Re: Synchronizing slots from primary to standby - Mailing list pgsql-hackers

From Bertrand Drouvot
Subject Re: Synchronizing slots from primary to standby
Date
Msg-id ZgvI9iAUWCZ17z5V@ip-10-97-1-34.eu-west-3.compute.internal
Whole thread Raw
In response to Re: Synchronizing slots from primary to standby  (Amit Kapila <amit.kapila16@gmail.com>)
List pgsql-hackers
Hi,

On Tue, Apr 02, 2024 at 02:19:30PM +0530, Amit Kapila wrote:
> On Tue, Apr 2, 2024 at 1:54 PM Bertrand Drouvot
> <bertranddrouvot.pg@gmail.com> wrote:
> > What about adding a "wait" injection point in LogStandbySnapshot() to prevent
> > checkpointer/bgwriter to log a standby snapshot? Something among those lines:
> >
> >        if (AmCheckpointerProcess() || AmBackgroundWriterProcess())
> >                INJECTION_POINT("bgw-log-standby-snapshot");
> >
> > And make use of it in the test, something like:
> >
> >        $node_primary->safe_psql('postgres',
> >                "SELECT injection_points_attach('bgw-log-standby-snapshot', 'wait');");
> >
> 
> Sometimes we want the checkpoint to log the standby snapshot as we
> need it at a predictable time, maybe one can use
> pg_log_standby_snapshot() instead of that. Can we add an injection
> point as a separate patch/commit after a bit more discussion?

Sure, let's come back to this injection point discussion after the feature
freeze. BTW, I think it could also be useful to make use of injection point for
the test that has been added in 7f13ac8123.

I'll open a new thread for this at that time.

>. One other
> idea to make such tests predictable is to add a developer-specific GUC
> say debug_bg_log_standby_snapshot or something like that but injection
> point sounds like a better idea.

Agree.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com



pgsql-hackers by date:

Previous
From: Alexander Korotkov
Date:
Subject: Re: Table AM Interface Enhancements
Next
From: Tomas Vondra
Date:
Subject: Re: pg_combinebackup --copy-file-range