邮件功能导致超时！在群发邮件期间

public function send_mail($event = '', $to=array(), $from=array(), $cc=array(), $bcc=array(), $reply_to = array(), $attachment=array(), $subject='', $body='', $is_html=true, $save_db=false, $immediate= true)
        {
            if(count($to)>0)
            {
                foreach($to as $key=>$value)
                {
                    if(!isset($value['name']))  
                        $value['name'] ='';
                    $this->AddAddress($value['address'], $value['name']);
                }
                $this->SetFrom($from['address'], $from['name']);    
                    }   
            else
                return false;   
        }

当超过 1000 条记录时，此函数会导致超时！