SIMP: Efficient XML Structural Index for Multiple Query Processing

XML indexing is an important method for accelerating query processing. Existing structural indexes suffer from the problems of redundant traversal and lack of scalability for answering multiple queries simultaneously. In this paper, we present a novel index called as SIMP, which is an efficient XML structural index for multiple query processing. We first introduce an index to cluster the concerned parts in XML document together and increase the distinction for avoiding redundant traversal. Then we come up with a method for clustering multiple queries efficiently. Based on the indexing methods for both XML document and a set of queries, we propose a novel query processing method, which employs hash operation to answer a set of queries simultaneously and efficiently. For further optimization, we use a suffix tree to explore both the prefix and suffix parts among queries. Experimental results demonstrate that SIMP brings a substantial performance improvement on query performance compared with the existing techniques.