Question about deleting expired session files.

Actually if you want there is a way to immediately remove sessions from the server, as they are kept in files. It's not recommended to do so but It's possible. Check out this link: http://php.net/manual/en/function.session-save-path.php

How the sessions are saved depends on the driver in use, which is why you should adjust the settings mentioned earlier. If your host won't permit you to change the settings and you have verified that the settings will not permit the GC to run, then you might need to resort to some other form of GC.

Bonfire

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