Re: Increased IO Overhead in 10g?

From: Robert Klemme <shortcutter_at_googlemail.com>
Date: Wed, 28 Mar 2007 17:31:49 +0200
Message-ID: <56vg2gF2b7lg1U1@mid.individual.net>

On 28.03.2007 17:09, Charles Hooper wrote:
> On Mar 28, 4:21 am, Robert Klemme <shortcut..._at_googlemail.com> wrote:

>> I know this question is going to sound a bit fuzzy as I cannot disclose
>> a lot of detail.  However my intention is to get a rather general
>> statement about your experience.  My question is basically: is anybody
>> here aware of higher overhead in Ora 10g disk IO vs., say 8.1.7?  One
>> thing that came to mind are all the management features; I know that
>> they are using functionality that has been available for several
>> versions but maybe more of these introspecting features are enabled by
>> default.

>
> One has to wonder if AWR (Automatic Workload Repository) data
> collection has any impact on IO overhead as it is flushed to disk.
> Even if you have not purchased the rights to use AWR, it is still
> collecting data. If you monitor the changes to extents for roughly
> two minutes and compare the delta values for the extents, you may see
> 900+ changes like this:

<snip/>

> If your IO system cannot handle the increased work load, then this
> might be part of the problem. Jonathan Lewis had something on his
> blog a while ago that described how to disable AWR.

http://jonathanlewis.wordpress.com/2006/11/24/disabling-awr/

Thanks for that info! This sounds interesting and worthy of further research.

Kind regards

robert Received on Wed Mar 28 2007 - 10:31:49 CDT