Exception when using SPARQL sort & statement identifiers

[raoulw]

Hi,

I have some data in my Bigdata store with attached statement identifiers (say http://example.com). When executing the following SPARQL query (with sort statement):

SELECT DISTINCT ?property ?hasValue ?isValueOf
WHERE {
  { ?isValueOf ?property <http://example.com> }
}
ORDER BY (!BOUND(?hasValue)) ?property ?hasValue ?isValueOf

an exception is thrown:

java.lang.ClassCastException: com.bigdata.rdf.internal.impl.bnode.SidIV cannot be cast to org.openrdf.model.Literal

Without the ORDER BY everything is fine. Is this a bug or am I doing something wrong here? (see attachment for full stack trace).

Thanks,
Raoul

[raoulw]

Stack trace

[thompsonbry]

Raoul,

Looks like a bug. I've been able to reproduce this on our end when comparing two SIDs. There also appears to be an ordering problem when comparing a SID and a URI (SIDs should be ordered before URIs if they are modeled as blank nodes).

I've expanded test coverage for this and modified the IVComparator to order SIDs (a) after normal blank nodes; and (b) lexically using their internal IV representation (this will group solutions with the same SidIV together).

You can update from SVN and test the fix if you like.

Committed revision r6085.

Thanks,
Bryan