This article describes the behavior of the COMBINEVALUES function in DAX, and how it can optimize the performance of DirectQuery with multi-column relationships.  Read more

This white paper describes how to use and optimizing DirectQuery with Analysis Services Tabular.  Read more

This article describes how DAX Studio can analyze the SQL queries sent to a relational database by Power BI or Analysis Services Tabular in DirectQuery mode.  Read more

This article describes a few query limits existing in DirectQuery for both Power BI and Analysis Services Tabular 2016, explaining when you can modify them.  Read more