On 2016-02-16 23:33:47 -0500, Tom Lane wrote:
> Yes, exactly. I'm not certain if there are any real platforms where
> a pointer-sized write wouldn't be atomic (it sure sounds inefficient
> for that to be true), but we have not assumed that to date and I'd
> just as soon not start here.
FWIW, there's no sizeof(void*) == 8 platform supported by PG where
aligned 8 byte writes aren't atomic. There are a number of supported
platforms with sizeof(void*) == 4 without atomic 8 byte writes though.