Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> I propose creating "Visibility Groups" that *explicitly* limit the
> ability of a transaction to access data outside its visibility group(s).
> By default, visibility_groups would be NULL, implying potential access
> to all tables.
I think this would be a lot of mechanism and complication that will go
completely unused in the field. It'll be impossible even to explain let
alone to use effectively, for anyone who's not intensely steeped in the
details of MVCC.
regards, tom lane