DAX optimization is essential for high-performing Power BI reports. Power BI developer should use variables to store intermediate results, reducing the number of repeated calculations. When working with large datasets, avoid using the "ALL" function excessively as it can slow down performance. Use appropriate functions like SUMX, AVERAGEX, and CALCULATE judiciously, and prefer simpler functions that require less processing. Aggregating data in SQL or other databases before bringing it into Power BI can also minimize complex DAX queries. Efficient DAX expressions help ensure faster calculations and report responsiveness.
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