On Apr 5, 2011, at 9:55 AM, Anthony wrote: > Yes, that's a race condition with writing. My point was that even if the > first action is merely reading (but not doing any writing), you can have > problems. For example: > > Action 1: read session > Action 2: read session > Action 2: write session > Action 1: make some decision/calculation based on session data that is no > longer up to date >
Actually, I don't see that sequence as a real problem, because the result is identical to this sequence: Action 1: read session Action 1: make some decision/calculation based on session data that predates write-2 Action 2: read session Action 2: write session That is, action 1 shouldn't rely on the timing of action 2. If only one of the actions is writing, then they both have a consistent view of the session.
