NULL default measure might improve querying performance

In some cases, it is not obvious or easy to create a default measure in AS2005 cubes.  In fact, there is no default measure by default, which can lead to long query times for queries that specify no measures.  We have seen slow behavior with several query tools that display an initial default query or heavily browse the hierarchies, especially Proclarity. 

Read more in then Nicholas Dritsas blog.