title: MapReduce execution sequence on Single Node
body: <p>I am learning Hadoop. <br>
  I am running Hadoop on single node. <br>
  According to my knowledge Reducer runs after completion of Mapper (and it makes sense as well). <br> 
  But when i ran MapReduce job on 200MB file, Reducer started before completion of Mapper. I didn't use any Combiner. <br>
  Can anyone explain why?</p>
  
  <p><img src="https://i.stack.imgur.com/bqIyG.png" alt="enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/DpJBU.png" alt="enter image description here"></p>