[jira] [Commented] (MAPREDUCE-6554) MRAppMaster servicestart failing with NPE in MRAppMaster#parsePreviousJobHistory

["Bibin A Chundatt (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-6554?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15062280#comment-15062280 ] 

Bibin A Chundatt commented on MAPREDUCE-6554:
---------------------------------------------

[~jlowe] 
Sorry for late response.
Instead of {{this.schema = parser.parse(in.readLine());}} before passing to parser.parse() we can check for null and the return IOException.
For IOException {{org.apache.hadoop.tools.rumen.CurrentJHParser#canParse}} returns false . 

Please do correct me if i am wrong.




> MRAppMaster servicestart failing  with NPE in MRAppMaster#parsePreviousJobHistory
> ---------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-6554
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-6554
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>            Reporter: Bibin A Chundatt
>            Assignee: Bibin A Chundatt
>            Priority: Critical
>         Attachments: 0001-MAPREDUCE-6554.patch
>
>
> Create scenario so that MR app master gets preempted.
> On next MRAppMaster launch tried to recover previous job history file {{MRAppMaster#parsePreviousJobHistory}}
> {noformat}
> 2015-11-21 13:52:27,722 INFO [main] org.apache.hadoop.service.AbstractService: Service org.apache.hadoop.mapreduce.v2.app.MRAppMaster failed in state STARTED; cause: java.lang.NullPointerException
> java.lang.NullPointerException
>         at java.io.StringReader.<init>(StringReader.java:50)
>         at org.apache.avro.Schema$Parser.parse(Schema.java:917)
>         at org.apache.avro.Schema.parse(Schema.java:966)
>         at org.apache.hadoop.mapreduce.jobhistory.EventReader.<init>(EventReader.java:75)
>         at org.apache.hadoop.mapreduce.jobhistory.JobHistoryParser.parse(JobHistoryParser.java:139)
>         at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.parsePreviousJobHistory(MRAppMaster.java:1256)
>         at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.processRecovery(MRAppMaster.java:1225)
>         at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.serviceStart(MRAppMaster.java:1087)
>         at org.apache.hadoop.service.AbstractService.start(AbstractService.java:193)
>         at org.apache.hadoop.mapreduce.v2.app.MRAppMaster$4.run(MRAppMaster.java:1570)
>         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:1673)
>         at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.initAndStartAppMaster(MRAppMaster.java:1566)
>         at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.main(MRAppMaster.java:1499)
> 2015-11-21 13:52:27,725 INFO [main] org.apache.hadoop.mapreduce.jobhistory.JobHistoryEventHandler: Stopping JobHistoryEventHandler. Size of the outstanding queue size is 0
> {noformat}
> EventReader(EventReader stream)
> {noformat}
>  this.version = in.readLine();
> ...
>     Schema myschema = new SpecificData(Event.class.getClassLoader()).getSchema(Event.class);
>     this.schema = Schema.parse(in.readLine());
> {noformat}



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