How do I increase Facebook API's session length?

I'm using Facebook's Graph API from Android.

First, what is the default session length (time)? The ONLY resource I've found stating anything helpful and relevant is from this Facebook blog post which suggests the default is 2 hours.

Is there a way to set the session timeout? If that's the default, one would reason that it can be set. It'd be great if I could set it for, say, 24 hours. If it can't be set,开发者_Go百科 do you have a strategy for how you deal with it, without making the user login all the time? For example, if the session time automatically increases on the server side (say, by 2 hours) with each call to the API, then I'd implement a strategy where I'd call SOME API method every, say, 2-ish hours.

Note that I am aware of the offline_access permission. That seems like overkill.