| From: | "Ross J(dot) Reedstrom" <reedstrm(at)rice(dot)edu> |
|---|---|
| To: | pgsql-admin(at)postgresql(dot)org |
| Subject: | Re: ALTER TABLE <name> ADD COLUMN Hangs |
| Date: | 2010-04-22 03:43:17 |
| Message-ID: | 20100422034317.GA3902@rice.edu |
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| Lists: | pgsql-admin |
On Thu, Apr 22, 2010 at 11:47:34AM +0930, Samuel Stearns wrote:
> Howdy,
>
> I'm running in an 8.3.3 environment. What could cause, or how can I diagnose, why an 'ALTER TABLE <name> ADD COLUMN' statement runs for hours eventually locking users out and requiring to be killed in the end?
>
ALTER TABLE commands require an exclusive lock on the table. I'm
guessing you've got a long-running transaction ahead of the ALTER TABLE.
take a look at pg_stat_activity, in particular 'waiting' and pg_locks.
Ross
--
Ross Reedstrom, Ph.D. reedstrm(at)rice(dot)edu
Systems Engineer & Admin, Research Scientist phone: 713-348-6166
The Connexions Project http://cnx.org fax: 713-348-3665
Rice University MS-375, Houston, TX 77005
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