Abstract
Data streams have been gaining importance over last few years as the information systems have become more complex and users have required up-to-date data. Processing data streams, however, causes difficulties since traditional data management systems are not optimized for particular features of data streams.
A flexible data item structure in XML data streams, varying arrival rate and bursts of data items, blocking operators in queries and system scalability; these are only few of issues that are need to be solved before the XML data stream management becomes common part of information systems. The purpose of this paper is to summarize current results on XML data stream processing, provide real-world motivation to study XML data streams, show the main problems in XML stream processing (e.g. approximate results in querying and data mining) and point out open issues for future research.