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courses:mapreduce-tutorial:perl-api [2012/01/23 21:33]
straka 		courses:mapreduce-tutorial:perl-api [2012/01/25 14:32]
straka
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   * ''hadoop_prefix'' -- the prefix of Hadoop instalation. Default value is fine in UFAL cluster.   * ''hadoop_prefix'' -- the prefix of Hadoop instalation. Default value is fine in UFAL cluster.
   * ''keep_env'' -- which environment variables are preserved when running perl mappers, reducers, combiners and partitioners   * ''keep_env'' -- which environment variables are preserved when running perl mappers, reducers, combiners and partitioners
 +
 +==== Command line arguments supported by Hadoop::Runner::run() ====
  
 ===== Hadoop::Mapper ===== ===== Hadoop::Mapper =====
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 requires 'map'; requires 'map';
  
-sub setup() { } +sub setup() {} 
-sub cleanup { }+sub cleanup {}
 </code> </code>
   * ''sub map($self, $key, $value, $context)'' -- executed for every (key, value) input pair. The variable '$content' has following methods:   * ''sub map($self, $key, $value, $context)'' -- executed for every (key, value) input pair. The variable '$content' has following methods:
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 requires 'reduce'; requires 'reduce';
  
-sub setup() { } +sub setup() {} 
-sub cleanup { }+sub cleanup {}
 </code> </code>
   * ''sub reduce($self, $key, $values, $context)'' -- executed for every ''$key''. The ''$values'' is an iterator with the following methods:   * ''sub reduce($self, $key, $values, $context)'' -- executed for every ''$key''. The ''$values'' is an iterator with the following methods:
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 requires 'getPartition'; requires 'getPartition';
  
-sub setup { } +sub setup {} 
-sub cleanup { }+sub cleanup {}
  
 </code> </code>
-  * ''sub getPartition($self, $key, $value, $partitions)'' -- executed for every (key, value) input pair. It must return a number in the range 0..$partitions-1, +  * ''sub getPartition($self, $key, $value, $partitions)'' -- executed for every output (key, value) pair. It must return a number of partition in range 0..$partitions-1, where the output (key, value) pair should be placed.
   * ''sub setup($self)'' -- executed once before any input (key, value) pairs are processed.   * ''sub setup($self)'' -- executed once before any input (key, value) pairs are processed.
   * ''sub cleanup($self)'' -- executed once after all input (key, value) pairs are processed.    * ''sub cleanup($self)'' -- executed once after all input (key, value) pairs are processed. 
  

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