title: What is the mapping for array of arrays in elasticsearch 2.3
body: <p>In ElasticSearch 2.3, I am planning to store data for a field in this way:</p>
  
  <pre><code>"pair_age": [
     [12, 19], [17,20], [34,35]
   ]
  </code></pre>
  
  <p>So in mapping how to set it:</p>
  
  <pre><code>"pair_age":  { "type":  "????" }
  </code></pre>
  
  <p>What should I set the value of <code>????</code> above?</p>