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courses:mapreduce-tutorial:step-12 [2012/01/28 23:09]
majlis Added links to previous and next chapter. 		courses:mapreduce-tutorial:step-12 [2012/01/29 14:55]
majlis
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 If a MR job runs without reducers, the output of mappers is written to output directory without further processing. In this case, environmental variable ''HADOOP_WORK_OUTPUT_PATH'' is present even in a mapper and the files created in this directory are copied to the job output directory. If a MR job runs without reducers, the output of mappers is written to output directory without further processing. In this case, environmental variable ''HADOOP_WORK_OUTPUT_PATH'' is present even in a mapper and the files created in this directory are copied to the job output directory.
  
-===== Exercise ===== 
-Change the word counting script {{:courses:mapreduce-tutorial:TODOstep-5-solution1.txt|TODOwc.pl}} to produce results in reducers manually using the mentioned environmental variables, and execute it using four reducers. 
- 
-{{:courses:mapreduce-tutorial:step-12-solution.txt|Solution.pl}} 
  
  

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