Set ActiveFlag to diActive when it is critical that the dimension item is available at all times. Set ActiveFlag to diAsNeeded instead if the dimension item is used less frequently. The decision cube swaps dimension items with Active set to diAsNeeded in and out of the cache depending on when they are actually used, in order to conserve memory. Set ActiveFlag to diInactive to collapse the multidimensional array maintained by the data store so that it does not include the dimension item. When ActiveFlag is diInactive, the data store can not provide information about the dimension item to a decision source object.  

The memory needs of a crosstabulated data store increase geometrically with each active dimension that is included. Memory needs increase linearly with each active summary that is included. Applications must find the best balance between the performance benefit of caching many dimensions and summaries so that they are immediately available to decision controls, and the need to keep the size of the cached multidimensional data array small enough so that it does not consume inordinate amounts of memory. 

GetMemoryUsage 

MaxDimensions 

MaxSummaries