Re: Ensuring hash tuples are properly maxaligned

On 2018-01-03 14:29:15 +1300, Thomas Munro wrote:
> On Wed, Jan 3, 2018 at 2:20 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Andres Freund <andres@anarazel.de> writes:
> >> But note that dsa_pointer can be wider than a regular pointer on
> >> platforms without atomics support.
> >
> > Hm.  I did not get that impression from the comments in dsa.h,
> > but if it's true then this approach won't work --- and indeed the
> > hash code would be actively broken in such a case, so it's a problem
> > we must fix.
> 
> Maybe Andres is thinking of dsa_pointer_atomic?  dsa_pointer is
> normally the size of a pointer (well, really, the size of size_t),
> though it could be *narrower* if you don't have atomics or ask for it
> with USE_SMALL_DSA_POINTER

Yep, I was.