Jeff Davis <pgsql@j-davis.com> writes:
> There are all kinds of challenges there, but it might be worth thinking
> about. Visibility information is highly compressible, and requires
> constant maintenance (updates, deletes, freezing, etc.). It also might
> make it possible to move to 64-bit xids, if we wanted to.
If you want it to be cheaply updatable (or even cheaply readable),
compression is not what you're going to do.
regards, tom lane
