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Re: Increased IO Overhead in 10g?

From: MTNorman <mtnorman_at_duke-energy.com>
Date: 29 Mar 2007 09:24:17 -0700
Message-ID: <1175185457.897861.144940@n76g2000hsh.googlegroups.com>


On Mar 28, 4:21 am, Robert Klemme <shortcut..._at_googlemail.com> wrote:
> Hi,
>
> 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.
>
> Thanks for any feedback!
>
> Kind regards
>
> robert

The biggest IO impact I have observed following a 10g upgrade is in materialized view data replication. Where 8i and 9i truncates a materialized view table when performing a full refresh, 10g uses delete to remove all the rows in the table; increasing the amount of redo and undo written, sometimes dramatically. Using the atomic_refresh=>FALSE parameter in the dbms_mview.refresh call will revert 10g back to the 8i/9i behavior. See Metalink Note:306502.1 for more info. Received on Thu Mar 29 2007 - 11:24:17 CDT

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