Bitmap-based indexes are known to be the most effective indexing method for retrieving and
answering selective queries in a read-only environment. Various types of encoding bitmap indexes
significantly improve query time efficiency by utilizing fast Boolean operations directly on the index
before retrieving the raw data. In particular, the dual bitmap index improves the performance of equality
queries in terms of the space vs. time trade-off. However, the performance of range queries is
unsatisfactory. In this paper, an optimizing algorithm is proposed to improve the range query processing
for the dual bitmap index. The results of the experiment conducted show that the proposed algorithm,
called Dual-simRQ, reduces the number of bitmap vectors scanned and the Boolean operations
performed, which impacts the overall performance for range query processing.
Keywords
Encoding bitmap indexes, dual bitmap index, range query processing, Dual-simRQ