Last updated: October 2 2024
Citus is an open-source PostgreSQL extension that grants it the ability to shard and distribute data to multiple nodes, and also to store data in a columnar fashion. It was recently purchased by Microsoft, but remains open-source.
Citus doesn’t market itself as a direct competitor to the ultra-scale databases with geographic distribution features like CockroachDB, Spanner, or Yugabyte. Rather, its ability to distribute data seems more aimed at clusters running within the same data center (or at least the same cloud region) to increase performance.