title: Node child_process vs Heroku worker
body: <p>Trying to get my mind around workers vs threads on Node and Heroku.  What happens when you call <code>exec</code> from within Node.js?  </p>
  
  <p>Is it correct to believe this runs on a separate thread, and does not block the main event loop?</p>
  
  <pre><code>    require('child_process').exec(cmd, function (err, stdout, stderr) {
        // ... do stuff          
      });
  </code></pre>
  
  <p>If on Heroku, is there an advantage to moving this to a separate worker? E.g.</p>
  
  <ul>
  <li>If computational intensive, would child_process slow the main app?</li>
  <li>Do worker dynos get their own memory limit?</li>
  <li>Would an uncaught error (heaven forbid) not crash the main app if in a worker?</li>
  </ul>