Re: Skipping logical replication transactions on subscriber side

On Tue, Dec 14, 2021 at 2:35 PM Greg Nancarrow <gregn4422@gmail.com> wrote:
>
> On Tue, Dec 14, 2021 at 3:23 PM vignesh C <vignesh21@gmail.com> wrote:
> >
> > While the worker is skipping one of the skip transactions specified by
> > the user and immediately if the user specifies another skip
> > transaction while the skipping of the transaction is in progress this
> > new value will be reset by the worker while clearing the skip xid. I
> > felt once the worker has identified the skip xid and is about to skip
> > the xid, the worker can acquire a lock to prevent concurrency issues:
>
> That's a good point.
> If only the last_error_xid could be skipped, then this wouldn't be an
> issue, right?
> If a different xid to skip is specified while the worker is currently
> skipping a transaction, should that even be allowed?
>

We don't expect such usage but yes, it could happen and seems not
good. I thought we can acquire Share lock on pg_subscription during
the skip but not sure it's a good idea. It would be better if we can
find a way to allow users to specify only XID that has failed.

Regards,

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