??? A solution to the problem of finding a well-defined encoding discussed by
Wu and Buchmann (1998) can be used to make PMaps more efficient. Bit
string representations of properties and their ordering can be decided using
a well-defined encoding so that fewer pstrings have to be searched. Vertical
partitioning of pstrings may be another way to improve PMap performance.
??? Although useful for our study of the impact of parameters on performance, the
database sizes used here are small compared to real data warehouse applications.
Further investigation into the scalability of PMaps is a topic for future
study.
Indexing in Data Warehouses 20
Copyright ?© 2007, Idea Group Inc. Copying or distributing in print or electronic forms without written permission
of Idea Group Inc. is prohibited.
??? Techniques for compressing bitmap indexes (Wu et al., 2006) increase effi-
ciency of in-memory logical operations. The impact of these techniques on
query processing with PMaps is an open question.
References
Chan, C. Y., & Ioannidis, Y. (1998). Bitmap index design and evaluation. Proceedings
of the ACM SIGMOD International Conference, Seattle, WA (pp. 355-366).
Darira, R., Davis, K. C., & Grommon-Litton, J. (2006). Heuristic design of property
maps. Proceedings of the 9th ACM Workshop on Data Warehousing and
On-Line Analytical Processing, McLean, VA.
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