如果服务器闲置，php会话将在第一次尝试时失败

Question

For some reason the first login attempt will fail if the server has been idle for some time, for example a couple of hours.

This is what happens:

1. The user navigates to a login script
2. The script sets session variables and redirects to the main page
3. The main page should be able to read the session variable (but fails in this case)

There are no remarks in the PHP error log and the second attempt works fine. It only happens for the first user accessing the page after a idle period. For example if another user tries to log in 5 seconds later, everything works fine.

This is on a IIS7 with PHP 5.3 using FastCGI.

Any ideas what's wrong here or what I can do to find a solution?

This is roughly how the scripts are set up login.php:

@session_start();
$_SESSION['userid'] = $userid;
session_write_close();
session_unset();
usleep(200000);     
header('Location:index.php');

main script

session_start();
if (isset($_SESSION['userid'])) {
   // Login successful
}

Answer 1

Remove the three lines.

session_write_close();
session_unset();
sleep(200000);