From: cluster <skrald@amossen.dk>
Subject: Re: Query only slow on first run
Date: Wed, 28 Nov 2007 22:15:59 +0100
Organization: Hub.Org Networking Services
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To: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
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To: pgsql-performance@postgresql.org

> The indexes don't contain visibility information, so Postgres has to look up
> the row on disk to verify it isn't dead.

I guess this fact drastically decreases the performance. :-(
The number of rows with a random_number will just grow over time while 
the number of questions with status = 1 will always be somewhat constant 
at about 10.000 or most likely much less.

I could really use any kind of suggestion on how to improve the query in 
order to make it scale better for large data sets The 6-7000 ms for a 
clean run is really a showstopper. Need to get it below 70 ms somehow.