Re: CompactCheckpointerRequestQueue versus pad bytes

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> The documentation on MacOS X isn't quite as explicit, but I'd still be
> astonished if we found any other behavior. TBH, I'd be kind of
> surprised if this is the only place in our code base that relies on
> the initial contents of shared memory being all-zeros.

Maybe so, but if we find any others, I'll be wanting to change them too.
It's bad practice and worse documentation for modules to be silently
assuming that anything has a value they didn't explicitly give it.

A related practice that probably costs us a lot more, in both code space
and time, is that most (all?) places that create Node objects explicitly
initialize every field of the Node struct, even though makeNode() has
a palloc0 underneath it and so setting fields to zero is redundant.
I believe that this is a good practice anyway, for documentation and
code greppability reasons.

regards, tom lane