title: Understanding elasticsearch jvm heap usage
body: <p>Folks,</p>
  
  <p>I am trying reduce my memory usage in my elasticsearch deployment (Single node cluster).</p>
  
  <p>I can see 3GB JVM heap space being used.
  To optimize I first need to understand the bottleneck.
  I have limited understanding of how is JVM usage is split.</p>
  
  <p>Field data looks to consume 1.5GB and filter cache &amp; query cache combined consume less than 0.5GB, that adds upto 2GB at the max.</p>
  
  <p>Can someone help me understand where does elasticsearch eats up rest of 1GB?</p>
  
  <p><a href="https://i.stack.imgur.com/tuwiL.png"><img src="https://i.stack.imgur.com/tuwiL.png" alt="Marvel screenshot"></a></p>