From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Sullivan <ajs@crankycanuck.ca>
Cc: pgsql-performance@postgresql.org
Subject: Re: Some queries starting to hang
Date: Mon, 05 Jun 2006 17:06:31 -0400
Message-ID: <23915.1149541591@sss.pgh.pa.us> (raw)
In-Reply-To: <20060605203851.GB7071@phlogiston.dyndns.org>
References: <1149534308.3583.56.camel@bg002441.pro-unlimited.com>
<22706.1149538039@sss.pgh.pa.us>
<20060605203851.GB7071@phlogiston.dyndns.org>
Andrew Sullivan <ajs@crankycanuck.ca> writes:
> On Mon, Jun 05, 2006 at 04:07:19PM -0400, Tom Lane wrote:
>> I'm wondering about out-of-date or nonexistent ANALYZE stats, missing
>> custom adjustments of statistics target settings, etc.
> But even the nested loop shouldn't be a "never returns" case, should
> it? For 1800 rows?
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). The hash plan will scale
to larger numbers of rows much more gracefully than the nestloop ...
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, ajs@crankycanuck.ca
Subject: Re: Some queries starting to hang
In-Reply-To: <23915.1149541591@sss.pgh.pa.us>
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