EllisLab/CodeIgniter — pull request #3018 by johnhunt (2014-04-22 14:11:39+00:00)
Title: Removed @ symbols from the connection calls.

This can cause massive confusion when trying to diagnose issues as it did for me. Try not having php-mysql installed and you'll see why it's a problem.

Other connection issues could occur that are fatal etc.

Please see http://www.phptherightway.com/#errors for reasons on why the @ symbol is a bad idea.