title: Liquibase: how is the loadUpdateData rolled back?
body: <p>The <strong>Liquibase</strong> documentation claims that the <a href="http://www.liquibase.org/manual/load_update_data" rel="nofollow"><code>loadUpdateData</code></a> refactoring action can be rolled back automatically. When faced with a scenario where some of the records during that operation were created anew and some were actually updated, with old values obviously overwritten, how does the <strong>Liquibase</strong> handle the rollback?</p>
  
  <p>It's especially curious since automatic rollback is supported neither for <a href="http://www.liquibase.org/manual/load_data" rel="nofollow"><code>loadData</code></a>, nor for <a href="http://www.liquibase.org/manual/update_data" rel="nofollow"><code>updateData</code></a>, but is supposed to be somehow magically possible for <a href="http://www.liquibase.org/manual/load_update_data" rel="nofollow"><code>loadUpdateData</code></a>, which one would expect to be more complicated to implement than both of them.</p>