RocksDB 8.8.1

8.8.1 (2023-11-17)

Bug fixes

• Make the cache memory reservation accounting in Tiered cache (primary and compressed secondary cache) more accurate to avoid over/under charging the secondary cache.
• Allow increasing the compressed_secondary_ratio in the Tiered cache after setting it to 0 to disable.

8.8.0 (2023-10-23)

New Features

• Introduce AttributeGroup by adding the first AttributeGroup support API, MultiGetEntity(). Through the use of Column Families, AttributeGroup enables users to logically group wide-column entities. More APIs to support AttributeGroup will come soon, including GetEntity, PutEntity, and others.
• Added new tickers rocksdb.fifo.{max.size|ttl}.compactions to count FIFO compactions that drop files for different reasons
• Add an experimental offpeak duration awareness by setting DBOptions::daily_offpeak_time_utc in "HH:mm-HH:mm" format. This information will be used for resource optimization in the future
• Users can now change the max bytes granted in a single refill period (i.e, burst) during runtime by SetSingleBurstBytes() for RocksDB rate limiter

Public API Changes

• The default value of DBOptions::fail_if_options_file_error changed from false to true. Operations that set in-memory options (e.g., DB::Open*(), DB::SetOptions(), DB::CreateColumnFamily*(), and DB::DropColumnFamily()) but fail to persist the change will now return a non-OK Status by default.
• Add new Cache APIs GetSecondaryCacheCapacity() and GetSecondaryCachePinnedUsage() to return the configured capacity, and cache reservation charged to the secondary cache.

Behavior Changes

• For non direct IO, eliminate the file system prefetching attempt for compaction read when Options::compaction_readahead_size is 0
• During a write stop, writes now block on in-progress recovery attempts
• Deleting stale files upon recovery are delegated to SstFileManger if available so they can be rate limited.

Bug Fixes

• Fix a bug in auto_readahead_size where first_internal_key of index blocks wasn't copied properly resulting in corruption error when first_internal_key was used for comparison.
• Fixed a bug where compaction read under non direct IO still falls back to RocksDB internal prefetching after file system's prefetching returns non-OK status other than Status::NotSupported()
• Add bounds check in WBWIIteratorImpl and make BaseDeltaIterator, WriteUnpreparedTxn and WritePreparedTxn respect the upper bound and lower bound in ReadOption. See 11680.
• Fixed the handling of wide-column base values in the max_successive_merges logic.
• Fixed a rare race bug involving a concurrent combination of Create/DropColumnFamily and/or Set(DB)Options that could lead to inconsistency between (a) the DB's reported options state, (b) the DB options in effect, and (c) the latest persisted OPTIONS file.
• Fixed a possible underflow when computing the compressed secondary cache share of memory reservations while updating the compressed secondary to total block cache ratio.

Performance Improvements

• Improved the I/O efficiency of DB::Open a new DB with create_missing_column_families=true and many column families.

RocksDB 8.7.3

8.7.3 (2023-10-30)

Behavior Changes

• Deleting stale files upon recovery are delegated to SstFileManger if available so they can be rate limited.

8.7.2 (2023-10-25)

Public API Changes

• Add new Cache APIs GetSecondaryCacheCapacity() and GetSecondaryCachePinnedUsage() to return the configured capacity, and cache reservation charged to the secondary cache.

Bug Fixes

• Fixed a possible underflow when computing the compressed secondary cache share of memory reservations while updating the compressed secondary to total block cache ratio.
• Fix an assertion failure when UpdeteTieredCache() is called in an idempotent manner.

8.7.1 (2023-10-20)

Bug Fixes

• Fix a bug in auto_readahead_size where first_internal_key of index blocks wasn't copied properly resulting in corruption error when first_internal_key was used for comparison.
• Add bounds check in WBWIIteratorImpl and make BaseDeltaIterator, WriteUnpreparedTxn and WritePreparedTxn respect the upper bound and lower bound in ReadOption. See 11680.

