Re: Check Replication lag

Hello Depesz,

Thanks for your quick response, let me give some overview of our cluster
setups. Actually we have a Patroni cluster running with one replica
(Replica 1) in the same data center with no data lag. whereas we have
configured one more replica(Replica 2) in a different data center
through AWS S3 WAL shipping and replaying.

So we can easily check Patroni replica (Replica1) lag using the patronictl
list command. but I am looking how I can check replication lag of Replica 2
which is configured through AWS.

As I have checked with above query I am getting same response from both the
replicas. whereas on Replica2 there is some lag exist.

I have created dummy table on master node and its synced on replica1
simultaneously but it taking hours to sync on replica2.

Regards,
Pawan

On Mon, Oct 11, 2021 at 6:22 PM hubert depesz lubaczewski <depesz(at)depesz(dot)com>
wrote:

> On Mon, Oct 11, 2021 at 05:58:03PM +0530, Pawan Sharma wrote:
> > Is there a way to monitor the replication lag, where replica nodes are
> > configured through aws s3.
>
> You can check it on replica, by issuing:
> select now() - pg_last_xact_replay_timestamp();
>
> and it will show you, more or less, what is your current lag.
>
> Best regards,
>
> depesz
>
>