Re: Single transaction in the tablesync worker?

Peter Smith <smithpb2250@gmail.com>

From: Peter Smith <smithpb2250@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Ajin Cherian <itsajin@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-02-03T10:09:57Z
Lists: pgsql-hackers
On Wed, Feb 3, 2021 at 2:51 PM Peter Smith <smithpb2250@gmail.com> wrote:
>
> On Wed, Feb 3, 2021 at 1:34 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Wed, Feb 3, 2021 at 6:38 AM Peter Smith <smithpb2250@gmail.com> wrote:
> > >
> > > On Wed, Feb 3, 2021 at 12:26 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > >
> > > > On Tue, Feb 2, 2021 at 3:31 PM Peter Smith <smithpb2250@gmail.com> wrote:
> > > > >
> > > > > After seeing Ajin's test [ac0202] which did a DROP TABLE, I have also
> > > > > tried a simple test where I do a DROP TABLE with very bad timing for
> > > > > the tablesync worker. It seems that doing this can cause the sync
> > > > > worker's MyLogicalRepWorker->relid to become invalid.
> > > > >
> > > >
> > > > I think this should be fixed by latest patch because I have disallowed
> > > > drop of a table when its synchronization is in progress. You can check
> > > > once and let me know if the issue still exists?
> > > >
> > >
> > > FYI - I confirmed that the problem scenario that I reported yesterday
> > > is no longer possible because now the V25 patch is disallowing the
> > > DROP TABLE while the tablesync is still running.
> > >
> >
> > Thanks for the confirmation. BTW, can you please check if we can
> > reproduce that problem without this patch? If so, we might want to
> > apply this fix irrespective of this patch. If not, why not?
> >
>
> Yes, this was an existing postgres bug. It is independent of the patch.
>
> I can reproduce exactly the same stacktrace using the HEAD src pulled @ 3/Feb.
>
> PSA my test logs showing the details.
>

Since this is an existing PG bug independent of this patch, I spawned
a new thread [ps0202] to deal with this problem.

----
[ps0202] https://www.postgresql.org/message-id/CAHut%2BPu7Z4a%3Domo%2BTvK5Gub2hxcJ7-3%2BBu1FO_%2B%2BfpFTW0oQfQ%40mail.gmail.com

Kind Regards,
Peter Smith.
Fujitsu Australia



Commits

  1. Fix relcache reference leak introduced by ce0fdbfe97.

  2. Fix Subscription test added by commit ce0fdbfe97.

  3. Allow multiple xacts during table sync in logical replication.

  4. Logical replication support for initial data copy