To: Simon Riggs <simon@2ndquadrant.com>
cc: Andrew Sullivan <ajs@crankycanuck.ca>, pgsql-performance@postgresql.org
Subject: Re: Some queries starting to hang 
In-reply-to: <1149604741.2621.487.camel@localhost.localdomain> 
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Comments: In-reply-to Simon Riggs <simon@2ndquadrant.com>
	message dated "Tue, 06 Jun 2006 15:39:01 +0100"
Date: Tue, 06 Jun 2006 10:43:25 -0400
Message-ID: <17148.1149605005@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Simon Riggs <simon@2ndquadrant.com> writes:
> On Mon, 2006-06-05 at 17:06 -0400, Tom Lane wrote:
>> Well, it's a big query.  If it ought to take a second or two, and
>> instead is taking an hour or two (1800 times the expected runtime), that
>> might be close enough to "never" to exhaust Chris' patience.  Besides,
>> we don't know whether the 1800 might itself be an underestimate (too bad
>> Chris didn't provide EXPLAIN ANALYZE results).  

> This is a good example of a case where the inefficiency of EXPLAIN
> ANALYZE would be a contributory factor to it not actually being
> available for diagnosing a problem.

Huh?  The problem is the inefficiency of the underlying query.

			regards, tom lane