Re: Stats for multi-column indexes

From: Peter Eisentraut <peter_e(at)gmx(dot)net>
To: pgsql-hackers(at)postgresql(dot)org
Cc: Alvaro Herrera <alvherre(at)commandprompt(dot)com>, Richard Huxton <dev(at)archonet(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Mark Kirkwood <markir(at)paradise(dot)net(dot)nz>, Jeff Davis <pgsql(at)j-davis(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: Stats for multi-column indexes
Date: 2007-03-20 14:37:21
Message-ID: 200703201537.23798.peter_e@gmx.net
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Alvaro Herrera wrote:
> Now, the hard question is deciding what to keep track of. I don't
> think MCV makes much sense, because what's the MCV of two columns?

The combination that occurs most often.

--
Peter Eisentraut
http://developer.postgresql.org/~petere/

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