1 Reply Latest reply on Jan 4, 2017 3:24 PM by Patrick A Van Der Hyde

    Performance recording - Why do 'Computing Total', 'Computing Layout' events run queries against DB?

    Sukumar Semalaiappan

      I have a Tableau 10.0 worksheet setup in LIVE mode pointing to Microsoft Database data source. It does aggregation on five dimensions and two measures, and has a subtotal enabled on one of those dimensions. I am debugging a performance issue on this worksheet using Performance Recording feature and here is what I have noticed on Performance Summary.

       

      Tableau has executed three SQLs,

      1.     A query to calculate aggregations on 5 dimensions and 2 measures (let's call it Main Query)
      2.     A query to calculate Subtotal on one of those dimension, running in parallel to 'Computing Totals' event (let's call it Subtotal Query)
      3.     The same 'Main Query' executed again in parallel to 'Computing Layout' event

       

      Why does tableau runs three SQLs while the chart can be created just using one query (the subtotals can be derived from Main query itself)? More importantly why does it execute the 'Main Query' redundantly?

      Worksheet.jpg

      performance.jpg