MDX

AS2008 Block Computation

A lot has been said about block computation as it’s the biggest feature coming in AS2008. Basically it means better performing MDX, but as you’d expect it doesn’t mean that all your MDX queries and calculations are going to run faster, just some. But how do you know whether you’re going to benefit? Well, digging through the latest update of AS2008 BOL today I found the following, very detailed description of when you will benefit from these performance improvements:
 
Very interesting… the list of set functions is a bit limited (where is Filter?) but in general it looks like all common calculations are going to get faster.

2 thoughts on “AS2008 Block Computation

  1. chris,
    I am trying to use the following script as a calculated metric, and the performance works great. However, I get an issue when trying to look at the Calculated metric using other attributes from the [Health Care Profesional] dimension like sex or age.

    I got the idea from Mosha. http://sqlblog.com/blogs/mosha/archive/2007/11/22/optimizing-count-filter-expressions-in-mdx.aspx

    sum([Health Care Profesional].[Health Care Professional Key].[Health Care Professional Key],IIF([Measures].[Assignment Day]>0,1,null))

    1. Chris Webb – My name is Chris Webb, and I work on the Fabric CAT team at Microsoft. I blog about Power BI, Power Query, SQL Server Analysis Services, Azure Analysis Services and Excel.
      Chris Webb says:

      What kind of problem are you hitting? An error, incorrect results or slow performance? If it’s incorrect results, try
      sum(existing [Health Care Profesional].[Health Care Professional Key].[Health Care Professional Key].members,IIF([Measures].[Assignment Day]>0,1,null))

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