Question

My Power BI report is slow when using multiple DISTINCTCOUNT() measures—what optimization techniques should I use?
I have a Power BI report that uses multiple DISTINCTCOUNT measures across large datasets, causing slow performance. What are the best optimization techniques, such as using summarization tables, pre-aggregating data, or restructuring DAX calculations, to improve report speed?

Answer 1

Here are a few ways to tune DISTINCT COUNT() in Power BI:

✔ Create summary tables to aggregate data beforehand and thereby cut the number of rows.
✔ Use APPROXIMATE DISTINCT COUNT () for faster performance when total accuracy is not a concern.
✔ Put DISTINCT COUNT () in a variable so it is not calculated more than once.
✔ Filter before counting to reduce dataset size.
✔ Use COUNTROWS(VALUES()) instead of DISTINCTCOUNT() on summarized data wherever applicable.

These techniques speed up reports and conserve memory.