Re: Java 8 OffsetDateTime clarification

On 5/6/19 11:11 PM, Thomas Kellerer wrote:
> David Wall schrieb am 07.05.2019 um 04:31:
>> This seems incorrect to me.
>> The backend, when using TIMESTAMP WITH TIME ZONE, stores the 
>> date+time+tzoffset
> No, it does not.
>
>  From https://www.postgresql.org/docs/current/datatype-datetime.html
>
>> For timestamp with time zone, the internally stored value is always
>> in UTC (Universal Coordinated Time, traditionally known as Greenwich
>> Mean Time, GMT). An input value that has an explicit time zone
>> specified is converted to UTC using the appropriate offset for that
>> time zone. If no time zone is stated in the input string, then it is
>> assumed to be in the time zone indicated by the system's TimeZone
>> parameter, and is converted to UTC using the offset for the timezone
>> zone.
>>
>> When a timestamp with time zone value is output, it is always
>> converted from UTC to the current timezone zone, and displayed as
>> local time in that zone

Okay, yes, that's true.  I shouldn't have used "store" as in what's 
written to disk as that's not of interest to most users of a DB, other 
then we expect to be able to order them in a meaningful way.

What I meant is that if we present it a date+time+tzoffset to JDBC, it 
stores the correct date and time in the DB, not one off by the specified 
tzoffset.

I don't change my OffsetDateTime variables to UTC before giving them to 
JDBC, and the timestamps are stored and retrieved as expected.

This challenges the notion that "Also note that all OffsetDateTime 
instances will have be in UTC (have offset 0)." is true, or am I just 
getting unexpectedly normal results of PG without giving OffsetDateTime 
instances in UTC?