$testConnection = function() {
            $mypid = getmypid();
            $lsof = shell_exec("lsof -i -P -n | grep 3306 | grep $mypid");
            echo ($lsof === null ? 'no connection' : 'connection established') . PHP_EOL;
        };

        // take your adapter with mysql driver inside
        $db = self::$infrastructure->db();

        $testConnection();

        $db->getDriver()->getConnection()->connect();

        $testConnection();

        $db->getDriver()->getConnection()->disconnect();

        $testConnection();

        $db->getDriver()->getConnection()->connect();

        $testConnection();

        $db->getPlatform()->quoteValue('test');
        $db->getDriver()->getConnection()->disconnect();

        $testConnection(); // are still connected? yes :(