[MAPREDUCE-838] Task succeeds even when committer.commitTask fails with IOException

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.20.1
• Fix Version/s: 0.20.1
• Component/s: task
• Release Note: Fixed a bug in the way commit of task outputs happens. The bug was that if commit fails with IOException, the task would be declared as successful.
• Assignee: Amareshwari Sriramadasu
• Reporter: Koji Noguchi
• Created: 07/Aug/09 20:08
• Updated: 31/Aug/09 05:02
• Resolved: 11/Aug/09 05:52

Description

In MAPREDUCE-837, job succeeded with empty output even though all the tasks were throwing IOException at commiter.commitTask.

2009-08-07 17:51:47,458 INFO org.apache.hadoop.mapred.TaskRunner: Task attempt_200907301448_8771_r_000000_0 is allowed to commit now
2009-08-07 17:51:47,466 WARN org.apache.hadoop.mapred.TaskRunner: Failure committing: java.io.IOException: Can not get the relative path: \
base = hdfs://mynamenode:8020/user/knoguchi/test2.har/_temporary/_attempt_200907301448_8771_r_000000_0 \
child = hdfs://mynamenode/user/knoguchi/test2.har/_temporary/_attempt_200907301448_8771_r_000000_0/_index
  at org.apache.hadoop.mapred.FileOutputCommitter.getFinalPath(FileOutputCommitter.java:150)
  at org.apache.hadoop.mapred.FileOutputCommitter.moveTaskOutputs(FileOutputCommitter.java:106)
  at org.apache.hadoop.mapred.FileOutputCommitter.moveTaskOutputs(FileOutputCommitter.java:126)
  at org.apache.hadoop.mapred.FileOutputCommitter.commitTask(FileOutputCommitter.java:86)
  at org.apache.hadoop.mapred.OutputCommitter.commitTask(OutputCommitter.java:171)
  at org.apache.hadoop.mapred.Task.commit(Task.java:768)
  at org.apache.hadoop.mapred.Task.done(Task.java:692)
  at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:417)
  at org.apache.hadoop.mapred.Child.main(Child.java:170)

2009-08-07 17:51:47,468 WARN org.apache.hadoop.mapred.TaskRunner: Failure asking whether task can commit: java.io.IOException: \
Can not get the relative path: base = hdfs://mynamenode:8020/user/knoguchi/test2.har/_temporary/_attempt_200907301448_8771_r_000000_0 \
child = hdfs://mynamenode/user/knoguchi/test2.har/_temporary/_attempt_200907301448_8771_r_000000_0/_index
  at org.apache.hadoop.mapred.FileOutputCommitter.getFinalPath(FileOutputCommitter.java:150)
  at org.apache.hadoop.mapred.FileOutputCommitter.moveTaskOutputs(FileOutputCommitter.java:106)
  at org.apache.hadoop.mapred.FileOutputCommitter.moveTaskOutputs(FileOutputCommitter.java:126)
  at org.apache.hadoop.mapred.FileOutputCommitter.commitTask(FileOutputCommitter.java:86)
  at org.apache.hadoop.mapred.OutputCommitter.commitTask(OutputCommitter.java:171)
  at org.apache.hadoop.mapred.Task.commit(Task.java:768)
  at org.apache.hadoop.mapred.Task.done(Task.java:692)
  at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:417)
  at org.apache.hadoop.mapred.Child.main(Child.java:170)

2009-08-07 17:51:47,469 INFO org.apache.hadoop.mapred.TaskRunner: Task attempt_200907301448_8771_r_000000_0 is allowed to commit now
2009-08-07 17:51:47,472 INFO org.apache.hadoop.mapred.TaskRunner: Task 'attempt_200907301448_8771_r_000000_0' done.