Generate Separate Cache For Logged In User With Coutputcache And Chttpcachefilter

I am using this code


public function filters()

{

    return array(

                array(

                    'COutputCache + index',

                    'duration'=>Yii::app()->user->isGuest ? 3600 : 0,

                    //'varyByParam'=>array(),

                ),

                array(

                    'CHttpCacheFilter + index',

                    'lastModified'=>Yii::app()->user->isGuest?Yii::app()->db->createCommand("SELECT MAX(`f_modified`) FROM {{post}}")->queryScalar():date('Y-m-d H:i:s'),

                ),

    );

}

As you can see I have given duration and last modified in both depending on whether user is guest. Now when I logout my page is still showing that user is logged in.