Key concepts for native XML processing

Abstract

Over the recent five years, we have designed, implemented, and optimized our prototype system XTC, a native XDBMS providing multi-user read/write transactions and supporting multi-lingual query interfaces (XQuery, XPath, DOM, SAX). We have compared competing concepts in various system layers and iteratively found salient solutions which drastically improved the overall XDBMS performance. XML query processing is critically affected by the smooth interplay of concepts and methods. Here, we focus on the physical level of XML processing: node labeling and mapping options for storage structures; design of suitable index mechanisms; enriched functionality of path processing operators, in particular, for holistic twig joins. In this survey, we outline our experiences gained during the evolution of XTC. We develop "key concepts" to enable fine-grained, effective, and efficient XML processing. © 2010 Springer-Verlag Berlin Heidelberg.