[teiid-issues] [JBoss JIRA] Commented: (TEIID-733) ConcurrentModificationException in SessionMonitor

[Steven Hawkins (JIRA)]

    [ https://jira.jboss.org/jira/browse/TEIID-733?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12477210#action_12477210 ] 

Steven Hawkins commented on TEIID-733:
--------------------------------------

The ways for the NPE to happen now is for his query to be long running, deeply queued, or for our dqp stop call to be interrupted.  Without seeing when stop was called its hard to know what happened.  I'd actually be in favor of changing the dqp stop call to be shutdownNow instead that should help fix the first two cases.

> ConcurrentModificationException in SessionMonitor
> -------------------------------------------------
>
>                 Key: TEIID-733
>                 URL: https://jira.jboss.org/jira/browse/TEIID-733
>             Project: Teiid
>          Issue Type: Bug
>          Components: Embedded, Query Engine
>    Affects Versions: 6.1.0
>            Reporter: Ted Jones
>            Assignee: Steven Hawkins
>             Fix For: 6.2.0
>
>
> While running a Seam CRUD Web App against Teiid, I am seeing the following intermittent error:
> 14:00:51,806 ERROR [STDERR] Exception in thread "SessionMonitor" 
> 14:00:51,814 ERROR [STDERR] java.util.ConcurrentModificationException
> 14:00:51,815 ERROR [STDERR] 	at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
> 14:00:51,815 ERROR [STDERR] 	at java.util.HashMap$ValueIterator.next(HashMap.java:822)
> 14:00:51,815 ERROR [STDERR] 	at com.metamatrix.platform.security.session.service.SessionServiceImpl.monitorSessions(SessionServiceImpl.java:97)
> 14:00:51,815 ERROR [STDERR] 	at com.metamatrix.platform.security.session.service.SessionServiceImpl.access$000(SessionServiceImpl.java:71)
> 14:00:51,815 ERROR [STDERR] 	at com.metamatrix.platform.security.session.service.SessionServiceImpl$1.run(SessionServiceImpl.java:340)
> 14:00:51,815 ERROR [STDERR] 	at java.util.TimerThread.mainLoop(Timer.java:512)
> 14:00:51,815 ERROR [STDERR] 	at java.util.TimerThread.run(Timer.java:462)
> 14:02:55,126 ERROR [STDERR] Exception in thread "Worker10" 
> 14:02:55,135 ERROR [STDERR] java.lang.NullPointerException
> 14:02:55,135 ERROR [STDERR] 	at com.metamatrix.cache.jboss.JBossCache.getChild(JBossCache.java:145)
> 14:02:55,135 ERROR [STDERR] 	at org.teiid.dqp.internal.cache.DQPContextCache.removeRequestScopedCache(DQPContextCache.java:60)
> 14:02:55,135 ERROR [STDERR] 	at org.teiid.dqp.internal.process.DQPCore.removeRequest(DQPCore.java:304)
> 14:02:55,135 ERROR [STDERR] 	at org.teiid.dqp.internal.process.RequestWorkItem.attemptClose(RequestWorkItem.java:357)
> 14:02:55,135 ERROR [STDERR] 	at org.teiid.dqp.internal.process.RequestWorkItem.process(RequestWorkItem.java:247)
> 14:02:55,135 ERROR [STDERR] 	at org.teiid.dqp.internal.process.AbstractWorkItem.run(AbstractWorkItem.java:44)
> 14:02:55,135 ERROR [STDERR] 	at com.metamatrix.common.queue.WorkerPoolFactory$StatsCapturingSharedThreadPoolExecutor$1.run(WorkerPoolFactory.java:211)
> 14:02:55,135 ERROR [STDERR] 	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> 14:02:55,135 ERROR [STDERR] 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> 14:02:55,135 ERROR [STDERR] 	at java.lang.Thread.run(Thread.java:619)

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