[Mondrian] Better understanding of hierarchies without an All Member

[Julian Hyde]

I don't recall exactly what RolapResult.loadSpecialMembers is doing; you may get some enlightenment by turning on "git annotate" and looking at the features that Richard Emberson was working on when we created that code. That is old code, and it is just possible that it is not needed.

A word about default members and "all" members. In general, we should use the default member of a hierarchy, not its all member. This applies especially to hierarchies mentioned in the MDX query. So, any code that is explicitly using the "all" member should be viewed skeptically.

But deeper down in the code, far away from the MDX, there are places where we want a hierarchy "not to have a filtering effect". This occurs, for example, when pulling dimensions into a virtual cube. For this reason, we make sure that every hierarchy internally has an "all" member, even if the user explicitly asked that it did not have one.

Julian