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.
