title: reindex elasticsearch api timeout with large size of document
body: <p>I am re-indexing one index from python but size of document is large (6gig) and it take 60 min, so I am getting <strong>time out</strong> in api. </p>
  
  <p><strong>Code:</strong></p>
  
  <pre><code>def Reindex(src, dest):
      query = {
  
          "source": {
              "index": src,
              "query": {
                  "range": {
                      "UTC_date": {
                          "lt": "now-15d/d"
                      }
                  }
              }
          },
          "dest": {
              "index": dest
          }
      }
      Query = {
          "query": {
              "range": {
                  "UTC_date": {
                      "lt": "now-15d/d"
                  }
              }
          }
      }
  
      try:
          result = es.reindex(query, wait_for_completion=True, request_timeout=300)
      except:
          pass
  </code></pre>