Re: [PoC] Improve dead tuple storage for lazy vacuum

On Sun, Apr 7, 2024 at 9:08 AM John Naylor <johncnaylorls(at)gmail(dot)com> wrote:
>
> I've attached a mostly-polished update on runtime embeddable values,
> storing up to 3 offsets in the child pointer (1 on 32-bit platforms).
> As discussed, this includes a macro to cap max possible offset that
> can be stored in the bitmap, which I believe only reduces the valid
> offset range for 32kB pages on 32-bit platforms. Even there, it allows
> for more line pointers than can possibly be useful. It also splits
> into two parts for readability. It would be committed in two pieces as
> well, since they are independently useful.

I pushed both of these and see that mylodon complains that anonymous
unions are a C11 feature. I'm not actually sure that the union with
uintptr_t is actually needed, though, since that's not accessed as
such here. The simplest thing seems to get rid if the union and name
the inner struct "header", as in the attached.