Update: BETWEEN ... a rock and a hard place

Ahem, well no sooner do you start looking at something then it changes.

While investigating the various fact tables that are used for this reporting exercise, we learn that some of the original requirements were changed post-implementation, as so while we're joining on about six dimensions, only two of them are actually being used. The rest are effectively ...
Where A between and lowest_possible_value and highest_possible_value
So, we'll take out these surplus joins from the universe definition, and see what happens to performance.