I've one doubt when we would compare size of Fact Index and Fact Table.
In our system , we have implemented one weekly cube where in we usually load daily data into it. This cube is loaded with process chain and has two aggregates created on top of this cube - we have also moved this cube onto BWA for faster reporting.
I check size of Fact Index and Fact Table weekly and found size of fact index increaes 10% week-by-week. Usually , size differ if we would delete data from cube but forget to synch with BWA but in this case we are not deleting any data from cube.
Later I analyzed that process chain by which I upload data into cube is first doing roll up and then it is doing compression so it might be possible that during roll up data get roll up into BWA and later same cube is compressed , thereby reduce actual fact table size but fact index remain same therefore , it may lead to size difference always.
Is my understanding is correct ?. if yes , would it be possible to do compression first then do roll up ?. Have you faced this situation before ?.