Well, first of all i want to mention that the recommendation, if you connect live to a cube with Power BI, is to make all your new measures in the cube. And keep Power BI just as a reporting interface. So, if you want to make a YTD measure, just do it in the cube, and it will show and can be used afterwards in Power BI.
Import is not really a recommended option, especially if you have a big data model.
But if you decide to try the import there are some advantages and some (bigger i would add) disadvantages:
- Adv:
- Changes and additions can be made to the cubes
- more cubes can be loaded.
- Practically, it uses the SSAS cube as any other source, that can and is intended to be modeled in Power BI.
- Disadv:
- the layout of the measures and dimensions is flattened. All measures and dimensions, attributes etc are listed one after another in a very long list (they are not grouped and separated)
- if you have some kind of calculated measures at low level they will not show and you have to redo them in Power BI
- and then there is the consideration of memory, performance, space depending on what you want to load in the pbix. The way it is intended is to choose just some measures and dimensions that you load in the .pbix and work with those, or even create an MDX/DAX when you load to make filtering in advance, before loading. If you want to load the whole cube with all measures/dimensions it might take long, might run out of memory or space, and might exceed the 1GB limitation, unless you don't have premium.
Regards,
ElenaN
