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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Merlin Moncure <mmoncure@gmail.com>
Cc: Claudio Freire <klaussfreire@gmail.com>
Cc: Robert Klemme <shortcutter@googlemail.com>
Cc: Stefan Keller <sfkeller@gmail.com>
Cc: Jeff Janes <jeff.janes@gmail.com>
Cc: Peter Geoghegan <peter@2ndquadrant.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Hash index use presently(?) discouraged since 2005: revive or bury it?
Date: Tue, 20 Sep 2011 12:25:19 -0400
Message-ID: <9496.1316535919@sss.pgh.pa.us> (raw)
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Merlin Moncure <mmoncure@gmail.com> writes:
> just selects.  update test is also very interesting -- the only test I
> did  for for updates is 'update foo set x=x+1' which was a win for
> btree (20-30% faster typically).  perhaps this isn't algorithm induced
> though -- lack of wal logging could actually hurt time to commit
> because it deserializes i/o.

In 9.1+, you could remove WAL from the comparison by doing the tests on
an unlogged table.

			regards, tom lane



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