Re: Skipping logical replication transactions on subscriber side

On Wed, Jul 7, 2021 at 11:47 AM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>
> On Tue, Jul 6, 2021 at 6:33 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > >
> > > According to the doc, ALTER SUBSCRIPTION ... SET is used to alter
> > > parameters originally set by CREATE SUBSCRIPTION. Therefore, we can
> > > specify a subset of parameters that can be specified by CREATE
> > > SUBSCRIPTION. It makes sense to me for 'disable_on_error' since it can
> > > be specified by CREATE SUBSCRIPTION. Whereas SKIP TRANSACTION stuff
> > > cannot be done. Are you concerned about adding a syntax to ALTER
> > > SUBSCRIPTION?
> > >
> >
> > Both for additional syntax and consistency with disable_on_error.
> > Isn't it just a current implementation that Alter only allows to
> > change parameters supported by Create? Is there a reason why we can't
> > allow Alter to set/change some parameters not supported by Create?
>
> I think there is not reason for that but looking at ALTER TABLE I
> thought there is such a policy.
>

If we are looking for precedent then I think we allow to set
configuration parameters via Alter Database but not via Create
Database. Does that address your concern?

> I thought the skipping transaction
> feature is somewhat different from disable_on_error feature. The
> former seems a feature to deal with a problem on the spot whereas the
> latter seems a setting of a subscription. Anyway, if we use the
> subscription option, we can reset the XID by setting 0? Or do we need
> ALTER SUBSCRIPTION RESET?

The other commands like Alter Table, Alter Database, etc, which
provides a way to Set some parameter/option, have a Reset variant. I
think it would be good to have it for Alter Subscription as well but
we might want to allow other parameters to be reset by that as well.

--
With Regards,
Amit Kapila.