title: Sorting in MapReduce Hadoop
body: <p>I have few basic questions in Hadoop MapReduce.</p>
  
  <ol>
  <li>Assume if 100 mappers were executed and zero reducer. Will it
  generate 100 files? All individual are sorted? Across all mapper
  output are sorted?</li>
  <li>Input for reducer is Key -> Values. For each key, all values are sorted?</li>
  <li>Assume if 50 reducers were executed. Will it generate 50 files? All individual files are sorted? Across all reducer output are sorted?</li>
  </ol>
  
  <p>Is there any place where guaranteed sorting happens in MapReduce?</p>