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.