[MAPREDUCE-1372] ConcurrentModificationException in JobInProgress

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.20.1
• Fix Version/s: 0.20.3, 0.21.0
• Component/s: jobtracker
• Hadoop Flags: Reviewed
• Assignee: Dick King
• Reporter: Amareshwari Sriramadasu
• Created: 12/Jan/10 08:30
• Updated: 24/Aug/10 21:20
• Resolved: 31/May/10 23:48

Description

We have seen the following ConcurrentModificationException in one of our clusters

java.io.IOException: java.util.ConcurrentModificationException
        at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
        at java.util.HashMap$KeyIterator.next(HashMap.java:828)
        at org.apache.hadoop.mapred.JobInProgress.findNewMapTask(JobInProgress.java:2018)
        at org.apache.hadoop.mapred.JobInProgress.obtainNewMapTask(JobInProgress.java:1077)
        at org.apache.hadoop.mapred.CapacityTaskScheduler$MapSchedulingMgr.obtainNewTask(CapacityTaskScheduler.java:796)
        at org.apache.hadoop.mapred.CapacityTaskScheduler$TaskSchedulingMgr.getTaskFromQueue(CapacityTaskScheduler.java:589)
        at org.apache.hadoop.mapred.CapacityTaskScheduler$TaskSchedulingMgr.assignTasks(CapacityTaskScheduler.java:677)
        at org.apache.hadoop.mapred.CapacityTaskScheduler$TaskSchedulingMgr.access$500(CapacityTaskScheduler.java:348)
        at org.apache.hadoop.mapred.CapacityTaskScheduler.addMapTask(CapacityTaskScheduler.java:1397)
        at org.apache.hadoop.mapred.CapacityTaskScheduler.assignTasks(CapacityTaskScheduler.java:1349)
        at org.apache.hadoop.mapred.JobTracker.heartbeat(JobTracker.java:2976)
        at sun.reflect.GeneratedMethodAccessor5.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:508)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:959)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:955)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:396)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:953)

Issue Links

• is related to: MAPREDUCE-1717 Topology resolution should be asynchronous