From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <david.rowley@2ndquadrant.com>
cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>,
        Simon Riggs <simon@2ndquadrant.com>,
        PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Performance improvement for joins where outer side is unique
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Comments: In-reply-to David Rowley <david.rowley@2ndquadrant.com>
	message dated "Wed, 09 Mar 2016 12:57:09 +1300"
Date: Tue, 08 Mar 2016 19:19:40 -0500
Message-ID: <24304.1457482780@sss.pgh.pa.us>
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David Rowley <david.rowley@2ndquadrant.com> writes:
> I also notice that some regression tests, which I think some of which
> Tom updated in the upper planner changes have now changed back again
> due to the slightly reduced costs on hash and nested loop joins where
> the inner side is unique.

?? I don't see anything in this patch that touches the same queries
that changed plans in my previous patch.

I do think that the verbosity this adds to the EXPLAIN output is not
desirable at all, at least not in text mode.  Another line for every
darn join is a pretty high price.

			regards, tom lane


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