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Optimization differences between 6.2.1 and 7.0 Beta


#1

Hi,

Happy New Year to everyone !!

This question is similar to a previous question I posted regarding the number of rewrites generated by the 6.2.1 Optimizer vs the 7.0 Beta one. This one, however, is simply that a SQL statement passed into 6.2.1 generated 413 rewrites - 26 alternatives with unique execution plans and yielded an 87% improvement and yet when the exact same statement is optimized using 7.0, there are no improvements to be found. (Same Intelligence Level - 4)

I understand the issue that was found in 6.2.1 in terms of the number of statements being incorrect, but the above example is going to be very confusing to customers and I feel will ultimately lead to a lot of Support calls.

Regards,

John


#2

Hi John,

Happy New Year to you also.

You said you optimized in 7.0, does it mean you optimize in Optimization Queue or in SQLab? I would like to understand more if you were comparing the result of the SQLab in 6.2.1 and 7.0; or that you were comparing the result of SQLab with that in Optimization Queue.

Also, to help check if it is a potential problem, please save the tuning session into file (using the Save Session button in SQLab) and then send us the files of the 2 optimization.

Thanks,
Alex