title: Need to limit rows used for facets in elastic search
body: <p>Is there a way to limit number of rows that are used for facet aggregates?
  For example:
  If my query filters records by date and also has size of 300, facets ignore the size and just return facets for that date range. Is there a way to just return facets only for these 300 records?</p>
  
  <pre><code>curl -X GET 'localhost:9200/some_index/some_type/_search?routing=1&amp;search_type=count&amp;size=300&amp;pretty' -d '{
    "query": {
      "bool": {
        "must": [
          {
            "query_string": {
              "query": "account:1"
            }
          },
          {
            "query_string": {
              "query": "\"postedTime:[2013-06-12T01:00 TO 2013-06-19T01:00]\""
            }
          }
        ]
      }
    },
    "sort": [
      {
        "postedTime": "asc"
      }
    ],
    "facets": {
      "products": {
        "terms": {
          "field": "product",
          "size": 10,
          "all_terms": false
        }
      },
      "types": {
        "terms": {
          "field": "type",
          "size": 10,
          "all_terms": false
        }
      }
    },
    "size": 300,
    "version": true
  }'
  </code></pre>