> > Separately, consider that calendar applications exchange times using UTC > offset contexts not time zone/region names. Why? Local Timezone UTC > offsets and DST rules are *variable*, UTC offsets are not. > > It's stored normalized to UTC, but the point in also store the region or > offset > is about to also record (to convert back when reading) the data as who > stored it.
What purpose does the original/source context have, if all the values are stored in UTC? This (AFAICT) is the only issue that we disagree on. > The PostgreSQL approach with conversions to session time zone seems very > problematic. > > Should I also say that to make things work I should set my session time zone > to +02:00 instead of -02:00? It's weird and crazy, but it's how it works. > > See it: https://stackoverflow.com/questions/47555028/postgresql-time- > zones I agree that the PostgreSQL handling of the "set time zone" value is backwards. It expects an offset "to" UTC, not the typical "from" ("offset is a numeric offset in hours west from UTC." https://www.postgresql.org/docs/9.6/static/datatype-datetime.html#DATATYPE-TIMEZONES ) What does Oracle report for the same? > > - You (in BrasÃlia) setup a phone call/meeting, 6 months ago, for > > today at 7am (Dec 12, 2017 == UTC -2) with customers in Mumbai (5:30pm > > -- UTC +5:30) and Adelaide Australia ( 10:30pm -- UTC +10:30) > > 7am in UTC -2 => 9am in UTC+0 > 9am in UTC+0 => 2:30pm in UTC+5:30 > 9am in UTC+0 => 7:30pm in UTC+10:30 > > Am I making a mistake or you? I did, I was editing the times to make them seems realistic and I screwed up. :''-[ grrr > > 2- the meeting Date/Time is stored with offset == -2. > > But normalized to UTC+0, so a change my TZ region in my TZ database does > not change conversions for others or cause problems in PK/UNIQUE keys. On this we agree. Sean ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