8.7.0 (2023-09-22)

New Features

• Added an experimental new "automatic" variant of HyperClockCache that does not require a prior estimate of the average size of cache entries. This variant is activated when HyperClockCacheOptions::estimated_entry_charge = 0 and has essentially the same concurrency benefits as the existing HyperClockCache.
• Add a new statistic COMPACTION_CPU_TOTAL_TIME that records cumulative compaction cpu time. This ticker is updated regularly while a compaction is running.
• Add GetEntity() API for ReadOnly DB and Secondary DB.
• Add a new iterator API Iterator::Refresh(const Snapshot *) that allows iterator to be refreshed while using the input snapshot to read.
• Added a new read option merge_operand_count_threshold. When the number of merge operands applied during a successful point lookup exceeds this threshold, the query will return a special OK status with a new subcode kMergeOperandThresholdExceeded. Applications might use this signal to take action to reduce the number of merge operands for the affected key(s), for example by running a compaction.
• For NewRibbonFilterPolicy(), made the bloom_before_level option mutable through the Configurable interface and the SetOptions API, allowing dynamic switching between all-Bloom and all-Ribbon configurations, and configurations in between. See comments on NewRibbonFilterPolicy()
• RocksDB now allows the block cache to be stacked on top of a compressed secondary cache and a non-volatile secondary cache, thus creating a three-tier cache. To set it up, use the NewTieredCache() API in rocksdb/cache.h..
• Added a new wide-column aware full merge API called FullMergeV3 to MergeOperator. FullMergeV3 supports wide columns both as base value and merge result, which enables the application to perform more general transformations during merges. For backward compatibility, the default implementation implements the earlier logic of applying the merge operation to the default column of any wide-column entities. Specifically, if there is no base value or the base value is a plain key-value, the default implementation falls back to FullMergeV2. If the base value is a wide-column entity, the default implementation invokes FullMergeV2 to perform the merge on the default column, and leaves any other columns unchanged.
• Add wide column support to ldb commands (scan, dump, idump, dump_wal) and sst_dump tool's scan command

Public API Changes

• Expose more information about input files used in table creation (if any) in CompactionFilter::Context. See CompactionFilter::Context::input_start_level,CompactionFilter::Context::input_table_properties for more.
• Options::compaction_readahead_size 's default value is changed from 0 to 2MB.
• When using LZ4 compression, the acceleration parameter is configurable by setting the negated value in CompressionOptions::level. For example, CompressionOptions::level=-10 will set acceleration=10
• The NewTieredCache API has been changed to take the total cache capacity (inclusive of both the primary and the compressed secondary cache) and the ratio of total capacity to allocate to the compressed cache. These are specified in TieredCacheOptions. Any capacity specified in LRUCacheOptions, HyperClockCacheOptions and CompressedSecondaryCacheOptions is ignored. A new API, UpdateTieredCache is provided to dynamically update the total capacity, ratio of compressed cache, and admission policy.
• The NewTieredVolatileCache() API in rocksdb/cache.h has been renamed to NewTieredCache().

Behavior Changes

• Compaction read performance will regress when Options::compaction_readahead_size is explicitly set to 0
• Universal size amp compaction will conditionally exclude some of the newest L0 files when selecting input with a small negative impact to size amp. This is to prevent a large number of L0 files from being locked by a size amp compaction, potentially leading to write stop with a few more flushes.
• Change ldb scan command delimiter from ':' to '==>'.
• For non direct IO, eliminate the file system prefetching attempt for compaction read when Options::compaction_readahead_size is 0

