Re: Streaming Replication replay lag

Hi Michael,

Sure, I will check on this parameter but i don't think there are any
queries running on th DR. If there are no queries running on the server
then will these parameters make any difference?

Thanks and Regards,
Nikhil

On Tue, Nov 24, 2020 at 8:08 PM MichaelDBA <MichaelDBA(at)sqlexec(dot)com> wrote:

> 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.
> >
>
>