Re: New feature request: FlashBack Query

On 2/17/07, elein <elein(at)varlena(dot)com> wrote:
>
> For other recent time travel ideas see:
> http://www.varlena.com/GeneralBits/122.php
> Time travel is not cheap, though.
>

I am sure this topic has probably been beaten to death in the past, but has
anyone talked about the advantages of Oracle's MVCC model versus
PostgreSQL's MVCC model? Oracle achieves multiversioning by using
rollback/undo segments, where PostgreSQL appears to place (essentially) the
undo in the same space as the table.

If I were to guess this is probably a major thing to change. Clearly there
are advantages to both, with Oracle essentially the space consumed by a
modified row is immediately available for reuse and generally there is
little row migration assuming there is enough space on the block so you
should be able to avoid updates to the index and the bloating that seems to
go along with vacuuming.

Is there any previous discussions that folks could point out here?