Facilitating XML Query Processing Via Execution Plan

Abstract

XML queries are based on path expressions which are composed of some elements connected to each other in a tree pattern structure, called Query Tree Pattern (QTP). Thus, the core operation of XML query processing is finding all instances of QTP in the XML document. A number of methods are offered for QTP matching, but they process too many elements in XML document while most of them have no opportunity to participate in the final result. In this paper we propose a novel method which doesn’t blindly processes elements of the document. We use a query execution plan called ResultGraph generated by execution of path expression on the abstraction of the XML document called QueryGuide. In contrast to the existing methods, in our method only elements in the document which have the same tag name as the leaves of QTP are processed. Also we only process elements which have a chance to produce a result and those which are definitely not part of any final result are ignored. Experimental results show the efficiency of our method.