[ Skip to the content ]

Institute of Formal and Applied Linguistics Wiki

[ Back to the navigation ]

You are here: start » courses » mapreduce-tutorial » step-12

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision Both sides next revision
courses:mapreduce-tutorial:step-12 [2012/01/25 21:29]
straka 		courses:mapreduce-tutorial:step-12 [2012/01/25 21:44]
straka
Line 14: Line 14:
 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:step-5-solution1.txt|wc.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}}

[ Back to the navigation ] [ Back to the content ]