Alvaro Herrera <alvherre@dcc.uchile.cl> writes:
> On Tue, Mar 15, 2005 at 06:51:19PM -0500, Tom Lane wrote:
>> I believe VACUUM already knows that xmin = xmax implies the tuple
>> is dead to everyone.
> Huh, that is too simplistic in a subtransactions' world, isn't it?
Well, it's still correct as a fast-path check. There are extensions
you could imagine making ... but offhand I agree that it's not worth
the trouble. Maybe in a few years when everyone and his sister is
using subtransactions constantly, we'll feel a need to optimize these
cases.
regards, tom lane