Bug Fixes

• Fix a bug where if there is an error reading from offset 0 of a file from L1+ and that the file is not the first file in the sorted run, data can be lost in compaction and read/scan can return incorrect results.
• Fix a bug where iterator may return incorrect result for DeleteRange() users if there was an error reading from a file.
• Fix a bug with atomic_flush=true that can cause DB to stuck after a flush fails (#11872).
• Fix a bug where RocksDB (with atomic_flush=false) can delete output SST files of pending flushes when a previous concurrent flush fails (#11865). This can result in DB entering read-only state with error message like IO error: No such file or directory: While open a file for random read: /tmp/rocksdbtest-501/db_flush_test_87732_4230653031040984171/000013.sst.
• Fix an assertion fault during seek with async_io when readahead trimming is enabled.
• When the compressed secondary cache capacity is reduced to 0, it should be completely disabled. Before this fix, inserts and lookups would still go to the backing LRUCache before returning, thus incurring locking overhead. With this fix, inserts and lookups are no-ops and do not add any overhead.
• Updating the tiered cache (cache allocated using NewTieredCache()) by calling SetCapacity() on it was not working properly. The initial creation would set the primary cache capacity to the combined primary and compressed secondary cache capacity. But SetCapacity() would just set the primary cache capacity. With this fix, the user always specifies the total budget and compressed secondary cache ratio on creation. Subsequently, SetCapacity() will distribute the new capacity across the two caches by the same ratio.
• Fixed a bug in MultiGet for cleaning up SuperVersion acquired with locking db mutex.
• Fix a bug where row cache can falsely return kNotFound even though row cache entry is hit.
• Fixed a race condition in GenericRateLimiter that could cause it to stop granting requests
• Fix a bug (Issue #10257) where DB can hang after write stall since no compaction is scheduled (#11764).
• Add a fix for async_io where during seek, when reading a block for seeking a target key in a file without any readahead, the iterator aligned the read on a page boundary and reading more than necessary. This increased the storage read bandwidth usage.
• Fix an issue in sst dump tool to handle bounds specified for data with user-defined timestamps.
• When auto_readahead_size is enabled, update readahead upper bound during readahead trimming when reseek changes iterate_upper_bound dynamically.
• Fixed a bug where rocksdb.file.read.verify.file.checksums.micros is not populated
• Fixed a bug where compaction read under non direct IO still falls back to RocksDB internal prefetching after file system's prefetching returns non-OK status other than Status::NotSupported()

Performance Improvements

• Added additional improvements in tuning readahead_size during Scans when auto_readahead_size is enabled. However it's not recommended for backward scans and might impact the performance. More details in options.h.
• During async_io, the Seek happens in 2 phases. Phase 1 starts an asynchronous read on a block cache miss, and phase 2 waits for it to complete and finishes the seek. In both phases, it tries to lookup the block cache for the data block first before looking in the prefetch buffer. It's optimized by doing the block cache lookup only in the first phase that would save some CPU.

RocksDB 8.6.7

8.6.7 (2023-09-26)

Bug Fixes

• Fixed a bug where compaction read under non direct IO still falls back to RocksDB internal prefetching after file system's prefetching returns non-OK status other than Status::NotSupported()

Behavior Changes

• For non direct IO, eliminate the file system prefetching attempt for compaction read when Options::compaction_readahead_size is 0

8.6.6 (2023-09-25)

Bug Fixes

• Fix a bug with atomic_flush=true that can cause DB to stuck after a flush fails (#11872).
• Fix a bug where RocksDB (with atomic_flush=false) can delete output SST files of pending flushes when a previous concurrent flush fails (#11865). This can result in DB entering read-only state with error message like IO error: No such file or directory: While open a file for random read: /tmp/rocksdbtest-501/db_flush_test_87732_4230653031040984171/000013.sst.
• When the compressed secondary cache capacity is reduced to 0, it should be completely disabled. Before this fix, inserts and lookups would still go to the backing LRUCache before returning, thus incurring locking overhead. With this fix, inserts and lookups are no-ops and do not add any overhead.

8.6.5 (2023-09-15)

Bug Fixes

• Fixed a bug where rocksdb.file.read.verify.file.checksums.micros is not populated.

8.6.4 (2023-09-13)

Public API changes

• Add a column family option default_temperature that is used for file reading accounting purpose, such as io statistics, for files that don't have an explicitly set temperature.

8.6.3 (2023-09-12)

Bug Fixes

• Fix a bug where if there is an error reading from offset 0 of a file from L1+ and that the file is not the first file in the sorted run, data can be lost in compaction and read/scan can return incorrect results.
• Fix a bug where iterator may return incorrect result for DeleteRange() users if there was an error reading from a file.

8.6.2 (2023-09-11)

Bug Fixes

• Add a fix for async_io where during seek, when reading a block for seeking a target key in a file without any readahead, the iterator aligned the read on a page boundary and reading more than necessary. This increased the storage read bandwidth usage.

