SCEND: An Efficient Semantic Cache to Adequately Explore Answerability of Views

摘要

Maintaining a semantic cache of materialized Xpath views inside or outside the database, is a novel, feasible and efficient approach to accelerate XML query processing. However, the main problems of existing approaches are that, they either can not exploit sufficient potential cached views to answer an issued query or need too much time for cache lookup. In this paper, we propose, SCEND, an efficient Semantic Cache based on dEcompositioN and Divisibility, which adequately explores the answerability of views, and speeds up cache lookup dramatically. We decompose complex Xpath queries into some much simpler and tractable ones to improve cache hit rate, moreover, we introduce a notion of the divisibility between two positive integers to accelerate cache lookup. In addition, we present a new replacement technique for SCEND to improve performance for caching. We experimentally demonstrate the efficiency of our caching techniques and performance gains obtained by employing such a cache.