High-performance XML Storage/Retrieval System
VYasuo Yamane · 2000
This paper describes a system that integrates full-text searching and database technologies for storing XML (eXtensible Markup Language) documents and retrieving information from them while providing a uniform interface. Our main goal with this system is to achieve high-performance, because there will be a large amount of XML documents in the near future if XML becomes a standard for structured documents and data exchange. We have therefore developed techniques for achieving highperformance storage and retrieval of XML documents. For full-text searches, we improved the Structure Index + Text Index model, which references both indexes alternately at retrieval. In our improved method, a hierarchical structure query is converted into a flat structure query by referencing just the structure index, then the optimized query can be quickly processed using only the text index. For storage, we developed an offset space, which is an address space in secondary memory that can compactly store any structure, for example, a tree. We use the offset space to solve the problem that occurs in other methods which store the analyzed result of XML documents as multiple relations in an RDB. In our method, the analyzed result can be stored in a single page in the best case. This makes it superior to other methods which store the analysis results in multiple relations so that storage of N relations needs at least N pages. As a result, generally, our method greatly reduces I/O costs.