You are viewing a plain text version of this content. The canonical link for it is here.
Posted to mapreduce-dev@hadoop.apache.org by "Todd Lipcon (JIRA)" <ji...@apache.org> on 2009/09/11 01:45:57 UTC
[jira] Created: (MAPREDUCE-969) NullPointerException during reduce
freezes job
NullPointerException during reduce freezes job
----------------------------------------------
Key: MAPREDUCE-969
URL: https://issues.apache.org/jira/browse/MAPREDUCE-969
Project: Hadoop Map/Reduce
Issue Type: Bug
Components: jobtracker, task, tasktracker
Affects Versions: 0.20.2
Reporter: Todd Lipcon
Assignee: Todd Lipcon
We experienced several jobs stuck in Reduce on a cluster. All of the stuck reduce tasks had a similar were stuck at "Need another 2 map output(s) where 0 is already in progress" despite all of the mappers having completed, and 0 scheduled. The stuck reducers had experienced the following exception early in the shuffle:
java.lang.NullPointerException
at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:768)
at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.getMapCompletionEvents(ReduceTask.java:2747)
at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.run(ReduceTask.java:2670)
Will attach more information and logs momentarily.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Resolved: (MAPREDUCE-969) NullPointerException during reduce
freezes job
Posted by "Todd Lipcon (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/MAPREDUCE-969?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Todd Lipcon resolved MAPREDUCE-969.
-----------------------------------
Resolution: Duplicate
The second patch from HADOOP-4744 did indeed fix this issue. Thanks.
> NullPointerException during reduce freezes job
> ----------------------------------------------
>
> Key: MAPREDUCE-969
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-969
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: jobtracker, task, tasktracker
> Affects Versions: 0.20.2
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Attachments: bad_job_events, bad_job_jt_logs, reduce_task_logs
>
>
> We experienced several jobs stuck in Reduce on a cluster. All of the stuck reduce tasks had a similar were stuck at "Need another 2 map output(s) where 0 is already in progress" despite all of the mappers having completed, and 0 scheduled. The stuck reducers had experienced the following exception early in the shuffle:
> java.lang.NullPointerException
> at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:768)
> at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.getMapCompletionEvents(ReduceTask.java:2747)
> at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.run(ReduceTask.java:2670)
> Will attach more information and logs momentarily.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.