+1
On Fri, Sep 29, 2023 at 10:51 AM Felipe Oliveira Carvalho <
felipe...@gmail.com> wrote:
> Yes, ListView is an implementation of Velox's ArrayVector [1] ("vector of
> arrays"). In Arrow we would naturally refer to them as "array of lists",
> but `ListArray` is taken by the existing offset-only list formats.
> Following the pattern adopted by other types in Arrow that use offsets and
> sizes, we adopt the suffix -View to differentiate list-views from lists.
>
> Velox doesn't offer the 64-bit variation, but since Arrow has both List and
> LargeList, it was natural to pair them with ListView and LargeListView.
>
> [2] is a link to the point of a talk by Mark Raasveldt where he describes
> the DuckDB list representation. Early in the talk, one of the slides [3]
> mentions how these formats were "co-designed together with Velox team".
>
> --
> Felipe
>
> [1]
> https://facebookincubator.github.io/velox/develop/vectors.html#arrayvector
> [2] https://youtu.be/bZOvAKGkzpQ?si=wgSwew3Ck8utteOI&t=1569
> [3] https://15721.courses.cs.cmu.edu/spring2023/slides/22-duckdb.pdf
>
> On Fri, Sep 29, 2023 at 9:32 AM Raphael Taylor-Davies
> <r.taylordav...@googlemail.com.invalid> wrote:
>
> > Hi Felipe,
> >
> > Can I confirm that DuckDB and Velox use the same encoding for these
> > types, and so we aren't going to run into similar issues as [1]?
> >
> > Kind Regards,
> >
> > Raphael Taylor-Davies
> >
> > [1]: https://lists.apache.org/thread/l8t1vj5x1wdf75mdw3wfjvnxrfy5xomy
> >
> > On 29/09/2023 13:09, Felipe Oliveira Carvalho wrote:
> > > Hello,
> > >
> > > I'd like to propose adding ListView and LargeListView arrays to the
> Arrow
> > > format.
> > > Previous discussion in [1][2], columnar format description and
> > flatbuffers
> > > changes in [3].
> > >
> > > There are implementations available in both C++ [4] and Go [5]. I'm
> > working
> > > on the integration tests which I will push to one of the PR branches
> > before
> > > they are merged. I've made a graph illustrating how this addition
> > affects,
> > > in a backwards compatible way, the type predicates and inheritance
> chain
> > on
> > > the C++ implementation. [6]
> > >
> > > The vote will be open for at least 72 hours not counting the weekend.
> > >
> > > [ ] +1 add the proposed ListView and LargeListView types to the Apache
> > > Arrow format
> > > [ ] -1 do not add the proposed ListView and LargeListView types to the
> > > Apache Arrow format
> > > because...
> > >
> > > Sincerely,
> > > Felipe
> > >
> > > [1] https://lists.apache.org/thread/r28rw5n39jwtvn08oljl09d4q2c1ysvb
> > > [2] https://lists.apache.org/thread/dcwdzhz15fftoyj6xp89ool9vdk3rh19
> > > [3] https://github.com/apache/arrow/pull/37877
> > > [4] https://github.com/apache/arrow/pull/35345
> > > [5] https://github.com/apache/arrow/pull/37468
> > > [6] https://gist.github.com/felipecrv/3c02f3784221d946dec1b031c6d400db
> > >
> >
>
