在if块中定义会话开始，导致会话在页面刷新时再次创建

if(!isset($_SESSION['SessData'])) {
    session_name('sess1');
    session_start();

    echo '----- In IF Condition -----';
    print_r($_SESSION['SessData']['Tracker']['Source']);
}
else {
    echo '----- In ELSE Condition -----';
    print_r($_SESSION['SessData']['Tracker']['Source']);
}

When executing the code its only going in the IF condition and not the else condition. Whats the reason behind it?

The working code is as follows:

if(phpversion()  < '5.4.0') {
    if(session_id() == '') {
        session_name('sess1');
        session_start();
        echo 'here1';
    }
    else {}
}
else if(phpversion()  >= '5.4.0') {
    if(session_status() == PHP_SESSION_NONE) {
        session_name('sess1');
        session_start();
        echo 'here2';
    }
    else {}
}


if(!isset($_SESSION['SessData'])) {
    echo '----- In IF Condition -----';
    print_r($_SESSION['SessData']['Tracker']['Source']);
    echo '<br />';
    echo session_id();
}
else {
    echo '----- In ELSE Condition -----';
    print_r($_SESSION['SessData']['Tracker']['Source']);
    echo '<br />';
    echo session_id();
}