QUETSAL is a novel query engine that combines a global join-aware source selection approach based on common prefixes with SPARQL query re-writing for federated SPARQL query processing. We compared our approach with state-of-the-art SPARQL query federation engines in terms of efficient source selection and overall query runtime on FedBench. Our evaluation shows that QUETSAL is the first engine to remain under 5% overall relevant sources overestimation with average source selection time under 160 msec. Moreover, our approach outperforms existing engines with respect to its execution time on most of the FedBench queries.
Following are the relevant AKSW projects to QUETSAL.