Re: Freeze avoidance of very large table.

On Mon, Apr 06, 2015 at 12:07:47PM -0500, Jim Nasby wrote:
> ...
> As I understand it, the goal here is to prevent huge amounts of
> periodic freeze work due to XID wraparound. I don't think we need
> the Freeze state to accomplish that.
> 
> With a single bit per page in the Frozen Map, checking a 800GB table
> would require reading a mere 100MB of FM. That's pretty tiny, and
> largely accomplishes the goal.
> 
> Obviously it would be nice to eliminate even that 100MB read, but I
> suggest you leave that for a 3rd patch. I think you'll find that
> just getting the first 2 accomplished will be a significant amount
> of work.
> 

Hi,
I may have my math wrong, but 800GB ~ 100M pages or 12.5MB and not
100MB.

Regards,
Ken