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https://issues.apache.org/jira/browse/MAPREDUCE-6?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Harsh J resolved MAPREDUCE-6.
-----------------------------
Resolution: Not A Problem
Gone stale. Not an observed problem anymore.
> Task attempt stopped shuffling and hung the job
> -----------------------------------------------
>
> Key: MAPREDUCE-6
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Reporter: Nathan Marz
> Attachments: ds04-bad-reducer-syslog, ds31-bad-reducer-syslog
>
>
> I was running a job and one of the reducer task attempts got stuck during the
> shuffle phase. The percentage complete froze at 33.1%, and the logs for the
> attempt looked like:
> 2009-04-29 15:21:24,431 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0: Got 0 new map-outputs & number of known
> map outputs is 0
> 2009-04-29 15:21:24,431 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0 Scheduled 0 of 0 known outputs (0 slow
> hosts and 0 dup hosts)
> 2009-04-29 15:22:24,580 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0 Need another 1 map output(s) where 0 is
> already in progress
> 2009-04-29 15:22:24,581 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0: Got 0 new map-outputs & number of known
> map outputs is 0
> 2009-04-29 15:22:24,581 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0 Scheduled 0 of 0 known outputs (0 slow
> hosts and 0 dup hosts)
> 2009-04-29 15:23:24,692 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0 Need another 1 map output(s) where 0 is
> already in progress
> 2009-04-29 15:23:24,693 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0: Got 0 new map-outputs & number of known
> map outputs is 0
> 2009-04-29 15:23:24,693 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0 Scheduled 0 of 0 known outputs (0 slow
> hosts and 0 dup hosts)
> 2009-04-29 15:24:24,718 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0 Need another 1 map output(s) where 0 is
> already in progress
> 2009-04-29 15:24:24,718 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0: Got 0 new map-outputs & number of known
> map outputs is 0
> 2009-04-29 15:24:24,719 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0 Scheduled 0 of 0 known outputs (0 slow
> hosts and 0 dup hosts)
> 2009-04-29 15:25:24,742 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0 Need another 1 map output(s) where 0 is
> already in progress
> 2009-04-29 15:25:24,743 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0: Got 0 new map-outputs & number of known
> map outputs is 0
> 2009-04-29 15:25:24,743 INFO org.apache.hadoop.mapred.ReduceTask:
> attempt_200904250602_2468_r_000024_0 Scheduled 0 of 0 known outputs (0 slow
> hosts and 0 dup hosts)
> The mappers and other reducers were long finished. When I manually killed the
> task attempt process after 20 minutes of seeing it frozen, it restarted on
> another machine and succeeded just fine.
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