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by needusername 3740 days ago
> What part of parent has not been your experience ?

We have several people in house (I know of 6) who can troubleshoot performance issues. For them the CBO is not a black box and they can explain what is happening and why.

I know of a local consulting company that has several very good people that you can "order". Said consulting company also offers very good CBO courses/workshops.
1 comments
chris_wot 3740 days ago
Really? I have a book on CBO performance troubleshooting from the foremost expert and even he says that he can't fully understand why the CBO does the things it does.

I doubt your in house experts fully understand the Oracle CBO. They may claim they do, but unless they have access to material that isn't public they can't possibly be able to diagnose the CBO fully.

You realise there are over a thousand hidden database parameters, right?

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needusername 3738 days ago
> Really? I have a book on CBO performance troubleshooting from the foremost expert and even he says that he can't fully understand why the CBO does the things it does.

> I doubt your in house experts fully understand the Oracle CBO. They may claim they do, but unless they have access to material that isn't public they can't possibly be able to diagnose the CBO fully.

Maybe. Let me put it this way, so far they could explain all CBO decisions where we had performance issues.

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