Multi-query optimization via common sub query elimination for SPARQL

As the main query language on RDF data, SPARQL constantly drawing attention from the Semantic Web communities. In this paper we present a mechanism that can identify common sub queries in multiple RDF queries and eliminate redundant sub queries, significantly improving the efficiency of executing multiple RDF queries, both simultaneously and sequentially. Unlike previous optimization works concentrated on optimizing a single RDF query, our method focus on improving the performance of multiple similar RDF queries, which commonly occur in real world applications related to RDF data. Extensive experiments over benchmark RDF repositories of millions of triples confirm that our method is superior to the state-of-the-art methods when common sub queries exist in multiple SPARQL queries.