title: Count of elements on kibana visualization
body: <p>I have inserted below JSON records on my elastic index. How do I get count of all the elements present in the "devices" array so that count can be visualized on Kibana Dashboard ? </p>
  
  <p>Filter condition - Devices count needs to be displayed as "4" for SAMPLE application and "2" for SAMPLE2 application on Kibana. </p>
  
  <p>Without Filter condition - Device count to be displayed as "6" devices. </p>
  
  <pre><code>{
      "status" : "SUCCESS",
      "request" : ["ABC"],
      "applicationName" : "SAMPLE",  
      "endTime" : 1478772517736,
      "devices" : ["d1","d2","d3","d4"]
  }
  ,
  {
      "status" : "FAILED",
      "request" : ["EDF"],
      "applicationName" : "SAMPLE2",
      "endTime" : 1478772517736,
      "devices" : ["d5","d12"]
  }
  </code></pre>