RE: Taktracker in namenode failure

[Ramya S]

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
 
Ramya.S

________________________________

From: Devaraj k [mailto:devara...@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.

 

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

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