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Re: [Format] Pointer types / span types


> Perhaps that could be an argument for making span a core logical type?

I think if anything, this argues that it should not be. Because "span"
references another array, which can be a different size, you need two
schemas to be able to make sense of it.

In either case, I would be interested to see what modifications would
be proposed to Schema.fbs and an example dataset described with such a
schema (that is a single array, instead of multiple -- i.e. a
non-composite representation).

For the record, if there are sufficiently common "composite" data
representations, I don't see a problem with developing community
standards based on the building blocks we already have

- Wes

On Wed, May 2, 2018 at 3:38 PM, Brian Hulette <brian.hulette@xxxxxxxx> wrote:
> If this were accomplished at the application level, how would it work with
> the IPC formats? I'd think you'd need to have two separate files (or
> streams), since array 1 and array 2 will be different lengths. Perhaps that
> could be an argument for making span a core logical type?
>
> Brian
>
>
>
> On 05/02/2018 03:34 PM, Antoine Pitrou wrote:
>>
>> On Wed, 2 May 2018 10:12:37 -0400
>> Wes McKinney <wesmckinn@xxxxxxxxx> wrote:
>>>
>>> It sounds like the "span" type could be implemented as a composite of
>>> multiple Arrow arrays / schemas:
>>>
>>> array 1 (data)
>>> any schema
>>>
>>> array 2 (view)
>>> struct <
>>>    start: int64,
>>>    stop: int64
>>>>
>>>>
>>>
>>> Unless I'm missing something, this feels like an application-level
>>> concern rather than something that needs to be addressed in the
>>> columnar format / metadata.
>>
>> Well, couldn't the same theoretically be said about list arrays?
>> In the end, I suppose it all depends whether there's enough demand to
>> make it a core logical type inside Arrow, rather than something people
>> write custom code for in their application.
>>
>> Regards
>>
>> Antoine.
>
>