Re: Replication lag in Postgres

On Fri, 2024-07-12 at 20:41 +0530, Mukesh Tanuku wrote:
> I have a question with postgres HA setup.
> We are setting up a 2 node postgres cluster with async streaming replication, we want to
> define a RPO (Recovery point objective) in case of primary failure. 
>
> How can we best define the RPO in this setup? since it's an async streaming replication
> setup there might be a chance of data loss which is proportional to the replication delay. 
>
> Is there any way we can configure the delay duration, like for example to make sure every
> 10 mins the standby sync has to happen with primary? 

When there is a delay, it is usually because replay at the standby is delayed.
The WAL information is still replicated.  You won't lose that information on
failover; it will just make the failover take longer.

Unless you have a network problem, you should never lose more than a fraction
of a second.

Yours,
Laurenz Albe