Don Baccus wrote:
>
> At 08:15 AM 5/24/01 +0900, Hiroshi Inoue wrote:
>
> >> Unless we want to abandon MVCC (which I don't), I think an overwriting
> >> smgr is impractical.
> >
> >Impractical ? Oracle does it.
>
> It's not easy, though ... the current PG scheme has the advantage of being
> relatively simple and probably more efficient than scanning logs like
> Oracle has to do (assuming your datafiles aren't thoroughly clogged with
> old dead tuples).
>
I think so too. I've never said that an overwriting smgr
is easy and I don't love it particularily.
What I'm objecting is to avoid UNDO without giving up
an overwriting smgr. We shouldn't be noncommittal now.
regards,
Hiroshi Inoue