Re: [Tzdist] Fwd: [tzdist] #32 (service): managing historical data

[Cyrus Daboo <[e-mail]>]

Hi Doug,

--On December 16, 2014 at 1:20:15 PM -0700 Doug Royer 
<[e-mail]> wrote:

>> As I proposed before I want to see the version number be part of the
>> meta-data associated with the time zone data - i.e., part of the list
>> action response. I don't want to see it in the time zone data due to
>> the fact that, with the current manner in which IANA tz data is
>> "tagged" with a version, the entire set of time zones would be marked
>> as changed.
>
> That point is valid, however as soon as the data is saved on the
> tzdist-server, and the first fetch is performed, is it not just as likely
> that it would trigger a everything is out of date when they compare it to
> 'nothing authoritative known about this TZID yet - so get it' ?

OK, so when a list action changedsince is done we need to make sure of the 
following:

1) The server only reports a time zone as changed if the underlying data or 
meta-data (other than version id) has changed.

2) The server always reports the latest versions now in use for each 
publisher.

So #1 allows clients to fetch the updated tzdata and update any meta-data 
associated with a "changed" time zone.

#2 allows the client to update the version id meta-data for any other time 
zone it has cached, but was not reported in #1.

Note that, if a publisher chooses to include a version number in time zones 
they publish, and they ensure those only change when the data changes, then 
having the version embedded in the time zone data works fine as part of #1.

-- 
Cyrus Daboo