Josh Berkus <josh(at)agliodbs(dot)com> writes:
>> timestamptz + interval is not immutable --- in fact, the particular
>> example you give (ts + '1 day') is certainly dependent on timezone
>> setting.
> Why not? Given that the time zone will be the same for both the
> timestamptz and the interval, how would the result not be immutable?
The reason it depends on the timezone is that the result varies if
"plus one day" means crossing a DST boundary.
regards, tom lane