8.6.1 (2023-08-30)

Public API Changes

• Options::compaction_readahead_size 's default value is changed from 0 to 2MB.

Behavior Changes

• Compaction read performance will regress when Options::compaction_readahead_size is explicitly set to 0

8.6.0 (2023-08-18)

New Features

• Added enhanced data integrity checking on SST files with new format_version=6. Performance impact is very small or negligible. Previously if SST data was misplaced or re-arranged by the storage layer, it could pass block checksum with higher than 1 in 4 billion probability. With format_version=6, block checksums depend on what file they are in and location within the file. This way, misplaced SST data is no more likely to pass checksum verification than randomly corrupted data. Also in format_version=6, SST footers are checksum-protected.
• Add a new feature to trim readahead_size during scans upto upper_bound when iterate_upper_bound is specified. It's enabled through ReadOptions.auto_readahead_size. Users must also specify ReadOptions.iterate_upper_bound.
• RocksDB will compare the number of input keys to the number of keys processed after each compaction. Compaction will fail and report Corruption status if the verification fails. Option compaction_verify_record_count is introduced for this purpose and is enabled by default.
• Add a CF option bottommost_file_compaction_delay to allow specifying the delay of bottommost level single-file compactions.
• Add support to allow enabling / disabling user-defined timestamps feature for an existing column family in combination with the in-Memtable only feature.
• Implement a new admission policy for the compressed secondary cache that admits blocks evicted from the primary cache with the hit bit set. This policy can be specified in TieredVolatileCacheOptions by setting the newly added adm_policy option.
• Add a column family option memtable_max_range_deletions that limits the number of range deletions in a memtable. RocksDB will try to do an automatic flush after the limit is reached. (#11358)
• Add PutEntity API in sst_file_writer
• Add timeout in microsecond option to WaitForCompactOptions to allow timely termination of prolonged waiting in scenarios like recurring recoverable errors, such as out-of-space situations and continuous write streams that sustain ongoing flush and compactions
• New statistics rocksdb.file.read.{get|multiget|db.iterator|verify.checksum|verify.file.checksums}.micros measure read time of block-based SST tables or blob files during db open, Get(), MultiGet(), using db iterator, VerifyFileChecksums() and VerifyChecksum(). They require stats level greater than StatsLevel::kExceptDetailedTimers.
• Add close_db option to WaitForCompactOptions to call Close() after waiting is done.
• Add a new compression option CompressionOptions::checksum for enabling ZSTD's checksum feature to detect corruption during decompression.

Public API Changes

• Mark Options::access_hint_on_compaction_start related APIs as deprecated. See #11631 for alternative behavior.

Behavior Changes

• Statistics rocksdb.sst.read.micros now includes time spent on multi read and async read into the file
• For Universal Compaction users, periodic compaction (option periodic_compaction_seconds) will be set to 30 days by default if block based table is used.

Bug Fixes

• Fix a bug in FileTTLBooster that can cause users with a large number of levels (more than 65) to see errors like "runtime error: shift exponent .. is too large.." (#11673).

RocksDB 8.5.4

8.5.4 (2023-09-26)

Bug Fixes

• Fixed a bug where compaction read under non direct IO still falls back to RocksDB internal prefetching after file system's prefetching returns non-OK status other than Status::NotSupported()

Behavior Changes

• For non direct IO, eliminate the file system prefetching attempt for compaction read when Options::compaction_readahead_size is 0

RocksDB 8.5.3

Please note 8.5.1 includes a fix for a persisted database corruption in an unlikely edge case. Upgrading to a version including this fix, like this one, is highly recommended!

8.5.3 (2023-09-01)

Bug Fixes

• Fixed a race condition in GenericRateLimiter that could cause it to stop granting requests

8.5.2 (2023-08-31)

Bug fixes

• Fix a bug where iterator may return incorrect result for DeleteRange() users if there was an error reading from a file.

8.5.1 (2023-08-31)

Bug fixes

• Fix a bug where if there is an error reading from offset 0 of a file from L1+ and that the file is not the first file in the sorted run, data can be lost in compaction and read/scan can return incorrect results.

