Forum Discussion

Community Champion

5 years ago

DAX Head Scratcher

Looking for some insight into why a DAX calculation coded in a particular way takes absolutely forever to return while a slightly different version returns quickly. I have the sample PBIX included be...

OptionsReport.pbix8.1 MB

Greg_Deckler

Community Champion

5 years ago

Jos_Woolley OK, but where is that captured in the actual DAX query from Performance Analyzer? In both cases the query is the following and I don't see an ALL anywhere:

// DAX Query
DEFINE
  VAR __DS0Core = 
    SUMMARIZECOLUMNS(
      ROLLUPADDISSUBTOTAL(
        ROLLUPGROUP('1OptionMaster'[OptionID], '1OptionMaster'[PlanID], '1Plans'[PlanID]), "IsGrandTotalRowTotal"
      ),
      "v1Frequency", '1OptionMaster'[1Frequency]
    )

  VAR __DS0PrimaryWindowed = 
    TOPN(
      502,
      __DS0Core,
      [IsGrandTotalRowTotal],
      0,
      '1OptionMaster'[OptionID],
      1,
      '1OptionMaster'[PlanID],
      1,
      '1Plans'[PlanID],
      1
    )

EVALUATE
  __DS0PrimaryWindowed

ORDER BY
  [IsGrandTotalRowTotal] DESC,
  '1OptionMaster'[OptionID],
  '1OptionMaster'[PlanID],
  '1Plans'[PlanID]