Re: Seq Scan vs. Index Scan

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: <pgsql-performance(at)postgresql(dot)org>, "Nassib Nassar" <nassar(at)renci(dot)org>
Subject: Re: Seq Scan vs. Index Scan
Date: 2011-08-04 15:07:42
Message-ID: 4E3A6F6E020000250003FA53@gw.wicourts.gov
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Nassib Nassar <nassar(at)renci(dot)org> wrote:

> In this example it looks to me like the planner is choosing a Seq
> Scan resulting in 18x running time compared to running it with
> enable_seqscan = 'off'.

I would try these settings:

random_page_cost = 2
cpu_tuple_cost = 0.02

Based on your estimated cost versus actual run times, there's a good
chance they'll better model your environment, and serve you well in
general.

-Kevin

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