From: William Yu <wyu@talisys.com>
Subject: Re: Forcing use of specific index
Date: Fri, 03 Jun 2005 16:22:49 -0700
Organization: Hub.Org Networking Services
Lines: 23
Message-ID: <d7qooc$4pf$1@news.hub.org>
References: <20050602020528.GL26100@tobias.exoweb.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US;
	rv:1.7.2) Gecko/20040803
In-Reply-To: <20050602020528.GL26100@tobias.exoweb.net>
To: pgsql-performance@postgresql.org

A pretty awful way is to mangle the sql statement so the other field 
logical statements are like so:

select * from mytable where 0+field = 100


Tobias Brox wrote:
> Is it any way to attempt to force the planner to use some specific index
> while creating the plan?  Other than eventually dropping all the other
> indices (which is obiously not a solution in production setting anyway)?
> 
> I have one case where I have added 16 indices to a table, many of them
> beeing partial indices.  The table itself has only 50k of rows, but are
> frequently used in heavy joins.  I imagine there can be exponential order on
> the number of alternative paths the planner must examinate as function of
> the number of indices?
> 
> It seems to me that the planner is quite often not choosing the "best"
> index, so I wonder if there is any easy way for me to check out what the
> planner think about a specific index :-)
>