Lock wait timeout Symfony2 Ratchet with PdoSessionHandler

Question

I use PdoSessionHandler to store the user's session in a database to communicate using the session Symfony2 server and Ratchet server.

It connects OK, sends messages OK, but when I change to other page in Symfony2 app, or close the session, it calls the onClose function. Then the application gets blocked and returns the following error:

SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction 500 Internal Server Error - PDOException

The server looks like:

$pdo = new PDO('mysql:host=localhost;dbname=XXXX', 'root', null);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$dbOptions = array(
    'db_table' => 'sessions',
    'db_id_col' => 'sess_id',
    'db_data_col' => 'sess_data',
    'db_time_col' => 'sess_time',
    'db_lifetime_col' => 'sess_lifetime',);

$session = new PdoSessionHandler($pdo, $dbOptions);
$myApp = new ServerSocket();

$loop = \React\EventLoop\Factory::create();
$server = new \React\Socket\Server($loop);
$server->listen(8080, '0.0.0.0');

new IoServer(new HttpServer(new WsServer(new SessionProvider($myApp,$session))), $server);
echo "server running \n";
$loop->run();

"MyApp" looks like:

class ServerSocket implements MessageComponentInterface {

protected $players;
private $users;

public function __construct()
{
    $this->players = [];
    $this->users = new \SplObjectStorage();
}

function onOpen(ConnectionInterface $conn)
{
    $this->users->attach($conn);
    $this->players[$conn->Session->get('current_user_id')] = $conn;
    print("new conection (". $conn->Session->get('current_user_id').")");
}

function onClose(ConnectionInterface $conn)
{
    $this->users->detach($conn);
    unset($this->players[$conn->Session->get('current_user_id')]);
    $conn->close();
}

   function onMessage(ConnectionInterface $from, $msg)
{
    $data = json_decode($msg);
    $to = $data->command;
    if (isset($this->players[$to])) {
        $this->players[$to]->send($data->message);
        echo $data->message;
    }
 }
}

The script for the Twig page is:

 var conn = new WebSocket('ws://localhost:8080');
    conn.onopen = function(e) {
        alert("Connection established!");
    };

    conn.onmessage = function(e) {
        alert(e.data);
    };

    function sendMessage(msg,user) {
        conn.send(JSON.stringify({command: user, message: msg}));
    };


    sendMessage("test",2);

What can I do to avoid that lock?

I have the same problem here. It seems to be known by Symfony team : github.com/symfony/symfony/issues/4976 — Moonchild

Moonchild Moonchild · Accepted Answer · 2015-11-12T13:52:12

According to Symfony 2 blocked concurrency, disabling the locking of sessions have solved my problem.

In your case, you should try :

$dbOptions = array(
    'db_table'        => 'sessions',
    'db_id_col'       => 'sess_id',
    'db_data_col'     => 'sess_data',
    'db_time_col'     => 'sess_time',
    'db_lifetime_col' => 'sess_lifetime',
    'lock_mode'       => 0
);

Lock wait timeout Symfony2 Ratchet with PdoSessionHandler

1 Answers