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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Scott Marlowe <scott.marlowe@gmail.com>
Cc: Matthew Wakeling <matthew@flymine.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: merge join killing performance
Date: Thu, 27 May 2010 21:16:26 -0400
Message-ID: <15062.1275009386@sss.pgh.pa.us> (raw)
In-Reply-To: <AANLkTik0NxYr5FAqlYOqseHhT7WaJv6uJuMvD7ScONnV@mail.gmail.com>
References: <AANLkTikmwxQJIDfefCoK_SQN2DTwQs1naLwS-RW8PgRU@mail.gmail.com>
	<alpine.DEB.2.00.1005182254110.1867@aragorn.flymine.org>
	<21497.1274287983@sss.pgh.pa.us>
	<AANLkTimfo4qryWUFj6sYRSlQrFZpgLaqB3__Vt0y2Rdl@mail.gmail.com>
	<alpine.DEB.2.00.1005192143570.6090@aragorn.flymine.org>
	<AANLkTilruHtb1cc-TwN_bPVypkhIQo7p8I0y7035xLZ-@mail.gmail.com>
	<AANLkTil5u_ZEPtdVfsl4-XZuieLcXvd9wn5G2jc6k4Eo@mail.gmail.com>
	<AANLkTik0NxYr5FAqlYOqseHhT7WaJv6uJuMvD7ScONnV@mail.gmail.com>

Scott Marlowe <scott.marlowe@gmail.com> writes:
> So, Tom, so you think it's possible that the planner isn't noticing
> all those nulls and thinks it'll just take a row or two to get to the
> value it needs to join on?

I've committed a patch for this, if you're interested in testing that
it fixes your situation.

			regards, tom lane



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