Re: optimizer_features

From: Wolfgang Breitling <breitliw_at_centrexcc.com>
Date: Thu, 19 Aug 2004 22:00:11 -0600
Message-Id: <6.1.0.6.2.20040819215444.02ed2860@pop.centrexcc.com>

I have not done exhaustive tests with that parameter, but based on my experience and from what I read from other people on newsgroups I have the impression that it is only certain features which get disabled when backdating optimizer_features enabled (just as the name suggests). You don't get total 8.1.7 behaviour by setting optimizer_features_enabled = 8.1.7. New algorithms and heuristics appear to be unaffected. But I could be wrong.
There is a metalink note that explains which features are enabled based on which setting.

At 07:23 PM 8/19/2004, you wrote:
>Hi,
>
>I have a question around the
>optimizer_features_enabled parameter. If we set this
>parameter to 8.1.7 in a 9.2 database does the RDBMS
>kernel use 8.1.7 optimization algorithms only or does
>it use the 9.2 optimization algorithms but limit the
>CBO to only using 8.1.7 CBO features?
>
>Any clarification on this would be much appreciated.
>
>Regards,
>
>Mark

Regards

Wolfgang Breitling
Centrex Consulting Corporation
http://www.centrexcc.com

Please see the official ORACLE-L FAQ: http://www.orafaq.com

To unsubscribe send email to: oracle-l-request_at_freelists.org put 'unsubscribe' in the subject line.

--
Archives are at http://www.freelists.org/archives/oracle-l/
FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------

Received on Thu Aug 19 2004 - 22:55:53 CDT

Re: optimizer_features_enabled