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Re: WIP Join Removal

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, List pgsql-patches <pgsql-patches(at)postgresql(dot)org>
Subject: Re: WIP Join Removal
Date: 2008-09-02 16:15:27
Message-ID: 1220372127.4371.456.camel@ebony.2ndQuadrant (view raw or flat)
Thread:
Lists: pgsql-patches
On Tue, 2008-09-02 at 12:02 -0400, Tom Lane wrote:
> Simon Riggs <simon(at)2ndQuadrant(dot)com> writes:
> >> Oh. How does the query look like after removing the join, then?
> 
> > Same answer, just slower. Removing the join makes the access to a into a
> > SeqScan, whereas it was a two-table index plan when both tables present.
> 
> I don't really believe this...

Yes, this will be changed. No need to review further at this stage.

-- 
 Simon Riggs           www.2ndQuadrant.com
 PostgreSQL Training, Services and Support


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