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Posted to dev@jena.apache.org by "Andy Seaborne (JIRA)" <ji...@apache.org> on 2013/01/26 20:51:12 UTC
[jira] [Commented] (JENA-289) Respect query timeouts in TDB
implementation
[ https://issues.apache.org/jira/browse/JENA-289?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13563611#comment-13563611 ]
Andy Seaborne commented on JENA-289:
------------------------------------
The situation for the original report (large number of hits for a triple pattern when using union default graphs queries) has been improved by recent (Jan 2013) changes to TDB.
> Respect query timeouts in TDB implementation
> --------------------------------------------
>
> Key: JENA-289
> URL: https://issues.apache.org/jira/browse/JENA-289
> Project: Apache Jena
> Issue Type: Improvement
> Components: TDB
> Affects Versions: TDB 0.9.1
> Reporter: Mark Buquor
> Assignee: Andy Seaborne
> Fix For: TDB 0.10.0
>
> Attachments: TestTimeout.java, TestTimeout.java
>
>
> In general use, we sometimes see queries throw QueryCancelledException several seconds/minutes after the expected timeout. This is acceptable to a degree, but it appears that there are cases where a rogue query could execute unmitigated. The attached testcase is an example of a query that will execute and consume CPU/heap until an OutOfMemoryError is thrown.
> Example: The following query with 10s timeouts executed for ~7 minutes before throwing an OOME.
> Aug 3, 2012 10:18:19 AM Executing query [limit=1,000 timeout1=10s timeout2=10s]: SELECT * WHERE { ?a ?b ?c . ?c ?d ?e }
> java.lang.OutOfMemoryError: GC overhead limit exceeded
> at java.util.HashSet.<init>(HashSet.java:86)
> at org.openjena.atlas.iterator.FilterUnique.<init>(FilterUnique.java:26)
> at org.openjena.atlas.iterator.Iter.distinct(Iter.java:438)
> at com.hp.hpl.jena.tdb.solver.StageMatchTuple.makeNextStage(StageMatchTuple.java:116)
> at com.hp.hpl.jena.tdb.solver.StageMatchTuple.makeNextStage(StageMatchTuple.java:44)
> at org.openjena.atlas.iterator.RepeatApplyIterator.hasNext(RepeatApplyIterator.java:49)
> at org.openjena.atlas.iterator.Iter$4.hasNext(Iter.java:295)
> 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:108)
> 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:108)
> 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:108)
> 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:108)
> 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:108)
> at com.hp.hpl.jena.sparql.engine.ResultSetStream.hasNext(ResultSetStream.java:72)
> at com.hp.hpl.jena.sparql.resultset.ResultSetApply.apply(ResultSetApply.java:41)
> at com.hp.hpl.jena.sparql.resultset.XMLOutput.format(XMLOutput.java:52)
> at com.hp.hpl.jena.query.ResultSetFormatter.outputAsXML(ResultSetFormatter.java:482)
> at com.hp.hpl.jena.query.ResultSetFormatter.outputAsXML(ResultSetFormatter.java:460)
> at TestTimout.main(TestTimout.java:84)
> Aug 3, 2012 10:25:41 AM Finished
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