Question

I need something like a session-id. I will need to track a couple of thousand users visiting a website. For load-balancing (multiple instances of PHP and NGINX) I will unfortunately not be able to use session_start() and capture the sessionid because it needs to span across multiple webservers.

These users are not logged in, so I will not know anything about them, except for their browser, ip and plugins.

I was thinking maybe using APC, and do something like
apc_store(‘count’, 1);

And give the current user the id = 1.

The next user will get apc_fetch(‘count’)+1, but I think that will be very slow, and probably also contain race-conditions.

Answer 1

To solve the problem of “multiple servers” with sessions, you could store your sessions in something else than the file system.

For example, you could :

• Store sessions in a database, shared by all webservers
• Or store sessions in a memcached cluster (better solution — and pretty easy)

A couple of interesting links :

• To specify your own session handler : session_set_save_handler()
• Enhance PHP session management
• Storing your PHP sessions using memcached