Re: full outer join performance

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Ben <bench(at)silentmedia(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: full outer join performance
Date: 2005-09-13 18:45:56
Message-ID: 25837.1126637156@sss.pgh.pa.us
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Ben <bench(at)silentmedia(dot)com> writes:
> Hrm, as I understand that page, there's not much that can be done about
> the join order for outer joins. At least, not when there's on 3 tables
> and 1 outer join involved. Am I missing something?

Without knowing what you want the query to do, it's difficult to say if
it's OK to rearrange the join order.

Frequently it's OK to rearrange the join order even without risking any
change in the query results, but PG doesn't currently have any smarts
about that, so you have to do it manually by changing the query.

regards, tom lane

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