A Join and Aggregate Algorithm for Complex Multi-Dimensional Hierarchies

Enormous volume of data reside in data warehouse, so it is important to process efficiently expensive queries including join and aggregate operation. In this paper, a new method （JACMDH algorithm） is proposed for processing time-consuming join and aggregate operation. This algorithm takes into consideration the characteristics of the complex multi-dimensional hierarchies and adopts hierarchy combined surrogate/pre-grouping and pre-sorting on the basis of bitmap join index. It improves the join and aggregate efficiency by translating join and aggregate operation of complex multi-dimensional hierarchies into range queries of fact table. The performance analysis and the experimental result, show that the performance of JACMDH algorithm can be improved dramatically, compared with current method for aggregation query evaluation.