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

Jan Wieck <JanWieck@Yahoo.com> writes:
> Depends. Specifically on transaction profiles and how long the blocks 
> linger around before being written. If you can set the all visible bit 
> by the time, the page is written the first time, what bit including the 
> is-frozen one cannot be set at that time too?

All-visible and is-frozen would be the same bit ...

> And even if some cases still required another page write because those 
> frozen bits cannot be set on first write, this seems to be a win-win. We 
> would get rid of the FrozenXid completely and shift to a bit, so we can 
> effectively have a min_ freeze_age of zero while keeping the xid's forever.

Right.  I don't see any downside, other than eating another status bit
per tuple, which we can afford.
        regards, tom lane