title: Is ini_set('max_execution_time', 0) a bad idea?
body: <p>Is there a good reason not to set the PHP configuration variable <a href="http://www.php.net/manual/en/info.configuration.php#ini.max-execution-time" rel="noreferrer"><code>max_execution_time</code></a> to 0?</p>
  
  <p>A coworker recently checked in a change to a file that added:</p>
  
  <pre><code>ini_set('max_execution_time', 0);
  </code></pre>
  
  <p>The default value had been too low for a page that did some complex processing before returning the output to the user.</p>
  
  <p>The manual states that the main purpose of the setting is to:</p>
  
  <blockquote>
    <p>prevent poorly written scripts from tying up the server.</p>
  </blockquote>
  
  <p>But also goes on to state:</p>
  
  <blockquote>
    <p>Your web server can have other timeout configurations that may also interrupt PHP execution. Apache has a <em>Timeout</em> directive and IIS has a CGI timeout function. Both default to 300 seconds. See your web server documentation for specific details.</p>
  </blockquote>
  
  <p>We're running under Apache, so that <em>Timeout</em> setting applies.  Is there any reason not to set <code>max_execution_time</code> to zero globally?  I'm mainly curious as to whether there are benefits I'm overlooking when <strong>not</strong> setting it to zero.</p>