title: why the size of stored index changed dramatically?
body: <p>There is a <code>company</code> index, today I found a strange phenomenon, that is the doc count does not change but the <code>size of stored index</code> is changed dramatically from 22.03GB to 27.14GB then instantly becomes 20.44GB. Why is so? What are done in the elasticsearch internal?</p>
  
  <p><a href="https://i.stack.imgur.com/rUbHw.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rUbHw.png" alt="enter image description here"></a></p>
  
  <p>More metrics</p>
  
  <p><a href="https://i.stack.imgur.com/peEsz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/peEsz.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/zTUwL.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zTUwL.png" alt="enter image description here"></a></p>
  
  <p>It seems the segment count and size both reduced, Did these metrics could explain this phenomenon?</p>