title: What are these autogenerated Db files?
body: <p>I'm developing a grails app that uses reentrant locking and database locking.  I just noticed some additional files that were autogenerated.  I am wondering what they are.  They are called:</p>
  
  <pre><code>devDb.h2.db
  devDb.lock.db
  devDb.trace.db
  </code></pre>
  
  <p>There is also a set for test configuration:</p>
  
  <pre><code>testDb.h2.db
  testDb.trace.db
  </code></pre>
  
  <p>I am assumming that *Db.h2.db is just my database (set to be a file rather than in memory in my DataSource.groovy).  But what about the other ones?</p>