From: Greg Stark <gsstark@mit.edu>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Mark Kirkwood <markir@paradise.net.nz>
Cc: Tobias Brox <tobias@nordicbet.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Limit + group + join
Date: 26 Aug 2005 23:03:30 -0400
Message-ID: <87mzn484jh.fsf@stark.xeocode.com> (raw)
In-Reply-To: <9501.1125071193@sss.pgh.pa.us>
References: <20050826002709.GK10328@tobias.lan>
<430E85ED.60109@paradise.net.nz>
<9501.1125071193@sss.pgh.pa.us>
Tom Lane <tgl@sss.pgh.pa.us> writes:
> As far as the "desc" point goes, the problem is that mergejoins aren't
> capable of dealing with backward sort order, so a merge plan isn't
> considered for that case (or at least, it would have to have a sort
> after it, which pretty much defeats the point for a fast-start plan).
> I have some ideas about fixing this but it won't happen before 8.2.
Of course in this case assuming "id" is an integer column you can just sort by
-id instead.
--
greg
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To: pgsql-performance@postgresql.org
Cc: gsstark@mit.edu, tgl@sss.pgh.pa.us, markir@paradise.net.nz, tobias@nordicbet.com
Subject: Re: Limit + group + join
In-Reply-To: <87mzn484jh.fsf@stark.xeocode.com>
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