Re: planner/optimizer question - Mailing list pgsql-performance

From Gary Doades
Subject Re: planner/optimizer question
Date
Msg-id 4092A928.27720.19838422@localhost
Whole thread Raw
In response to Re: planner/optimizer question  (Jeff <threshar@torgo.978.org>)
Responses Re: planner/optimizer question
List pgsql-performance
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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