8.5.0 (2023-07-21)

Public API Changes

• Removed recently added APIs GeneralCache and MakeSharedGeneralCache() as our plan changed to stop exposing a general-purpose cache interface. The old forms of these APIs, Cache and NewLRUCache(), are still available, although general-purpose caching support will be dropped eventually.

Behavior Changes

• Option periodic_compaction_seconds no longer supports FIFO compaction: setting it has no effect on FIFO compactions. FIFO compaction users should only set option ttl instead.
• Move prefetching responsibility to page cache for compaction read for non directIO use case

Performance Improvements

• In case of direct_io, if buffer passed by callee is already aligned, RandomAccessFileRead::Read will avoid realloacting a new buffer, reducing memcpy and use already passed aligned buffer.
• Small efficiency improvement to HyperClockCache by reducing chance of compiler-generated heap allocations

Bug Fixes

• Fix use_after_free bug in async_io MultiReads when underlying FS enabled kFSBuffer. kFSBuffer is when underlying FS pass their own buffer instead of using RocksDB scratch in FSReadRequest. Right now it's an experimental feature.
• Fix a bug in FileTTLBooster that can cause users with a large number of levels (more than 65) to see errors like "runtime error: shift exponent .. is too large.." (#11673).

RocksDB 8.4.4

8.4.4 (2023-09-01)

Bug Fixes

• Fix a bug where if there is an error reading from offset 0 of a file from L1+ and that the file is not the first file in the sorted run, data can be lost in compaction and read/scan can return incorrect results.
• Fix a bug where iterator may return incorrect result for DeleteRange() users if there was an error reading from a file.
• Fixed a race condition in GenericRateLimiter that could cause it to stop granting requests

8.4.3 (2023-07-27)

Bug Fixes

• Fix use_after_free bug in async_io MultiReads when underlying FS enabled kFSBuffer. kFSBuffer is when underlying FS pass their own buffer instead of using RocksDB scratch in FSReadRequest.

8.4.0 (2023-06-26)

New Features

• Add FSReadRequest::fs_scratch which is a data buffer allocated and provided by underlying FileSystem to RocksDB during reads, when FS wants to provide its own buffer with data instead of using RocksDB provided FSReadRequest::scratch. This can help in cpu optimization by avoiding copy from file system's buffer to RocksDB buffer. More details on how to use/enable it in file_system.h. Right now its supported only for MultiReads(async + sync) with non direct io.
• Start logging non-zero user-defined timestamp sizes in WAL to signal user key format in subsequent records and use it during recovery. This change will break recovery from WAL files written by early versions that contain user-defined timestamps. The workaround is to ensure there are no WAL files to recover (i.e. by flushing before close) before upgrade.
• Added new property "rocksdb.obsolete-sst-files-size-property" that reports the size of SST files that have become obsolete but have not yet been deleted or scheduled for deletion
• Start to record the value of the flag AdvancedColumnFamilyOptions.persist_user_defined_timestamps in the Manifest and table properties for a SST file when it is created. And use the recorded flag when creating a table reader for the SST file. This flag is only explicitly record if it's false.
• Add a new option OptimisticTransactionDBOptions::shared_lock_buckets that enables sharing mutexes for validating transactions between DB instances, for better balancing memory efficiency and validation contention across DB instances. Different column families and DBs also now use different hash seeds in this validation, so that the same set of key names will not contend across DBs or column families.
• Add a new ticker rocksdb.files.marked.trash.deleted to track the number of trash files deleted by background thread from the trash queue.
• Add an API NewTieredVolatileCache() in include/rocksdb/cache.h to allocate an instance of a block cache with a primary block cache tier and a compressed secondary cache tier. A cache of this type distributes memory reservations against the block cache, such as WriteBufferManager, table reader memory etc., proportionally across both the primary and compressed secondary cache.
• Add WaitForCompact() to wait for all flush and compactions jobs to finish. Jobs to wait include the unscheduled (queued, but not scheduled yet).
• Add WriteBatch::Release() that releases the batch's serialized data to the caller.

