RDFCube: A P2P-Based Three-Dimensional Index for Structural Joins on Distributed Triple Stores

Abstract

Today, RDF data/triples are scattered everywhere and their total size is rapidly increasing. Centralized RDF triple stores have limitations on both their failure tolerance and scalability. Therefore, RDF query processing in a P2P environment is an important issue. So far, several conventional P2P-based RDF triple stores have been proposed. They, however, are designed merely for triple retrieval rather than for triple join query processing. Consequently, they suffer from an unnecessary data transfer problem. This paper presents an RDF query processing technique based on a three-dimensional hash index. The triples are mapped into the index; then bit information that represents the presence or absence of triples in the index is introduced. We implemented our approach on the top of an emulated P2P environment. Evaluation results show that our approach can achieve good performance and scalability.