RE: Changes to RULE based optimizer between Oracle8 and 9i
Logic says one thing, experience says another. Question one, are the tables analyzed? If so, since RBO is deprecated in 9i even setting OPTIMIZER_MODE=RULE will invoke the CBO. Dick GouletSenior Oracle DBAOracle Certified 8i DBA -Original Message-From: Keith Moore [mailto:[EMAIL PROTECTED]Sent: Friday, January 30, 2004 11:54 AMTo: Multiple recipients of list ORACLE-LSubject: Changes to RULE based optimizer between Oracle8 and 9i We move an application that uses OPTIMIZER_MODE=RULE from Oracle8 to 9i. Most of it is fine, but there are two queries that have a very different execution plan. In one case, the execution time increases from less than a minute to more than an hour. Neither query uses any of the new Oracle 9i features. My understanding is that the Rule optimizer code has not changed, except to account for new features like IOT's. Has anyone else seen this type of behavior? Keith MooreOracle Certified Professional972-431-5126[EMAIL PROTECTED]
RE: Changes to RULE based optimizer between Oracle8 and 9i
Title: Message Keith, To my knowledge, RBO has not changed. That includes NOT dealing w/ IOT. So, I think if you execute a query that references an IOT, you'll implicitly invoke the CBO. That would explain why the plan is changing. So, did you change a table from heap to IOT when you moved to 9i? If so, that's what's invoking CBO. -Mark PS fatcity is going away, use freelists.org! Mark J. Bobak Oracle DBA ProQuest Company Ann Arbor, MI "Imagination was given to man to compensate him for what he is not, and a sense of humor was provided to console him for what he is." --Horace Walpole -Original Message-From: Keith Moore [mailto:[EMAIL PROTECTED] Sent: Friday, January 30, 2004 11:54 AMTo: Multiple recipients of list ORACLE-LSubject: Changes to RULE based optimizer between Oracle8 and 9i We move an application that uses OPTIMIZER_MODE=RULE from Oracle8 to 9i. Most of it is fine, but there are two queries that have a very different execution plan. In one case, the execution time increases from less than a minute to more than an hour. Neither query uses any of the new Oracle 9i features. My understanding is that the Rule optimizer code has not changed, except to account for new features like IOT's. Has anyone else seen this type of behavior? Keith MooreOracle Certified Professional972-431-5126[EMAIL PROTECTED]
Changes to RULE based optimizer between Oracle8 and 9i
We move an application that uses OPTIMIZER_MODE=RULE from Oracle8 to 9i. Most of it is fine, but there are two queries that have a very different execution plan. In one case, the execution time increases from less than a minute to more than an hour. Neither query uses any of the new Oracle 9i features. My understanding is that the Rule optimizer code has not changed, except to account for new features like IOT's. Has anyone else seen this type of behavior? Keith MooreOracle Certified Professional972-431-5126[EMAIL PROTECTED] The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. If the reader of this message is not the intended recipient, you are hereby notified that your access is unauthorized, and any review, dissemination, distribution or copying of this message including any attachments is strictly prohibited. If you are not the intended recipient, please contact the sender and delete the material from any computer.