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| Both sides previous revision Previous revision Next revision | Previous revision | ||
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courses:mapreduce-tutorial:step-4 [2012/01/29 23:43] majlis |
courses:mapreduce-tutorial:step-4 [2012/01/31 09:40] (current) straka Change Perl commandline syntax. |
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| Sometimes it is useful to count events differently than outputting them as (key, value) pairs. For that reason Hadoop offers simple counter framework. | Sometimes it is useful to count events differently than outputting them as (key, value) pairs. For that reason Hadoop offers simple counter framework. | ||
| - | Hadoop maintains a collection of pre-defined and user-defined counters. Every counter is identified by its group name and counter name. To increment a counter, the following code can be used: | + | Hadoop maintains a collection of pre-defined and user-defined counters. Every counter is identified by its group name and counter name. The group name and counter name is an arbitrary string -- for example group " |
| <code perl> | <code perl> | ||
| Line 21: | Line 21: | ||
| # NOW EDIT THE FILE | # NOW EDIT THE FILE | ||
| # $EDITOR step-4-exercise.pl | # $EDITOR step-4-exercise.pl | ||
| - | rm -rf step-4-out-ex; | + | rm -rf step-4-out-ex; |
| less step-4-out-ex/ | less step-4-out-ex/ | ||
| Line 29: | Line 29: | ||
| # NOW VIEW THE FILE | # NOW VIEW THE FILE | ||
| # $EDITOR step-3-solution.pl | # $EDITOR step-3-solution.pl | ||
| - | rm -rf step-4-out-sol; | + | rm -rf step-4-out-sol; |
| less step-4-out-sol/ | less step-4-out-sol/ | ||