COMPACT DATA STRUCTURES ARE DATA STRUC-TURES THAT ALLOW COMPACTING DATA WITHOUT LOSING THEABILITY OF QUERYING THEM IN THEIR COMPACT FORM. WEPRESENT ALGORITHMS TO EXTEND THE FUNCTIONALITY OF THECOMPACT DATA STRUCTURE CMHD (COMPACT REPRESEN-TATION OF MULTIDIMENSIONAL DATA ON HIERARCHICAL DO-MAINS), WHICH ALLOWS THE COMPUTATION OF AGGREGATEQUERIES WITH SUM FUNCTION ON MULTIDIMENSIONAL MATRICES.WE IMPLEMENT THE REST OF AGGREGATE FUNCTIONS, I.E., FUNC-TIONS MIN,MAX,COUNT AND AVG. WE USE THE CMHD OVERDATA WAREHOUSES (DWS), THAT ARE COLLECTION OF DATAORGANIZED TO SUPPORT THE DECISION-MAKING PROCESS. THEIMPROVEMENT OF E?CIENCY OF QUERY PROCESSING IN DWS ISA VERY IMPORTANT ISSUE. THEREFORE, VARIOUS E?ORTS HAVEBEEN MADE IN THAT DIRECTION, SUCH AS MATERIALIZATION OFVIEWS, USE OF INDEXES, AMONG OTHERS. WE SHOW THROUGHEXPERIMENTATION OVER DWS WITH SYNTHETIC DATA, THAT BYUSING A COMPACT REPRESENTATION OF DWS, WE CAN ACHIEVEBETTER PERFORMANCE IN PROCESSING AGGREGATE QUERIES.