On 2013-10-10 08:59:47 -0400, Robert Haas wrote:
> On Tue, Oct 8, 2013 at 6:24 PM, Andres Freund <andres@2ndquadrant.com> wrote:
> > Do you have a better alternative? Making the computation unconditionally
> > 64bit will have a runtime overhead and adding a StaticAssert in the
> > existing macro doesn't work because we use it in array sizes where gcc
> > balks.
> > We could try using inline functions, but that's not going to be pretty
> > either.
> >
> > I don't really see that many further usecases that will align 64bit
> > values on 32bit platforms, so I think we're ok for now.
>
> I'd be inclined to make the computation unconditionally 64-bit. I
> doubt the speed penalty is enough to worry about, and I think we're
> going to have more and more cases where optimizing for 32-bit
> platforms is just not the right decision.
MAXALIGN is used in several of PG's hottest functions in many
scenarios. att_align_nominal is used in slot_deform_tuple,
heap_deform_tuple, nocachegetattr, etc. So I don't think that's viable
yet. At least not with much more benefit than this...
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services
