2017 Logical Replication Internal

A replication slot ensures that the needed WAL files for the standby are not removed in the primary server before the standby server processes

About the replication slots that you are seeing: pg_16480_sync_16394_7358104072011291410, etc Those are temporary slots responsible for the

replication slot already exists active Call in the pg_auto_failover Node Active conf identify Run the IDENTIFY_SYSTEM replication command on given host pg_autoctl do primary slot

replication slot is active for pid Replication slot is not active for a standby or replication data lagging values are null Meaning: The standby replication slot active flag value is false or