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courses:mapreduce-tutorial:step-4 [2012/01/29 23:43] majlis |
courses:mapreduce-tutorial:step-4 [2012/01/30 15:47] straka |
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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> | ||