How to discover the capabilities of a SPARQL endpoint en route to enhancing SPARQL-FED usage from Virtuoso instances.

There are features supported in Virtuoso SPARQL that aren't supported by other SPARQL engines. There are also a lot of Virtuoso instances behind bubbles in the LOD cloud. Net effect, a Virtuoso instance operator is faced with varied behavior when attempting to use SPARQL-FED functionality.

Run this command to load metadata (or lack thereof) from an external SPARQL endpoint:

SPARQL LOAD SERVICE <{sparql-endpoint-iri> DATA
  1. Run:

    Query result:
     Load service <> data -- done.
     Trying to query <> as SPARQL web service endpoint, POST mode...
  2. Check the retrieved data:

    SELECT *
      FROM virtrdf:
           <> ?p ?o
     LIMIT 10
    Query result:
    p                                                                o
    ANY                                                              ANY                000037ff