基于语义贡献值的XML查询缓存替换策略

摘要

Traditional cache replacement strategy lacks pertinence to the semantic cache, and it can not reuse the data in cache effectively, it affects the performance of the cache.This paper proposes an eXtensible Markup Language(XML) query cache replacement strategy based on semantic contribution value for the characteristics of XML query algebra.It processes cluster analysis according to the cache item of user history query, forecasts the semantic contribution values of future query, and replaces the item which has minimum value of semantic contribution in insufficient space.Experimental results show that this strategy can effectively shorten the inquires time, and improves cache hit than both Least Frequency Used(LFU) and Least Recently Used(LRU).%传统缓存替换策略对语义缓存替换缺乏针对性,不能有效重用缓存中的数据,影响缓存命中率.为此,针对可扩展标记语言查询(XML)代数查询的特点,提出一种基于语义贡献值的XML查询缓存替换策略,根据用户历史查询的缓存项进行聚类分析,预测其对未来查询的语义贡献值,当缓存空间不足时替换语义贡献值最小的项,从而提高用户查询效率.实验结果表明,相比最不经常使用策略和最近最少使用策略,该策略能有效缩短查询时间,提高缓存命中率.