Re: retry shm attach for windows (WAS: Re: OK, so culicidae is *still* broken)

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Tue, Jun 6, 2017 at 12:44 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> By definition, the address range we're trying to reuse worked successfully
>> in the postmaster process. I don't see how forcing a specific address
>> could do anything but create an additional risk of postmaster startup
>> failure.

> If the postmaster picked an address where other things are unlikely to
> get loaded, then that would increase the chances of child processes
> finding it available, wouldn't it?

But how would we know that a particular address range is more unlikely
than others to have a conflict? (And even if we do know that, what
happens when there is a conflict anyway?) I sure don't want to be in
the business of figuring out what to use across all the different Windows
versions there are, to say nothing of the different antivirus products
that might be causing the problem.

Also, the big picture here is that we ought to be working towards allowing
our Windows builds to use ASLR; our inability to support that is not
something to be proud of in 2017. No predetermined-address scheme is
likely to be helpful for that.

regards, tom lane