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From: Ron Mayer <rm_pg@cheapcomplexdevices.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: TB-sized databases
Date: Fri, 07 Dec 2007 12:46:21 -0800
Message-ID: <4759B11D.1030201@cheapcomplexdevices.com> (raw)
In-Reply-To: <10359.1197000850@sss.pgh.pa.us>
References: <4544e0330711260904g45d893a8ub1731e245aa8fc84@mail.gmail.com>
	<13851.1196351131@sss.pgh.pa.us>
	<1196352866.4246.1304.camel@ebony.site>
	<200712051507.22745.xzilla@users.sourceforge.net>
	<1196933896.4255.340.camel@ebony.site>
	<20071206154212.GP5294@mathom.us>
	<15753.1196957598@sss.pgh.pa.us>
	<4758A1B8.20501@cheapcomplexdevices.com>
	<4758C425.3080105@cheapcomplexdevices.com>
	<10359.1197000850@sss.pgh.pa.us>

Tom Lane wrote:
> Ron Mayer <rm_pg@cheapcomplexdevices.com> writes:
>> Tom Lane wrote:
>>> There's something fishy about this --- given that that plan has a lower
>>> cost estimate, it should've picked it without any artificial
>>> constraints.

One final thing I find curious about this is that the estimated
number of rows is much closer in the "offset 0" form of the query.

Since the logic itself is identical, I would have expected the
estimated total number of rows for both forms of this query to
be identical.

Any reason the two plans estimate a different total number of rows?



(explain statements for the two forms of the same query
from earlier in the thread here:
http://archives.postgresql.org/pgsql-performance/2007-12/msg00088.php )

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