Message-ID: <4485BF25.4080701@modgraph-usa.com>
Date: Tue, 06 Jun 2006 10:45:09 -0700
From: "Craig A. James" <cjames@modgraph-usa.com>
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To: pgsql-performance@postgresql.org
Subject: Re: Some queries starting to hang
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Simon Riggs 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.

This is a frustration I have, but Simon expressed it much more concisely.  The first question one gets in this forum is, "did you run EXPLAIN ANALYZE?"  But if EXPLAIN ANALYZE never finishes, you can't get the information you need to diagnose the problem.  Simon's proposal,

> e.g. EXPLAIN ANALYZE ERRLIMIT 10 SELECT ...

or something similar, would be a big help.  I.e. "If you can't finish in a reasonable time, at least tell me as much as you can."

Craig