This release brings the follow changes:
- The Java client can now use the extended SPARQL support addedd by the Sage 1.1 server release
- Join processing is handled using parallelized Bound joins, as introduced in FedX article [1].
- Some UNIONs and FILTERs are now evaluated server-side.
- HTTP requests sent to the server are made using the new SPARQL plain text support, i.e., the client now send SPARQL queries through GET/POST requests.
- Implementation of the OptJoin algorithm, as introduced in the sage WWW'19 article [2]. It speeds up the evaluation of some OPTIONAL clauses.
- Federated query processing using the FedX model: ASK-based source selection, exclusive groups optimization, extended with the OptJoin support.
- CLI updated to support the new federated query processing module.
- Support for parallelizing physical query operators used during query processing.
- More intensive testing.
[1] Schwarte, A., Haase, P., Hose, K., Schenkel, R., & Schmidt, M. (2011, October). Fedx: Optimization techniques for federated query processing on linked data. In International Semantic Web Conference (pp. 601-616). Springer, Berlin, Heidelberg.
[2] Thomas Minier, Hala Skaf-Molli and Pascal Molli. SaGe: Web Preemption for Public SPARQL Query services in Proceedings of the 2019 World Wide Web Conference (WWW'19), San Francisco, USA, May 13-17, 2019