Re: HashJoin order, hash the large or small table? Postgres likes to hash the big one, why?

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: "Scott Carey" <scott(at)richrelevance(dot)com>, "Mladen Gogala" <mladen(dot)gogala(at)vmsinfo(dot)com>
Cc: "pgsql-performance(at)postgresql(dot)org Performance" <pgsql-performance(at)postgresql(dot)org>, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: HashJoin order, hash the large or small table? Postgres likes to hash the big one, why?
Date: 2010-10-19 15:16:31
Message-ID: 4CBD6FFF0200002500036B27@gw.wicourts.gov
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Mladen Gogala <mladen(dot)gogala(at)vmsinfo(dot)com> wrote:

> how is the query cost calculated? What are
> the units? I/O requests? CPU cycles? Monopoly money?

http://www.postgresql.org/docs/current/interactive/runtime-config-query.html#RUNTIME-CONFIG-QUERY-CONSTANTS

-Kevin

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