Re: Skipping logical replication transactions on subscriber side

On Mon, Oct 18, 2021 at 6:07 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Mon, Oct 11, 2021 at 1:00 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> >
> > On Sun, Oct 10, 2021 at 11:04 PM Peter Eisentraut
> > <peter(dot)eisentraut(at)enterprisedb(dot)com> wrote:
> > >
> > > On 04.10.21 02:31, Masahiko Sawada wrote:
> > > > I guess disabling subscriptions on error/conflict and skipping the
> > > > particular transactions are somewhat different types of functions.
> > > > Disabling subscriptions on error/conflict seems likes a setting
> > > > parameter of subscriptions. The users might want to specify this
> > > > option at creation time. Whereas, skipping the particular transaction
> > > > is a repair function that the user might want to use on the spot in
> > > > case of a failure. I’m concerned a bit that combining these functions
> > > > to one syntax could confuse the users.
> > >
> > > Also, would the skip option be dumped and restored using pg_dump? Maybe
> > > there is an argument for yes, but if not, then we probably need a
> > > different path of handling it separate from the more permanent options.
> >
> > Good point. I don’t think the skip option should be dumped and
> > restored using pg_dump since the utilization of transaction ids in
> > another installation is different.
> >
>
> This is a xid of publisher which subscriber wants to skip. So, even if
> one restores the subscriber data in a different installation why would
> it matter till it points to the same publisher?
>
> Either way, can't we handle this in pg_dump?

Because of backups (dumps), I think we cannot expect that the user
restore it somewhere soon. If the dump is restored several months
later, the publisher could be a different installation (by rebuilding
from scratch) or XID of the publisher could already be wrapped around.
It might be useful to dump the skip_xid by pg_dump in some cases, but
I think it should be optional if we want to do that.

Regards,

--
Masahiko Sawada
EDB: https://www.enterprisedb.com/