Hi Folks,
I ran into an issue is both the existing SingleTdbDatasetTcProvider and
my customized version (see CLEREZZA-736).
How to reproduce:
1) Have some process constantly inject new named graphs (I had a process
injecting 1000 named graphs)
2) perform a query while 1 is still running. I used the following query:
SELECT ?graphName WHERE { GRAPH ?graphName {} } LIMIT 10 OFFSET 0
3) repeat step 2 a number of times (since the error does not always occur)
This results in a ConcurrentModificationException (see stacktrace
below). I am not sure whether this is a Clerezza or Jena issue.
Anyone an idea what is causing this? Or more importantly how to fix it?
Should I create a Jira issue for this?
Regards,
--
ir. ing. Minto van der Sluis
Software innovator / renovator
Xup BV
Stacktrace:
java.util.ConcurrentModificationException: Iterator: started at 7103, now 7105
at
com.hp.hpl.jena.tdb.sys.DatasetControlMRSW.policyError(DatasetControlMRSW.java:157)
at
com.hp.hpl.jena.tdb.sys.DatasetControlMRSW.access$000(DatasetControlMRSW.java:32)
at
com.hp.hpl.jena.tdb.sys.DatasetControlMRSW$IteratorCheckNotConcurrent.checkCourrentModification(DatasetControlMRSW.java:110)
at
com.hp.hpl.jena.tdb.sys.DatasetControlMRSW$IteratorCheckNotConcurrent.hasNext(DatasetControlMRSW.java:118)
at org.openjena.atlas.iterator.Iter$4.hasNext(Iter.java:295)
at
com.hp.hpl.jena.tdb.store.GraphTDBBase$ProjectQuadsToTriples.hasNext(GraphTDBBase.java:173)
at
com.hp.hpl.jena.util.iterator.WrappedIterator.hasNext(WrappedIterator.java:76)
at
org.apache.clerezza.rdf.jena.storage.JenaGraphAdaptor$1.hasNext(JenaGraphAdaptor.java:106)
at
org.apache.clerezza.rdf.core.impl.AbstractTripleCollection$1.hasNext(AbstractTripleCollection.java:78)
at
org.apache.clerezza.rdf.core.access.LockingIterator.hasNext(LockingIterator.java:47)
at
org.apache.clerezza.rdf.jena.facade.JenaGraph$1.hasNext(JenaGraph.java:95)
at
com.hp.hpl.jena.util.iterator.WrappedIterator.hasNext(WrappedIterator.java:76)
at
com.hp.hpl.jena.sparql.engine.iterator.QueryIterTriplePattern$TripleMapper.hasNextBinding(QueryIterTriplePattern.java:151)
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:79)
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.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:79)
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.QueryIterSlice.hasNextBinding(QueryIterSlice.java:76)
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:39)
at
org.apache.clerezza.rdf.jena.sparql.JenaSparqlEngine.execute(JenaSparqlEngine.java:68)
at
org.apache.clerezza.rdf.core.access.TcManager.executeSparqlQuery(TcManager.java:272)
...
