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@ 2021-03-30 07:06 Devendra Yadav <devendra.857@gmail.com>
0 siblings, 2 replies; 4+ messages in thread
From: Devendra Yadav @ 2021-03-30 07:06 UTC (permalink / raw)
To: pgsql-admin@lists.postgresql.org
Hello,
Hope everything is well with you.
We are running on PostgreSQL v 12.1 , Redhat 7.8.
We are running a query - ALTER TABLE mytable ADD COLUMN deposited DOUBLE
PRECISION;
This query is blocked by pid 0. It's not a postgres PID and won't allow to
terminate from postgres.
What would be the way forward to troubleshoot this?
Thanks and Regards,
Devendra Yadav
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: ALTER TABLE blocked
@ 2021-03-30 11:09 Laurenz Albe <laurenz.albe@cybertec.at>
parent: Devendra Yadav <devendra.857@gmail.com>
1 sibling, 1 reply; 4+ messages in thread
From: Laurenz Albe @ 2021-03-30 11:09 UTC (permalink / raw)
To: Devendra Yadav <devendra.857@gmail.com>; pgsql-admin@lists.postgresql.org
On Tue, 2021-03-30 at 12:36 +0530, Devendra Yadav wrote:
> Hope everything is well with you.
Thanks, yes. I hope you are fine too.
> We are running on PostgreSQL v 12.1 , Redhat 7.8.
> We are running a query - ALTER TABLE mytable ADD COLUMN deposited DOUBLE PRECISION;
>
> This query is blocked by pid 0. It's not a postgres PID and won't allow to terminate from postgres.
> What would be the way forward to troubleshoot this?
That is probably a stale prepared transaction.
Look into "pg_prepared_xacts" for any prepared transactions and use
ROLLBACK PREPARED 'name';
to remove stale entries.
When using prepared transactions, you must use a transaction manager
that does these things for you. Also, you should monitor prepared
transactions.
Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: ALTER TABLE blocked
@ 2021-03-30 11:26 Devendra Yadav <devendra.857@gmail.com>
parent: Laurenz Albe <laurenz.albe@cybertec.at>
0 siblings, 0 replies; 4+ messages in thread
From: Devendra Yadav @ 2021-03-30 11:26 UTC (permalink / raw)
To: Laurenz Albe <laurenz.albe@cybertec.at>; +Cc: pgsql-admin@lists.postgresql.org
Thanks a ton Laurenz.
It worked
Regards,
Devendra Yadav
On Tue, 30 Mar 2021, 16:39 Laurenz Albe, <laurenz.albe@cybertec.at> wrote:
> On Tue, 2021-03-30 at 12:36 +0530, Devendra Yadav wrote:
> > Hope everything is well with you.
>
> Thanks, yes. I hope you are fine too.
>
> > We are running on PostgreSQL v 12.1 , Redhat 7.8.
> > We are running a query - ALTER TABLE mytable ADD COLUMN deposited
> DOUBLE PRECISION;
> >
> > This query is blocked by pid 0. It's not a postgres PID and won't allow
> to terminate from postgres.
> > What would be the way forward to troubleshoot this?
>
> That is probably a stale prepared transaction.
>
> Look into "pg_prepared_xacts" for any prepared transactions and use
>
> ROLLBACK PREPARED 'name';
>
> to remove stale entries.
>
> When using prepared transactions, you must use a transaction manager
> that does these things for you. Also, you should monitor prepared
> transactions.
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com
>
>
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re:
@ 2021-03-30 13:41 Tom Lane <tgl@sss.pgh.pa.us>
parent: Devendra Yadav <devendra.857@gmail.com>
1 sibling, 0 replies; 4+ messages in thread
From: Tom Lane @ 2021-03-30 13:41 UTC (permalink / raw)
To: Devendra Yadav <devendra.857@gmail.com>; +Cc: pgsql-admin@lists.postgresql.org
Devendra Yadav <devendra.857@gmail.com> writes:
> We are running on PostgreSQL v 12.1 , Redhat 7.8.
> We are running a query - ALTER TABLE mytable ADD COLUMN deposited DOUBLE
> PRECISION;
> This query is blocked by pid 0. It's not a postgres PID and won't allow to
> terminate from postgres.
It would be better if you showed the evidence that makes you think this,
as it's fairly likely that the true problem is somewhere else than
you think.
At a guess, however, a pg_locks display that suggests a lock is held
by "pid 0" might be trying to represent a lock held by a prepared-but-
uncommitted transaction. Try looking into the pg_prepared_xacts view.
regards, tom lane
^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2021-03-30 13:41 UTC | newest]
Thread overview: 4+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2021-03-30 07:06 Devendra Yadav <devendra.857@gmail.com>
2021-03-30 11:09 ` Re: ALTER TABLE blocked Laurenz Albe <laurenz.albe@cybertec.at>
2021-03-30 11:26 ` Re: ALTER TABLE blocked Devendra Yadav <devendra.857@gmail.com>
2021-03-30 13:41 ` Re: Tom Lane <tgl@sss.pgh.pa.us>
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