Re: AIX support

On Wed, Apr 24, 2024 at 11:39:37PM -0400, Bruce Momjian wrote:
> On Sat, Apr 20, 2024 at 12:25:47PM -0400, Tom Lane wrote:
>> So I'm totally not in favor of #1, at least not without some hard
>> commitments and follow-through on really cleaning up the mess
>> (which maybe looks more like your #2). What's needed here, as
>> you said, is for someone with a decent amount of expertise in
>> modern AIX to review all the issues. Maybe framing that as a
>> "new port" per #3 would be a good way to think about it. But
>> I don't want to just revert the AIX-ectomy and continue drifting.
>>
>> On the whole, it wouldn't be the worst thing in the world if PG 17
>> lacks AIX support but that comes back in PG 18. That approach would
>> solve the schedule-crunch aspect and give time for considered review
>> of how many of the hacks removed in 0b16bb877 really need to be put
>> back, versus being obsolete or amenable to a nicer solution in
>> late-model AIX. If we take a "new port" mindset then it would be
>> totally reasonable to say that it only supports very recent AIX
>> releases, so I'd hope at least some of the cruft could be removed.
>
> I agree that targeting PG 18 for a new-er AIX port is the reasonable
> approach. If there is huge demand, someone can create an AIX fork for
> PG 17 using the reverted patches --- yeah, lots of pain there, but we
> have carried the AIX pain for too long with too little support.

Some of the portability changes removed in 0b16bb877 feel indeed
obsolete, so it may not hurt to start an analysis from scratch to see
the minimum amount of work that would be really required with the
latest versions of xlc, using the newest compilers as a supported
base. I'd like to think backporting these to stable branches should
be OK at some point, once the new port is proving baked enough.

Anyway, getting an access to such compilers to be able to debug issues
on hosts that take less than 12h to just compile the code would
certainly help its adoption. So seeing commitment in the form of
patches and access to environments would help a lot. Overall,
studying that afresh with v18 looks like a good idea, assuming that
anybody who commits such patches has access to hosts to evaluate them,
with buildfarm members running on top, of course.

My 2c.
--
Michael