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From Reto Bachmann-Gmür <r...@wymiwyg.com>
Subject Re: ERROR: Quad: object cannot be null
Date Fri, 12 Jul 2013 12:55:22 GMT
Hi Minto

>From the stacktrace we see that the query is not fastlaned (this is
because it is directed against all graphs). I'm not sure what's going
wrong. Maybe something in JenaGraphAdaptor.java. Would be ineteresting
to see if and how the value got from jena in JenaGraph.java:88
differst from the value returned to jena in JenaGraphAdaptor.java:115
After all all that happens is a wrapping to clerezza and wrapping back
to jena. We could add some optimization here but it should work
nevertheless.

Cheers,
Reto

On Fri, Jul 12, 2013 at 2:34 PM, Minto van der Sluis <minto@xup.nl> wrote:
> Hi Folks,
>
> I ran into some odd behaviour when doing a simple query (counting the
> number of graphs). This is the query I used:
>
> SELECT (COUNT(DISTINCT ?graphName) as ?nrOfGraphs)
> WHERE {
>   GRAPH ?graphName {
>     ?s ?p ?o
>   }
> }
>
> Running this query while using Clerezza gives me a "Quad: object cannot
> be null" (see stack trace below). However the exact same query using
> Jena Fuseki result in a proper answer. Both Clerezza and Fuseki are
> configured to use the exact same TDB storage on disk. Fuseki gives the
> following response:
>
> --------------
> | nrOfGraphs |
> ==============
> | 20538      |
> --------------
>
>
> Using Clerezza from a while ago seems to run the query just fine
> (although it takes way to long to respond).
>
> Now I wonder whether this behaviour is cause by recent Clerezza changes,
> but I am not sure about this. Maybe there is another cause.
>
> Anyone a clue?
>
> Regards,
>
> Minto
>
> Stacktrace:
> =========
> 2013-07-12 12:39:49,093 | ERROR | qtp2144814644-44 |
> RestAnnotationService            | us.rest.dm.RestAnnotationService  165
> | 213 - tmvplus-remote - 0.6.3.SNAPSHOT | Quad: object cannot be null
> java.lang.UnsupportedOperationException: Quad: object cannot be null
>         at com.hp.hpl.jena.sparql.core.Quad.<init>(Quad.java:63)
>         at com.hp.hpl.jena.tdb.lib.TupleLib.quad(TupleLib.java:162)
>         at com.hp.hpl.jena.tdb.lib.TupleLib.quad(TupleLib.java:153)
>         at com.hp.hpl.jena.tdb.lib.TupleLib.access$100(TupleLib.java:45)
>         at com.hp.hpl.jena.tdb.lib.TupleLib$4.convert(TupleLib.java:87)
>         at com.hp.hpl.jena.tdb.lib.TupleLib$4.convert(TupleLib.java:83)
>         at org.apache.jena.atlas.iterator.Iter$4.next(Iter.java:301)
>         at
> com.hp.hpl.jena.tdb.store.GraphTDBBase$ProjectQuadsToTriples.next(GraphTDBBase.java:175)
>         at
> com.hp.hpl.jena.tdb.store.GraphTDBBase$ProjectQuadsToTriples.next(GraphTDBBase.java:163)
>         at
> com.hp.hpl.jena.util.iterator.WrappedIterator.next(WrappedIterator.java:94)
>         at
> org.apache.clerezza.rdf.jena.storage.JenaGraphAdaptor$1.next(JenaGraphAdaptor.java:115)
>         at
> org.apache.clerezza.rdf.jena.storage.JenaGraphAdaptor$1.next(JenaGraphAdaptor.java:96)
>         at
> org.apache.clerezza.rdf.core.impl.AbstractTripleCollection$1.next(AbstractTripleCollection.java:83)[
> 181:org.apache.clerezza.rdf.core:0.13.0.SNAPSHOT]
>         at
> org.apache.clerezza.rdf.core.impl.AbstractTripleCollection$1.next(AbstractTripleCollection.java:72)[
> 181:org.apache.clerezza.rdf.core:0.13.0.SNAPSHOT]
>         at
> org.apache.clerezza.rdf.jena.facade.JenaGraph$1.next(JenaGraph.java:99)
>         at
> org.apache.clerezza.rdf.jena.facade.JenaGraph$1.next(JenaGraph.java:88)
>         at
> com.hp.hpl.jena.util.iterator.WrappedIterator.next(WrappedIterator.java:94)
>         at
> com.hp.hpl.jena.mem.TrackingTripleIterator.next(TrackingTripleIterator.java:47)
>         at
> com.hp.hpl.jena.mem.TrackingTripleIterator.next(TrackingTripleIterator.java:31)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterTriplePattern$TripleMapper.hasNextBinding(QueryIterTriplePattern.java:153)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterRepeatApply.hasNextBinding(QueryIterRepeatApply.java:81)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterBlockTriples.hasNextBinding(QueryIterBlockTriples.java:64)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterProcessBinding.hasNextBinding(QueryIterProcessBinding.java:60)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.main.iterator.QueryIterGraph$QueryIterGraphInner.hasNextBinding(QueryIterGraph.java:123)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterRepeatApply.hasNextBinding(QueryIterRepeatApply.java:81)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterGroup$1.initializeIterator(QueryIterGroup.java:85)
>         at
> org.apache.jena.atlas.iterator.IteratorDelayedInitialization.init(IteratorDelayedInitialization.java:37)
>         at
> org.apache.jena.atlas.iterator.IteratorDelayedInitialization.hasNext(IteratorDelayedInitialization.java:47)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterPlainWrapper.hasNextBinding(QueryIterPlainWrapper.java:54)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterProcessBinding.hasNextBinding(QueryIterProcessBinding.java:60)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterConvert.hasNextBinding(QueryIterConvert.java:59)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:40)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:40)
>         at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:112)
>         at
> com.hp.hpl.jena.sparql.engine.ResultSetStream.hasNext(ResultSetStream.java:72)
>         at
> org.apache.clerezza.rdf.jena.sparql.ResultSetWrapper.<init>(ResultSetWrapper.java:40)
>         at
> org.apache.clerezza.rdf.jena.sparql.JenaSparqlEngine.execute(JenaSparqlEngine.java:115)
>         at
> org.apache.clerezza.rdf.core.access.TcManager.executeSparqlQuery(TcManager.java:294)
>         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native
> Method)[:1.7.0_25]
>         at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)[:1.7.0_25]
>         at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)[:1.7.0_25]
>         at java.lang.reflect.Method.invoke(Method.java:606)[:1.7.0_25]
>         at
> org.apache.aries.proxy.impl.ProxyHandler$1.invoke(ProxyHandler.java:54)
>         at
> org.apache.aries.proxy.impl.ProxyHandler.invoke(ProxyHandler.java:119)
>         at
> org.apache.clerezza.rdf.core.access.$TcManager552685843.executeSparqlQuery(Unknown
> Source)
>         at
> nl.overheid.stelsel.digimelding.astore.storage.clerezza.ClerezzaStorageProvider.query(ClerezzaStorageProvider.java:250)
>         ...
>

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