I want to partition my data by using R reducer tasks to produce R reduce
output files, and each reduce task also writes a binary file for the
corresponding partition on DFS. Is there an easy way to generate
matching file names for the reduce output and the extra file?
reduce output: part-0 part-1 ... part-<R-1>
extra file: file-0 file-1 ... file-<R-1>
I can't find how to access task id in reduce.