Public API Changes

• Add C API rocksdb_options_add_compact_on_deletion_collector_factory_del_ratio.
• change the FileSystem::use_async_io() API to SupportedOps API in order to extend it to various operations supported by underlying FileSystem. Right now it contains FSSupportedOps::kAsyncIO and FSSupportedOps::kFSBuffer. More details about FSSupportedOps in filesystem.h
• Add new tickers: rocksdb.error.handler.bg.error.count, rocksdb.error.handler.bg.io.error.count, rocksdb.error.handler.bg.retryable.io.error.count to replace the misspelled ones: rocksdb.error.handler.bg.errro.count, rocksdb.error.handler.bg.io.errro.count, rocksdb.error.handler.bg.retryable.io.errro.count ('error' instead of 'errro'). Users should switch to use the new tickers before 9.0 release as the misspelled old tickers will be completely removed then.
• Overload the API CreateColumnFamilyWithImport() to support creating ColumnFamily by importing multiple ColumnFamilies It requires that CFs should not overlap in user key range.

Behavior Changes

• Change the default value for option level_compaction_dynamic_level_bytes to true. This affects users who use leveled compaction and do not set this option explicitly. These users may see additional background compactions following DB open. These compactions help to shape the LSM according to level_compaction_dynamic_level_bytes such that the size of each level Ln is approximately size of Ln-1 * max_bytes_for_level_multiplier. Turning on this option has other benefits too: see more detail in wiki: https://github.com/facebook/rocksdb/wiki/Leveled-Compaction#option-level_compaction_dynamic_level_bytes-and-levels-target-size and in option comment in advanced_options.h (#11525).
• For Leveled Compaction users, CompactRange() will now always try to compact to the last non-empty level. (#11468)
  For Leveled Compaction users, CompactRange() with bottommost_level_compaction = BottommostLevelCompaction::kIfHaveCompactionFilter will behave similar to kForceOptimized in that it will skip files created during this manual compaction when compacting files in the bottommost level. (#11468)
• RocksDB will try to drop range tombstones during non-bottommost compaction when it is safe to do so. (#11459)
• When a DB is openend with allow_ingest_behind=true (currently only Universal compaction is supported), files in the last level, i.e. the ingested files, will not be included in any compaction. (#11489)
• Statistics rocksdb.sst.read.micros scope is expanded to all SST reads except for file ingestion and column family import (some compaction reads were previously excluded).

Bug Fixes

• Reduced cases of illegally using Env::Default() during static destruction by never destroying the internal PosixEnv itself (except for builds checking for memory leaks). (#11538)
• Fix extra prefetching during seek in async_io when BlockBasedTableOptions.num_file_reads_for_auto_readahead is 1 leading to extra reads than required.
• Fix a bug where compactions that are qualified to be run as 2 subcompactions were only run as one subcompaction.
• Fix a use-after-move bug in block.cc.

RocksDB 8.3.3

8.3.3 (2023-09-01)

Bug Fixes

• Fix a bug where if there is an error reading from offset 0 of a file from L1+ and that the file is not the first file in the sorted run, data can be lost in compaction and read/scan can return incorrect results.
• Fix a bug where iterator may return incorrect result for DeleteRange() users if there was an error reading from a file.
• Fixed a race condition in GenericRateLimiter that could cause it to stop granting requests

RocksDB 8.3.2

8.3.2 (2023-06-14)

Bug Fixes

• Reduced cases of illegally using Env::Default() during static destruction by never destroying the internal PosixEnv itself (except for builds checking for memory leaks). (#11538)

8.3.1 (2023-06-07)

Performance Improvements

• Fixed higher read QPS during DB::Open() reading files created prior to #11406, especially when reading many small file (size < 52 MB) during DB::Open() and partitioned filter or index is used.

8.3.0 (2023-05-19)

New Features

• Introduced a new option block_protection_bytes_per_key, which can be used to enable per key-value integrity protection for in-memory blocks in block cache (#11287).
• Added JemallocAllocatorOptions::num_arenas. Setting num_arenas > 1 may mitigate mutex contention in the allocator, particularly in scenarios where block allocations commonly bypass jemalloc tcache.
• Improve the operational safety of publishing a DB or SST files to many hosts by using different block cache hash seeds on different hosts. The exact behavior is controlled by new option ShardedCacheOptions::hash_seed, which also documents the solved problem in more detail.
• Introduced a new option CompactionOptionsFIFO::file_temperature_age_thresholds that allows FIFO compaction to compact files to different temperatures based on key age (#11428).
• Added a new ticker stat to count how many times RocksDB detected a corruption while verifying a block checksum: BLOCK_CHECKSUM_MISMATCH_COUNT.
• New statistics rocksdb.file.read.db.open.micros that measures read time of block-based SST tables or blob files during db open.
• New statistics tickers for various iterator seek behaviors and relevant filtering, as *_LEVEL_SEEK_*. (#11460)

