Known Issues and Limitations

This section describes limitations and known issues related to the Dimension Calculation Groups.

Tableau formatting Limitation

Tableau allows workbook designers to control Numeric Formatting options for Measures, not table columns or rows. Consequently, a singular Measure formatting option is applied to all metric values produced by a Calculation Group, effectively ignoring AtScale's Calculation Group Format option.

To work around this limitation, it is recommended that you change the Calculation name in AtScale from "Percentage" to "Fraction". This way it should be more clear to the report audience that they are not viewing percentages.

If you are willing to hide the non-percentage calculations, you can do this in Tableau in the following way:

  1. Use the Filters panel to uncheck all non-percentage calculations from the Calculation Group.

  2. For Floating Point measures:

    1. Click on the Measure Value's pill and select "Format" from the context menu to expose the Formatting form.
    2. In the "Numbers" select list, choose "Percentage".
  3. For Integer measures:

    1. Follow the Floating Point measures steps above.

    2. Click on the Measure Value's pill and select "Measure ()" and choose "Average".

      This will cause Tableau to treat the integer value as a floating point number, and apply the formatting set in the previous step.

As a reminder, non-additive measures, such as Count Distinct measures, do not produce visually additive subtotals or grand totals. As a result, formatting these measures as Percentages will result in subtotals and grand totals that do not equal 100%.


Formatting Dimension Calculation Groups in Power BI

Power BI ignores the Calculation Format String specified in a Calculation Group Calculation. For example, if the Format string is set to "Percent" for the "Percent of Total" calculation, the expected result is that Power BI displays the value multiplied by 100, rounded to the desired number of decimal places, and shown with a '%' symbol. Instead, Power BI displays the unformatted floating point value.

In this case, it is recommended that the Calculation Group expression be customized by multiplying by the desired factor and the Calculation Name updated to include the '%' symbol.


Query Limitation

You should use only one Dimension Calculation Group in a Query at time. Using more than one would result in either empty results or a query error.


Performance recommendation

The run-time duration of queries using Calculated Dimension Groups is directly proportional to the type and number of calculations defined in the Calculation Group. Therefore, it is recommended to limit the number of calculations in a single Dimension Calculation Group to no more than 5 calculations.