ABSTRACT An Evaluation of XML Indexes for Structural Join

XML queries differ from relational queries in that the former are expressed as path expressions. The efficient handling of structural relationships has become a key factor in XML query processing. Many index-based solutions have been proposed for efficient structural join in XML queries. This work explores the state-of-the-art indexes, namely, B +-tree, XB-tree and XR-tree, and analyzes how well they support XML structural joins. Experiment results indicate that all three indexes yield comparable performances for nonrecursive XML data, while the XB-tree outperforms the rest for highly recursive XML data. 1