Re: XMIN semantic at peril ?

Erik Jones <erik@myemma.com> writes:
> If the query is always based on a primary key + XMIN, and since
> vacuum is the only thing that sets FrozenTransactionId, would it be
> unsane to change the update to

> - update row with "... where pk=... and XMIN IN (old_xmin_from_read,
> FrozenTransactionId)

I wouldn't risk it, because that *would* fail in the case Karsten
mentioned of an update sequence taking so long that a concurrent
update got frozen.

            regards, tom lane