Diagnosis
Flat aggregates can be filled directly with database tools, this means adetour through the ABAP is not necessary and DIMIDs do not have to beretrieved because the characteristic is exactly one dimension and thedimension tables are replaced with a view of the SID table of thecharacteristics (a "Line Item" Dimension). An exception is the package
and unit dimensions, which are both not split into line item dimensions.
Flat aggregates provide performance advantages during data loading(rollup) and possibly also during reporting.
For technical reasons, flat aggregates are not possible for non-cumulative cubes!