RE: Taktracker in namenode failure

[Devaraj k]

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.

Thanks
Devaraj k

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

Hi,

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,
Ramya