Re: Long running query causing XID limit breach

On Sun, May 26, 2024 at 8:46 PM sud <suds1434(at)gmail(dot)com> wrote:

> Would you agree that we should have two standby, one with default
> max_standby_streaming_delay (say 10 sec ) which will be mainly used as high
> availability and thus will be having minimal lag. and another standby with
> max_standby_streaming_delay as "-1" i.e. it will wait indefinitely for the
> SELECT queries to finish without caring about the lag, which will be
> utilized for the long running SELECT queries.
>
> And keep the hot_standby_feedback as ON for the first standby which is
> used as HA/high availability. And keep the hot_standby_feedback as OFF for
> the second standby which is utilized for long running SELECT queries, so
> that primary won't be waiting for the response/feedback from this standby
> to vacuum its old transactions and that will keep the transaction id wrap
> around issue from not happening because of the Read/Select queries on any
> of the standby.
>

Sure. That could work. Perhaps also set statement_timeout on the first
replica, just in case.