RocksDB 4.9

Public API changes

• Add bottommost_compression option, This option can be used to set a specific compression algorithm for the bottommost level (Last level containing files in the DB).
• Introduce CompactionJobInfo::compression, This field state the compression algorithm used to generate the output files of the compaction.
• Deprecate BlockBaseTableOptions.hash_index_allow_collision=false
• Deprecate options builder (GetOptions()).

New Features

• Introduce NewSimCache() in rocksdb/utilities/sim_cache.h. This function creates a block cache that is able to give simulation results (mainly hit rate) of simulating block behavior with a configurable cache size.

v4.8

Public API Change

• Allow preset compression dictionary for improved compression of block-based tables. This is supported for zlib, zstd, and lz4. The compression dictionary's size is configurable via CompressionOptions::max_dict_bytes.
• Delete deprecated classes for creating backups (BackupableDB) and restoring from backups (RestoreBackupableDB). Now, BackupEngine should be used for creating backups, and BackupEngineReadOnly should be used for restorations. For more details, see https://github.com/facebook/rocksdb/wiki/How-to-backup-RocksDB%3F
• Expose estimate of per-level compression ratio via DB property: "rocksdb.compression-ratio-at-levelN".
  Added EventListener::OnTableFileCreationStarted. EventListener::OnTableFileCreated will be called on failure case. User can check creation status via TableFileCreationInfo::status.

New Features

• Add ReadOptions::readahead_size. If non-zero, NewIterator will create a new table reader which performs reads of the given size.

RocksDB 4.6.1

Public API Changes

• Change default of BlockBasedTableOptions.format_version to 2. It means default DB created by 4.6 or up cannot be opened by RocksDB version 3.9 or earlier.
• Added strict_capacity_limit option to NewLRUCache. If the flag is set to true, insert to cache will fail if no enough capacity can be free. Signature of Cache::Insert() is updated accordingly.
• Tickers [NUMBER_DB_NEXT, NUMBER_DB_PREV, NUMBER_DB_NEXT_FOUND, NUMBER_DB_PREV_FOUND, ITER_BYTES_READ] are not updated immediately. The are updated when the Iterator is deleted.
• Add monotonically increasing counter (DB property "rocksdb.current-super-version-number") that increments upon any change to the LSM tree.

New Features

• Add CompactionPri::kMinOverlappingRatio, a compaction picking mode friendly to write amplification.
• Deprecate Iterator::IsKeyPinned() and replace it with Iterator::GetProperty() with prop_name="rocksdb.iterator.is.key.pinned"

RocksDB 4.5.1

Public API Changes

• Add a new perf context level between kEnableCount and kEnableTime. Level 2 now does not include timers for mutexes.
• Statistics of mutex operation durations will not be measured by default. If you want to have them enabled, you need to set Statistics::stats_level_ to kAll.
• DBOptions::delete_scheduler and NewDeleteScheduler() are removed, please use DBOptions::sst_file_manager and NewSstFileManager() instead

New Features

• ldb tool now supports operations to non-default column families.
• Add kPersistedTier to ReadTier. This option allows Get and MultiGet to read only the persited data and skip mem-tables if writes were done with disableWAL = true.
• Add DBOptions::sst_file_manager. Use NewSstFileManager() in include/rocksdb/sst_file_manager.h to create a SstFileManager that can be used to track the total size of SST files and control the SST files deletion rate.

RocksDB 4.4.1

New Features

• Dynamic slow-down on writes. When slow down on writes is triggered, RocksDB will dynamically optimize the slow-down per write based on the estimated pending compaction bytes. If the number of pending compaction bytes keeps increasing, then RocksDB will slow down on writes more to make compaction able to catch up to avoid write stall.
• Introduce CompactionJobInfo::compaction_reason, this field include the reason to trigger the compaction.
• Added a new parameter --path to ldb tool. --path accepts the name of either MANIFEST, SST or a WAL file. Either --db or --path can be used when calling ldb.

Public API Changes

• Deprecate options.soft_rate_limit and add options.soft_pending_compaction_bytes_limit.
• If options.max_write_buffer_number > 3, writes will be slowed down when writing to the last write buffer to delay a full stop.
• Increase default options.delayed_write_rate to 2MB/s.
• Change names in CompactionPri and add a new one.

