Logical Replication Slot

A PostgreSQL logical replication slot maintains state for consuming a database’s logical change stream. It retains resources needed for decoding and persists independently of a client connection. It is PostgreSQL-specific, not a generic name for every connector checkpoint.

A stalled consumer can leave required WAL and catalog versions retained. Monitor retained bytes, progress and disk capacity, and define what happens if the required range becomes unavailable. A slot name alone does not prove that a restored or promoted source continues the same stream.

If the connector has delivered to a broker, slot progress can be ahead of the final analytical table. Monitor that consumer separately. Repeated delivery is possible after recovery; applying rows and saving destination progress must tolerate it. Dropping a slot can release needed recovery input, so use an explicit lifecycle policy.

Reference: PostgreSQL logical decoding concepts.