MyRocks: A space- and write-optimized MySQL database
At Facebook we use MySQL to manage many petabytes of data, along with the InnoDB storage engine that serves social activities such as likes, comments, and shares. While InnoDB provides great performance and reliability for a variety of workloads, it has inefficiencies on space and write amplification when used with flash storage. A few years ago, we built RocksDB, an embeddable, persistent key-value store for fast storage that has several advantages compared with InnoDB for space efficiency.
Despite its advantages, RocksDB does not support replication or an SQL layer, and we wanted to continue using those features from MySQL. This led us to build MyRocks, a new open source project that integrates RocksDB as a new MySQL storage engine. With MyRocks, we can use RocksDB as backend storage and still benefit from all the features in MySQL.
While there are some databases at Facebook that will still use InnoDB, we’re in the process of migrating to MyRocks on our user database (UDB) tier. After deploying MyRocks to this database tier in one of our data center regions, we were able to use 50 percent less storage for the same amount of data compared with compressed InnoDB. Ultimately this will allow us to use half as many UDB servers. By sharing MyRocks with the community through open source, we hope that others can take advantage of these efficiencies.
