This article describes how variables should be used in DAX expressions involving IF and SWITCH statements in order to improve performance.  Read more

Estimating the cardinality of iterators is an important skill when optimizing DAX code. This article explains how to use this technique, evaluating different ways of computing the number of working days between two dates.  Read more

This article describes possible optimization approaches to improve the performance of nested iterators in DAX.  Read more

This article describes how to optimize DAX expressions with mutually exclusive calculations that might cause slow query performance.  Read more

This article describes a very common optimization pattern that relies on variables to optimize conditional expressions in DAX.  Read more

This article describes how to use DAX Studio to capture DAX queries generated by Power BI. Analyzing DAX queries can be helpful to better understand performance issues, and to improve the writing of DAX queries.  Read more

This article describes how to use variables to optimize the performance of DAX expressions containing multiple instances of the same measure or the same sub-expression.  Read more

DAX Studio 2.7 largely improved the debug experience by adding several feature described in this video: Tooltips for column statistics, capture all queries, and generate dependent measures.  Watch now

This article explains how to correctly measure the dictionary size of a column in a model created in Power BI, Power Pivot, or Analysis Services Tabular.  Read more

This article presents different techniques to compute a rownumber column in DAX based on a specific ranking, comparing slow and optimized approaches.  Read more