Hi all, Thanks for all the feedback so far! I've opened up two more draft PRs implementing [1] an API for owning buffers (precursor to creating struct ArrowArrays) and [2] an API for creating ArrowSchema objects for all Arrow types. All comments welcome!
-dewey [1] https://github.com/paleolimbot/nanoarrow/pull/9 [2] https://github.com/paleolimbot/nanoarrow/pull/10 On Wed, Jun 15, 2022 at 12:18 AM Dewey Dunnington <de...@voltrondata.com> wrote: > Hi all, > > I drafted a second PR [1] drafting a design for storing parsed information > obtained from a struct ArrowSchema (i.e., parsing the format string into > usable C structures). There are some unsolved problems that could use a > fresh perspective...all comments welcome! > > [1] https://github.com/paleolimbot/arrow-c/pull/5 > > On Fri, Jun 10, 2022 at 12:27 PM Dewey Dunnington <de...@voltrondata.com> > wrote: > >> Hi all, >> >> As promised, I converted the design document [1] into an initial PR [2]. >> Rather than draft the whole header, I started with README + implementations >> + testing for error handling and schema allocation (depending on feedback, >> next week I will draft another reviewable chunk). >> >> Also feel free to suggest another place to put this if one exists (the >> choice to put it in its own repo was based on informal feedback that >> perhaps that might be the best way to go). >> >> [1] >> https://docs.google.com/document/d/11n7ICVZO8exZ-z3GRlI26VLzKPXlYlEz5xjLl1y0ujU/edit?usp=sharing >> [2] https://github.com/paleolimbot/arrow-c/pull/1/files >> >> On Fri, Jun 3, 2022 at 12:41 PM Dewey Dunnington <de...@voltrondata.com> >> wrote: >> >>> Hi all, >>> >>> Based on the points raised above and a few adventures implementing some >>> of this in related projects, I put together a brief design document >>> proposing a scope and structure to perhaps solidify a few of these >>> discussions: >>> https://docs.google.com/document/d/11n7ICVZO8exZ-z3GRlI26VLzKPXlYlEz5xjLl1y0ujU/edit?usp=sharing >>> . >>> >>> Any and all should feel free to add, rewrite, or propose a new >>> structure...I wrote many of the pieces for argument's sake or because >>> that's how I'd implemented them before. >>> >>> Next week I will phrase it as a skeleton header (like the one in the >>> excellent ADBC design discussions) depending on feedback to keep the >>> discussion going! >>> >>> Cheers, >>> >>> -dewey >>> >>> On Fri, Jun 3, 2022 at 9:57 AM Hannes Mühleisen <han...@duckdblabs.com> >>> wrote: >>> >>>> Hello List, >>>> >>>> we at DuckDB are happy users of the Arrow C Data Interface and use it to >>>> feed SQL queries and also use it to provide query results in Arrow >>>> format >>>> again. It is particularly appealing to us that the interface is merely a >>>> (C) header file that we just ship with our source code [1]. Internally, >>>> our >>>> implementation then constructs DuckDB internal vectors from the Arrow >>>> format [2] or vice-versa [3]. >>>> >>>> As you can see from [2, 3] there is some complexity in getting the >>>> conversion right, especially for more complex data types like nested >>>> types >>>> (list, strings). A lightweight, dependency-free library to help >>>> constructing those would certainly be appreciated. What would also help >>>> a >>>> lot is validation code, Arrow structures are very delicate and one wrong >>>> pointer can lead to disaster (which is then blamed on us), so a way to >>>> verify the structures in said lightweight library would be very helpful. >>>> >>>> Best from Amsterdam, and Quack >>>> >>>> Hannes >>>> >>>> [1] >>>> >>>> https://github.com/duckdb/duckdb/blob/master/src/include/duckdb/common/arrow.hpp >>>> [2] >>>> >>>> https://github.com/duckdb/duckdb/blob/master/src/function/table/arrow.cpp >>>> [3] >>>> >>>> https://github.com/duckdb/duckdb/blob/master/src/common/types/data_chunk.cpp >>>> >>>> >>>> On Fri, Jun 03, 2022 at 15:34:42, Jonathan Keane <jke...@gmail.com> >>>> wrote: >>>> >>>> > cc Hannes Mühleisen from DuckDB Labs >>>> > >>>> > -Jon >>>> > >>>> > >>>> > On Tue, May 31, 2022 at 5:03 PM Wes McKinney <wesmck...