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Re: Problem analyzing explain analyze output

From: Guillaume Smet <guillaume(dot)smet(at)openwide(dot)fr>
To: "Steinar H(dot) Gunderson" <sgunderson(at)bigfoot(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Problem analyzing explain analyze output
Date: 2005-10-24 06:33:03
Message-ID: 435C801F.1030709@openwide.fr (view raw or flat)
Thread:
Lists: pgsql-performance
Steinar,

> which seems to make sense; you have one run of about 257ms, plus 514 runs
> taking about 0.035ms each (ie. about 18ms), which should add up to become
> about 275ms (which is close enough to the reality of 281ms).

Yep. The line that disturbed me was the bitmap index scan with a cost of 
"actual time=254.143..254.143". I was more looking for something like 
"actual time=0..254.143" which is what I usually have for an index scan. 
So I suppose that the bitmap index scan returns rows only when it's 
totally computed.

Thanks for your help.

Regards.

--
Guillaume

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