Technical Report No. 147 - Abstract

Pedro Jose Marron, Georg Lausen
HLCaches: An LDAP-based Distributed Cache Technology for XML

The proliferation of XML and its settlement as the de facto standard for information interchange in Internet, as well as the development of querying languages for XML, like XPath, have lead to a paradigm transition in the Internet database world, where the use of classical database systems has decreased in favor of techniques and standards based on semistructured data models, from which XML is the most prominent example. At the same time, there has been an increase in the support, development and deployment of implementations of the LDAP protocol to store the most varied information. Its data model characteristics lie closer to the semistructured model as to the relational or object model used in traditional database systems, and therefore, its use as a caching system for semistructured databases is fully justified. In this paper, we present the design, internal data representation and query model of HLCaches, a hierarchical distributed caching system for semistructured documents based on LDAP technology that brings both, the semistructured data model and the LDAP data model together into a system that provides the ideal characteristics for the efficient processing of XPath queries over XML documents. We also show transformation algorithms and experimental results that prove the feasibility of HLCaches as a distributed caching system especially tailored for semistructured data.