@gmail.com> >>>> wrote: >>>> > >>>> > I'm also supportive of having a small vendorable C/C++ "Arrow >>>> > middleware" that provides: >>>> > >>>> > * Schemas and types >>>> > * Columnar data structures and minimal APIs to build them and iterate >>>> over >>>> > them >>>> > * C data interface >>>> > * Minimal validation (at the level of Validate but not ValidateFull) >>>> > >>>> > I don't think it's going to be practical to try to refactor parts of >>>> > the existing Arrow C++ core to be vendorable since there are many >>>> > features / requirements (e.g. an extensible buffer and device API) >>>> > that these C++ classes include that aren't needed in this >>>> > limited-feature middleware library. >>>> > >>>> > This also relates to the "Improving Arrow's database support" project >>>> > that David Li raised some time ago [1]. If we want to encourage >>>> > database driver libraries to add new APIs that emit the Arrow C >>>> > interface, we need to make it easier to generate the C interface >>>> > without requiring a new library dependency. >>>> > >>>> > [1]: https://lists.apache.org/thread/gnz1kz2rj3rb8rh8qz7l0mv8lvzq254w >>>> > >>>> > On Mon, May 30, 2022 at 11:31 AM Jonathan Keane <jke...@gmail.com> >>>> wrote: >>>> > > >>>> > > Thanks for working on this. I've heard people asking about something >>>> > > like this from a number of different fronts on top of the obvious >>>> use >>>> > > case in geoarrow | other geospatial libraries. I think a minimal >>>> piece >>>> > > of Arrow that other packages could depend on without needing to >>>> bring >>>> > > in all of arrow would be super valuable in building the bridges we >>>> > > want across other systems. >>>> > > >>>> > > Do you have any (design) documentation that describes the scope of >>>> > > what you're thinking? I know there have been others floating around >>>> > > [1] [2] that were in a similar spirit. >>>> > > >>>> > > A few more questions I hope will spark more conversation: How do the >>>> > > header files you linked in [3] overlap with these other efforts? Are >>>> > > those headers something we could|should "just" PR into apache/arrow >>>> > > and write up how to use them? If not what is the work to make them >>>> so >>>> > > that they could be (the answer of course could be design something >>>> > > else entirely and PR that!)? >>>> > > >>>> > > [1] https://github.com/paleolimbot/narrow >>>> > > [2] https://paleolimbot.github.io/narrow/articles/why-narrow.html >>>> > > [3] >>>> https://github.com/paleolimbot/geoarrow-cpp/tree/main/src/geoarrow/ >>>> > internal/arrow-hpp >>>> > > >>>> > > -Jon >>>> > > >>>> > > -Jon >>>> > > >>>> > > >>>> > > On Wed, May 25, 2022 at 9:29 AM Dewey Dunnington < >>>> de...@voltrondata.com> >>>> > wrote: >>>> > > > >>>> > > > I'm writing to gauge interest in a set of helpers in C and/or C++ >>>> for >>>> > > > reading/exporting Arrow C Data interface structures. My use-case >>>> is >>>> > > > building Arrow geospatial support in R [1], and while the set of >>>> > helpers >>>> > > > I've been using [2] has served the purpose of me writing about the >>>> > > > opportunities for Arrow + geospatial [3], I would like to rewrite >>>> the >>>> > > > prototype based on something developed by/with the Arrow >>>> community. >>>> > > > >>>> > > > Does a set of C/C++ helpers for Arrow C Data interface structures >>>> > already >>>> > > > exist? *Should* it exist? >>>> > > > >>>> > > > If it doesn't, what should the name/scope of that library be? The >>>> names >>>> > > > 'nanoarrow', 'narrow', 'sparrow', and 'arrow-hpp' have all >>>> surfaced in >>>> > my >>>> > > > limited discussion of this so far. For the purpose of starting the >>>> > > > discussion, I'll posit that the library should include helpers to >>>> > > > allocate/destroy C Data interface structures, a schema metadata >>>> > > > encoder/decoder, validation of a schema/array pair, and something >>>> like >>>> > the >>>> > > > ArrayBuilder C++ class. >>>> > > > >>>> > > > [1] >>>> https://lists.apache.org/thread/yb7p9wpg3k128njskhwj9j788opb67g7 >>>> > > > [2] >>>> > > > >>>> https://github.com/paleolimbot/geoarrow-cpp/tree/main/src/geoarrow/ >>>> > internal/arrow-hpp >>>> > > > [3] >>>> > > > https://docs.google.com/document/d/ >>>> > 1A6e3XCerjhXVFHBDaoAlBBNFb2HG4RB9SVRpuBru7E4/edit?usp=sharing >>>> > >>>> > >>>> >>>
