I'm storing some user information in session so I don't have to query the database every single time user changes page. What if this user uses multiple browsers/computers and olders sessions have invalid data now? How do I keep them in sync? Logging out the older sessions of the user is fine, but I would like to avoid writing session info to db, if possible.
I do realize it's a fairly common problem, but I couldn't come up with right stuff after googling.