Here you go:
https://www.timeanddate.com/time/change/russia/moscow?year=1919
That was what I was talking about, on 1st July, 1919 the clocks were turned
backwards by 31 minutes and 19 seconds. That accounts for the difference you see
here (plus or minus a leapsecond or two, or so, don't know). The remaining hours
difference are something about DST, but I'm too busy to look that up in detail.
What I wanted to say is that timezones do not only take *current* changes into
account, but also *past* changes. Actually, any known clock change is taken into
account, that includes leap seconds and any other adjustment of the clock (may
it be adding or removing time).
On 27.03.2018 13:04, Vlad Alexeenkov wrote:
> On server - UTC
> Local - Europe/Moscow
>
> For example, from 1920 all right:
>
> If run in DataGrip:
>
> select '1900-01-01 15:11:10'::timestamp t1, '1900-01-01 15:11:10'::timestamp at
> time zone 'Europe/Moscow' as t2
>
> 1900-01-01 15:11:10.000000 1900-01-01 12:40:53.000000
>
> select '1920-01-01 15:11:10'::timestamp t1, '1920-01-01 15:11:10'::timestamp at
> time zone 'Europe/Moscow' as t2
>
> 1920-01-01 15:11:10.000000 1920-01-01 12:11:10.000000
>
> select '1900-01-01 15:11:10'::timestamp t1, '1900-01-01 15:11:10'::timestamp at
> time zone 'UTC-3' as t2
>
> 1900-01-01 15:11:10.000000 1900-01-01 12:11:10.000000
>
> Thanks
>
> On 27.03.2018 12:46, Robert Zenz wrote:
>> That is not necessarily a strange behavior, as the Timezome most likely includes
>> all the adjustments that were made in the period of time (leap seconds and the
>> like). At least as far as I know.
>>
>> How does it behave if you try a more current date, like today? What is your
>> system/database timezone?
>>
>>
>> On 27.03.2018 11:40, Vlad Alexeenkov wrote:
>>> Hi!
>>>
>>> Can anyone explain this behavior?
>>>
>>> select '1900-01-01 15:11:10'::timestamp t1, '1900-01-01 15:11:10'::timestamp at
>>> time zone 'Europe/Moscow' as t2
>>>
>>> t1 t2
>>> =================== ===================
>>> 01.01.1900 15:11:10 01.01.1900 15:40:53
>>>
>>> Strange behavior of the timezone
>>>
>>>
>>>
>>>
>>> select version()
>>>
>>> version
>>> ========================================================================================================
>>>
>>>
>>> PostgreSQL 9.6.5 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623
>>> (Red Hat 4.8.5-11), 64-bit
>>>
>>> Thanks
>>>
>
>