优化使用mysql存储session

这两天仔细考虑下，大致给出一个方案，但还没有具体详细的测试。
1、session处理和统计结合起来。同时游客也都有记录。
2、完全使用数据库和cookie来模拟session的功能。
3、用户的对session的操作都尽量保证在一条sql语句完成。不用到session的时候，绝对不多一条查询。
4、为了效率起见，session的回收没有集成进来，推荐另外写程序调用。

暂时给出代码，不具体解释。
sql

CREATE TABLE `*****_session` (
`sid` char(32) NOT NULL,
`uid` int(10) NOT NULL,
`username` char(32) NOT NULL,
`usertype` tinyint(1) NOT NULL,
`activetime` int(10) NOT NULL,
`ip` char(15) NOT NULL,
`url` char(80) NOT NULL,
`value` char(255) NOT NULL,
PRIMARY KEY (`sid`)
) ENGINE=MEMORY DEFAULT CHARSET=utf8;

php代码

<?

class session{

private $_sessionPrex= '';

private $_time = '';

private $_model = null;

private $_expiry = 3600;

private $_domain = '';

protected $isNew = 0;//0 更新 1 增加

protected $isGetSession = 0;//0还没有取出session 1 已经取出了

protected $session = array();

public function __construct($options){

$this->_setOptions($options);

if(empty($this->_time))$this->_time = time();

$this->session['activetime'] = $this->_time;

}

public function start(){

$this->_getSid();

}

public function set($key,$value){

if(in_array($key,array('uid','username','usertype','url'))){

$this->session[$key] = $value;

}else{

$other = $this->session['value'];

$other[$key] = $value;

$this->session['value'] = $other;

}

}

public function get($key){

if($this->isGetSession == 0){

//从数据库读取session记录

$this->_getSession();

$this->isGetSession = 1;

}

if(in_array($key,array('uid','username','usertype','url'))){

return $this->session[$key];

}else{

if(isset($this->session['value'][$key])){

return $this->session['value'][$key];

}

return null;

}

}

public function destroy(){

$this->session['uid'] = 0;

$this->session['username'] = '';

$this->session['usertype'] = '';

$this->session['value'] = array();

}

public function __destruct(){

$this->_save();

echo '<br>'.$this->_model->getDb()->getQNum();

}

private function _save(){

$dbSession = $this->session;

$dbSession['value'] = serialize($dbSession['value']);

if(strlen($dbSession['value'])>255)$this->_error('session->value is too long!');

if($this->isNew == 1){

//增加

$this->_model->insert($dbSession);

}else{

//更新

$sid = $dbSession['sid'];

unset($dbSession['sid']);

$this->_model->update($dbSession,'sid=/''.$sid.'/'');

}

}

private function _getSession(){

$dbSession = $this->_model->detail('sid = /''.$this->session['sid'].'/'');

$dbSession['value'] = unserialize($dbSession['value']);

$this->session = array_merge($dbSession,$this->session);

}

private function _getSid(){

$sid = strip_tags($_COOKIE[$this->_sessionPrex.'_sid']);

if (strlen($sid)!=32) {

//new

$sid = md5(time().mt_rand(1000,10000));

$this->_setCookie($this->_sessionPrex.'_sid',$sid);

$this->_setCookie($this->_sessionPrex.'_uid',0);

$this->session = array(

'uid' => 0,

'username' => '',

'usertype' => -1,

'activetime' => $this->_time,

'ip' => $this->_getip(),

'url' => strip_tags($_SERVER['REQUEST_URI']),

'value' => array()

);

$this->isNew = 1;

}

$this->session['sid'] = $sid;

}

private function _setCookie($name,$value){

if(empty($this->_domain)){

setcookie($name,$value,$this->_time + $this->_expiry,'/');

}else{

setcookie($name,$value,$this->_time + $this->_expiry,'/',$this->_domain);

}

}

private function _getip(){

return getip();

}

private function _setOptions($options){

foreach ($options as $key=>$value){

if(in_array($key,array('sessionPrex','time','model','expiry','domain'))){

$key = '_'.$key;

$this->$key = $value;

}

}

}

private function _error($msg){

throw new Phpbean_Exception($msg);

}

}

?>