Re: Further open item (Was: Status of 7.2)

Hannu Krosing <hannu@tm.ee> writes:
> But could we not make it so that rollback will also reset xmax and cmax 
> to 0.

We never have done that and I don't see why we should start.
(And no, I'm not sure that it'd be entirely safe; there are
concurrency/atomicity issues involved, because we do not
insist on getting exclusive lock to set the it's-dead-Jim
flag bit.)

We could make the user readout of xmax/cmax be zeroes if the flag
bits show they are invalid.  But this really just begs the question
of what use they are to users in the first place.  I can't see any;
and if we make them read as zeroes then they for sure won't have any.
        regards, tom lane