Public API Changes

• EXPERIMENTAL: Add new API DB::ClipColumnFamily to clip the key in CF to a certain range. It will physically deletes all keys outside the range including tombstones.
• Add MakeSharedCache() construction functions to various cache Options objects, and deprecated the NewWhateverCache() functions with long parameter lists.
• Changed the meaning of various Bloom filter stats (prefix vs. whole key), with iterator-related filtering only being tracked in the new *_LEVEL_SEEK_*. stats. (#11460)

Behavior changes

• For x86, CPU features are no longer detected at runtime nor in build scripts, but in source code using common preprocessor defines. This will likely unlock some small performance improvements on some newer hardware, but could hurt performance of the kCRC32c checksum, which is no longer the default, on some "portable" builds. See PR #11419 for details.

Bug Fixes

• Delete an empty WAL file on DB open if the log number is less than the min log number to keep
• Delete temp OPTIONS file on DB open if there is a failure to write it out or rename it

Performance Improvements

• Improved the I/O efficiency of prefetching SST metadata by recording more information in the DB manifest. Opening files written with previous versions will still rely on heuristics for how much to prefetch (#11406).

RocksDB 8.1.1

8.1.1 (2023-04-06)

Bug Fixes

• In the DB::VerifyFileChecksums API, ensure that file system reads of SST files are equal to the readahead_size in ReadOptions, if specified. Previously, each read was 2x the readahead_size.

8.1.0 (2023-03-18)

Behavior changes

• Compaction output file cutting logic now considers range tombstone start keys. For example, SST partitioner now may receive ParitionRequest for range tombstone start keys.
• If the async_io ReadOption is specified for MultiGet or NewIterator on a platform that doesn't support IO uring, the option is ignored and synchronous IO is used.

Bug Fixes

• Fixed an issue for backward iteration when user defined timestamp is enabled in combination with BlobDB.
• Fixed a couple of cases where a Merge operand encountered during iteration wasn't reflected in the internal_merge_count PerfContext counter.
• Fixed a bug in CreateColumnFamilyWithImport()/ExportColumnFamily() which did not support range tombstones (#11252).
• Fixed a bug where an excluded column family from an atomic flush contains unflushed data that should've been included in this atomic flush (i.e, data of seqno less than the max seqno of this atomic flush), leading to potential data loss in this excluded column family when WriteOptions::disableWAL == true (#11148).

New Features

• Add statistics rocksdb.secondary.cache.filter.hits, rocksdb.secondary.cache.index.hits, and rocksdb.secondary.cache.filter.hits
• Added a new PerfContext counter internal_merge_point_lookup_count which tracks the number of Merge operands applied while serving point lookup queries.
• Add new statistics rocksdb.table.open.prefetch.tail.read.bytes, rocksdb.table.open.prefetch.tail.{miss|hit}
• Add support for SecondaryCache with HyperClockCache (HyperClockCacheOptions inherits secondary_cache option from ShardedCacheOptions)
• Add new db properties rocksdb.cf-write-stall-stats, rocksdb.db-write-stall-statsand APIs to examine them in a structured way. In particular, users of GetMapProperty() with property kCFWriteStallStats/kDBWriteStallStats can now use the functions in WriteStallStatsMapKeys to find stats in the map.

Public API Changes

• Changed various functions and features in Cache that are mostly relevant to custom implementations or wrappers. Especially, asychronous lookup functionality is moved from Lookup() to a new StartAsyncLookup() function.

RocksDB 7.10.2

7.10.2 (2023-02-10)

Bug Fixes

• Fixed a bug in DB open/recovery from a compressed WAL that was caused due to incorrect handling of certain record fragments with the same offset within a WAL block.

