Why does postgresql have so many replication slots open?

PostgreSQL Error - Replication Slot Not Found replication slot postgres A replication slot exists solely on the instance that created it, and PostgreSQL does not replicate it on the standby servers As a result, after a failover or replication slot already exists Replication slots are used to safeguard against the premature deletion of WAL segments before they have been applied by the standby server, thus

replication slot is active for pid Checking for replication slots Starting from PostgreSQL , it is also necessary and useful to check for leftover replication slots