Pruning nested XQuery queries

We present in this paper an approach for XQuery optimization that exploits minimization opportunities raised in composition-style nesting of queries. More precisely, we consider the simplification of XQuery queries in which the intermediate result constructed by a subexpression is queried by another subexpression. Based on a large subset of XQuery, we describe a rulebased algorithm that recursively prunes query expressions, eliminating useless intermediate results. Our algorithm takes as input an XQuery expression that may have navigation within its subexpressions and outputs a simplified, equivalent XQuery expression, and is thus readily usable as an optimization module in any existing XQuery processor. We demonstrate by experiments the impact of our rewriting approach on query evaluation costs, and prove formally its correctness.

• Type: Conference
• Year: 2008
• Where: CIKM
• Authors: Bilel Gueni, Talel Abdessalem, Bogdan Cautis, Emmanuel Waller
• Keywords: CIKM 2008, Information Management, XQuery, XQuery Expression, XQuery Queries