RE: Risk of RULE mode in 10g+

  • From: "Goulet, Richard" <Richard.Goulet@xxxxxxxxxxx>
  • To: <zollarja@xxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 15 Mar 2010 15:29:53 -0400

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: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Jeffrey Zollars
Sent: Monday, March 15, 2010 3:22 PM
To: oracle-l@xxxxxxxxxxxxx
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
10.2.0.4 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
ZollarJA@xxxxxxxxx 

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