Monthly Archives: November 2014

Implementing Partitioners and Combiners for MapReduce

Partitioners and Combiners in MapReduce Partitioners are responsible for dividing up the intermediate key space and assigning intermediate key-value pairs to reducers. In other words, the partitioner specifies the task to which an intermediate key-value pair must be copied. Within each reducer, keys are processed in sorted order. Combiners are an optimization in MapReduce that […]

Excel InputFormat for Hadoop MapReduce

Excel Spreadsheet Input Format for Hadoop Map Reduce I want to read a Microsoft Excel spreadsheet using Map Reduce, and found that I cannot use Text Input format of Hadoop to fulfill my requirement. Hadoop does not understand Excel spreadsheet so I landed upon writing custom Input format to achieve the same. Hadoop works with […]