"RocksDB is a high performance embedded database for key-valuedata. It is a fork of LevelDB by Facebook optimized to exploit many central processing unit (CPU) cores, and make efficient use of fast storage, such as solid-state drives (SSD), for input/output (I/O) bound workloads. It is based on a log-structured merge-tree (LSM tree) data structure. It is written in C++ and provides official application programming interface (API) language bindings for C++, C, and Java; alongside many third-party language bindings. RocksDB is open-source software..."
Podcast interview with great technical description of this DB engine:
RocksDB with Dhruba Borthakur and Igor Canadi - Software Engineering Daily
RocksDB was created in Facebook, as a fork of Google's LevelDB that is used as embedded DB of Chrome web browser.
RocksDB is different from typical databases that are using standard b-tree for storing indexes.
Instead, it is using "LSM" data storage, that is optimized for SSD and "cloud" storage.
compaction of data in a Log-Structured Merge tree
RocksDB is used in combination with various database front-ends:
- MyRocks = MySQL + RocksDB engine
- MongoRocks = MongoDB + RocksDB engine
- Cassandra + RocksDB
Company Rockset is providing products and services related to RocksDB.