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tz database community up in arms over proposals to merge certain time zones

(2021/09/28)


The time zone database hosted at the Internet Assigned Numbers Authority (IANA) has been updated following threats, earlier this year, of a fork over a proposal to merge time zones.

The update, the 2021b release of the tz code and date, was published over the weekend and omits some, but not all, of the issues that have caused concern in the project's mailing list.

The tz database is a hugely important resource that contains information on the world's time zones. It also attempts to keep track of historical changes since 1970. Its usage is relatively straightforward; a time zone has an offset from UTC and a set of rules governing daylight saving time (should it apply).

[1]

The system gets regular updates, the last being 2021a. These do not usually generate drama – 2021a, for example, tweaked timestamps for South Sudan.

[2]

[3]

However, a proposal to merge multiple regions that have had the same data post-1970 into a single time zone has been met with controversy amid fears that an ID cull could result in pre-1970 data becoming difficult to get hold of – as well as causing backwards-compatibility issues.

In a nutshell, put "Europe/Berlin" or "Europe/Oslo" with a pre-1970 date into the system, and out will come an answer. But the answer will be different for each option as there was a time when the two zones were different. However, as they've been the same for the past 50+ years, the proposal was to have "Europe/Oslo" simply be an alias of "Europe/Berlin" – meaning that Oslo's pre-1970 data would be effectively replaced by Berlin's.

[4]

"Why can Berlin keep its status and full history, but Oslo gets effectively deleted?" [5]asked Java developer and maintainer of the Joda-Time classes Stephen Colebourne. "The answer is that Berlin has the greater population."

"The project leader," Colebourne told The Register , "is trying to force through a merger of time zones affecting timestamps pre-1970. Data that has been present in the database for many years is to be effectively removed."

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Describing the rationale for the move as "extremely limited," Colebourne went on to say: "No consideration is being taken of the big impacts on downstream systems – Joda-Time is particularly affected because of the way it handles links as full aliases.

"If a Joda-Time user were to adopt the proposed release, then it would no longer be possible to hold a time zone ID for Oslo, Stockholm or Amsterdam in memory – a catastrophic outcome."

The patch itself was proposed some months ago, and controversy has rumbled on ever since. Aside from a wholesale reversion of the patch, Colebourne suggested alternative approaches [10]back in June before [11]suggesting a fork in order to keep the time zone data as it was before.

[12]

The protests of Colebourne and other users have not completely fallen on deaf ears, and primary tz coordinator Paul Eggert [13]announced the 2021b release over the weekend with some of the changes absent. The clock had been ticking due to daylight saving time observance being dropped in Samoa.

However, as well as changes for Samoa and Jordan, some merging of time zones still occurred, although the announcement noted "it omits most proposed changes that merged all Zones agreeing since 1970, as concerns were raised about doing too many of these changes at once."

The Register contacted Eggert for his take on the furore, but he preferred not to make a comment.

Eggert's announcement said of the merge: "This is part of a process that has been ongoing since 2013.

"This does not affect post-1970 timestamps, and timezone historians who build with 'make PACKRATDATA=backzone' should see no changes to pre-1970 timestamps."

As for Colebourne, he admitted that the battle was lost for now and blogged: "Tonight 9 of the 30 changes have been included in release 2021b. These are not the ones affecting Europe.

"Stay tuned as I try and work out how best to resolve this completely unecessary [sic] drama." ®

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[1] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/databases&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YVLn8EmHcnfI194AakmcEAAAAAw&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/databases&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YVLn8EmHcnfI194AakmcEAAAAAw&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/databases&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33YVLn8EmHcnfI194AakmcEAAAAAw&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/databases&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YVLn8EmHcnfI194AakmcEAAAAAw&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[5] https://blog.joda.org/2021/09/big-problems-at-timezone-database.html

[6] https://www.theregister.com/2021/09/24/yugabytes_doubledecker_dbaas_follows_cochroach/

[7] https://www.theregister.com/2021/09/20/dsag_sap_cloud_survey/

[8] https://www.theregister.com/2021/09/16/cabinet_office_cans_erp_search/

[9] https://www.theregister.com/2021/09/15/pinecone_2_0/

[10] https://mm.icann.org/pipermail/tz/2021-June/030273.html

[11] https://mm.icann.org/pipermail/tz/2021-September/030400.html

[12] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/databases&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33YVLn8EmHcnfI194AakmcEAAAAAw&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[13] https://mm.icann.org/pipermail/tz/2021-September/030760.html

[14] https://whitepapers.theregister.com/



She who controls the past

Anonymous Coward

controls the future.

Anonymous Coward

She who commands the future, conquers the past.

Is the database really that big

John Robson

that the merge is necessary in any way?

I don't really see that there is much additional overhead to keeping the separate, not like they update five times a day each.

Re: Is the database really that big

Pascal Monett

The database is less than [1]500kb .

Five. Hundred. Kilobytes. We can leave it as it is for the next hundred millenia before we start getting into a size issue.

This really is a storm in a teacup.

[1] https://www.iana.org/time-zones

Anonymous Coward

Oh ffs, is it really necessary to merge zones and delete pre-1970 changes? We're not running on mainframes with 64kwords of memory any more. Utterly pointless changes from an arsey developer who WONTFIX anything he's philosophically opposed to regardless of arguments or consensus to the contrary. Oslo isn't even in the fucking EU, it's a separate political entity with control of it's own timezone and could easily potentially diverge again in the future.

We need more like Linus

Greybearded old scrote

This is the sort of "breaking userspace" change that used to break Linus' patience. Many of the sweary rants were directed at repeat offenders on that front.

If others are relying on you, don't "move fast, break things." Use care and deliberation, don't honk off the folks downstream.

Just another dissociated idiot

W.S.Gosset

"Optimising" according to a theoretical elegance in his head. Not oblivious to the world, just dismissing it ; angry at people not recognising their virtue. "Make a change! Make a difference! BE the difference!"

Fork.

PACKRATDATA

disgruntled yank

Not judgmental, are we?

Lennart Poettering would approve!

Gene Cash

This sort of mess is just up his alley.

herman

Sounds like a Make Work project.

Hum

Julz

ICANN strikes again.

From Wiki:

"ICANN took responsibility for the maintenance of the database on 14 October 2011. The full database and a description of current and future plans for its maintenance are available online from IANA".

Footnotes are for things you believe don't really belong in LDP manuals,
but want to include anyway.
-- Joel N. Weber II discussing the 'make' chapter of LPG