Re: Database perfortmance degraded drastically after upgrading the database from Oracle 102.0.4 to Oracle 11.2.0.3

Did you check what your top most wait events have been after the upgrade? Direct path read behavior has changed drastically in 11.2, we were back to normal BAU performance after setting optimizer_features_enable to 10g.

Why didn't you upgrade your DB to the latest 11g patchset 11.2.0.4, it has all the bug fixes for 11.2?

Thanks,
Harinder Singh

On Mon, Oct 19, 2015, 14:22 Mandal, Ashoke <ashoke.k.mandal_at_medtronic.com> wrote:

> Greetings All,
>
> After the upgrade of one of my databases from Oracle 10.2.0.4 to Oracle
> 11.2.0.3 the users are experiencing poor query performance. The response
> time of the queries have increased by 15 times.
>
> I have tried the following without any luck but checking if you have any
> other suggestions
>
> 1. Changed optimizer_dynamic_sampling from 2 to 1 => No performance
> improvement
>
> 2. Changed optimizer_features_enable to '10.2.0.4' => No performance
> improvement
>
> 3. Try setting cursor_sharing to force => No performance improvement
>
> 4. Set “_optimizer_skip_scan_enabled" = FALSE => No performance
> improvement
>
> Please let me know if you any suggestions to resolve this issue
>
>
>
> Appreciate your help in advance,
> Ashoke
>
>
>
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