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https://issues.apache.org/jira/browse/MAPREDUCE-5513?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13770815#comment-13770815
]
Jason Lowe commented on MAPREDUCE-5513:
---------------------------------------
Sample backtrace when this occurs in a Pig job:
{noformat}
org.apache.pig.backend.executionengine.ExecException: ERROR 2043: Unexpected
error during execution.
at org.apache.pig.PigServer.launchPlan(PigServer.java:1286)
at org.apache.pig.PigServer.executeCompiledLogicalPlan(PigServer.java:1260)
at org.apache.pig.PigServer.execute(PigServer.java:1250)
at org.apache.pig.PigServer.executeBatch(PigServer.java:362)
at org.apache.pig.tools.grunt.GruntParser.executeBatch(GruntParser.java:132)
at
org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:193)
at
org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:165)
at org.apache.pig.tools.grunt.Grunt.exec(Grunt.java:84)
at org.apache.pig.Main.run(Main.java:435)
at org.apache.pig.PigRunner.run(PigRunner.java:49)
at org.apache.oozie.action.hadoop.PigMain.runPigJob(PigMain.java:283)
at org.apache.oozie.action.hadoop.PigMain.run(PigMain.java:223)
at org.apache.oozie.action.hadoop.LauncherMain.run(LauncherMain.java:37)
at org.apache.oozie.action.hadoop.PigMain.main(PigMain.java:76)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at
org.apache.oozie.action.hadoop.LauncherMapper.map(LauncherMapper.java:494)
at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:54)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:400)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:335)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:158)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1262)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:153)
Caused by: java.util.ConcurrentModificationException
at java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:953)
at java.util.LinkedList$ListItr.next(LinkedList.java:886)
at
org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl.toList(JobControl.java:83)
at
org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl.getSuccessfulJobList(JobControl.java:125)
at
org.apache.hadoop.mapred.jobcontrol.JobControl.getSuccessfulJobs(JobControl.java:75)
at
org.apache.pig.tools.pigstats.PigStatsUtil.accumulateStats(PigStatsUtil.java:244)
at
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher.launchPig(MapReduceLauncher.java:304)
at org.apache.pig.PigServer.launchPlan(PigServer.java:1275)
... 26 more
{noformat}
> ConcurrentModificationException in JobControl
> ---------------------------------------------
>
> Key: MAPREDUCE-5513
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-5513
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Affects Versions: 2.1.0-beta, 0.23.9
> Reporter: Jason Lowe
>
> JobControl.toList is locking individual lists to iterate them, but those
> lists can be modified elsewhere without holding the list lock. The locking
> approaches are mismatched, with toList holding the lock on the actual list
> object while other methods hold the JobControl lock when modifying the lists.
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