On August 16, 2017 10:47:23 AM PDT, Robert Haas <robertmh...@gmail.com> wrote: >On Wed, Aug 16, 2017 at 1:40 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> I was wondering why the shm_toc code was using BUFFERALIGN and not >> MAXALIGN, and I now suspect that the answer is "it's an entirely >> undocumented kluge to make the atomics code not crash on 32-bit >> machines, so long as nobody puts a pg_atomic_uint64 anywhere except >> in a shm_toc". > >Well, shm_toc considerably predates 64-bit atomics, so I think the >causality cannot run in that direction. shm_toc.c first appeared in >the tree in January of 2014. src/include/port/atomics didn't show up >until September of that year, and 64-bit atomics weren't actually >usable in practice until e8fdbd58fe564a29977f4331cd26f9697d76fc40 in >April of 2017.
Well, not for core code. I certainly know about production code using it, because crusty platforms are considered irrelevant... Independent of that, a comment explaining what the BUFFERALIGN is intending would be good. Andres -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers