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Re: select count(*) and limit

From: Verena Ruff <lists(at)triosolutions(dot)at>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: select count(*) and limit
Date: 2006-05-18 16:28:31
Message-ID: 446CA0AF.1000001@triosolutions.at (view raw or flat)
Thread:
Lists: pgsql-novice
Hi,

Sean Davis schrieb:
> It should still work just fine, again with the caveat that it is an
> approximation and depends on the statistics available.  Try comparing the
> output a few times for your count(*) and using EXPLAIN.
>   
sometimes the difference is to much to go this way. EXPLAIN extimates 
71000 rows but there are 95000. 10% would have been accaptle. I did 
these tests on a freshly vacuumed database.

regards,
Verena

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