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amit.s 8 posts Joined 03/10
08 Jun 2010
Problem with DBQLogTbl data

According to my understanding, the value returned by subtracting StartTime from FirstRespTime should be equal to AMPCpuTime. But this doesnt seem to work. Can anyone please help me understand how are all these values related/calculated?

dnoeth 4628 posts Joined 11/04
08 Jun 2010

No,
FirstRespTime - StartTime is the elapsed time needed to create the answer set.

AMPCpuTime is the cpu seconds used by all AMPs to create that answer set.
As you got lots of CPUs you might have lots of cpu seconds per second runtime.

Dieter

Dieter

monisiqbal 119 posts Joined 07/09
09 Jun 2010

Also, AmpCpuTime should be a subset of the FirstRespTime - FirstStepTime. Please correct me if I'm wrong.

pawan0608 101 posts Joined 12/07
10 Jun 2010

Not exactly, AmpCpuTime / NumOfActiveAMPs would be subset of FirstRespTime - FirstStepTime,where NumOfActiveAMPs <>0

AbeK 24 posts Joined 08/09
26 Jul 2010

AMPCPUTime is the constant across any system if you need to gauge a SQL, the firstresptime - firststeptime will provide you with the elapsed time, the end user would experience as a response time and this will depend on the workload on the system and the adept place for the phrase 'your mileage may vary'.

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