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courses:mapreduce-tutorial:step-26 [2012/01/28 15:40] straka |
courses:mapreduce-tutorial:step-26 [2012/01/28 15:43] straka |
* ''set(String name, String value)'' -- set the value of the ''name'' property to ''value''. | * ''set(String name, String value)'' -- set the value of the ''name'' property to ''value''. |
* ''setBoolean'', ''setClass'', ''setFile'', ''setFloat'', ''setInt'', ''setLong'', ''setStrings'' -- set the typed value of the ''name'' property (i.e., number, file name, class name, ...). | * ''setBoolean'', ''setClass'', ''setFile'', ''setFloat'', ''setInt'', ''setLong'', ''setStrings'' -- set the typed value of the ''name'' property (i.e., number, file name, class name, ...). |
| * in a mapper or a reducer, the ''context'' object also provides the ''getConfiguration()'' method, so the job properties can be accessed in the mappers and reducers too. |
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Apart from already mentioned [[.:step-9#a-brief-list-of-hadoop-options|brief list of Hadoop properties]], there is one important Java-specific property: | Apart from already mentioned [[.:step-9#a-brief-list-of-hadoop-options|brief list of Hadoop properties]], there is one important Java-specific property: |
| * **''mapred.child.java.opts''** with default value **''-Xmx200m''**. This property sets the Java options used for every task attempt (mapper, reducer, combiner, partitioner). The ''-Xmx200m'' set the |