Distributed Structural and Value XML Filtering
Many XML ﬁltering systems have emerged in recent years identifying XML data that structurally match XPath queries in an eﬃcient way. However, apart from structural matching, it is considered equally important to deal with valuebased predicates. In this paper, we propose methods to combine both structural and value XML ﬁltering in a distributed environment based on distributed hash tables. Structural matching is performed using automata, while we study different methods for evaluating value-based predicates. As a result, our algorithms scale in both the size of the query set and the number of the predicates per query. We perform an experimental evaluation and demonstrate the strengths and weaknesses of the proposed methods in both a controlled environment of a cluster and on a real testbed provided by the PlanetLab network.