title: Reusing the database connection used by the doctrine entity manager
body: <p>Doctrine encapsulates the native, driver specific database connection resource handle inside of its Connection classes. I'm talking about the resource returned from, for example, <code>mysqli_connect()</code>. I don't see any way to access the raw connection resource - there's no getter methods that I've been able to find. This strong encapsulation should probably be a hint that I shouldn't try to access it, and use it, but of course, that's exactly what I want to do.</p>
  
  <p><strong>Would it cause any problem if I were to issue read-only select queries from the same connection?</strong> I'm not sure how doctrine's work flow operates under the hood. Database connections are stateful, and I'm a bit scared that I might jump in and issue an sql query at a moment when doctrine has some multi-step transaction partially in progress, and that would obviously cause a problem. But with php's single threaded nature I think there's a decent chance it might not be possible in practice, depending on how doctrine works. </p>
  
  <p><sub>Aside: The reason I want to do this is for performance. I have some other code that isn't written with doctrine, and it wants a raw database connection because it uses the native db extension functions. I could just open another db connection, but opening a second connection has significant performance implications in my scenario...making it very appealing to try to reuse the doctrines connection.</sub></p>