title: An app that uses both elastic search and mysql
body: <p>I am writing a classifieds website that will provide search functionality. Throughout my experience I have been relying on mySQL acting as a data storage so the developing with Elastic Search is something new for me.</p>
  
  <p>I can see three options:</p>
  
  <ul>
  <li><p>Use Elastic Search as the only storage (there is doctrine ES extension) in my app and let it store everything - users, permissions, activity log, so on so forth</p></li>
  <li><p>Use MySQL and store only ID for the classified, and pull all the data from ES separately </p></li>
  <li><p>Replicating the data in both MySQL and Elastic Search</p></li>
  </ul>
  
  <p>What is the approach that is usually taken?</p>