Re: How to force an Index ? - Mailing list pgsql-admin

From Bruno Wolff III
Subject Re: How to force an Index ?
Date
Msg-id 20030826194558.GA19181@wolff.to
Whole thread Raw
In response to How to force an Index ?  (Rhaoni Chiu Pereira <rhaoni@sistemica.info>)
List pgsql-admin
On Tue, Aug 26, 2003 at 16:11:56 -0300,
  Rhaoni Chiu Pereira <rhaoni@sistemica.info> wrote:
> Hi List,
>
>      I'm looking for a way to force an Index to be used in a SQL query. In a
> Oracle SQL query it would be like:
>
>     Select /*+ my_index*/ * from my_table where my_name="rhaoni";
>
>    So it would use the index my_index to execute the query. How can I make this
> in a PostgreSQL SQL query.

There isn't a way to force specific indexes to be used. You can raise the
cost of sequential scans so that index scans will almost always be used
if they are possible. Use: set enable_seqscan = false;

In general it is best to use this only to find out why an index scan isn't
being used and then potentially change some cost functions so that the
proper plan is chosen.

pgsql-admin by date:

Previous
From: Rhaoni Chiu Pereira
Date:
Subject: How to force an Index ?
Next
From: Naomi Walker
Date:
Subject: Re: Tuning: WAL disk speed