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Message Posted: Tue, 29 Jul 2003 @ 23:30:12 GMT

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Hi Michael,

Once a user process doing database work gets acccess to an AMP worker task, it will hold onto that AWT until the step is complete or the query is aborted. The query may not be accumulating very much CPU, but it will hold onto all resources is has obtained, including locks.

However, I don't think such a query could be getting "no" CPU. The minimum relative weight any allocation group can be pushed down to is 1%. If your schmon -m output shows a zero for relative weight, that is usually because there are no decimal places being reported, and the relative weight has come out mathematically to be a fraction (decimal places truncated). Priority Scheduler transforms any relative weight that is less than 1 to 1% when it does its allocating. If you are using an absolute policy, a similar thing is true. You can't ask for a ceiling less than 1%.

One of trade-offs of using penalty boxes is how much you can tolerate queries that get demoted there hanging on to those other resources for a longer duration. In the balance, you may have the ceiling set too low, so you might consider relaxing it a bit. Or it's possible that your algorithm for relocating queries into the penalty box is overly aggressive and too many queries at a time are ending up there. Don't know what your settings are, but I'd avoid a 1% absolute penalty box unless you are relatively confident that no more than 1 or 2 queries are going to be residing there at a time.

Thanks, --Carrie

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