Date: Tue, 7 Aug 2007 08:15:37 -0500
From: Kenneth Marshall <ktm@rice.edu>
To: Mark Makarowsky <bedrockconstruction@yahoo.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Update table performance
Message-ID: <20070807131537.GE12924@it.is.rice.edu>
References: <435532.80672.qm@web32210.mail.mud.yahoo.com>
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Mark,

You are not alone in the fact that when you post your system
specifications, CPU and memory are always listed while the
disk I/O subsystem invariably is not. This is a very disk
intensive operation and I suspect that your disk system is
maxed-out. If you want it faster, you will need more I/O
capacity.

Regards,
Ken

On Tue, Aug 07, 2007 at 05:58:35AM -0700, Mark Makarowsky 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?  There
> aren't any indexes, triggers, constraints or anything
> on this table.  The version of Postgres is "PostgreSQL
> 8.2.4 on i686-pc-mingw32, compiled by GCC gcc.exe
> (GCC) 3.4.2 (mingw-special)".  The operating
> environment is Windows 2003 Standard Edition w/service
> pack 2.  It is 2.20 Ghz with 1.0 GB of RAM.  Here is
> the results from Explain:
> 
> "Seq Scan on valley  (cost=0.00..1034083.57
> rows=4897257 width=601)"
> 
> Here are the settings in the postgresql.conf.  Any