Citus is a PostgreSQL extension that transforms a standard database into a distributed system. It functions as a sharding framework and distributed SQL engine, enabling horizontal scaling by partitioning tables across a cluster of nodes. By utilizing a coordinator-worker topology, the system manages metadata and routes queries to the appropriate nodes, allowing for parallel execution of complex operations across distributed data shards.
The platform distinguishes itself through its specialized support for multi-tenant architectures and real-time analytical processing. It enables tenant-based distribution and schema-based sharding, which allows for the isolation of tenant data and the migration of high-volume workloads to dedicated nodes. To accelerate analytical performance, the system integrates columnar storage with data compression and supports pre-aggregated rollups, ensuring that large-scale datasets remain performant as the cluster grows.
Beyond its core distribution capabilities, the project provides comprehensive tools for cluster administration and data lifecycle management. It automates shard rebalancing, schema propagation via a two-phase commit protocol, and the maintenance of time-based partitions. The system also includes diagnostic utilities for monitoring query performance, detecting resource contention, and analyzing index usage across the distributed environment.
