Search

What is identity Reducer ?



It is a reduce phase’s counter part for Identity mapper in map phase. It simply passes on the input key/value pairs into output directory. Its class name is org.apache.hadoop.mapred.lib.IdentityReducer.
When no reducer class is specified in Mapreduce job, then this class will be picked up by the job automatically.
Posted by at
Labels:
  • What are the main components of Mapreduce Job ?
      Main driver class which provides job configuration parameters. Mapper class which must extend org.apache.hadoop.mapredu...
  • TO_CHAR
       This will be used to extract various date formats.     The available date formats as follows.     Syntax: to_char ( date , fo...