Arrow `string_view` raises DuckDB `NotImplementedException`

[manzt]

23 led to a regression for string data types, specifically with the string_view Arrow data type not being recognized by DuckDB. I'm going to add some tests to ensure our Arrow/DuckDB connection code works, as we should have end-to-end tests to catch this.

cc: @kylebarron

import polars as pl
import pyarrow as pa
import quak

movies = pl.read_json("movies.json")
print(pa.table(movies).schema)
quak.Widget(movies.select("Director"))

Title: string_view
US Gross: int64
Worldwide Gross: int64
US DVD Sales: int64
Production Budget: int64
Release Date: string_view
MPAA Rating: string_view
Running Time min: int64
Distributor: string_view
Source: string_view
Major Genre: string_view
Creative Type: string_view
Director: string_view
Rotten Tomatoes Rating: int64
IMDB Rating: double
IMDB Votes: int64
Director: string_view

---------------------------------------------------------------------------
NotImplementedException                   Traceback (most recent call last)
Cell In[9], line 7
      5 movies = pl.read_json("movies.json")
      6 print(pa.table(movies).schema)
----> 7 quak.Widget(movies.select("Director"))

File ~/github/manzt/quak/src/quak/_widget.py:60, in Widget.__init__(self, data, table)
     55     else:
     56         raise ValueError(
     57             "input must be a DuckDB connection, DataFrame-like, an Arrow IPC "
     58             "table, or an Arrow object exporting the Arrow C Stream interface."
     59         )
---> 60     conn.register(table, arrow_table)
     61 self._conn = conn
     62 super().__init__(
     63     _table_name=table,
     64     _columns=get_columns(conn, table),
     65     temp_indexes=True,
     66     sql=f'SELECT * FROM "{table}"',
     67 )

NotImplementedException: Not implemented Error: Unsupported Internal Arrow Type vu

[kylebarron]

😢

I'd argue this is a DuckDB bug, since DuckDB says it supports Arrow input, and so it should check for these data types. The Arrow PyCapsule Interface actually has a mechanism to fix this: it allows data consumers to check the input schema and ask the producer to cast the data to a desired output schema.

For now, it shouldn't be too hard to manually work around this using pyarrow APIs

[manzt]

All good!

For now, it shouldn't be too hard to manually work around this using pyarrow APIs

So once we get back the table we should cast some columns?

[kylebarron]

Yeah, we should be able to check for any string view (probably also binary view, and maybe run-end-array) and cast those to duckdb-supported types. It would be nice if there were a resource in DuckDB that said which Arrow types it supports.

[manzt]

Yeah, we should be able to check for any string view (probably also binary view, and maybe run-end-array) and cast those to duckdb-supported types.

Ok working on a PR!

[manzt]

Looks like it's coming from here:

https://github.com/duckdb/duckdb/blob/4e3a192ce94a793510f11b598805f104d7531c15/src/function/table/arrow.cpp#L80

[kylebarron]

Oh so the latest version (maybe unreleased) of duckdb should support it: https://github.com/duckdb/duckdb/blame/4e3a192ce94a793510f11b598805f104d7531c15/src/function/table/arrow.cpp#L88-L89

[manzt]

Acually, it looks like it's here lol https://github.com/duckdb/duckdb/blob/4e3a192ce94a793510f11b598805f104d7531c15/src/function/table/arrow.cpp#L88-L89

[manzt]

Oh... yup lol you beat me to it

[kylebarron]

I made a little note in my argument for DuckDB to support the interface: https://github.com/duckdb/duckdb/discussions/10716#discussioncomment-10339017

[manzt]

Made a PR, but the implementation isn't working since the string_view -> string cast doesnt' seem to be supported. I'll try to dig into it later... but it would suck if we needed to pull the data into a pylist first.

[kylebarron]

😱 how is string_view -> string not a valid cast??

I would suggest temporarily using arro3 to do the cast, but arrow-rs won't support view types until the next major release (in ~one month)

The other option to support polars specifically for now is to call polars' to_arrow method, which allows Polars to cast to non-view array types if you set the CompatLevel as such.

[manzt]

😱 how is string_view -> string not a valid cast??

Lol i know...

I would suggest temporarily using arro3 to do the cast, but arrow-rs won't support view types until the next major release (in ~one month)

I would defer to you here as the arrow guru :) what do you think would be the best choice for the time being?

I could definitely do the polars patch today... but i am not familiar enough with the arro3 yet :)

[kylebarron]

Just checking re https://github.com/duckdb/duckdb/discussions/10716#discussioncomment-10339331 you're on the latest DuckDB version?

[kylebarron]

It turns out that was a simple repro. This fails:

import polars as pl
import duckdb
import pyarrow as pa

df = pl.DataFrame({"a": ["a", "b", "c"]})
table = pa.table(df)
duckdb.from_arrow(table)

---------------------------------------------------------------------------
NotImplementedException                   Traceback (most recent call last)
File /Users/kyle/github/kylebarron/arro3/tests/core/test_ffi.py:[1](https://file+.vscode-resource.vscode-cdn.net/Users/kyle/github/kylebarron/arro3/tests/core/test_ffi.py:1)
----> 1 duckdb.from_arrow(table)

File ~/github/kylebarron/arro3/.venv/lib/python3.11/site-packages/duckdb/__init__.py:505, in from_arrow(arrow_object, **kwargs)
    [503](https://file+.vscode-resource.vscode-cdn.net/Users/kyle/github/kylebarron/arro3/~/github/kylebarron/arro3/.venv/lib/python3.11/site-packages/duckdb/__init__.py:503) else:
    [504](https://file+.vscode-resource.vscode-cdn.net/Users/kyle/github/kylebarron/arro3/~/github/kylebarron/arro3/.venv/lib/python3.11/site-packages/duckdb/__init__.py:504)     conn = duckdb.connect(":default:")
--> [505](https://file+.vscode-resource.vscode-cdn.net/Users/kyle/github/kylebarron/arro3/~/github/kylebarron/arro3/.venv/lib/python3.11/site-packages/duckdb/__init__.py:505) return conn.from_arrow(arrow_object, **kwargs)

NotImplementedException: Not implemented Error: Unsupported Internal Arrow Type vu

With polars 1.4.1, duckdb 1.0.0, pyarrow 17.0.0.

[manzt]

Just checking re duckdb/duckdb#10716 (reply in thread) you're on the latest DuckDB version?

Yes, and just tried out with nightly 1.0.1.dev4096

[kylebarron]

I would defer to you here as the arrow guru :) what do you think would be the best choice for the time being?

I don't think there's a good way today to handle string view -> string data type casting. I suppose the best workaround right now is to hard-code support for polars, check for a polars.DataFrame object, and call its to_arrow() method.

Even though this goes against what I want with the pycapsule interface, which is for consumers to not have to think about where the data is coming from 😛

arro3 isn't capable of this until the next arrow-rs release

[manzt]

Done, see #42

[kylebarron]

Yes, and just tried out with nightly 1.0.1.dev4096

Oh it works for me with this same nightly

And the upstream was closed for being fixed on latest main https://github.com/duckdb/duckdb/issues/13424

[manzt]

ok maybe I didn't restart my jupyter kernel :(

[manzt]

Yup, can confirm that 1.0.1.dev4096 is working:

I'll revert #42 after the next python release