Efficient algorithms for evaluating xpath over streams
Gang Gou, Rada Y. Chirkova · 2007
In this paper we address the problem of evaluating XPath queries over streaming XML data. We consider a practical XPath fragment called Univariate XPath, which includes the commonly used '/' and '//' axes and allows *-node tests and arbitrarily nested predicates. It is well known that this XPath fragment can be efficiently evaluated in O(|D||Q|) time in the non-streaming environment, where |D| is the document size and |Q| is the query size. However, this is not necessarily true in the streaming environment, since streaming algorithms have to satisfy stricter requirement than non-streaming algorithms, in that all data must be read sequentially in one pass. Therefore, it is not surprising that state-of-the-art stream-querying algorithms have higher time complexity than O(|D||Q|).