php设置session入库

<?php  
ini_set("session.save_handler","user");    
//session.gc_probability = 1 分子    
ini_set("session.gc_probability",1);    
//session.gc_divisor = 1000 分母    
ini_set("session.gc_divisor",2);    
//session.gc_maxlifetime = 1440 垃圾回收时间，session有效期    
session_set_save_handler( "open","close","read","write","destroy","gc" );  
//连接数据库    
function open(){    
    @$link = mysql_connect('127.0.0.1', 'root', 'root');    
    mysql_query('set names utf8');    
    mysql_query('use session');    
}    
function close(){    
    mysql_close();    
}    
function read($sess_id){    
    $sql = "select session_data from `session` where session_id = '$sess_id'";    
    $result = mysql_query($sql);    
    if($rows = mysql_fetch_assoc($result)){  
        return $rows['session_data']; }  
    else{  
        return '';  
    }    
}    
function write($sess_id,$sess_data){    
    $sql = "insert into `session` (session_id,session_data,session_time) values('$sess_id','$sess_data', now()) on duplicate key update session_data = '$sess_data' , session_time = now()";  //这是为了gc()    
    return mysql_query($sql);    
    
}    
function destroy($sess_id){    
    echo __FUNCTION__;    
    $sql = "delete from `session` where session_id = '$sess_id'";    
    return mysql_query($sql);    
    
}    
function gc($sess_id){    
    $maxlifetime = ini_set("session.gc_maxlifetime",'1440');    
    echo __FUNCTION__;    
    $sql = "delete from `session` where now()-session_time > '$maxlifetime' ";    
    return mysql_query($sql);    
}    
header("content-type:text/html;charset=utf8");    
session_start();    
$_SESSION['name']='aa';    
//echo session_id();    
echo $_SESSION['name'];