2013 12011 02012 12013 1
mapper node1
your mapper
skip the title successfully
split and read
done by hadoop MapReduce
line by linestdout
combiner、partitioner、shuffle and sort
2011 02011 12012 12012 12013 02013 12013 1
line by line stdout
suppose our job has two map tasks
line by line stdin
line by linestdin
mapper node2
your reducer
2012 12013 02011 1
