From: Tom Lane <tgl@sss.pgh.pa.us>
To: Owen Jacobson <ojacobson@osl.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: How to force PostgreSQL using an index
Date: Wed, 15 Feb 2006 18:02:47 -0500
Message-ID: <20580.1140044567@sss.pgh.pa.us> (raw)
In-Reply-To: <144D12D7DD4EC04F99241498BB4EEDCC220865@nelson.osl.com>
References: <144D12D7DD4EC04F99241498BB4EEDCC220865@nelson.osl.com>
"Owen Jacobson" <ojacobson@osl.com> writes:
> On Wed, Feb 15, 2006 at 04:58:54PM -0500, Daniel Caune wrote:
>> I see, but that doesn't explain whether it is possible to specify the
>> index to use. It seems that those options just force PostgreSQL using
>> another plan.
> Drop the simple index and re-create it when you're done?
BTW, the cute way to do that is
BEGIN;
DROP INDEX unwanted;
EXPLAIN ANALYZE whatever...;
ROLLBACK;
No need to actually rebuild the index when you are done.
This does hold an exclusive lock on the table for the duration of your
experiment, so maybe not such a good idea in a live environment ... but
then again, dropping useful indexes in a live environment isn't a good
idea either, and this at least reduces the duration of the experiment by
a good deal.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, ojacobson@osl.com
Subject: Re: How to force PostgreSQL using an index
In-Reply-To: <20580.1140044567@sss.pgh.pa.us>
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