Re: planner/optimizer question

From: "Gary Doades" <gpd(at)gpdnet(dot)co(dot)uk>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: planner/optimizer question
Date: 2004-04-30 18:29:44
Message-ID: 4092A928.27720.19838422@localhost
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On 30 Apr 2004 at 8:32, Jeff wrote:
>
> A better comparision query may be a simple "select a from mytable
> where a between foo and bar" to get an index scan. In that case its a
> straight up, vanilla index scan. Nothing else getting in the way.
>

Yes, you're right and I have done this just to prove to myself that it is the index scan that
is the bottleneck. I have some complex SQL that executes very quickly with Postgres,
similar to MSSQL, but the index scans in most of those only touch a few rows for a few
loops. It seems to be a problem when the index scan is scanning very many rows and
for each of these it has to go to the table just to find out if the index it just looked at is
still valid.

Gary.

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