A tale of two approaches: Query performance study of XML storage strategies in relational databases

Abstract

Several recent papers have investigated a relational approach to store XML data and there is a growing evidence that schema-conscious approaches are a better option than schema-oblivious techniques as far as query performance is concerned. This paper studies three strategies for storing XML document including one representing schema-conscious approach (SHARED-INLINING) and two representing schema-oblivious approach (XParent and SUCXENT++). We implement and evaluate each approach using benchmark non-recursive XQueries. Our analysis shows an interesting fact that schema-conscious approaches are not always a better option than schema-oblivious approaches! In fact, it is possible for a schema-oblivious approach (SUCXENT++) to be faster than a schema-conscious approach (SHARED-INLINING) for 55% of the benchmark queries (the highest observed factor being 87.8 times). SUCXENT++ also outperforms XParent by up to 1700 times. © Springer-Verlag Berlin Heidelberg 2006.