Re: 9.4 broken on alpha

Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> Aaron W. Swenson wrote:
>> In the 4 years that that particular line has been there, not once had
>> anyone else run into it on Gentoo until a couple months ago.
>> And it isn't a case of end users missing it as we have arch testers
>> that test packages before marking them suitable for public consumption.
>> Alpha is one of the arches.

> This means that not once has anybody compiled in an Alpha in 4 years.

Well, strictly speaking, there were no uses of pg_read_barrier until 9.4.
However, pg_write_barrier (which used "wmb") was in use since 9.2; so
unless you're claiming your assembler knows wmb but not rmb, the code's
failed to compile for Alpha since 9.2.

>> As for the dropped support, has the Alpha specific code been ripped
>> out? Would it still presumably run on Alpha?

> Yes, code has been ripped out.  I would assume that it doesn't build at
> all anymore, but maybe what happens is you get spinlocks emulated with
> semaphores and it's only horribly slow.

The whole business about laxer-than-average memory coherency gives me the
willies, though.  It's fairly likely that PG has never worked right on
multi-CPU Alphas.
        regards, tom lane