title: elasticsearch number of facets returned
body: <p>I have faceted queries working with elasticsearch 0.19.9. However I would like to return all facets that have a count > 0.</p>
  
  <p>According to the documentation I should be able to:</p>
  
  <pre><code>{
      "query" : {
          "match_all" : {  }
      },
      "facets" : {
          "tag" : {
              "terms" : {
                  "field" : "tag",
                  "all_terms" : true
              }
          }
      }
  </code></pre>
  
  <p>}</p>
  
  <p>As I understand, this should give me all facets even if count is 0.</p>
  
  <p>However, this is still only returning the top 10 facets by count. Which is the default size. The only thing that seems to affect the number of returned facets is by actually setting <code>"size" : N</code>  where <code>N</code> is the number of facets which will be returned.</p>
  
  <p>I could set this to a really high number but that just seems to hack-ish.</p>
  
  <p>Any ideas as to what I may be doing wrong?</p>