Thanks for the response guys. That was really useful. BTW, I was thinking on these lines...since SCNs are generated for every committed transaction, Oracle can recognize those committed transactions; but then, SCNs are only written to data file headers and control file I guess. So incase committed data is just in the archive logs, perhaps there is no way to know whether it was committed or not as jmodic says.

But if there is a flag in the archive logs that suggests that the data was committed (which I guess must be there), Oracle can apply only when it identifies the flag. But if the flag is in one archive log and the data in another, then it makes complete sense the way Oracle functions.

Any thoughts / inferences?