug Fixes

• Fix a data loss bug for 2PC write-committed transaction caused by concurrent transaction commit and memtable switch (#9571).

6.29.2 (2022-02-15)

Performance Improvements

• DisableManualCompaction() doesn't have to wait scheduled manual compaction to be executed in thread-pool to cancel the job.

6.29.1 (2022-01-31)

Bug Fixes

• Fixed a major bug in which batched MultiGet could return old values for keys deleted by DeleteRange when memtable Bloom filter is enabled (memtable_prefix_bloom_size_ratio > 0). (The fix includes a substantial MultiGet performance improvement in the unusual case of both memtable_whole_key_filtering and prefix_extractor.)

6.29.0 (2022-01-21)

Note: The next release will be major release 7.0. See #9390 for more info.

Public API change

• Added values to TraceFilterType: kTraceFilterIteratorSeek, kTraceFilterIteratorSeekForPrev, and kTraceFilterMultiGet. They can be set in TraceOptions to filter out the operation types after which they are named.
• Added TraceOptions::preserve_write_order. When enabled it guarantees write records are traced in the same order they are logged to WAL and applied to the DB. By default it is disabled (false) to match the legacy behavior and prevent regression.
• Made the Env class extend the Customizable class. Implementations need to be registered with the ObjectRegistry and to implement a Name() method in order to be created via this method.
• Options::OldDefaults is marked deprecated, as it is no longer maintained.
• Add ObjectLibrary::AddFactory and ObjectLibrary::PatternEntry classes. This method and associated class are the preferred mechanism for registering factories with the ObjectLibrary going forward. The ObjectLibrary::Register method, which uses regular expressions and may be problematic, is deprecated and will be in a future release.
• Changed BlockBasedTableOptions::block_size from size_t to uint64_t.
• Added API warning against using Iterator::Refresh() together with DB::DeleteRange(), which are incompatible and have always risked causing the refreshed iterator to return incorrect results.

Behavior Changes

• DB::DestroyColumnFamilyHandle() will return Status::InvalidArgument() if called with DB::DefaultColumnFamily().
• On 32-bit platforms, mmap reads are no longer quietly disabled, just discouraged.

New Features

• Added Options::DisableExtraChecks() that can be used to improve peak write performance by disabling checks that should not be necessary in the absence of software logic errors or CPU+memory hardware errors. (Default options are slowly moving toward some performance overheads for extra correctness checking.)

Performance Improvements

• Improved read performance when a prefix extractor is used (Seek, Get, MultiGet), even compared to version 6.25 baseline (see bug fix below), by optimizing the common case of prefix extractor compatible with table file and unchanging.

Bug Fixes

• Fix a bug that FlushMemTable may return ok even flush not succeed.
• Fixed a bug of Sync() and Fsync() not using fcntl(F_FULLFSYNC) on OS X and iOS.
• Fixed a significant performance regression in version 6.26 when a prefix extractor is used on the read path (Seek, Get, MultiGet). (Excessive time was spent in SliceTransform::AsString().)

New Features

• Added RocksJava support for MacOS universal binary (ARM+x86)