Re: Single transaction in the tablesync worker?

On Fri, Feb 12, 2021 at 2:49 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Fri, Feb 12, 2021 at 10:08 AM Ajin Cherian <itsajin(at)gmail(dot)com> wrote:
> >
> > On Fri, Feb 12, 2021 at 2:46 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > >
> > > Thanks, I have pushed the patch but getting one failure:
> > > https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=thorntail&dt=2021-02-12%2002%3A28%3A12
> > >
> > > The reason seems to be that we are trying to connect and
> > > max_wal_senders is set to zero. I think we can write this without
> > > trying to connect. The attached patch fixes the problem for me. What
> > > do you think?
> >
> > Verified this with installcheck and modified configuration to have
> > wal_level = minimal and max_wal_senders = 0.
> > Tests passed. The changes look good to me.
> >
>
> Thanks, I have pushed the fix and the latest run of 'thorntail' has passed.

I got the following WARNING message from a logical replication apply worker:

WARNING: relcache reference leak: relation "pg_subscription_rel" not closed

The cause of this is that GetSubscriptionRelState() doesn't close the
relation in SUBREL_STATE_UNKNOWN case. It seems that commit ce0fdbfe9
forgot to close it. I've attached the patch to fix this issue.

Here is a reproducible step:

1. On both publisher and subscriber:
create table test (a int primary key);

2. On publisher:
create publication test_pub for table test;

3. On subscriber:
create subscription test_sub connection 'dbname=postgres' publication test_pub";
-- wait until table sync finished
drop table test;
create table test (a int primary key);

From this point, you will get the WARNING message when doing
insert/update/delete/truncate to 'test' table on the publisher.

Regards,

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