Re: Improving planning of outer joins

From: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: Improving planning of outer joins
Date: 2005-12-16 20:24:49
Message-ID: 20051216202449.GD27602@surnet.cl
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Tom Lane wrote:
> Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> > I wonder if the code is already able to transform right joins to left
> > joins, like
> > (A rightjoin B on (Pab)) = (B leftjoin A on (Pab))
>
> Yeah, we already know that part. It's a freebie --- I didn't even
> bother mentioning rightjoin in my post, since it's equivalent to
> leftjoin after swapping the inputs.

Why the thing about the mergejoinable conditions then? Is that even
true?

--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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