Chapter

Intelligent Data Engineering and Automated Learning – IDEAL 2008

Volume 5326 of the series Lecture Notes in Computer Science pp 378-386

Improving the Relational Evaluation of XML Queries by Means of Path Summaries

  • Sherif SakrAffiliated withNational ICT Australia (NICTA)

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Abstract

XML query languages such as XQuery, XSLT and SQL/XML are mainly dependent on XPath as the search and extraction language. XPath expressions often define complicated navigations which require expensive query processing costs especially when they are executed over large collections of XML documents. In this paper, we describe an approach of exploiting materialized XPath views to improve the efficiency of relational query processing of XML queries. The main contribution of this paper is to show that an intuitive and very cheap Data Guide synopsis of XML path summaries in addition a light-wight tracing of XPath steps can significantly reduce the XML query-evaluation costs in the relational hosts. Our experiments shows that the overhead introduced by the use of path summaries and an additional path identifier of node-based relational encoding of the XML documents is negligible but can result in significant reduction of the processing costs of relational evaluation of XML queries.