Re: Clear logical slot's 'synced' flag on promotion of standby

On Wed, Sep 24, 2025 at 9:42 AM shveta malik <shveta.malik@gmail.com> wrote:
>
> On Tue, Sep 23, 2025 at 6:41 PM Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
> >
> > > 3)
> > > + ereport(LOG,
> > > + (errmsg("reset synced flag for replication slot \"%s\"",
> > > + NameStr(s->data.name))));
> > >
> > > a) Shall we change it to DEBUG1?
> > > b) Shall the msg be:
> > > synced flag reset for replication slot \"%s\" during promotion
> > >
> >
> > I think this can stay as a LOG message, it only runs once at startup
> > and applies just to logical slots, so it won’t be noisy.
>
> It does not run at startup, it runs during promotion. Having said
> that, if there are a lot many slots, and we have one message per slot,
> overall logs can still be more. I somehow find DEBUG better here. But
> we can leave it as LOG and can revisit later when others review.
>
> > I’d also
> > avoid mentioning “during promotion,” since the flag might accidentally
> > be set on the primary and then reset later during startup, making that
> > description inaccurate.
>
> This function is called only during promotion (see check 'if
> (promoted)') and thus the suggested message ( “during promotion")
> seems better to me.
>

ResetSyncedSlots might be called during promotion, but
RestoreSlotFromDisk (which runs during standard PostgreSQL startup)
performs the same functionality. This creates a scenario where the
sync flag could be reset during either promotion or regular startup. I
think we should either remove it, or ensure it is present in both
places for consistency.

--
With Regards,
Ashutosh Sharma.