page caching

class UserController extends Zend_Controller_Action
{
    protected $_pageCache;

    public function init()
    {
        $this->_pageCache = Zend_Cache::factory(
            'Page',
            'File',
            array ('debug_header' => true),
            array ('cache_dir' => '/tmp')
        );
    }

    public function indexAction()
    {
        $this->_pageCache->start();
        $user = new Application_Model_DbTable_User();
        $users = array ();
        try {
            $users = $user->fetchAll();
        } catch (Zend_Db_Exception $e) {
            echo $e->getMessage() . "<br/>";
        }
        $this->view->users = $users;
    }