# Rocksdb Change Log## 2.7.0 (01/28/2014)### Public API changes* Renamed `StackableDB::GetRawDB()` to `StackableDB::GetBaseDB()`.* Renamed `WriteBatch::Data()``const std::string& Data() const`.* Renamed class `TableStats` to `TableProperties`.* Deleted class `PrefixHashRepFactory`. Please use `NewHashSkipListRepFactory()` instead.* Supported multi-threaded `EnableFileDeletions()` and `DisableFileDeletions()`.* Added `DB::GetOptions()`.* Added `DB::GetDbIdentity()`.### New Features* Added [BackupableDB](https://github.com/facebook/rocksdb/wiki/How-to-backup-RocksDB%3F)* Implemented [TailingIterator](https://github.com/facebook/rocksdb/wiki/Tailing-Iterator), a special type of iterator that doesn't create a snapshot (can be used to read newly inserted data) and is optimized for doing sequential reads.* Added property block for table, which allows (1) a table to store its metadata and (2) end user to collect and store properties they are interested in.* Enabled caching index and filter block in block cache (turned off by default).* Supported error report when doing manual compaction.* Supported additional Linux platform flavors and Mac OS.* Put with `SliceParts` - Variant of `Put()` that gathers output like `writev(2)`* Bug fixes and code refactor for compatibility with upcoming Column Family feature.### Performance Improvements* Huge benchmark performance improvements by multiple efforts. For example, increase in readonly QPS from about 530k in 2.6 release to 1.1 million in 2.7 [1]* Speeding up a way RocksDB deleted obsolete files - no longer listing the whole directory under a lock -- decrease in p99* Use raw pointer instead of shared pointer for statistics: [5b825d](https://github.com/facebook/rocksdb/commit/5b825d6964e26ec3b4bb6faa708ebb1787f1d7bd) -- huge increase in performance -- shared pointers are slow* Optimized locking for `Get()` -- [1fdb3f](https://github.com/facebook/rocksdb/commit/1fdb3f7dc60e96394e3e5b69a46ede5d67fb976c) -- 1.5x QPS increase for some workloads* Cache speedup - [e8d40c3](https://github.com/facebook/rocksdb/commit/e8d40c31b3cca0c3e1ae9abe9b9003b1288026a9)* Implemented autovector, which allocates first N elements on stack. Most of vectors in RocksDB are small. Also, we never want to allocate heap objects while holding a mutex. -- [c01676e4](https://github.com/facebook/rocksdb/commit/c01676e46d3be08c3c140361ef1f5884f47d3b3c)* Lots of efforts to move malloc, memcpy and IO outside of locks