Date: Wed, 20 Jun 2007 17:40:24 -0400
From: Andrew Sullivan <ajs@crankycanuck.ca>
To: pgsql-performance@postgresql.org
Subject: Re: Performance query about large tables, lots of concurrent access
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On Wed, Jun 20, 2007 at 05:29:41PM -0400, Karl Wright wrote:
> A nice try, but I had just completed a VACUUM on this database three 
> hours prior to starting the VACUUM that I gave up on after 27 hours. 

You keep putting it that way, but your problem is essentially that
you have several tables that _all_ need to be vacuumed.  VACUUM need
not actually be a database-wide operation.

> earlier finished in six hours - but to accomplish that I had to shut 
> down EVERYTHING else that machine was doing.)

This suggests to me that you simply don't have enough machine for the
job.  You probably need more I/O, and actually more CPU wouldn't
hurt, because then you could run three VACUUMs on three separate
tables (on three separate disks, of course) and not have to switch
them off and on the CPU.

A

-- 
Andrew Sullivan  | ajs@crankycanuck.ca
A certain description of men are for getting out of debt, yet are
against all taxes for raising money to pay it off.
		--Alexander Hamilton