Content-aware DataGuides: Interleaving IR and DB indexing techniques for efficient retrieval of textual XML data

Not only since the advent of XML, many applications call for efficient structured document retrieval, challenging both Information Retrieval (IR) and database (DB) research. Most approaches combining indexing techniques from both fields still separate path and content matching, merging the hits in an expensive join. This paper shows that retrieval is significantly accelerated by processing text and structure simultaneously. The Content-Aware DataGuide (CADG) interleaves IR and DB indexing techniques to minimize path matching and suppress joins at query time, also saving needless I/O operations during retrieval. Extensive experiments prove the CADG to outperform the DataGuide [11,14] by a factor 5 to 200 on average. For structurally unselective queries, it is over 400 times faster than the DataGuide. The best results were achieved on large collections of heterogeneously structured textual documents.