Sparql Filter Issue using IN

[Mark James]

Hi Guys,

We've encountered an issue where one of our automatically constructed queries (in a webservice) is returning incomplete results. We're not using any inferencing. The query mixes the xsd type's in an IN filter.

A simplified version is below -

SELECT ?s ?p ?o 

WHERE { GRAPH <http://acme.com/dataset/blah/7387081998900703837>  {

?s ?p ?o .

?s a <http://acme.com/ontology/event/Event> .

?s ?p1 ?o1 .

FILTER (

(?p1 in (<http://acme.com/ontology/event/AtomicDismissed>,<http://acme.com/ontology/event/SituationStatus>))

&& ((?o1 in ("Ongoing"^^xsd:string, "false"^^xsd:boolean)))

)

}

}

The query will only return triples relating to the first value in the IN filter highlighted in red. So in the example above for values where o1 = Ongoing. Swapping the order only returns triples with an o1 value of boolean false.

I'm assuming this is a bug? I didn't think there was anything in the sparql spec that suggest every value in an IN must be of the same type?

We're producing this on 4.0.5.

cheers

Mark

[Pavel Klinov]

Mark,

You are correct that IN doesn't impose any restrictions on types of the expressions.

Any chance you can send us the data so that we can verify that 4.1.1 doesn't have this problem? 

Also if your queries are of this form, you may gain some performance improvements if you re-write them using VALUES (for ?p1, ?o1) rather than IN or even UNIONs if the number of constants is low. Optimizer in the latest Stardog already converts some of IN filters into VALUES but not (yet) in the presence of boolean connectives.

Best,

Pavel

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[Mark James]

Thanks Pavel,

I hadn't considered using the values filter in this way.

Replacing the filter IN's with the following works. And it is faster to.

values (?p1 ?o1)

  {

    ( <http://acme.com/ontology/event/AtomicDismissed> "Ongoing"^^xsd:string )

    ( <http://acme.com/ontology/event/AtomicDismissed> "false"^^xsd:boolean )

    ( <http://acme.com/ontology/event/SituationStatus> "Ongoing"^^xsd:string )

    ( <http:/acme.com/ontology/event/SituationStatus> "false"^^xsd:boolean )

  }

I'll send some data and the original query to you shortly. It will be good to know if it is indeed fixed for 4.1.1.

cheers

Mark

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Mark James | Smarta Systems Pty Ltd
+61 433 922 944 | mja...@smarta.io | smarta.io