Tom Lane wrote: > > Peter Eisentraut <[EMAIL PROTECTED]> writes: > > Tom Lane writes:
> To my mind, full SERIALIZABLE mode is the only approach that can be > explained in terms of simple notions like "you see only the data that > existed at time T". There's another way. If the current value is different from that at time T, we may be able to reset the time when the statement begun, which is equivalent to replaceing the snapshot (this isn't allowed in serializable mode). Of cource it would be very difficult to implement(at least effectively). As I've already mentioned many times SELECT and SELECT .. FOR UPDATE are alike in appearance but quite different in nature. For example, the meaning of the snapshot isn't the same as you've pointed out already in this thread. It's meaingless for SELECT and UPDATE(SELECT .. FOR UPDATE) to have a common snapshot. regards, Hiroshi Inoue ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
