Re: Operational issues when max_replication_slots is exhausted

On Mon, 2025-12-15 at 12:58 +0100, Ahmed Et-tanany wrote:
> Our problem is that when our customers use up all available replication slots for logical replication,
> our database management tasks that also require a slot fail (for example, creating the required
> replication slot for a new physical standby). Since increasing `max_replication_slots` requires
> a restart, we would like to avoid that if possible.
>
> One idea we have considered is patching PostgreSQL to add a new GUC parameter that would allow
> a superuser to reserve a certain number of replication slots usable only for management tasks.
>
> Is this a known issue that might be addressed in PostgreSQL at some point? If not,
> what would be a good way to solve this problem?

It is conceivable that somebody might change the behavior at some point (compare
"reserved_connections"). If you write or sponsor a patch, that would increase
the likelihood.

Right now, my only suggestion is to set "max_replication_slots" high.

Yours,
Laurenz Albe