Re: failover logical replication slots

However, the problem still persists: it is currently not possible to
perform an automatic switchover after creating a new subscription.

Would it be reasonable to consider adding a GUC to address this issue?
I can propose a patch in that sense if it seems appropriate.

What is your opinion

Regards,

Fabrice

On Thu, Jun 12, 2025 at 11:37 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:

> On Thu, Jun 12, 2025 at 2:32 PM Fabrice Chapuis <fabrice636861(at)gmail(dot)com>
> wrote:
> >
> > Thanks for the reply Amit,
> >
> > I don't really understand the logic of the implementation. If the slot
> name matches that of the primary slot and this slot is in failover mode,
> how could it be any different on the standby slot?
> >
>
> On the standby's we do allow creating logical slots (For example, one
> can use pg_create_logical_replication_slot()). So, the same name slot
> can be created on standby by the user before we start sync. As of now,
> we don't allow setting the failover option for slots on standby's but
> in future, it could be supported to allow syncing slots from standbys
> (something like cascaded replication).
>
> > After the first failover, the following failovers will work given that
> the sync flag is true on both the primary and standby slots.
> >
> > After new sandby is attached to the primary, can we imagine that when
> the sync worker process is started we check if a failover slot exists on
> the standby, if so we drop it before recreating a new one for syncing?
> >
>
> This has the risk of dropping an unwarranted slot.
>
> --
> With Regards,
> Amit Kapila.
>