BitCube: A Bottom- Up Cubing Engineering

Enhancing on line analytical processing through efficient cubecomputation plays a key role in Data Warehouse management. Hashing,grouping and mining techniques are commonly used to improve cubepre-computation. BitCube, a fast cubing method which uses bitmapsas inverted indexes for grouping, is presented. It horizontally partitionsdata according to the values of one dimension and for each resulting fragment it performs grouping following bottom-up criteria. BitCube allowsalso partial materialization based on iceberg conditions to treat largedatasets for which a full cube pre-computation is too expensive. Spacerequirement of bitmaps is optimized by applying an adaption of theWAH compression technique. Experimental analysis, on both syntheticand real datasets, shows that BitCube outperforms previous algorithmsfor full cube computation and results comparable on iceberg cubing.Keywords: Data Mining, Cubing, Data Warehouse, Bitmap.