- Recursion in XQuery: put your distributivity safety belt on
- ACM International Conference Proceedings Series
- Pages (from-to)
- Document type
- Faculty of Science (FNWI)
- Informatics Institute (IVI)
We introduce a controlled form of recursion in XQuery, an inflationary fixed point operator, familiar from the context of relational databases. This operator imposes restrictions on the expressible types of recursion, but it is sufficiently versatile to capture a wide range of interesting use cases, including Regular XPath and its core transitive closure operator.
While the optimization of general user-defined recursive functions in XQuery appears elusive, we describe how inflationary fixed points can be efficiently evaluated, provided that the recursive XQuery expressions are distributive. We test distributivity syntactically and algebraically, and provide experimental evidence that XQuery processors can benefit substantially from this mode of evaluation.
- Proceedings title: EDBT 2009, 12th International Conference on Extending Database Technology, Saint Petersburg, Russia
Place of publication: New York
Editors: M. Kersten, B. Novikov, J. Teubner, V. Polutin, S. Manegold