Re: speed up a logical replica setup

On Thu, Jan 4, 2024 at 12:30 PM Ashutosh Bapat
<ashutosh(dot)bapat(dot)oss(at)gmail(dot)com> wrote:
>
> On Wed, Jan 3, 2024 at 2:49 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > c) Drop the replication slots d) Drop the
> > > publications
> > >
> >
> > I am not so sure about dropping publications because, unlike
> > subscriptions which can start to pull the data, there is no harm with
> > publications. Similar to publications there could be some user-defined
> > functions or other other objects which may not be required once the
> > standby replica is converted to subscriber. I guess we need to leave
> > those to the user.
> >
>
> IIUC, primary use of pg_subscriber utility is to start a logical
> subscription from a physical base backup (to reduce initial sync time)
> as against logical backup taken while creating a subscription. Hence I
> am expecting that apart from this difference, the resultant logical
> replica should look similar to the logical replica setup using a
> logical subscription sync. Hence we should not leave any replication
> objects around. UDFs (views, and other objects) may have some use on a
> logical replica. We may replicate changes to UDF once DDL replication
> is supported. But what good is having the same publications as primary
> also on logical replica?
>

The one use case that comes to my mind is to set up bi-directional
replication. The publishers want to subscribe to the new subscriber.

--
With Regards,
Amit Kapila.