[Rpm-maint] [rpm-software-management/rpm] Please support smaller build-ids (#950)

[Mark Wielaard]

Hi Frank,

Thanks so much for trying to come up with actual numbers!

On Tue, 2019-11-26 at 13:07 -0800, Frank Ch. Eigler wrote:
> Argh, very sorry @espindola but I was 3 orders of magnitude too high
> with my extrapolated numbers.  I hereby hand back my math card.  The
> collision probability is more in the 10e-6 range.

This seems mood since the issue is already closed and lld will probably
switch to a 128 or 160 bit build-id anyway. But I am still interested
in the actual numbers and I am now also a little confused.

When you say you were off by 3 orders of magnitude to you mean that for
one architecture (x86_64) and one release (fedora 30) you estimate that
there are ~600.000 build-ids (instead of ~600.000.000) because that is
the number of executable artifacts? Or that you extrapolated it (which
number?) wrongly when looking at the number of arches (i386 and x86_64
can be installed concurrently) and actual distros (3 normally) that
overlap in maintenance?

Or asked differently, which number of build-ids are you expecting to
come to a collision probability of 10e-6 when the build-id is just
64bits?

Thanks,

Mark