> read-1 > read-2 > write-2 > write-1 > > ...so any changes #2 makes are lost.
I think this sequence is okay, as long as the write's are atomic and they use up-to-date information. It would be undesirable for read-1 to extract a variable and to update it with write-1. But if write-1 manipulates variables atomically, then we don't problems. Consider a simple example with a counter like this. a = read-1 b = read-2 write-2.update(counter = counter + 1, a = "hello") write-1.update(counter = counter + 1) We don't have any problem. I think databases automatically take care of these synchronization. Even if process 1 does something with "a", after process 2 modifies it. Conceptually, that should be okay. Information process 1 gets is stale, but that's life. I don't think this is a problem either: >>A database ... would not automatically handle locking >>while an application function is potentially manipulating the session (prior >>to updating it in the database).
