Citus: Distributed PostgreSQL for Data-Intensive Applications

Citus is an open source distributed database engine for PostgreSQL that is implemented as an extension. Citus gives users the ability to distribute data, queries, and transactions in PostgreSQL across a cluster of PostgreSQL servers to handle the needs of data-intensive applications. The development of Citus has largely been driven by conversations with companies looking to scale PostgreSQL beyond a single server and their workload requirements. This paper describes the requirements of four common workload patterns and how Citus addresses those requirements. It also shares benchmark results demonstrating the performance and scalability of Citus in each of the workload patterns and describes how Microsoft uses Citus to address one of its most challenging data problems.