Re: Add last commit LSN to pg_last_committed_xact()

Hi,

On 2022-01-28 18:43:57 -0500, James Coleman wrote:
> Alternatively I see pg_attribute_aligned, but that's not defined
> (AFAICT) on clang, for example, so I'm not sure that'd be acceptable?

clang should have it (it defines __GNUC__). The problem would be msvc, I
think. Not sure if there's a way to get to a common way of defining it between
gcc-like compilers and msvc (the rest is niche enough that we don't need to
care about the efficiency I think).

> Is there an approach I'm missing? Or does one of these seem reasonable?

I'd probably just slap a char *pad[PG_CACHELINE_SIZE] in there if the above
can't be made work.

Greetings,

Andres Freund