title: Elasticsearch array value count aggregation
body: <p><strong>Sample documents</strong>:</p>
  
  <pre><code>{
      "id": "62655",
      "attributes": [
          {
              "name": "genre",
              "value": "comedy"
          },
          {
              "name": "year",
              "value": "2016"
          }
      ]
  }
  
  {
      "id": "62656",
      "attributes": [
          {
              "name": "genre",
              "value": "horror"
          },
          {
              "name": "year",
              "value": "2016"
          }
      ]
  }
  
  {
      "id": "62657",
      "attributes": [
          {
              "name": "language",
              "value": "english"
          },
          {
              "name": "year",
              "value": "2015"
          }
      ]
  }
  </code></pre>
  
  <p><strong>Expected Output</strong>:</p>
  
  <pre><code>{
      "hits" : {
          "total": 3,
          "hits": []
      },
      "aggregations": {
          "attribCount": {
              "language": 1,
              "genre": 2,
              "year": 3
          },
          "attribVals": {
              "language": {
                  "english": 1
              },
              "genre": {
                  "comedy": 1,
                  "horror": 1
              },
              "year": {
                  "2016": 2,
                  "2015": 1
              }
          }
      }
  }
  </code></pre>
  
  <p><strong>My Query</strong>:</p>
  
  <p>I could get the "<em>attribCount</em>" aggregation using below query. But I don't know how to get each attribute value count.</p>
  
  <pre><code>{
      "query": {
          "filtered": {
              "query": {
                  "match_all": {}
              }
          }
      },
      "aggs": {
          "attribCount": {
              "terms": {
                  "field": "attributes.name",
                  "size": 0
              }
          }
      },
      "size": 0
  }
  </code></pre>
  
  <p>When I aggregate using attributes.value, it gives overall count. But I need it listed under the name value as given in expected output.</p>