title: What does @Preload do (Jira Active Objects)?
body: <p>I use Active Objects for persisting data. What exactly does this annotation do? </p>
  
  <p>P.S. I found this description (<a href="https://ecosystem.atlassian.net/browse/AO-486" rel="nofollow noreferrer">https://ecosystem.atlassian.net/browse/AO-486</a>):</p>
  
  <blockquote>
    <p>We hit the problem several times where AO will load each field of an object by a separate SQL query:
    <a href="https://jira.atlassian.com/browse/CONFDEV-21100" rel="nofollow noreferrer">https://jira.atlassian.com/browse/CONFDEV-21100</a>
    <a href="https://jira.atlassian.com/browse/CONFDEV-21206" rel="nofollow noreferrer">https://jira.atlassian.com/browse/CONFDEV-21206</a> 
    It can be bypassed with @Preload annotation on a class but preloading is not a default behaviour. Obviously not preload introduces a big performance hit when client code needs more than one attribute. I would imagine preloading would be a sensible default given that it would cause very little overhead</p>
  </blockquote>