RocksDB 3.5发布,key-value存储系统

　　RocksDB 3.5 发布，此版本现已提供下载，更新内容如下：

新特性

• Add include/utilities/write_batch_with_index.h, providing a utility class to query data out of WriteBatch when building it.

• new ReadOptions.total_order_seek to force total order seek when block-based table is built with hash index.

公共 API 改进

• The Prefix Extractor used with V2 compaction filters is now passed user key to SliceTransform::Transform instead of unparsed RocksDB key.

• Move BlockBasedTable related options to BlockBasedTableOptions from Options. Change corresponding JNI interface. Options affected include: no_block_cache, block_cache, block_cache_compressed, block_size, block_size_deviation, block_restart_interval, filter_policy, whole_key_filtering. filter_policy is changed to shared_ptr from a raw pointer.

• Remove deprecated options: disable_seek_compaction and db_stats_log_interval

• OptimizeForPointLookup() takes one parameter for block cache size. It now builds hash index, bloom filter, and block cache.

　　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。