DAX Performance

Bill Anton reminds me that I don’t know a thing about DAX:

As you can see, using DAX variables is a much better solution than using the aliases…the performance improvement is about the same, however, variables we can wrapped up in the calculated measures inside the model allowing us to take advantage of the performance gain with all tools (not just those allowing us to hand-craft the DAX queries).

The query used in this post is too simple to highlight the performance benefit (small data dataset, simple calculation)…but it did make it easier to cruise the query plans and SE requests. In reality, a better use case for highlighting the performance benefits of these optimizations is with a query that hammers the Formula Engine (FE).

Interesting stuff, even for someone with no knowledge of DAX.

Related Posts

Table Variables And Parallelism

Erik Darling shows your brain on table variables: Inserts and other modifications to table variables can’t be parallelized. This is a product limitation, and the XML warns us about it. The select could go parallel if the cardinality estimate were more accurate. This could potentially be addressed with a recompile hint, or with Trace Flag […]

Read More

DAX: Caching And IF Statement Optimization

Kevin Feasel

2018-06-05

DAX

Marco Russo shows us a way of improving performance on conditional statements: Consider the following measure. 1 2 3 4 5 Margin := IF (     [Sales Amount] > 0 && [Total Cost] > 0,     [Sales Amount] - [Total Cost] ) The basic idea is that the difference between Sales Amount and Total Cost should be […]

Read More

Categories

November 2015
MTWTFSS
« Jan Dec »
 1
2345678
9101112131415
16171819202122
23242526272829
30