10.05.2018 20:29, Adriano dos Santos Fernandes пишет:
On 10/05/2018 14:23, Vlad Khorsun via Firebird-devel wrote:
Look how MSK time zone was changed at 2014.10.26
https://www.timeanddate.com/time/zone/russia/moscow
I think about something like this:
ID Name Valid from Offset
... MSK 2011.03.27 02:00 +4
... MSK 2014.10.26 02:00 +3
Is it makes sence ?
America/Sao_Paulo changes every year because DST (when starting to -02
and ending to -03).
The case is not about DST. It is about *change of rule* for particular
time zone. Does you read table at link above ?
If i understand it correct:
2010.03.01 04:00 MSK == 2010.03.01 00:00 UTC,
2013.03.01 04:00 MSK == 2013.03.01 00:00 UTC, but
2016.03.01 04:00 MSK == 2016.03.01 01:00 UTC
In practical terms, it's the same as a DST change.
According to:
https://www.timeanddate.com/time/time-zones.html
---
Daylight Saving Time Zones
Regions that use Daylight Saving Time (DST) change the time zone name and time during the DST period. The words “daylight” or
“summer” are then usually included in the time zone name. The areas that don't use DST remain on standard time zone all year.
For example, California uses Pacific Daylight Time (PDT) during the DST period, but Pacific Standard Time (PST) during the rest of
the year.
---
So, in Moscow:
2010.03.01 used MSK (UTC +3)
2010.03.28 DST start (MSK -> MSD)
2010.04.01 used MSD (UTC +4)
2010.10.31 DST end (MSD -> MSK)
2011.03.01 used MSK (UTC +3)
2011.03.27 used MSK (UTC +4) <<<--- rule for MSK was changed !!!
... don't use DST, don't use MSD
2014.10.26 used MSK (UTC +3) <<<--- rule for MSK was changed again !!!
... don't use DST, don't use MSD
A DST is nothing different than a "rule change" and another "rule
change" every year.
Nope. DST doesn't affect time zone. It affects what time zone is actual
at given region. Before 2011 it was MSK "at winter" and MSD "at summer" at
Moscow area.
Regards,
Vlad
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