Re: Using failover slots for PG-non_PG logical replication

On Wed, Jul 2, 2025 at 10:50 AM Ashutosh Bapat
<ashutosh(dot)bapat(dot)oss(at)gmail(dot)com> wrote:
>
> Hi All,
>
> The failover slots documentation [1] is good for PG - PG logical
> replication, but the first two queries require pg_subscription which
> may not be present in non-PG downstream. Somebody looking to setup
> failover slots for non-PG subscriber may not find the page useful.

Okay. It appears to me that the entire document at [1] is
specifically intended for a built-in replication setup, and the
corresponding page was written with that context in mind.

> However, the third query, when modified to mention the replication
> slots relevant to the downstream is useful to them. How to find the
> replication slots to be synchronized is a problem specific to the type
> of downstream. Such a setup should add those slots to
> sync_replication_slots. I think the chapter should mention that the
> 3rd query should also include the slots mentioned in
> sync_replication_slots for PG-non_PG logical replication setup.
>

sync_replication_slots is a boolean which enables a physical standby
to synchronize logical failover slots. Did you mean something else?

We could include a general note in the documentation something like:
'For non-native replication, it is the responsibility of the plugin
author to define the required slots'. Then, we can directly use the
third query. Thoughts?

[1]: https://www.postgresql.org/docs/current/logical-replication.html

thanks
Shveta