title: PHP - performance and memory issue with global variables
body: <p>Hypothetical situation:
  I'm running a complex site in php, and i use a lot of global variables.</p>
  
  <p>i could store the variables in an existing global scope, say <code>$_REQUEST['userInfo']</code>, <code>$_REQUEST['foo']</code>, and <code>$_REQUEST['bar']</code> etc. and put a lot of different things into the request scope (which would be appropriate use, as these data refer to the request itself).</p>
  
  <p>or</p>
  
  <p>i could keep using lines like <code>global $userInfo, $foo, $bar;</code> in most of my functions.</p>
  
  <p>is there a performance hit, or a difference in memory usage for either solution?</p>
  
  <p>one is a little easier to type... so is there a best-practices guideline?</p>