Release of Sage 1.1: A SPARQL Engine for Public LOD provider

Dear Semantic Web, Linked Data Community,

We are proud to announce the release of Sage 1.1.

Sage is a SPARQL query engine designed for public Linked Data providers.
Thanks to web preemption, the server can run without quotas on query
execution time and consequently process arbitrary long-running queries with
complete results.

The software and an online demo are freely available at:

http://sage.univ-nantes.fr/

The paper explaining the Sage approach [1] is accepted at WWW’19 and
available as a postprint on HAL:
https://hal.archives-ouvertes.fr/hal-02017155

Changes from version 1.0:

Sage Server:

   -

   SPARQL Unions are supported natively.
   -

   Some SPARQL Filters are supported natively. For now, only logical
   expression (<, =, &&, …) are allowed.
   -

   The Sage server API now supports plain text SPARQL queries: you can send
   a SPARQL query using a GET/POST request. See
   http://sage.univ-nantes.fr/documentation for details.
   -

      For example, you can now call
      http://sage.univ-nantes.fr/sparql?query=SELECT+%3Fcc+WHERE+%7B+++%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FBarack_Obama%3E+%3Chttp%3A%2F%2Fwww.w3.org%2F2002%2F07%2Fowl%23sameAs%3E+%3Fcc+.+%7D+&default-graph-uri=http://sage.univ-nantes.fr/sparql/sameAs


Sage JS Client :

   -

   Updated to take advantage of new server features
   -

      Uses parallelized Bound joins, as in FedX.


Sage Java Client:

   -

   Updated to take advantage of new server features
   -

      Uses parallelized Bound joins, as in FedX.
      -

      Some UNIONs and FILTERs are now evaluated server-side.
      -

   OptJoin implementation as described in the WWW’19 paper [1]. The OptJoin
   algorithm 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. See the README of the java client
   https://github.com/sage-org/sage-jena.


Sage Website:

   -

   New preset queries selection UI, highlighting supported SPARQL features.
   -

   GraphQL support (see the GraphQL tab). GraphQL queries are translated
   into SPARQL queries, thanks to [4].
   -

   Automatic VOID description generation:
   -

      http://sage.univ-nantes.fr/void/
      -

      http://sage.univ-nantes.fr/.well-known/void
      -

   New rendering engine based on Mithril.js.
   -

   Monitoring of the progression of query execution. Run the preset query
   <http://sage.univ-nantes.fr/#query=prefix+dbo%3A+%3Chttp%3A%2F%2Fdbpedia.org%2Fontology%2F%3E%0Aprefix+rdfs%3A+%3Chttp%3A%2F%2Fwww.w3.org%2F2000%2F01%2Frdf-schema%23%3E%0A%0ASELECT+%3Fcity+%3Fperson+%3Fname%0AWHERE+%7B%0A++%3Fcity+a+dbo%3ACity%3B%0A++++++++rdfs%3Alabel+%3Fname.%0A++%3Fperson+a+dbo%3APerson%3B%0A++++++++rdfs%3Alabel+%3Fname.%0A%7D%0A&dataset=http%3A%2F%2Fsage.univ-nantes.fr%2Fsparql%2Fdbpedia-2016-04>
   on “Famous people with the same name as a city” to see it in action.


We appreciate your feedback/comments/questions to be sent to our mailing
list [2] or our issue tracker on github [3].

On behalf of the Sage team,

---

Pascal Molli, Hala-Skaf-Molli, Thomas Minier - GDD Team
<https://sites.google.com/site/gddlina/home>, LS2N
<https://www.ls2n.fr/?lang=en>, University of Nantes
<http://www.univ-nantes.fr/>.

[1] 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
https://hal.archives-ouvertes.fr/hal-02017155

[2] sage@univ-nantes.fr

[3] https://github.com/sage-org/sage-engine/issues

[4] https://www.npmjs.com/package/graphql-to-sparql



-- 
Pascal Molli <http://pagesperso.lina.univ-nantes.fr/~molli-p>
Full Professor, Nantes University <http://www.univ-nantes.fr/>
Head of GDD <https://sites.google.com/site/gddlina/>* team*, LS2N
<http://ls2n.fr/>,
UFR de Sciences et Techniques
2, rue de la Houssinière
BP 92208
44322 NANTES CEDEX 3
Tel : +33 251125810
pascal.molli@univ-nantes.fr