Efficiently computing the top N averages in iceberg cubes

  • Authors:
  • Pauline LienHua Chou;Xiuzhen Zhang

  • Affiliations:
  • School of CS & IT, RMIT University, GPO Box 2476V, Melbourne 3001, Australia;School of CS & IT, RMIT University, GPO Box 2476V, Melbourne 3001, Australia

  • Venue:
  • ACSC '03 Proceedings of the 26th Australasian computer science conference - Volume 16
  • Year:
  • 2003

Quantified Score

Hi-index 0.00

Visualization

Abstract

Data cubes are an enabling approach for efficient on-line analytical processing (OLAP) systems. Iceberg cubes are special cubes consisting of the aggregates of multi-dimensional groups that satisfy user-specified thresholds. When there are a relatively large number of dimensions, the number of groups in an iceberg cube is huge. End users cannot fully understand the aggregate results or directly use them to make a decision. Approaches for the efficient computation of the top n groups have been proposed and have been shown to work well on iceberg cubes with simple aggregate functions such as COUNT and SUM. In this paper, we study the efficient computation of the top n groups with the complex aggregate function AVERAGE. As the average of a sub-group does not increase/decrease monotonically with its super-group, AVERAGE constraints cannot be used directly for pruning. We propose a new technique upper-bounding average which is anti-monotonic and can be used for low-cost effective pruning. Based on a tree structure representing groups, search and pruning techniques are developed, and an algorithm is proposed to compute the top n averages efficiently.