[tz] What data should TZDB offer?

David Patte dpatte at relativedata.com
Sun Jun 6 19:05:44 UTC 2021

I would agree to both of these.

I also think it would be preferable to restore (with corrections if 
necessary) all the distinct zones per ISO country that have varied since 
1970. Russia and Canada have numerous timezones, just as the USA has, 
and it would simplify access, as well as providing more historical data 
per country.

Overall my preference is to make historical data available for as many 
cities as possible / per country, in one place; or for at least all 
zones per country that have differed since 1970. If they link is to 
generic 'noname' zones which crosses political boundaries, then I could 
also be happy with that, as long as no historical data is lost.

In the long run, app developers will also want historical data for 
separate zones that merged before 1970, and they could exist in a 
secondary table, managed by tz, or even managed by someone else as a 
separate project.

On 2021-06-06 12:44, Fred Gleason via tz wrote:
> On Jun 6, 2021, at 11:02, Tom Lane via tz <tz at iana.org 
> <mailto:tz at iana.org>> wrote:
>> One other issue that I think deserves more attention than it has
>> gotten lately is that tzdb has become a de facto standard and users
>> rely on its stability.  I would like to see some sort of principle
>> adopted that minimizes changes in historical data.  In particular,
>> I think it's past time to prohibit data changes adopted for
>> essentially-administrative reasons (as opposed to new findings of
>> historical fact).  I'd put the recent reorganization under the
>> heading of things that would be forbidden by this principle, and also
>> the changes a few years ago that removed "made up" zone abbreviations.
>> Whatever the justification for those abbreviations originally, some
>> people had come to depend on them, and little was to be gained by
>> removing them.
>> […]
>> The idea of having at least one zone per ISO-3166-1 country does
>> seem like a good one, though.  Aside from possibly deflecting
>> politically-based complaints, this seems basically like future
>> proofing: even if two countries have shared clocks since 1970,
>> they could diverge at any time.  Being prepared with an appropriate
>> zone name should minimize the pain to users.  Also notice that
>> splitting an existing zone creates no compatibility problems, since
>> no one is obligated to switch to the new zone name immediately.
> These two points in particular are synergistic; stability of 
> historical data is just a Good Thing, but no one here wants to see the 
> TZDB maintainer receiving ‘vitriolic’ e-mail, nor getting sued 
> [again]. Hence, politically ‘future-proofing' the DB seems a prudent move.
> Cheers!
> |---------------------------------------------------------------------|
> | Frederick F. Gleason, Jr. |             Chief Developer         |
> |                           |             Paravel Systems         |
> |---------------------------------------------------------------------|
> |         A room without books is like a body without a soul.         |
> |         |
> |                                                         -- Cicero   |
> |---------------------------------------------------------------------|
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mm.icann.org/pipermail/tz/attachments/20210606/4b82a945/attachment-0001.html>

More information about the tz mailing list