RocksDB 4.3.1

New Features

• CompactionFilter has new member function called IgnoreSnapshots which allows CompactionFilter to be called even if there are snapshots later than the key.
• RocksDB will now persist options under the same directory as the RocksDB database on successful DB::Open, CreateColumnFamily, DropColumnFamily, and SetOptions.
• Introduce LoadLatestOptions() in rocksdb/utilities/options_util.h. This function can construct the latest DBOptions / ColumnFamilyOptions used by the specified RocksDB intance.
• Introduce CheckOptionsCompatibility() in rocksdb/utilities/options_util.h. This function checks whether the input set of options is able to open the specified DB successfully.

Public API Changes

• When options.db_write_buffer_size triggers, only the column family with the largest column family size will be flushed, not all the column families.

RocksDB 4.2

New Features

• Introduce CreateLoggerFromOptions(), this function create a Logger for provided DBOptions.
• Add GetAggregatedIntProperty(), which returns the sum of the GetIntProperty of all the column families.
• Add MemoryUtil in rocksdb/utilities/memory.h. It currently offers a way to get the memory usage by type from a list rocksdb instances.

Public API Changes

• CompactionFilter::Context includes information of Column Family ID
• The need-compaction hint given by TablePropertiesCollector::NeedCompact() will be persistent and recoverable after DB recovery. This introduces a breaking format change. If you use this experimental feature, including NewCompactOnDeletionCollectorFactory() in the new version, you may not be able to directly downgrade the DB back to version 4.0 or lower.
• TablePropertiesCollectorFactory::CreateTablePropertiesCollector() now takes an option Context, containing the information of column family ID for the file being written.
• Remove DefaultCompactionFilterFactory.

RocksDB 4.1

New Features

• Added single delete operation as a more efficient way to delete keys that have not been overwritten.
• Added experimental AddFile() to DB interface that allow users to add files created by SstFileWriter into an empty Database, see include/rocksdb/sst_file_writer.h and DB::AddFile() for more info.
• Added support for opening SST files with .ldb suffix which enables opening LevelDB databases.
• CompactionFilter now supports filtering of merge operands and merge results.

Public API Changes

• Added SingleDelete() to the DB interface.
• Added AddFile() to DB interface.
• Added SstFileWriter class.
• CompactionFilter has a new method FilterMergeOperand() that RocksDB applies to every merge operand during compaction to decide whether to filter the operand.
• We removed CompactionFilterV2 interfaces from include/rocksdb/compaction_filter.h. The functionality was deprecated already in version 3.13.

RocksDB 4.0

New Features

• Added support for transactions. See include/rocksdb/utilities/transaction.h for more info.
• DB::GetProperty() now accepts "rocksdb.aggregated-table-properties" and "rocksdb.aggregated-table-properties-at-levelN", in which case it returns aggregated table properties of the target column family, or the aggregated table properties of the specified level N if the "at-level" version is used.
• Add compression option kZSTDNotFinalCompression for people to experiment ZSTD although its format is not finalized.
• We removed the need for LATEST_BACKUP file in BackupEngine. We still keep writing it when we create new backups (because of backward compatibility), but we don't read it anymore.

Public API Changes

• Removed class Env::RandomRWFile and Env::NewRandomRWFile().
• Renamed DBOptions.num_subcompactions to DBOptions.max_subcompactions to make the name better match the actual functionality of the option.
• Added Equal() method to the Comparator interface that can optionally be overwritten in cases where equality comparisons can be done more efficiently than three-way comparisons.
• Previous 'experimental' OptimisticTransaction class has been replaced by Transaction class.

RocksDB 4.1

New Features

• Added single delete operation as a more efficient way to delete keys that have not been overwritten.
• Added experimental AddFile() to DB interface that allow users to add files created by SstFileWriter into an empty Database, see include/rocksdb/sst_file_writer.h and DB::AddFile() for more info.
• Added support for opening SST files with .ldb suffix which enables opening LevelDB databases.
• CompactionFilter now supports filtering of merge operands and merge results.

Public API Changes

• Added SingleDelete() to the DB interface.
• Added AddFile() to DB interface.
• Added SstFileWriter class.
• CompactionFilter has a new method FilterMergeOperand() that RocksDB applies to every merge operand during compaction to decide whether to filter the operand.
• We removed CompactionFilterV2 interfaces from include/rocksdb/compaction_filter.h. The functionality was deprecated already in version 3.13.