Building a scalable native XML database engine on infrastructure for a relational database

We describe the architecture and some aspects of System R/X, a native XML database engine that is built on the same mature infrastructure for a relational database and integrated with the relational engine. We describe what parts of the infrastructure can be reused, what need to be extended, and what are totally new to the XML database and their techniques. Our overall strategy is to base XML storage and search on the scalable relational technology with substantial extensions. Many techniques are novel to our knowledge. We also provide perspectives along the discussion and point out some open research issues.