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Users Report Faster SQL Siebel Execution with CBO
May 13
, 2004

In this article from Oracle-l, we see that some Oracle Siebel users are deliberately going un-supported in order to move their Siebel database from the obsolete rule-based SQL optimizer (RBO) to cost-based SQL optimization:
Ken Naim reports that his Oracle Siebel Database ran far faster when he changed his optimizer_mode and analyzed statistics:
"While using the RBO our OLTP type queries were measured in minutes and after analyzing and using the CBO, execution time dropped to several seconds; a 30-60 fold increase in performance."
Naim also reports that Oracle Siebel databases will benefit from using function-based indexes (FBI):
"Once we were on the CBO we felt our hands were untied and we started to add function based indexes for case insensitive searches, partitioning etc so
our execution time for most queries became sub-second."
Of course, customizing an Oracle Siebel database by adding indexes and using cost-based SQL optimization may make your Siebel Database unsupported, but this person felt it was worth it:
"Siebel was not happy to say the least and they said they wouldn't support us, my company decided such a performance gain was worth canceling support
so we got the performance increase and saved ourselves a lot of cash at the same time."



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