php - Session data not getting destroyed from cache in CodeIgniter -

i new codeigniter. in website have logout option. have written code destroy session , logout works first time in both ie , chrome. if login again logout not work till clear cache , manual refresh. both ie , chrome showing problem. have tried writing cache clear method not working. known issue or doing wrong.

my logout code

class logout extends ci_controller {   public function __construct() {      parent::__construct(); }  function index() {     $this->home_model->unsetsessions();     redirect('', 'refresh');  }} 

my home model

 function unsetsessions() {      $newdata = array(         'session_id' => '',         'user_id' => 0,         'user_name' => null,         'user_type' => null     );     $this->session->unset_userdata($newdata); }