KuzuNif

Very unfinished attempt at adapting KuzuDB's Rust crate into Elixir via NIF, supported by the Rustler package.

See native/kuzu_ex/src/lib.rs for the NIF.

My solution involves copying the query result, which sounds kind of silly because ideally we'd take advantage of the underlying arrow format and do something akin to the Explorer package, which also implements NIF in order to adapt Polars DataFrames into Elixir. KuzuDB's Rust crate's QueryResult supports arrow_array::arrow::RecordBatch, but I couldn't figure out how to adapt it.

Try it out

# Seed the database.
> pip install kuzu
> python main.py

# Run the test. This takes a while to build.
# See test/kuzu_nif_test.exs
> mix test
Running ExUnit with seed: 706086, max_cases: 20

%{
  result: [
    [{:string, "Waterloo"}, {:null}, {:int64, 150000}],
    [{:string, "Kitchener"}, {:null}, {:int64, 200000}],
    [{:string, "Guelph"}, {:null}, {:int64, 75000}],
    [{:string, "Adam"}, {:int64, 30}, {:null}],
    [{:string, "Karissa"}, {:int64, 40}, {:null}],
    [{:string, "Zhang"}, {:int64, 50}, {:null}],
    [{:string, "Noura"}, {:int64, 25}, {:null}]
  ],
  __struct__: KuzuNif.QueryResult
}
.
Finished in 0.07 seconds (0.00s async, 0.07s sync)
1 test, 0 failures

There are some unused Rust deps from an attempt at adapting the Kuzu QueryResult into a Polars dataframe. They could be removed if needed.

References

• https://mainmatter.com/blog/2023/02/01/using-rust-crates-in-elixir/
• https://stackoverflow.com/questions/78959357/convert-arrow-data-to-polars-dataframe
• https://stackoverflow.com/questions/78084066/arrow-recordbatch-as-polars-dataframe
• https://arrow.apache.org/rust/arrow_array/array/trait.Array.html#
• https://docs.rs/polars-arrow/0.43.1/polars_arrow/array/trait.Array.html#
• https://docs.rs/polars/latest/polars/series/struct.Series.html#method.from_arrow
• https://docs.rs/arrow-array/43.0.0/arrow_array/array/trait.Array.html
• https://docs.rs/kuzu/latest/kuzu/struct.QueryResult.html
• https://docs.rs/kuzu/latest/kuzu/struct.ArrowIterator.html
• https://docs.rs/kuzu/latest/kuzu/enum.Value.html
• Discord thread in KuzuDB community

Installation

If available in Hex, the package can be installed by adding kuzu_nif to your list of dependencies in mix.exs:

def deps do
  [
    {:kuzu_nif, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/kuzu_nif.