Both CDbHttpSession and CHttpSession seem to be ignoring the timeout value and garbage collect data after a fairly short time (less than 12 hours).
What could be the problem?
        'session' => array(
		'class'=> 'CDbHttpSession',
		'autoCreateSessionTable' => true,
         	'autoStart'=>true,
		'timeout' => 1209600,
           	'cookieMode' => 'only',
        ),