RE: Oracle 10g upgrade - performance issue

>Jhonatan lewis book cost optimizer, includes a list of new hidden parameter, you can try to disable one by one and see which is causing problems.
 

actually, it is possible to do one thing when a new Oracle version is released:  

make 10053 traces for Oracle version x and y. Compare optimizer related parameters from both versions.  

Alternatively: *wait* untill Jhonathan writes a new book and upgrade then. Long live Jonathan.            

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Juan Carlos Reyes Pacheco Sent: 12. júlí 2006 13:19
To: peterdixon001_at_hotmail.com
Cc: oracle-l_at_freelists.org
Subject: Re: Oracle 10g upgrade - performance issue

Hi Peter,
There are bugs, for example in union all, I had to apply 10.2.0.2 patch, or you can try to set all optimizer features to 8.1.74, then 9.2, etc., Jhonatan lewis book cost optimizer, includes a list of new hidden parameter, you can try to disable one by one and see which is causing problems. One problem I got when moving to from 7 to 9.2, was merge, I had to include in some complex queries a NO_MERGE hint. If you are migrating a system having complex, and sometimes not too complex queries, you must expect problems with some queries. :)

On 7/11/06, Peter Dixon <peterdixon001_at_hotmail.com> wrote:

        Help!         

	Upgraded 8.1.7.4 to 10g rel 2 smoothly over the weekend. Batch works fine,
	but OLTP is causing CPU and disk i/o to max out at 100%, i believe the
	optimiser is making bad decisions as my introducing rule hints the problem 
	has slightly improved. Any ideas as our SR with Oracle says "tune the code"
	also we never got the issues in test.
	
	Peter Dixon
	
	
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