When comparing CPU consumption time between DBQLogTbl.AMPCPUTime and DBC.Acctg against User/Hour/Day, we notice difference in CPU time recorded. Sometime a net difference of 1-2% recorded high or less in Acctg when compared to DBQL.
What makes this difference, is this difference in CPU is respect to Query type or system internal resource.
Appreciate your inputs.
even if you log all SQL in DBQL the resource usage of the last step of an aborted query will be missing (afaik 14.10 should fix this).
Assuming you have Account String Expansion on day/hour: all resource usage for a query runing for multiple hours will be logged into a single row in AmpUsage.
And the algorithms for collections are a bit different, when you compare the same query in DBQL/AmpUsage there will be a small difference.
So 1-2% difference is perfectly fine :-)