> At some point someone will want MONTH as a time unit (to support SQL’s year-to-month interval type) There is an interval type here for that: https://github.com/apache/arrow/blob/39c7274fc36b5f405f1dbfa48067dde52abec5ce/format/Message.fbs#L98
On Fri, Mar 17, 2017 at 1:23 PM, Julian Hyde <jh...@apache.org> wrote: > Am I correct that timestamp is a 64 bit signed integer representing > microseconds since 1970? If so, it would be helpful to state the minimum > and maximum values in the spec. > > I can’t quite imagine a use case for microsecond time, given that it takes > the same number of bits as a timestamp. But still, no harm in including it. > > At some point someone will want MONTH as a time unit (to support SQL’s > year-to-month interval type) and someone will want nanosecond timestamp > (problematic, because it needs more than 64 bits for a useful range to > dates). But these can wait until version 2. > > Julian > > > > On Mar 17, 2017, at 9:51 AM, Wes McKinney <wesmck...@gmail.com> wrote: > > > > hi folks, > > > > We have some format decisions to make about all 3 of the primary > > temporal types in Arrow: > > > > ARROW-617 - Time type > > - It is proposed to add the type bit width to the metadata for > > clarity, and using the smallest type that can accommodate a particular > > time unit > > - PATCH: https://github.com/apache/arrow/pull/385 > > > > ARROW-316: Date type > > - It is proposed to add a DateUnit to indicate day-based date (a la > > PostgreSQL and other systems) as int32 vs. millisecond-based date as > > int64 (a la Joda, and current Arrow Java) > > - PATCH: https://github.com/apache/arrow/pull/390 > > > > ARROW-637: Timestamp type > > - It is proposed to add a timezone string to the metadata as to > > disambiguate TZ-naive vs. TZ-aware data, but otherwise display only > > (changing the time zone does not alter the physical int64 timestamp > > values) > > - PATCH: https://github.com/apache/arrow/pull/388 > > > > There seems to be some degree of consensus on all 3 of these, but it > > would be good to reach a final decision and merge patches so that we > > can do the corresponding dev work in Java and C++, and hopefully get > > integration tests working in time for the Arrow 0.3 release. > > > > Thanks! > > Wes > > -- Julien
