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Message Posted: Fri, 26 Apr 2013 @ 21:42:48 GMT
| Subj: || || Re: Viewpoint High IMPACT CPU |
| From: || || Anomy Anom |
<-- Anonymously Posted: Friday, April 26, 2013 15:39 -->
IMPACT CPU is Max AMP CPU for the most recent sample period times number of AMPs. The term "impact" reflects the idea that "the system will
only be perceived to be as fast as the slowest (busiest) AMP". DELTA CPU is total CPU consumed across all AMPs during the most recent sample
period. Both these values are used primarily to rank / compare queries running concurrently and not as absolute numbers.
PJI or Product Join Indicator is a ratio between CPU consumption and I/O activity. The higher the number, the more "CPU bound" the query (and
the more impact it is likely to have on other concurrent work). Ratios near 1.0 are typical for many workloads; anything over 3.0 is worth looking
at more closely.