Re: Synchronizing slots from primary to standby

Hi,

On Thu, Feb 15, 2024 at 02:49:54PM +0530, Amit Kapila wrote:
> On Thu, Feb 15, 2024 at 9:05 AM Zhijie Hou (Fujitsu)
> <houzj(dot)fnst(at)fujitsu(dot)com> wrote:
> >
> > On Thursday, February 15, 2024 10:49 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > > On Wed, Feb 14, 2024 at 7:26 PM Bertrand Drouvot
> > >
> > > Right, we can do that or probably this test would have made more sense with a
> > > worker patch where we could wait for the slot to be synced.
> > > Anyway, let's try to recreate the slot/subscription idea. BTW, do you think that
> > > adding a LOG when we are not able to sync will help in debugging such
> > > problems? I think eventually we can change it to DEBUG1 but for now, it can help
> > > with stabilizing BF and or some other reported issues.
> >
> > Here is the patch that attempts the re-create sub idea.
> >
>
> Pushed this.
>
> >
> I also think that a LOG/DEBUG
> > would be useful for such analysis, so the 0002 is to add such a log.
> >
>
> I feel such a LOG would be useful.

Same here.

> + ereport(LOG,
> + errmsg("waiting for remote slot \"%s\" LSN (%X/%X) and catalog xmin"
> + " (%u) to pass local slot LSN (%X/%X) and catalog xmin (%u)",
>
> I think waiting is a bit misleading here, how about something like:
> "could not sync slot information as remote slot precedes local slot:
> remote slot \"%s\": LSN (%X/%X), catalog xmin (%u) local slot: LSN
> (%X/%X), catalog xmin (%u)"
>

This wording works for me.

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
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