Re: 9.4 broken on alpha

Michael Cree wrote:
> On Tue, Aug 25, 2015 at 06:09:17PM -0400, Tom Lane wrote:

> > Oh really? If rmb were a figment of someone's imagination, it would
> > explain the build failure (although not why nobody's reported it till
> > now).
>
> I reported the failure to build on Alpha, with an explanation and a
> patch to fix it, to the Debian package maintainers over a year ago,
> and within about of a month of version 9.4 being uploaded to Debian.

It's a pretty disappointing packaging process failure that the bug
report wasn't sent to upstream immediately, rather than waiting for a
whole year. That would have made a lot less likely that the removal of
the port would have passed muster in the first place. Supposedly we
were only removing stuff that was pretty clearly dead.

> It has been built and running at Debian-Ports for over a year now as
> I uploaded the fixed version to the Alpha unreleased distribution.

Has this been battle-tested under high load in multi-core servers?
Because based on other comments in this and other threads, it seems
likely that the port is subtly broken.

> > It'd be easy enough to s/rmb/mb/ in 9.4 ... but not sure it's worth
> > the trouble, since we're desupporting Alpha as of 9.5 anyway.
>
> That is disappointing to hear. Why is that? It is still in use on
> Alpha. What is the maintenance load for keeping the Alpha arch
> specific code?

The amount of code that was removed by the commit isn't all that much:
http://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=a6d488cb538c8761658f0f7edfc40cecc8c29f2d
but there's been rather a lot of work after that to add support for
atomic primitives as well as barriers, which would presumably not
trivial to implement and test on Alpha. Someone would have to volunteer
to writing, testing and maintaining that code. A buildfarm machine
would be mandatory, too.

I'm under the impression that Alpha machines are no longer being built,
so I'm doubtful that this would be a good use of anybody's time.

> > If the effective desupport date is 9.4 instead,
>
> It's not. The fixed and built 9.4 version was uploaded to Debian-Ports
> Alpha (in the unreleased distribution) and has been in use for over a
> year.

I think we could apply the bugfix to 9.4, but this doesn't help with
9.5.

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