Re: Skipping logical replication transactions on subscriber side

On Thu, Oct 28, 2021 at 1:29 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Wed, Oct 27, 2021 at 4:07 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Wed, Oct 27, 2021 at 8:32 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> > >
> > > On Tue, Oct 26, 2021 at 7:29 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > >
> > > > You have a point. The other alternatives on this line could be:
> > > >
> > > > Alter Subscription <sub_name> SKIP ( subscription_parameter [=value] [, ... ] );
> > > >
> > > > where subscription_parameter can be one of:
> > > > xid = <xid_val>
> > > > lsn = <lsn_val>
> > > > ...
> > >
> > > Looks better.
> > >
> >
> > If we want to follow the above, then how do we allow users to reset
> > the parameter? One way is to allow the user to set xid as 0 which
> > would mean that we reset it. The other way is to allow SET/RESET
> > before SKIP but not sure if that is a good option.
> >
>
> After thinking some more on this, I think it is better to not use
> SET/RESET keyword here. I think we can use a model similar to how we
> allow setting some of the options in Alter Database:
>
> # Set the connection limit for a database:
> Alter Database akapila WITH connection_limit = 1;
> # Reset the connection limit
> Alter Database akapila WITH connection_limit = -1;
>
> Thoughts?

Agreed.

Another thing I'm concerned is that the syntax "SKIP (
subscription_parameter [=value] [, ...])" looks like we can specify
multiple options for example, "SKIP (xid = '100', lsn =
'0/12345678’)”. Is there a case where we need to specify multiple
options? Perhaps when specifying the target XID and operations for
example, “SKIP (xid = 100, action = ‘insert, update’)”?

Regards,

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