title: What's the fastest way to copy a collection within the same database?
body: <p>I want to copy a collection within the <strong>same</strong> database and give it a 
  different name - basically take a snapshot.</p>
  
  <p>What's the best way to do this? Is there a command, or do I have to 
  copy each record in turn? </p>
  
  <p>I'm aware of the <code>cloneCollection</code> command, but it seems to be for 
  copying to another server only. </p>
  
  <p>I'm also aware of <code>mongoimport</code> and <code>mongoexport</code>, but as I'm doing this via PHP I'd prefer not to make calls out to the shell.</p>