Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM on-access)

On Wed, Dec 3, 2025 at 6:07 PM Melanie Plageman
<melanieplageman@gmail.com> wrote:
>
> If we're just talking about the renaming, looking at procarray.c, it
> is full of the word "removable" because its functions were largely
> used to examine and determine if everyone can see an xmax as committed
> and thus if that tuple is removable from their perspective. But
> nothing about the code that I can see means it has to be an xmax. We
> could just as well use the functions to determine if everyone can see
> an xmin as committed.

In the attached v27, I've removed the commit that renamed functions in
procarray.c. I've added a single wrapper GlobalVisTestXidNotRunning()
that is used in my code where I am testing live tuples. I think you'll
find that I've addressed all of your review comments now -- as I've
also gotten rid of the confusing blk_known_av logic through a series
of refactors.

The one outstanding point is which commits should bump
XLOG_PAGE_MAGIC. (also review of the reworked patches).

- Melanie