Sharding overview

Note

This feature is under active development. It's not quite ready for production. This documentation reflects a future state of the feature.

Sharding PostgreSQL databases involves splitting the database between multiple machines and routing read and write queries to the correct machines using a sharding function. Like its predecessor, pgDog supports sharded PostgreSQL deployments and can route queries to the correct shards automatically using a routing plugin.

Three (3) sharded primaries

Routing queries

There are two ways for database clients to retrieve data from sharded databases: by querying an individual shard, or by querying all shards and aggregating the results. The former is commonly used in OLTP (transactional) systems, e.g. real time applications, and the latter is more commonly used in OLAP (analytical) databases, e.g. batch reports generation.

pgDog has good support for querying individual shards using a sharding key extracted automatically from queries.