Re: ExclusiveLock without a relation in pg_locks

From: "Carlos Oliva" <carlos(at)pbsinet(dot)com>
To: "'Michael Fuhr'" <mike(at)fuhr(dot)org>
Cc: <pgsql-general(at)postgresql(dot)org>
Subject: Re: ExclusiveLock without a relation in pg_locks
Date: 2006-02-23 18:23:36
Message-ID: 200602231824.NAA24243@pbsi.pbsinet.com
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Yes. I am seeing that situation often in our database.

The query field of pg_stat_activity is SELECT ..., not SLECT UPDATE or
UPDATE or INSERT or DELETE. I was expecting the query to say something like
SLECT UPDATE or something like that. Also the query seems to have just
columns in the select statement; not functions.

I will look further into these queries in case that they are using
functions.

-----Original Message-----
From: pgsql-general-owner(at)postgresql(dot)org
[mailto:pgsql-general-owner(at)postgresql(dot)org] On Behalf Of Michael Fuhr
Sent: Thursday, February 23, 2006 1:09 PM
To: Carlos Oliva
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] ExclusiveLock without a relation in pg_locks

On Thu, Feb 23, 2006 at 11:08:07AM -0500, Carlos Oliva wrote:
> Thank you very much for your answer. I think that I am seeing those self
> transaction id locks as "ExclusiveLocks"
>
> Would you expect to see an "ExclusiveLock" with a query of type Select
(not
> Select Update or Update or Insert)?

Not in general, unless perhaps the select called a function that
acquired such a lock. The Concurrency Control chapter in the
documentation has a section on lock types and the commands that
acquire them:

http://www.postgresql.org/docs/8.1/interactive/explicit-locking.html

Are you just curious or are you seeing such a situation?

--
Michael Fuhr

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