Description
Efficient XML filtering has been the fundamental technique in recent Web service and XML publish/subscribe applications. In this article, we consider the problem of filtering a streaming XML data efficiently against a large number of branch XPath queries. To improve the performance of XML filtering, branch queries are grouped into similar queries, and the common paths between queries in the same group are identified. After performing structural matching of queries, queries are organized in a way that multiple queries can be evaluated simultaneously in the post-processing phase. In the post-processing phase, join operations are executed in a pipeline fashion, and intermediate join results are shared amongst the queries in the same group. As a result, the total number of join operations performed in the post-processing phase is significantly reduced. In addition, we also present how to efficiently return all matching elements for each matching branch query. Experiments show that our proposal is efficient and scalable compared to previous work.