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From "Ramya S" <ram...@suntecgroup.com>
Subject RE: Taktracker in namenode failure
Date Fri, 12 Jul 2013 09:57:02 GMT
Both the map output value  class configured and the output value  written from the mapper is
Text class. So there is no mismatch in the value class.
 But when the same MR program is run with 2 tasktrackers(without tasktracker in namenode)
exception is not occuring.
The problem is only with the tasktracker running in the namenode.
Thanks & Regards


From: Devaraj k [mailto:devaraj.k@huawei.com]
Sent: Fri 7/12/2013 3:04 PM
To: user@hadoop.apache.org
Subject: RE: Taktracker in namenode failure

Could you tell, what is the Map Output Value class you are configuring while submitting Job
and what is the type of the value writing from the Mapper. If both of these mismatches then
it will trow the below error.



Devaraj k


From: Ramya S [mailto:ramyas@suntecgroup.com] 
Sent: 12 July 2013 14:46
To: user@hadoop.apache.org
Subject: Taktracker in namenode failure




Why only tasktracker in namenode faill during  job execution with error.

I have attached the snapshot of error screen with this mail

java.io.IOException: Type mismatch in value from map: expected org.apache.hadoop.io.Text,
recieved org.apache.hadoop.io.IntWritable
        at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:1019)
        at org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:691)
        at org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputContext.java:80)
        at WordCount$TokenizerMapper.map(WordCount.java:30)
        at WordCount$TokenizerMapper.map(WordCount.java:19)
        at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
        at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
        at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:416)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
        at org.apache.hadoop.mapred.Child.main(Child.java:249)
but  this same task is reassigned to another tasktracker and getting executed. why?



Best Regards,


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