关键词: 数据仓库, 位图索引, 多维查询, 编码

Abstract: The storage requirements for simple bitmap index is unacceptable when cardinality （the number of distinct values）of the attribute is very high. A common approach to solve this problem is to build bitmap index with binning. This technique builds a bitmap for each bin in a certain attribute range rather than distinct values. But this approach cause the time waste during candidate check because candidate check usually dominates the most of query processing time. In order to improve query performance, a new sort method for attributes was propsed to reduce the number of candidate check. And then a dynamic prescan algorithm was proposed. The experimental results show that our approach has a significant improvement over traditional strategies.

Key words: data warehouse, bitmap index, multi-dimensional query, encoding