PHP - Storing Session in a Database

Question

I am setting up a EC2 cluster with a load balancer. I have seperate DB server which has mysql running on it. I have 3 webservers running, mostly for high availability, and of course its round-robin load balancing it seems, so every page you go to you get a different server which looses your session.

I am trying to setup PHP to store it in the DB. I have setup a table, and setup all the functions (open,close,etc). and I have set:

session_set_save_handler('_open',
                         '_close',
                         '_read',
                         '_write',
                         '_destroy',
                         '_clean');

But when I login or anything on the site I check the table and nothing has been written. I am not sure If i need to change something in the php.ini file. If so what is the value to change?

Thanks!!

EDIT: functions:

function _open(){    
    global $con;
    connect();
} 
    
function _close(){  
    global $con;  
    //mysql_close();
}

function _read($id){    
    global $con;    
    $id = mysql_real_escape_string($id);     
    $sql = "SELECT data FROM sessions WHERE id = '$id'";     
    if ($result = mysql_query($sql, $con)) {        
        if (mysql_num_rows($result)) {            
            $record = mysql_fetch_assoc($result);             
            return $record['data'];        
        }    
    }     
    return '';
}

function _write($id, $data)
{
    global $con;
 
    $access = time();
 
    $id = mysql_real_escape_string($id);
    $access = mysql_real_escape_string($access);
    $data = mysql_real_escape_string($data);
 
    $sql = "REPLACE
            INTO    sessions
            VALUES  ('$id', '$access', '$data')";
 
    return mysql_query($sql, $con);
}

function _destroy($id)
{
   global $con;
    $id = mysql_real_escape_string($id);
    $sql = "DELETE
            FROM   sessions
            WHERE  id = '$id'";
    return mysql_query($sql, $con);
}

function _clean($max)
{
    global $con;
 
    $old = time() - $max;
    $old = mysql_real_escape_string($old);
 
    $sql = "DELETE
            FROM   sessions
            WHERE  access < '$old'";
 
    return mysql_query($sql, $con);
}

session_set_save_handler('_open',
                         '_close',
                         '_read',
                         '_write',
                         '_destroy',
                         '_clean');

Answer 1

The function you're using will interrupt the normal session function and insert your code in to act, then carry on with other internal functions.

In the functions where you aren't really doing anything session-wise (things like '_open' and '_close'), you need return something to carry on the command or it will just die right there.

Example:

function _open($save_path, $session_name){    
    global $con;
    connect();

    return true; //Do nothing but carry on
} 

function _close(){  
    global $con;  
    //mysql_close();

    return true; //Do nothing but carry on
}