From: Alan Hodgson <ahodgson@simkin.ca>
Organization: Simkin Network Consulting
To: pgsql-performance@postgresql.org
Subject: Re: Update table performance
Date: Tue, 7 Aug 2007 09:03:49 -0700
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On Tuesday 07 August 2007 05:58, Mark Makarowsky 
<bedrockconstruction@yahoo.com> wrote:
> I have a table with 4,889,820 records in it.  The
> table also has 47 fields.  I'm having problems with
> update performance.  Just as a test, I issued the
> following update:
>
> update valley set test='this is a test'
>
> This took 905641 ms.  Isn't that kind of slow?  

PostgreSQL has to write a full new version of every row that gets updated. 
Updates are, therefore, relatively slow. 

I'm guessing you're doing this on a single SATA drive, too, which probably 
doesn't help.

-- 
"If a nation values anything more than freedom, it will lose its freedom;
and the irony of it is that if it is comfort or money that it values more,
it will lose that too." -- Somerset Maugham, Author