title: Elasticsearch Gateway timeout 504
body: <p>I updated some indices mapping to simply add a <code>keyword</code> field to a text property and reloaded Kibana's index patterns. I was told I should run this command at the end:</p>
  
  <pre><code>POST 11ad.pi.prod.test-case-18/_update_by_query?conflicts=proceed
  </code></pre>
  
  <p>after doing it I get an error:</p>
  
  <pre><code>{
  "statusCode": 504,
  "error": "Gateway Time-out",
  "message": "Client request timeout"
  }
  </code></pre>
  
  <p>does it mean the timeout is too short? how can it be changed?</p>