Re: A structured format for dates?

[Brian Campbell <[e-mail]>]

+1 to Tommy "no hats" Pauly's rational

On Tue, Aug 23, 2022 at 7:30 AM Tommy Pauly <[e-mail]> wrote:

>
>
> > On Aug 23, 2022, at 4:00 AM, Poul-Henning Kamp <[e-mail]>
> wrote:
> >
> > --------
> > Roberto Polli writes:
> >> Hi Poul-Henning,
> >>
> >> Il giorno mar 23 ago 2022 alle ore 10:19 Poul-Henning Kamp
> >> <[e-mail]> ha scritto:
> >>>> Just tried to get some more feedback on twitter on the topic
> >>>> https://twitter.com/ioggstream/status/1561752931417952258
> >>>> feel free to RT.
> >>
> >>> Making timestamps human readable is pointless, because, statistically
> >>> speaking, no humans ever read these headers in the raw.
> >> While statistically speaking humans do not read headers nor contents,
> >> not having a human readable format for dates will just lead people that
> >> cares for readability to:
> >>
> >> - either continue using HTTP-date;
> >> - or using a generic ISO8601 string, e.g. "2020-02-02T10:10:10+01:00".
> >
> > And they are welcome to do that, so what's the problem ?
> >
> > Again: Not even one out of a billion HTTP headers is ever read by a
> human,
> > so insisting on human readability makes no sense.
> >
> > For that one out of a billion, there is absolutely nothing preventing
> tools,
> > for instance the browsers "developer tools" from nice-printing the field
> > as human-readable.
> >
> >>> The necessary handling of leap-second is complex and a layer-violation.
> >>
> >> Syslog does not use them
> >> https://www.rfc-editor.org/rfc/rfc5424.html#section-6.2.3
> >
> > A: What does that have to do with anything ?
> >
> > B: That is a really bad (13 year old!) choice, in a world where people
> have
> >   started to apply leap-smearing and other platform-level mitigations of
> >   leap-seconds.
> >
> > Both HTTP and Syslog should transmit whatever time the platform provides,
> > respecting whatever leap-second handling that platfrom has decided to
> apply.
> >
> >>> And finally: it is much more expensive in terms of CPU power.
> >>
> >> This makes the more computationally intensive HTTP-date
> >> the only human readable option.
> >
> > I literally dont know what that means ?
> >
> > If only one out of a billion HTTP date headers are ever read by a
> > human, and that is probably way overestimated, then clearly the
> > extra processing cost of humanizing the field value should be
> > borne only by those requests ?
> >
> >> In general, I am not sure whether CPU power issues should be addressed
> at
> >> a different level than field content (e.g. at messaging level) since it
> is
> >> not possible to predict the spillovers of those micro-optimizations:
> >> honestly I have no data on that. This is an interesting topic that
> >> needs further (and proper) investigation though.
> >
> > Well /I/ have experience with that, quite a lot in fact, and I'm
> > telling you that converting to and from "human" timestamp format
> > is a massive waste of computing power.
> >
> > ...in particular when we are talking about a globally load-bearing
> protocol like HTTP.
>
> The numeric type is not only simpler to process for a computer, but also
> should be generally smaller on the wire, particularly if we have binary
> structured fields one day. The scale of that alone can have a great impact.
>
> I imagine it’s also a lot easier to translate *to* the human readable /
> localized format for a date from the number, since the number is an
> unambiguous form. Parsing dates the other way (from human readable to
> machine readable) is where much of the complexity and ambiguity arises, so
> a scheme that only requires transformations in one direction seems
> preferable.
>
> Tommy (no hats)
>
> >
> > Poul-Henning
> >
> >
> > --
> > Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> > [e-mail]         | TCP/IP since RFC 956
> > FreeBSD committer       | BSD since 4.3-tahoe
> > Never attribute to malice what can adequately be explained by
> incompetence.
> >
>
>

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