Monitoring the status and progress of your replication is essential. We'll start by looking at the server status and then query the progress of replication.
You'll need to start by checking the state of your server (s).
Check whether a server is up using
pg_isready or another program that uses the
PQping() API call. You'll get one of the following responses:
PQPING_OK (return code 0): The server is running and appears to be accepting connections.
PQPING_REJECT (return code 1): The server is running but is in a state that disallows connections (startup, shutdown, or crash recovery) or a standby that is not enabled with Hot Standby.
PQPING_NO_RESPONSE (return code 2): The server could not be contacted. This might indicate ...