note 68537 deleted from ref.session by danbrown

Note Submitter: Eric dot Deplagne at nerim dot net ---- One more note on session duration, and especially long sessions. I hope I've now understood the problem, and this may be useful. The duration of a session is indeed controlled by many things (too many for my taste). The first thing is session.cache_expire, which should be *the* thing, you can set it with ini_set(), or with session_cache_expire(). The value is in minutes, and defaults to 180, which is 3 hours and should be enough. <?php //ini_set("session.cache_expire","180"); // default is 180, which is 3 hours... ?> But that does not work ! Second thing to take into account, session.gc_maxlifetime. Indeed, if the garbage collector kills your session data, you're lost. So we set it with ini_set. The value is in seconds, and defaults to 1440, which is only 24 minutes and might be a little short. <?php ini_set("session.gc_maxlifetime","3600"); // default is 1440, which is only 24 minutes ?> Here I should have a 1 hour session. But in fact, I don't ! Third thing to take into account, session.save_path. If other people mess up with it, like if it's "/tmp" as it is by default, and their gc has not the same idea as yours, you're lost. So we set it with ini_set or session_save_path. <?php session_save_path("/my/own/path/without/url/sessions"); ?> Here we are. As you can read in the example it should be a path you control (and your web server can write), with no access via URL. Of course, all these parameters must be set before calling session_start(). In fact, two other variables (at least) play a role in session duration, and will explain that the session might last more than expected. The gc erasing your data is a probabilistic thing. Each time a session is opened, the probability the gc is started is session.gc_probability/session.gc_divisor. session.gc_probability defaults to 1 and session.gc_divisor defaults to 100, which makes a 1% probability. This is to have sessions long enough. I'm unsure about having sessions lasting exactly the time we want them to.