That's what I'm wondering. It seems that if you use the threshold, then your saved time isn't updated on each request, so when garbage collection is randomly triggered, your session time may look old (and therefore could be deleted) when it is really not old. Because the saved time is not updated, my session may look like it was last saved 20 minutes ago, triggering cleanup if my lifetime is 15 minutes. But in reality, I've been surfing the site actively. If I understand this correctly, then this seems like an issue that's entirely specific to the threshold feature.

So @drak is right that this doesn't affect the triggering of GC, but it does seem like the threshold will affect the behavior once the GC has been triggered. Do you agree? Perhaps it's just a wording issue and this would be better:

>Be aware that if the session is not written on every request, a session's last
>"saved" time may appear to be older than it really is. During the garbage collection
>process, this could trigger the session to appear older than your session lifetime
>and cause it to be removed. The result is that users may reach the session lifetime
>and be logged out even while actively using the site.

What do you think?