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Re: Why the difference in plans ??

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Joost Kraaijeveld" <J(dot)Kraaijeveld(at)Askesis(dot)nl>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Why the difference in plans ??
Date: 2006-09-15 14:08:35
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Lists: pgsql-performance
"Joost Kraaijeveld" <J(dot)Kraaijeveld(at)Askesis(dot)nl> writes:
> Why the difference and can I influence the result so that the first
> query plan (which is the fastest) is actually used in both cases (I
> would expect that the limit would be done after the sort?)? 

It likes the second plan because 6694025.41/353 < 41812.78.  It would
probably be right, too, if the number of matching rows were indeed 353,
but it seems there are only 7.  Try increasing your statistics target
and re-analyzing.

			regards, tom lane

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