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courses:mapreduce-tutorial:step-4 [2012/01/24 21:22] straka |
courses:mapreduce-tutorial:step-4 [2012/01/24 21:28] straka |
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====== MapReduce Tutorial : Counters ====== | ====== MapReduce Tutorial : Counters ====== | ||
- | Sometimes it is useful to | + | Sometimes it is useful to count events differently than outputting them (key, value) pairs. For that reason Hadoop offers simple counter framework. |
+ | |||
+ | <code perl> | ||
+ | ... | ||
+ | sub map() { | ||
+ | |||
+ | } | ||
+ | ... | ||
+ | </ | ||
===== Exercise ===== | ===== Exercise ===== | ||
- | {{.:step-4-Solution.txt|Solution.pl}} | + | Run a MR job on / |
+ | |||
+ | {{.:step-4-solution.txt|Solution.pl}} |