Re: Improve pg_sync_replication_slots() to wait for primary to advance

On Fri, Jul 18, 2025 at 11:25 AM shveta malik <shveta(dot)malik(at)gmail(dot)com> wrote:
>
> Okay. I see your point. Yes, it was non-blocking earlier but it was
> not giving ERROR, it was just dumping in logilfe that primary is
> behind and thus slot-sync could not be done.
>
> If we continue using the non-blocking mode, there’s a risk that the
> API may never successfully sync the slots. This is because it
> eventually drops the temporary slot on exit, and when it tries to
> create a new one later on subsequent call, it’s likely that the new
> slot will again be ahead of the primary. This may happen if we have
> continuous ongoing writes on the primary and the logical slot is not
> being consumed at the same pace.
>
> My preference would be to avoid including such an option as it is
> confusing. With such an option in place, users may think that
> slot-sync is completed while that may not be the case.

Fair enough

But if it's
> necessary for backward compatibility, it should be okay to provide it
> as a non-default option as you suggested. Would like to know what
> others think of this.

I think we don't need to maintain backward compatibility here as it
was not behaving sanely before, so I am fine with providing the
behaviour we are doing with the patch.

--
Regards,
Dilip Kumar
Google