>
> Do we want to keep the historical "C++ and Java" requirement or
> do we want to make it a more flexible "two independent official
> implementations", which could be for example C++ and Rust, Rust and
> Java, etc.
I think flexibility here is a good idea, I'd like to hear other opinions.
For this particular case if there aren't volunteers to help out in another
implementation I'm willing to help with Java (I don't have bandwidth to
do both C++ and Java).
Cheers,
-Micah
On Tue, Mar 8, 2022 at 8:23 AM Antoine Pitrou <anto...@python.org> wrote:
>
> Le 07/03/2022 à 20:26, Micah Kornfield a écrit :
> >>
> >> Relaxing from {128,256} to {32,64,128,256} seems a low risk
> >> from an integration perspective, as implementations already need to read
> >> the bitwidth to select the appropriate physical representation (if they
> >> support it).
> >
> > I think there are two reasons for having implementations first.
> > 1. Lower risk bugs in implementation/spec.
> > 2. A mechanism to ensure that there is some boot-strapped coverage in
> > commonly used reference implementations.
>
> That sounds reasonable.
>
> Another question that came to my mind is: traditionally, we've mandated
> implementations in the two reference Arrow implementations (C++ and
> Java). However, our implementation landscape is now much richer than it
> used to be (for example, there is a tremendous activity on the Rust
> side). Do we want to keep the historical "C++ and Java" requirement or
> do we want to make it a more flexible "two independent official
> implementations", which could be for example C++ and Rust, Rust and
> Java, etc.
>
> (by "independent" I mean that one should not be based on the other, for
> example it should not be "C++ and Python" :-))
>
> Regards
>
> Antoine.
>
>
> >
> > I agree 1, is fairly low-risk.
> >
> > On Mon, Mar 7, 2022 at 11:11 AM Jorge Cardoso Leitão <
> > jorgecarlei...@gmail.com> wrote:
> >
> >> +1 adding 32 and 64 bit decimals.
> >>
> >> +0 to release it without integration tests - both IPC and the C data
> >> interface use a variable bit width to declare the appropriate size for
> >> decimal types. Relaxing from {128,256} to {32,64,128,256} seems a low
> risk
> >> from an integration perspective, as implementations already need to read
> >> the bitwidth to select the appropriate physical representation (if they
> >> support it).
> >>
> >> Best,
> >> Jorge
> >>
> >>
> >>
> >>
> >> On Mon, Mar 7, 2022, 11:41 Antoine Pitrou <anto...@python.org> wrote:
> >>
> >>>
> >>> Le 03/03/2022 à 18:05, Micah Kornfield a écrit :
> >>>> I think this makes sense to add these. Typically when adding new
> >> types,
> >>>> we've waited on the official vote until there are two reference
> >>>> implementations demonstrating compatibility.
> >>>
> >>> You are right, I had forgotten about that. Though in this case, it
> >>> might be argued we are just relaxing the constraints on an existing
> type.
> >>>
> >>> What do others think?
> >>>
> >>> Regards
> >>>
> >>> Antoine.
> >>>
> >>>
> >>>>
> >>>> On Thu, Mar 3, 2022 at 6:55 AM Antoine Pitrou <anto...@python.org>
> >>> wrote:
> >>>>
> >>>>>
> >>>>> Hello,
> >>>>>
> >>>>> Currently, the Arrow format specification restricts the bitwidth of
> >>>>> decimal numbers to either 128 or 256 bits.
> >>>>>
> >>>>> However, there is interest in allowing other bitwidths, at least 32
> >> and
> >>>>> 64 bits for this proposal. A 64-bit (respectively 32-bit) decimal
> >>>>> datatype would allow for precisions of up to 18 digits (respectively
> 9
> >>>>> digits), which are sufficient for some applications which are mainly
> >>>>> looking for exact computations rather than sheer precision.
> Obviously,
> >>>>> smaller datatypes are cheaper to store in memory and cheaper to run
> >>>>> computations on.
> >>>>>
> >>>>> For example, the Spark documentation mentions that some decimal types
> >>>>> may fit in a Java int (32 bits) or long (64 bits):
> >>>>>
> >>>>>
> >>>
> >>
> https://spark.apache.org/docs/latest/api/java/org/apache/spark/sql/types/DecimalType.html
> >>>>>
> >>>>> ... and a draft PR had even been filed for initial support in the C++
> >>>>> implementation (https://github.com/apache/arrow/pull/8578).
> >>>>>
> >>>>> I am therefore proposing that we relax the wording in the Arrow
> format
> >>>>> specification to also allow 32- and 64-bit decimal types.
> >>>>>
> >>>>> This is a preliminary discussion to gather opinions and potential
> >>>>> counter-arguments against this proposal. If no strong
> counter-argument
> >>>>> emerges, we will probably run a vote in a week or two.
> >>>>>
> >>>>> Best regards
> >>>>>
> >>>>> Antoine.
> >>>>>
> >>>>
> >>>
> >>
> >
>
