Re: Risk of RULE mode in 10g+

From: Andrew Kerber <>
Date: Mon, 15 Mar 2010 14:34:37 -0500
Message-ID: <>

I think the rule hint still works, even if the RBO is no longer available.

On Mon, Mar 15, 2010 at 2:29 PM, Goulet, Richard <
> wrote:

> Jeffrey,
> OH Dear, I'll try to find the url that says this for you, but in 10g
> the rule based optimizer isn't deprecated, it's dead period. You can put
> rule in there all you want, but it will run in cost mode. Isn't suppose to
> cause problems with the result set that I've heard of, nor does it cause a
> problem with executing the sql.
> *Dick Goulet***
> Senior Oracle DBA/NA Team Lead
> PAREXEL International
> ------------------------------
> *From:* [mailto:
>] *On Behalf Of *Jeffrey Zollars
> *Sent:* Monday, March 15, 2010 3:22 PM
> *To:*
> *Subject:* Risk of RULE mode in 10g+
> We are upgrading an application to the current version and also upgrading
> the DB version from 9i to 10g. The application code has several bits of code
> that are explicitly setting RULE mode. One in a configuration table that can
> be updated. Second, in several hints coded in SQL statements which cannot be
> easily changed.
> I have provided Oracle documentation to the application vendor showing that
> RULE mode is desupported in 10g+ versions. They were skeptical to say the
> least.
> I had thought that I'd seen stronger warnings that RULE mode could actually
> generate incorrect result sets when running queries. I have searched but
> could not find those warnings now. I am trying to make a case to request the
> application vendor to go back and modify the code before we update to the
> current version of the application on Oracle version. I'm concerned
> about the integrity of the result sets.
> I am wondering if anyone knows of or can provide a link to the warning that
> result sets may be incorrect in 10g+ using RULE mode.
> Thanks,
> Jeff
> --
> J. A. Zollars

Andrew W. Kerber

'If at first you dont succeed, dont take up skydiving.'

Received on Mon Mar 15 2010 - 14:34:37 CDT

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