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help / color / mirror / Atom feedFrom: Achilleas Mantzios <[email protected]>
To: Tom Lane <[email protected]>
Cc: pgsql-admin <[email protected]>
Cc: [email protected]
Subject: Re: PostgreSQL 16.6 , query stuck with STAT Ssl, wait_event_type : IPC , wait_event : ParallelFinish
Date: Sun, 1 Jun 2025 08:32:06 +0300
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
<[email protected]>
<[email protected]>
On 1/6/25 07:19, Tom Lane wrote:
> Achilleas Mantzios<[email protected]> writes:
>>> a query is stuck with the above, it seems it waits for parallel worker
>>> to finish, however , there are no parallel works running :
> You didn't explain the subject about "STAT Ssl", but if you mean
> that that was what ps was showing for the backend process, there's
> something very wrong there. According to "man ps", the "l" means
>
> l is multi-threaded (using CLONE_THREAD, like NPTL pthreads
> do)
Yes. sorry, I didn't include this info, you are spot on, yes this the
output of ps aux .
> which is something that a Postgres backend should never be
> (in existing releases anyway). So I'm speculating that
> the process somehow became multi-threaded and then some
> wakeup signal went to the wrong thread.
>
> We've had issues with perl or python introducing multi-threading
> because of plperl or plpython functions doing things they
> probably shouldn't. Do you have any of those in your system?
Yes we have two perl functions only that I'd be happy to get rid off :
postgres@[local]/dynacom=# select p.proname, l.lanname from pg_language
l, pg_proc p where p.prolang=l.oid and l.lanname ~* '.*perl.*';
proname | lanname
----------+---------
basename | plperlu
filetype | plperlu
(2 rows)
Nothing used in the app, just some two utility functions to help us
batch insert some attachments, guess mimetype etc. However the calling
client is Perl , based on libpg-perl (not DBI), basically this is a
descendant of DBMirror.pl (we are still using it).
The strange thing is that we run pgsql 16.* since November, also we run
our version of DBMirror since 2005 (and PostgreSQL since 2001) and we
never had this problem before (at least from what I know).
>
> regards, tom lane
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Subject: Re: PostgreSQL 16.6 , query stuck with STAT Ssl, wait_event_type : IPC , wait_event : ParallelFinish
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