title: Core Data and iOS 7: Different behavior of persistent store
body: <p>I'm preparing an update for a Core Data based app for fixes with iOS 7. I use Xcode 5 and iOS 7 SDK GM. However I realized a different behavior of the persistent store (which is a <code>UIManagedDocument</code>): Prior to iOS 7 builds there was only one file <code>persistentStore</code> in the documents folder (sometimes there was a second one <code>persistentStore-journal</code>).</p>
  
  <p>In iOS 7 builds (clean installation) there are now three files for the persistent store:</p>
  
  <ul>
  <li><code>persistentStore</code></li>
  <li><code>persistentStore-wal</code> and</li>
  <li><code>persistentStore-shm</code></li>
  </ul>
  
  <p>Did Apple change the journal mode by default to WAL now? I wonder if there is an impact on my app (think of users how update from the last version)? Would it be best to disable WAL - and if so, how can I do this with iOS 7/<code>UIManagedDocument</code>?</p>