Saturday, February 25, 2012

DefaultMember Slows Down Time Intelligence

I searched for this and found no web hits so I thought I'd post a warning here.

As of SP2, the function Hierarchy.DefaultMember is still not optimized very well in MDX expressions and queries. By replacing it with the literal member equivalent from the hierarchy (eg. Hierarchy.[Current Period]), I've been able to improve performance of my time intelligence queries by a scale of magnitude or more.

As a fair warning about the output from the time intelligence wizard, you need to fix the generated calculations in the following ways:

Get rid of DefaultMember references

Replace * operator for the CrossJoin() function

Hope these hints save others as much time as I've wasted discovering them. Please let me know if anybody else has general hints to improve the performance of time intelligence calculations.

Chris mentioned your post and gave some more guidelines at:

http://cwebbbi.spaces.live.com/Blog/cns!7B84B0F2C239489A!1076.entry

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