Robert Haas <robertmhaas@gmail.com> writes:
> I believe that we're in trouble with XIDs as soon as you have two
> active XIDs that are separated by a billion, because then you could
> have a situation where some people think a given XID is in the future
> and others think it's in the past. I have been wondering if we should
> have some sort of active guard against that scenario; I don't think we
> do at present.
Sure we do. It's covered by the XID wraparound prevention logic.
regards, tom lane