7.10.1 (2023-02-01)

Bug Fixes

• Fixed a data race on ColumnFamilyData::flush_reason caused by concurrent flushes.
• Fixed DisableManualCompaction() and CompactRangeOptions::canceled to cancel compactions even when they are waiting on conflicting compactions to finish
• Fixed a bug in which a successful GetMergeOperands() could transiently return Status::MergeInProgress()
• Return the correct error (Status::NotSupported()) to MultiGet caller when ReadOptions::async_io flag is true and IO uring is not enabled. Previously, Status::Corruption() was being returned when the actual failure was lack of async IO support.

7.10.0 (2023-01-23)

Behavior changes

• Make best-efforts recovery verify SST unique ID before Version construction (#10962)
• Introduce epoch_number and sort L0 files by epoch_number instead of largest_seqno. epoch_number represents the order of a file being flushed or ingested/imported. Compaction output file will be assigned with the minimum epoch_number among input files'. For L0, larger epoch_number indicates newer L0 file.

Bug Fixes

• Fixed a regression in iterator where range tombstones after iterate_upper_bound is processed.
• Fixed a memory leak in MultiGet with async_io read option, caused by IO errors during table file open
• Fixed a bug that multi-level FIFO compaction deletes one file in non-L0 even when CompactionOptionsFIFO::max_table_files_size is no exceeded since #10348 or 7.8.0.
• Fixed a bug caused by DB::SyncWAL() 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 (#10892).
• Fixed a BackupEngine bug in which RestoreDBFromLatestBackup would fail if the latest backup was deleted and there is another valid backup available.
• Fix L0 file misorder corruption caused by ingesting files of overlapping seqnos with memtable entries' through introducing epoch_number. Before the fix, force_consistency_checks=true may catch the corruption before it's exposed to readers, in which case writes returning Status::Corruption would be expected. Also replace the previous incomplete fix (#5958) to the same corruption with this new and more complete fix.
• Fixed a bug in LockWAL() leading to re-locking mutex (#11020).
• Fixed a heap use after free bug in async scan prefetching when the scan thread and another thread try to read and load the same seek block into cache.
• Fixed a heap use after free in async scan prefetching if dictionary compression is enabled, in which case sync read of the compression dictionary gets mixed with async prefetching
• Fixed a data race bug of CompactRange() under change_level=true acts on overlapping range with an ongoing file ingestion for level compaction. This will either result in overlapping file ranges corruption at a certain level caught by force_consistency_checks=true or protentially two same keys both with seqno 0 in two different levels (i.e, new data ends up in lower/older level). The latter will be caught by assertion in debug build but go silently and result in read returning wrong result in release build. This fix is general so it also replaced previous fixes to a similar problem for CompactFiles() (#4665), general CompactRange() and auto compaction (commit 5c64fb6 and 87dfc1d).
• Fixed a bug in compaction output cutting where small output files were produced due to TTL file cutting states were not being updated (#11075).

New Features

• When an SstPartitionerFactory is configured, CompactRange() now automatically selects for compaction any files overlapping a partition boundary that is in the compaction range, even if no actual entries are in the requested compaction range. With this feature, manual compaction can be used to (re-)establish SST partition points when SstPartitioner changes, without a full compaction.
• Add BackupEngine feature to exclude files from backup that are known to be backed up elsewhere, using CreateBackupOptions::exclude_files_callback. To restore the DB, the excluded files must be provided in alternative backup directories using RestoreOptions::alternate_dirs.

Public API Changes

• Substantial changes have been made to the Cache class to support internal development goals. Direct use of Cache class members is discouraged and further breaking modifications are expected in the future. SecondaryCache has some related changes and implementations will need to be updated. (Unlike Cache, SecondaryCache is still intended to support user implementations, and disruptive changes will be avoided.) (#10975)
• Add MergeOperationOutput::op_failure_scope for merge operator users to control the blast radius of merge operator failures. Existing merge operator users do not need to make any change to preserve the old behavior

Performance Improvements

• Updated xxHash source code, which should improve kXXH3 checksum speed, at least on ARM (#11098).
• Improved CPU efficiency of DB reads, from block cache access improvements (#10975).