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From Mark <static.void....@gmail.com>
Subject KeyValueTextInputFormat
Date Thu, 26 Aug 2010 18:07:53 GMT
  When I configure my job to use a KeyValueTextInputFormat doesn't that 
imply that the key and value to my mapper will be both Text?

I have it set up like this and I am using the default Mapper.class ie 
IdentityMapper
- KeyValueTextInputFormat.addInputPath(job, new Path(otherArgs[0]));

but I keep receiving this error:
- java.lang.ClassCastException: org.apache.hadoop.io.LongWritable cannot 
be cast to org.apache.hadoop.io.Text

I would expect this error if I was using the FileInputFormat because 
that return the key as a LongWritable and the value as Text but I am 
unsure of why its happening here.

Also on the same note, when I supply FileInputFormat or 
KeyValueTextInputFormat does that implicitly set 
job.setMapOutputKeyClass and job.setMapOutputValueClass. When are these 
used?

Thanks for the clarification





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