Using 2.10.0 jena.core and arq with an in-memory model, I am getting a
warning:
WARN [2013-03-23 14:06:34,218]
com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorCheck: Open iterator:
QueryIterSingleton/40500
...when closing the QueryExecution for the following query:
select (count(distinct ?a) as ?n)
where {
?a a <urn:example.com:Something> .
?a <urn:example.com:hasSomethingElse> ?c .
}
In this case the count happens to be zero.
If I take out the second pattern in the where clause, the count is
2000-something and there is no warning about an open iterator.
The last bit of the stack trace looks like:
QueryIteratorCheck.dump(ExecutionContext, boolean) line: 87
QueryIteratorCheck.checkForOpenIterators(ExecutionContext) line: 59
QueryIteratorCheck.close() line: 50
QueryIteratorCloseable(QueryIteratorWrapper).closeIterator() line: 50
QueryIteratorCloseable(QueryIteratorBase).close() line: 185
QueryIteratorCloseable.close() line: 39
QueryExecutionBase.close() line: 168
