apache / apache/datafusion-python

Simplified filter expression has a Null type instead of Int64 type across the FFI layer

Abierto
#1,551 11 comentarios 0 reacciones 0 asignados Ver en GitHub
bug
Lenguaje dominante
Python
Estrellas
604
Forks
174
Merge medio
1 d 7 h
PR fusionados (30 d)
4

Descripción

**Describe the bug**

A custom table provider for a ParquetSource with a trivial catalog and an Int64 column yields some errors when a SQL query has a filter with a literal limit on that column of the form

```
assertion `left == right` failed: Simplified expression should have the same data type as the original
left: Null
right: Int64
```

The error does not occur when using datafusion-python 52; it also does not occur when running the query purely in a Rust SessionContext; the backtrace for the above error shows it coming from datafusion-ffi code as well.

This may of course not be a bug, but instead some bad practice that the version 52 set of crates tolerates but which is now invalid. A MRE of this custom table provider can be found in the public repo https://github.com/jwimberl/datafusion_python_53_int64filter_repro, which contains

- a non-working datafusion53 version (in branch [main](https://github.com/jwimberl/datafusion_python_53_int64filter_repro))
- a baseline working version (in branch [datafusion52](https://github.com/jwimberl/datafusion_python_53_int64filter_repro/tree/datafusion52))

and a canned dummy dataset. The README.md of this repo has more details.

**To Reproduce**

In the `main` branch, build the `py_repro_provider` crate with `maturin develop` and run `python repro.py`. This loads the dummy dataset as a table `dummy_table` and runs two queries
- `SELECT * FROM dummy_table LIMIT 1`, which is successful
- `SELECT * FROM dummy_table LIMIT 5`, which panics

Itss output should be something like

```
Successful query:
a b
0 0 42
Unsuccesful query:

thread '' panicked at /home/jwimberley/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/datafusion-physical-expr-53.1.0/src/simplifier/mod.rs:76:17:
assertion `left == right` failed: Simplified expression should have the same data type as the original
left: Null
right: Int64
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```

followed by backtrace information.

**Expected behavior**

In the `datafusion52` branch, build the`py_repro_provider` with `maturin develop` and run `python repro.py`. It runs the same two queries, and its output should be

```
Successful query:
a b
0 0 42
Also successful query:
a b
0 0 42
1 1 42
2 2 42
3 3 42
4 4 42
```

**Additional context**

In either the `main` branch or `datafusion52` branch, the Rust code for the table provider is in the directory `repro_provider`, and there is a corresponding cargo test that runs `SELECT * FROM dummy_table WHERE a < 5`. Without the FFI layer, this is successful with both datafusion 52 and 53.

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