On 28 Feb 2018, at 14:47, Denver Gingerich <den...@ossguy.com> wrote: > > On Wed, Feb 28, 2018 at 08:59:01AM +0000, Kevin Smith wrote: >> On 13 Feb 2018, at 16:57, Simon Friedberger <simon.jab...@a-oben.org> wrote: >>> E3. Simply make the ID: FROM-TIMESTAMP. >>> Here FROM needs to be the eventual FROM after possible >>> rewriting. Can >>> that be done? >>> And TIMESTAMP has to be strictly increasing so should have >>> sub-second >>> resolution. >>> I assume this is impossible because otherwise it would be to >>> easy. But >>> why is it impossible? :) >> >> Because timestamps aren’t monotonic? :) > > Do you mean because most people use Unix time and/or other UTC-based > timestamps (that have leap seconds)? > > If so, this can be mostly solved by using TAI timestamps. Unfortunately, it > is tricky in most OSes to obtain a TAI timestamp, but I found some code that > does this (on many platforms anyway): > > https://ossguy.com/tai.c > > We've used this code for implementing usage tracking in JMP (to ensure a > day's length doesn't vary from day to day - it is always exactly 86,400 > seconds long). For details, see > https://gitlab.com/ossguy/sgx-catapult/commit/31c2cb7c8fbea1ad4cc6753a4343dbfc65552fa5 > . As you might suspect, we'd like to port the above TAI code to Ruby, but > it works ok as-is for now. > > I realize that clock skew could still cause the TAI timestamp that your OS > returns to be non-monotonic (i.e. a machine issue, not an issue with TAI time > itself); I'm not sure if that's a substantial issue for the message IDs being > discussed here.
I meant because clock skew is a thing, so relying on the monotonicity doesn’t work. Seems like it shouldn’t be a thing, but is. /K _______________________________________________ Standards mailing list Info: https://mail.jabber.org/mailman/listinfo/standards Unsubscribe: standards-unsubscr...@xmpp.org _______________________________________________
