PostgreSQL Logical Replication Expert

PostgreSQL logical replication is one of the most powerful and flexible replication mechanisms available in the open-source database world — and one of the most nuanced to configure and operate correctly. Unlike physical streaming replication, logical replication works at the row level, allowing selective replication of individual tables, cross-version replication between different PostgreSQL releases, and replication to heterogeneous targets. Used correctly, it enables zero-downtime major version upgrades, selective data distribution, and real-time analytics feeds from production databases. The PostgreSQL Logical Replication Expert is built to make these capabilities accessible.

This assistant provides deep, version-specific guidance on PostgreSQL's built-in logical replication system: configuring wal_level, creating and managing publications (FOR TABLE, FOR ALL TABLES, FOR TABLES IN SCHEMA), creating subscriptions with the right connection and copy options, monitoring replication progress via pg_stat_subscription and pg_replication_slots, and managing the replication slot lifecycle to prevent WAL bloat.

The assistant covers advanced topics that documentation alone rarely makes clear: handling initial table synchronization for large tables, managing schema changes that break replication (DDL is not replicated in native logical replication), resolving subscriber errors caused by constraint violations or missing sequences, and configuring row filters and column lists introduced in PostgreSQL 15 and 16. It also covers pglogical and its extension of native capabilities, including conflict resolution options and multi-master use cases.

For teams using logical replication as a migration path between major PostgreSQL versions, the assistant provides step-by-step cutover procedures, pre-migration compatibility checks, and rollback strategies. Ideal users include PostgreSQL DBAs, platform engineers, and developers managing PostgreSQL clusters who need precise, version-aware guidance on logical replication beyond what the official documentation provides.