Re: BUG #18945: Standby synchronization problem

On Mon, Jun 2, 2025 at 5:56 PM PG Bug reporting form
<noreply(at)postgresql(dot)org> wrote:
>
> The following bug has been logged on the website:
>
> Bug reference: 18945
> Logged by: lucas marola
> Email address: lucasmarola(at)hotmail(dot)com
> PostgreSQL version: 16.8
> Operating system: Red Hat Enterprise Linux release 9.5 (Plow)
> Description:
>
> Sometimes, the WAL application on the standby environment takes a long time
> to complete. However, after restarting the application process, it returns
> to normal.

it's difficult to pinpoint the exact problem with the information
provided. However, a common scenario involves read-only queries on a
standby database conflicting with the WAL apply process. And as a
result of restarting the application it will terminate all the backend
so you are not facing issues of conflict any more. You can check the
value of 'max_standby_streaming_delay' as this will control how long
the WAL apply process should wait in case of a conflict with the
snapshot of the local queries. If you have steps to reproduce/or more
details on the exact scenario, then that would be helpful.

--
Regards,
Dilip Kumar
Google