Re: speed up a logical replica setup

On Thu, May 23, 2024 at 8:43 PM Euler Taveira <euler@eulerto.com> wrote:
>
> On Thu, May 23, 2024, at 5:54 AM, Amit Kapila wrote:
>
>
> Why in the first place do we need to ensure that primary_slot_name is
> active on the primary? You mentioned something related to WAL
> retention but I don't know how that is related to this tool's
> functionality. If at all, we are bothered about WAL retention on the
> primary that should be the WAL corresponding to consistent_lsn
> computed by setup_publisher() but this check doesn't seem to ensure
> that.
>
> Maybe it is a lot of checks. I'm afraid there isn't a simple way to get and
> make sure the replication slot is used by the physical replication. I mean if
> there is primary_slot_name = 'foo' on standby, there is no guarantee that the
> replication slot 'foo' exists on primary. The idea is to get the exact
> replication slot name used by physical replication to drop it. Once I posted a
> patch it should be clear. (Another idea is to relax this check and rely only on
> primary_slot_name to drop this replication slot on primary. The replication slot
> might not exist and it shouldn't return an error in this case.)
>

I think your other idea is better than what we are doing currently.
Let's ignore the ERROR even if the primary_slot_name doesn't exist on
the primary.

--
With Regards,
Amit Kapila.