title: ElasticSearch Highlighting Inner Field
body: <p>I can't seem to get highlighting with ElasticSearch 0.90 to work on inner fields.
  For instance, here's my document:  </p>
  
  <pre><code>{ "foo": {  
      "bar": "test bonsai"  
  }}
  </code></pre>
  
  <p>Queried as the following:</p>
  
  <pre><code>{ "query": {  
      "query_string": {  
        "query": "bonsai"
      }
    },  
    "highlight": { 
       "pre_tags": ["&lt;b&gt;"],
       "post_tags": ["&lt;/b&gt;"], 
       "fields": { 
         "foo.bar": {}
       }  
    }  
  }
  </code></pre>
  
  <p>It returns the query result, but without the highlighting information. If I don't nest my field (e.g. {"foo": "test bonsai"}, and request highlighting for "foo" field instead of "foo.bar") then it all works fine. But I can't get it work with nested fields.</p>
  
  <p>I have tried different possible settings for fields, including "foo", "bar", "_all", "foo.<em>", and "</em>". I have also tried playing around with the mapping, including defining the "term_vector" (with_positions_offsets), "index", "analyzer", "stored" and "include_in_all". None does the trick.<br>
  On the documentation it seems to be supported (<a href="http://www.elasticsearch.org/guide/reference/api/search/highlighting/" rel="nofollow">here</a>, have a look at "bio.title" for example). But it doesn't work even when I use the exact same query.</p>