Re: dbms_resource_manager.calibrate_io, strange numbers

From: Greg Rahn <greg_at_structureddata.org>
Date: Fri, 7 Oct 2011 22:40:21 -0700
Message-ID: <CAGXkmisdT57Q3f5BJLb0TatRbJkU+-CLbJH-bwk==4ZdGBdb8w_at_mail.gmail.com>

If you just need this for auto dop, my recommendation would just follow that note and use 200 for MAX_PMBPS (commands below).

delete from resource_io_calibrate$;
insert into resource_io_calibrate$ values(current_timestamp, current_timestamp, 0, 0, 200, 0, 0);
commit;
(bounce instances to take affect)

On Thu, Oct 6, 2011 at 12:04 AM, Randolf Geist <info_at_www.sqltools-plusplus.org> wrote:
> Freek,
>
> you might want to have a look at the MOS document "Automatic Degree of Parallelism in 11.2.0.2 [ID 1269321.1]" where it is also mentioned that the calibration routine at present might sometimes produce questionable results.
>
> For your information the only relevant parameter for Auto DOP in 11.2.0.2 at present seems to be MAX_PMBPS, it looks like that the others are ignored for the Auto DOP calculation anyway - at least what the MOS document seems to suggest by setting / hacking this parameter manually e.g. on Exadata environments.
>
> I've blogged about that recently: http://oracle-randolf.blogspot.com/2011/07/cost-is-time-next-generation.html
>

-- 
Regards,
Greg Rahn
http://structureddata.org
--
http://www.freelists.org/webpage/oracle-l

Received on Sat Oct 08 2011 - 00:40:21 CDT