Re: Idea for getting rid of VACUUM FREEZE on cold pages

On Tue, 2010-06-08 at 18:03 -0400, Robert Haas wrote:
> OK, yes, I see what you're getting at now.  There are two possible
> ways to do freeze the tuples and keep the xmin: we can either rely on
> the PD_ALL_VISIBLE page-level bit (as I previously proposed) or we can
> additionally have a HEAP_XMIN_FROZEN bit as you propose here.  I am
> not sure which way is better.

Doing it at tuple level is more flexible and allows more aggressive
freezing. It also works better with existing tuple visibility code.

-- Simon Riggs           www.2ndQuadrant.com