RocksDB 3.4 发布，此版本更新内容如下：

新特性

• Support Multiple DB paths in universal style compactions

• Add feature of storing plain table index and bloom filter in SST file.

• CompactRange() will never output compacted files to level 0. This used to be the case when all the compaction input files were at level 0.

公共 API 修改

• DBOptions.db_paths now is a vector of a DBPath structure which indicates both of path and target size

• NewPlainTableFactory instead of bunch of parameters now accepts PlainTableOptions, which is defined in include/rocksdb/table.h

• Moved include/utilities/.h to include/rocksdb/utilities/.h

• Statistics APIs now take uint32_t as type instead of Tickers. Also make two access functions getTickerCount and histogramData const

• Add DB property rocksdb.estimate-num-keys, estimated number of live keys in DB.

• Add DB::GetIntProperty(), which returns DB properties that are integer as uint64_t.

其他 bug 修复

• Fixed a data race bug that might cause segment fault

• Fixed a bug of manual compaction.

RocksDB 是一个来自 facebook 的可嵌入式的支持持久化的 key-value 存储系统，也可作为 C/S 模式下的存储数据库，但主要目的还是嵌入式。RocksDB 基于 LevelDB 构建。关于 RocksDB 的性能说明。

新闻来源：RocksDB 3.4 发布​，key-value 存储系统