Is it possible that you have cycles in your subgraphs, in the prop:next predicate?
ajs6f > On Jul 6, 2018, at 3:29 AM, Davide <kasted...@gmail.com> wrote: > > In the dataset I've many not connected subgraphs. And each subgraph has > many chained data. So, when I've to retrieve a subgraph, I execute a query, > where "?a" is the root, and I visit the graph with prop:next+. Am I doing > wrong to handle the problem? > > Thanks > > 2018-07-05 18:07 GMT+02:00 Andy Seaborne <a...@apache.org>: > >> >> >> On 05/07/18 10:52, Davide wrote: >> >>> Hi, >>> I've a question. First I created a TDB dataset with Fuseki, I loaded data, >>> and I make a query adding in the where construct a condition like this: >>> >>> ?a prop:next+ ?next >>> >> >> What does the data look link? >> >> There seems to be an extreme chain of prop:next. >> >> Andy >> >> >> >>> with LIMIT 100 >>> >>> And it worked. >>> Now I create a new TDB2 dataset with Fuseki, I loaded more data than the >>> other time, and I make the same query. But after 2 seconds I obtained this >>> error: >>> >>> "Fuseki WARN [15] RC = 500 : null >>> java.lang.StackOverflowError >>> at >>> org.apache.jena.dboe.base.file.BlockAccessMapped.getByteBuff >>> er(BlockAccessMapped.java:146) >>> at >>> org.apache.jena.dboe.base.file.BlockAccessMapped.read(BlockA >>> ccessMapped.java:91) >>> at >>> org.apache.jena.dboe.base.block.BlockMgrFileAccess.getBlock( >>> BlockMgrFileAccess.java:71) >>> at >>> org.apache.jena.dboe.base.block.BlockMgrFileAccess.getRead( >>> BlockMgrFileAccess.java:61) >>> at >>> org.apache.jena.dboe.base.block.BlockMgrWrapper.getRead(Bloc >>> kMgrWrapper.java:47) >>> at >>> org.apache.jena.dboe.base.page.PageBlockMgr.getRead$(PageBlo >>> ckMgr.java:104) >>> at org.apache.jena.dboe.base.page.PageBlockMgr.getRead(PageBloc >>> kMgr.java:77) >>> at org.apache.jena.dboe.trans.bplustree.BPTreeNode.get(BPTreeNo >>> de.java:159) >>> at >>> org.apache.jena.dboe.trans.bplustree.BPTreeNode.findHere(BPT >>> reeNode.java:476) >>> at >>> org.apache.jena.dboe.trans.bplustree.BPTreeNode.internalSear >>> ch(BPTreeNode.java:462) >>> at >>> org.apache.jena.dboe.trans.bplustree.BPTreeNode.internalSear >>> ch(BPTreeNode.java:463) >>> at >>> org.apache.jena.dboe.trans.bplustree.BPTreeNode.internalSear >>> ch(BPTreeNode.java:463) >>> at >>> org.apache.jena.dboe.trans.bplustree.BPTreeRangeIteratorMapp >>> er.loadStack(BPTreeRangeIteratorMapper.java:122) >>> at >>> org.apache.jena.dboe.trans.bplustree.BPTreeRangeIteratorMapp >>> er.<init>(BPTreeRangeIteratorMapper.java:62) >>> at >>> org.apache.jena.dboe.trans.bplustree.BPTreeRangeIteratorMapp >>> er.create(BPTreeRangeIteratorMapper.java:43) >>> at >>> org.apache.jena.dboe.trans.bplustree.BPlusTree.iterator(BPlu >>> sTree.java:356) >>> at >>> org.apache.jena.dboe.trans.bplustree.BPlusTree.iterator(BPlu >>> sTree.java:351) >>> at >>> org.apache.jena.tdb2.store.tupletable.TupleIndexRecord.findW >>> orker(TupleIndexRecord.java:202) >>> at >>> org.apache.jena.tdb2.store.tupletable.TupleIndexRecord.findO >>> rScan(TupleIndexRecord.java:129) >>> at >>> org.apache.jena.tdb2.store.tupletable.TupleIndexRecord.perfo >>> rmFind(TupleIndexRecord.java:124) >>> at >>> org.apache.jena.tdb2.store.tupletable.TupleIndexBase.find( >>> TupleIndexBase.java:91) >>> at >>> org.apache.jena.tdb2.store.tupletable.TupleTable.find(TupleT >>> able.java:165) >>> at >>> org.apache.jena.tdb2.store.nodetupletable.NodeTupleTableConc >>> rete.find(NodeTupleTableConcrete.java:161) >>> at >>> org.apache.jena.tdb2.store.nodetupletable.NodeTupleTableConc >>> rete.find(NodeTupleTableConcrete.java:150) >>> at >>> org.apache.jena.tdb2.store.nodetupletable.NodeTupleTableConc >>> rete.findAsNodeIds(NodeTupleTableConcrete.java:141) >>> at org.apache.jena.tdb2.store.TripleTable.find(TripleTable.java:64) >>> at >>> org.apache.jena.tdb2.store.DatasetGraphTDB.findInDftGraph(Da >>> tasetGraphTDB.java:104) >>> at >>> org.apache.jena.sparql.core.DatasetGraphBaseFind.find(Datase >>> tGraphBaseFind.java:47) >>> at org.apache.jena.sparql.core.GraphView.graphBaseFind(GraphVie >>> w.java:124) >>> at org.apache.jena.graph.impl.GraphBase.find(GraphBase.java:255) >>> at >>> org.apache.jena.sparql.path.eval.PathEngine.graphFind2(PathE >>> ngine.java:205) >>> at >>> org.apache.jena.sparql.path.eval.PathEngine.graphFind(PathEn >>> gine.java:189) >>> at >>> org.apache.jena.sparql.path.eval.PathEngine.graphFind(PathEn >>> gine.java:171) >>> at org.apache.jena.sparql.path.eval.PathEngine.doOne(PathEngine.java:92) >>> at >>> org.apache.jena.sparql.path.eval.PathEvaluator.visit(PathEva >>> luator.java:57) >>> at org.apache.jena.sparql.path.P_Link.visit(P_Link.java:37) >>> at org.apache.jena.sparql.path.eval.PathEval.eval$(PathEval.java:68) >>> at org.apache.jena.sparql.path.eval.PathEval.eval$(PathEval.java:74) >>> at org.apache.jena.sparql.path.eval.PathEngine.eval(PathEngine.java:75) >>> at >>> org.apache.jena.sparql.path.eval.PathEngineSPARQL.ALP_1(Path >>> EngineSPARQL.java:129) >>> at >>> org.apache.jena.sparql.path.eval.PathEngineSPARQL.ALP_1(Path >>> EngineSPARQL.java:133) >>> at >>> org.apache.jena.sparql.path.eval.PathEngineSPARQL.ALP_1(Path >>> EngineSPARQL.java:133) >>> at >>> org.apache.jena.sparql.path.eval.PathEngineSPARQL.ALP_1(Path >>> EngineSPARQL.java:133) >>> at >>> org.apache.jena.sparql.path.eval.PathEngineSPARQL.ALP_1(Path >>> EngineSPARQL.java:133) >>> at >>> org.apache.jena.sparql.path.eval.PathEngineSPARQL.ALP_1(Path >>> EngineSPARQL.java:133)" >>> >>> What could be the problem? >>> Thanks a lot >>> >>> Regards, >>> >>> Davide >>> >>>
