This article describes the types of relationships available in Power BI and Analysis Services, clarifying the differences in cardinality and filter propagation of physical relationships.  Read more

This article describes the reasons why an Excel pivot table may be slow when using the Analyze in Excel feature of Power BI.  Read more

Another year has gone by and it has now been 10 years since DAX was first introduced in late 2009. As usual, it is time to review the past year and to take a look at the year ahead.  Read more

If you created a Tabular model using one of the preview versions (CTP, RC, …) of Analysis Services 2019, you don’t have the final structure for the Ordinal attribute that Microsoft defined in the final version of compatibility level 1500.…  Read more

This article describes the differences between eager evaluation and strict evaluation in DAX, empowering you to choose the best evaluation type for your data models.  Read more

This article describes how blank values considered in a DAX conditional expression can affect its query plan and how to apply possible optimizations to improve performance in these cases.  Read more

I often get questions about use cases for Azure Analysis Services. So I wanted to do a quick recap of the points I commonly discuss in these conversations, and have them readily available for the next conversation… As a bonus,…  Read more

This article provides information to help choose between DAX and Power Query when a table needs to compute additional columns.  Read more

In 2015 I released the first version of VertiPaq Analyzer, a tool to quickly analyze the structure and data distribution of a Tabular model that can be used with Analysis Services and Power BI.  Read more

The second edition of The Definitive Guide to DAX is now available worldwide! This blog post explains why we felt the need to rewrite the book and describes what happens behind the scenes when producing a book.  Read more