Querying XML Documents in Xyleme

XML is a standard to exchange structured data over the Web. It is being widely adopted. Undoubtedly, more and more data on the Web will be in XML form, as more and more DTDs will be available to describe it. Given this, the Xyleme project proposes to study and build a dynamic World Wide XML warehouse, i.e., a data warehouse capable of storing all the XML data available on the planet. Among the many problems addressed by the Xyleme team, we focus in this paper on query processing.