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Message Posted: Thu, 21 Jan 2010 @ 13:50:47 GMT

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These are measures of performance based upon DBQL logs and you can set your own limits as to what is acceptable in your environment.

IOEFF describes IO skewing and for we look for IOEFF to be less than 1.25 on large queries.

CPUEFF describes CPU skewing, and again we expect it to be less than 1.25 on large queries.

SUMCPU is the CPU consumed by the query. This can be used to identify highly consumptive queries (for example, those using more than 25,000 CPU).

IMPACTCPU is SUMCPU multiplied by CPUEFF. It projects the "impact" of a query on a parallel system based upon the peak amp. It can be used the same was as SUMCPU to identify highly consumptive queries or queries taking a toll on the parallelism of the system.

PJI is a measure of CPU consumption in relation to IO. For mid-sized to large-sized queries we look for this number to be less than 6.0. A higher number "may" indicate an inordinately large product-join or some other problem.

Thanks.

Dirk Anderson
Architect
Enterprise Information Management

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