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MapReduce >> mail # user >> RE: Using hadoop streaming with binary data

Venkatesh Kavuluri 2013-02-06, 21:38
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Using hadoop streaming with binary data
Is it possible to pass unmolested binary data through a map-only streaming
job from the command line?  I.e., is there a way to avoid extra tabs and
newlines in the output?  I don't need input splits or key/value pairs, I
just want one whole input file fed unmodified into a program, and its
output written unmodified to HDFS.  For example, I'd like to run:

    hadoop jar hadoop-streaming.jar -mapper cat -numReduceTasks 0 -input in
-output out

and have 'out' be exactly the same as 'in'.

There does not seem to be a way to set
mapreduce.output.textoutputformat.separator to the empty string, and
typedbytes prepends the size.  Is there a way to leave data alone out of
the box, or will I have to write a custom InputFormat and OutputFormat?