Is Query Folding Taking Place?

Chris Webb has a quick way of seeing if query folding is taking place when importing data from Analysis Services into Power Query (either Power BI or Excel):

As a quick follow-on from last week’s post on how to detect whether query folding is taking place when importing from OData data sources, if you’re importing data from Analysis Services you have a similar problem: how do you know whether query folding is taking place? Ensuring that query folding takes place for as many of the steps in your query – especially those that filter or otherwise reduce the amount of data returned – is very important for data refresh performance.

Although the Power Query engine generates MDX queries when importing from Analysis Services in the same way it generates SQL queries when it imports from a relational database, the View Native Query option doesn’t work for Analysis Services data sources. You can of course use a Profiler trace or xEvents to see the MDX, but for most users that will not be an option for security reasons.

Read on for a better alternative.

Related Posts

Performing Linear Regression With Power BI

Jason Cantrell shows how to create a simple linear regression in Power BI: Linear Regression is a very useful statistical tool that helps us understand the relationship between variables and the effects they have on each other. It can be used across many industries in a variety of ways – from spurring value to gaining […]

Read More

Considerations When Using Sort By Column In DAX

Marco Russo shows us some things to keep in mind when using Sort By Column in DAX: A query in MDX automatically inherits the correct column sort order from the data model; the result of an MDX query is always sorted according to the Sort By Column setting. However, DAX does not have any implicit […]

Read More

Categories

May 2018
MTWTFSS
« Apr Jun »
 123456
78910111213
14151617181920
21222324252627
28293031