Check replication settings:
max_standby_archive_delay
max_standby_streaming_delay
hot_standby_feedback
These can delay wals being applied to the replica while queries are
still running.
Regards,
Michael Vitale
Nikhil Shetty wrote on 11/24/2020 9:24 AM:
Hi,
We have one Primary and three Standby Postgresql setup. Two standby in
DC and one standby in DR.
We have configured streaming replication.When there are a lot of write
transactions in the master, we observed that DR lags behind the master
for 5-6 hours. We initially thought this could be because of the slow
network between DC and DR and this is normal but when we saw the
replay_lsn and receive_lsn , they had a huge difference.
DR standby was receiving the WAL's in time and there was no delay, the
delay was in replaying the lag. Can anybody point me to where I can
start with the investigation?
DC (Master and 2 Standby) and DR(Standby) have the same setup in terms
of storage and some database configuration parameters but DR has a
little less CPU and RAM.
Attaching replay and receive wal difference.
