Re: Logical replication slots on slaves/replicas?

Piotr Andreassen Blasiak schrieb am 01.08.2024 um 10:42:
> I know that currently logical replication slots are available only
> for primary servers. Is there any plan to add this feature to read
> slaves as well? My problem is this:
>
> I want to use debezium to stream changes from postgresql. But, if I
> stream changes from the master I can not query my read slaves for
> related data to these changes - I need to always query the master
> which is not scalable. So either I need a way to be able to know
> when the change has been propagated to my read replica so that I can
> reliably query it, or I am hoping I can simply read all the changes
> from the read replica which will mean it is already up to date when
> I query it.

I don't really know how Debezium uses this, but will this enhancement
in Postgres 17 help here?

https://www.postgresql.org/docs/17/functions-admin.html#PG-SYNC-REPLICATION-SLOTS

> Synchronize the logical failover replication slots from the primary
> server to the standby server. This function can only be executed on
> the standby server. Temporary synced slots, if any, cannot be used
> for logical decoding and must be dropped after promotion.