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Date: Fri, 18 Apr 2008 14:24:22 -0400
From: Alvaro Herrera <alvherre@commandprompt.com>
To: Jeffrey Baker <jwbaker@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-performance@postgresql.org
Subject: Re: 3-days-long vacuum of 20GB table
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Jeffrey Baker escribió:

> That's rather more like it.  I guess I always imagined that VACUUM was
> a sort of linear process, not random, and that it should proceed at
> sequential scan speeds.

It's linear for the table, but there are passes for indexes which are
random in 8.1.  That code was rewritten by Heikki Linnakangas to do
linear passes for indexes in 8.2 AFAIR.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.