摘要
SPARQL查询过程中产生的大量中间结果严重影响查询效率。针对该问题,提出一种两阶段的查询优化方法。在第一阶段,将查询内含有相同变量的联结划分为一块,通过计算每块内的选择度重新排列联结。在第二阶段,利用属性路径索引对剩余的联结进行中间结果过滤。实验结果表明,该方法能够有效减少查询的中间结果,提高查询的执行效率。
A large number of intermediate results during executing SPARQL query greatly affect the query efficiency.For this,a query optimization method with two phases is proposed.In the first phase,it divides a query that contains the same variable into a block by calculating the selectivity within each block to rearrange the join.In the second phase,it emploies the longest property path index to filter intermediate results.Experimental results show that the proposed method can effectively reduce the number of intermediate results and improve the query performance.
作者
林晓庆
张富
程经纬
LIN Xiaoqing;ZHANG Fu;CHENG Jingwei(School of Computer Science and Engineering,Northeastern University,Shenyang 110819,China;School of Information Engineering,Eastern Liaoning University,Dandong,Liaoning 118003,China)
出处
《计算机工程》
CAS
CSCD
北大核心
2018年第11期7-13,共7页
Computer Engineering
基金
国家自然科学基金(61672139)
辽宁省自然科学基金(2015020048)
关键词
资源描述框架
SPARQL查询
选择度
属性路径
三元组过滤
中间结果
Resource Description Framework(RDF)
SPARQL query
selectivity
property path
triple filtering
intermediate result
