pgstream

pgstream is an open source CDC command-line tool and library that offers Postgres replication support with DDL changes to any provided output. One of the main differentiators of pgstream is the fact that it tracks and replicates schema changes automatically. It relies on SQL triggers that will populate a Postgres table (pgstream.schema_log) containing a history log of all DDL changes for a given schema. Whenever a schema change occurs, this trigger creates a new row in the schema log table with the schema encoded as a JSON value. This table tracks all the schema changes, forming a linearised change log that is then parsed and used within the pgstream pipeline to identify modifications and push the relevant changes downstream.