Logical replication improvements in Amazon RDS for PostgreSQL 18

This article explores logical replication improvements in PostgreSQL 18 available on Amazon RDS for PostgreSQL, addressing key operational challenges in production environments.

• STORED generated columns can now be replicated through the replication stream using the new publish_generated_columns parameter
• Seven new conflict counters in pg_stat_subscription_stats provide detailed breakdown of replication conflicts by type instead of opaque error counts
• Parallel streaming is now the default for subscriptions, reducing memory consumption and replication lag for large transactions
• ALTER SUBSCRIPTION now allows toggling two-phase commit on live subscriptions without requiring full resynchronization
• idle_replication_slot_timeout automatically invalidates abandoned replication slots to prevent WAL accumulation and disk space exhaustion

These PostgreSQL 18 features significantly improve operational management of logical replication in production environments on RDS for PostgreSQL and Aurora PostgreSQL.