From: Tom Lane <tgl@sss.pgh.pa.us>
To: Hell, Robert <Robert.Hell@fabasoft.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Cursors and different settings for default_statistics_target
Date: Tue, 01 Apr 2008 11:30:05 -0400
Message-ID: <2798.1207063805@sss.pgh.pa.us> (raw)
In-Reply-To: <B710F3299F04664DB6B37C258FDEEB940158AFF9@FABAMAIL.fabagl.fabasoft.com>
References: <B710F3299F04664DB6B37C258FDEEB940158AFF9@FABAMAIL.fabagl.fabasoft.com>
"Hell, Robert" <Robert.Hell@fabasoft.com> writes:
> When we use 20 as default_statistics_target the retrieval of the data
> takes 7.5 seconds - with 25 as default_statistics_target (with restart
> and analyze) it takes 0.6 seconds.
> The query plan is identical in both situations (row estimation differs a
> little bit) - the query is always fast when it is executed without a
> cursor.
A cursor doesn't necessarily use the same plan as a straight query does.
Try "EXPLAIN DECLARE curs_285058224 CURSOR FOR ..." and see if you
aren't getting different plans in these two cases.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, Robert.Hell@fabasoft.com
Subject: Re: Cursors and different settings for default_statistics_target
In-Reply-To: <2798.1207063805@sss.pgh.pa.us>
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