hadoop-mapreduce-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jian He (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MAPREDUCE-6852) Job#updateStatus() failed with NPE due to race condition
Date Wed, 01 Mar 2017 02:28:46 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-6852?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15889376#comment-15889376

Jian He commented on MAPREDUCE-6852:

lgtm, committing tomorrow  

> Job#updateStatus() failed with NPE due to race condition
> --------------------------------------------------------
>                 Key: MAPREDUCE-6852
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-6852
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>            Reporter: Junping Du
>            Assignee: Junping Du
>         Attachments: MAPREDUCE-6852.patch, MAPREDUCE-6852-v2.patch
> Like MAPREDUCE-6762, we found this issue in a cluster where Pig query occasionally failed
on NPE - "Pig uses JobControl API to track MR job status, but sometimes Job History Server
failed to flush job meta files to HDFS which caused the status update failed." Beside NPE
in o.a.h.mapreduce.Job.getJobName, we also get NPE in Job.updateStatus() and the exception
is as following:
> {noformat}
> Caused by: java.lang.NullPointerException
> 	at org.apache.hadoop.mapreduce.Job$1.run(Job.java:323)
> 	at org.apache.hadoop.mapreduce.Job$1.run(Job.java:320)
> 	at java.security.AccessController.doPrivileged(Native Method)
> 	at javax.security.auth.Subject.doAs(Subject.java:422)
> 	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1833)
> 	at org.apache.hadoop.mapreduce.Job.updateStatus(Job.java:320)
> 	at org.apache.hadoop.mapreduce.Job.isComplete(Job.java:604)
> {noformat}
> We found state here is null. However, we already check the job state to be RUNNING as
code below:
> {noformat}
>   public boolean isComplete() throws IOException {
>     ensureState(JobState.RUNNING);
>     updateStatus();
>     return status.isJobComplete();
>   }
> {noformat}
> The only possible reason here is two threads are calling here for the same time: ensure
state first, then one thread update the state to null while the other thread hit NPE issue
> We should fix this NPE exception.

This message was sent by Atlassian JIRA

To unsubscribe, e-mail: mapreduce-issues-unsubscribe@hadoop.apache.org
For additional commands, e-mail: mapreduce-issues-help@hadoop.apache.org

View raw message