I'm running this query:
SELECT subname, received_lsn, latest_end_lsn,
last_msg_send_time, last_msg_receipt_time
FROM pg_catalog.pg_stat_subscription;
And "last_msg_send_time" will sometimes be null. All I can find in the
documentation is that this value represents: "Send time of last message
received from origin WAL sender; NULL for parallel apply workers"
But I have no context for what parallel apply workers are or why they are
NULL sometimes and other times not.
Can anyone explain?
Regards,
Koen De Groote