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 that the server is not running, there is something wrong with the given connection parameters (for example, wrong port number), or there is a network connectivity problem (for example, a firewall blocking the connection request).PQPING_NO_ATTEMPT...