[ARROW-12339] [Rust][DataFusion] COUNT DISTINCT does not support for `Boolean`

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Invalid
• Component/s: Rust - DataFusion
• External issue URL: https://github.com/apache/arrow/issues/18612
• Assignee: Unassigned
• Reporter: Andrew Lamb
• Created: 12/Apr/21 13:08
• Updated: 11/Jan/23 08:25
• Resolved: 26/Apr/21 13:33

Description

If you try to run a `COUNT (DISTINCT ..)` query on a boolean column you get the following panic:

thread 'tokio-runtime-worker' panicked at 'Unexpected DataType for list', datafusion/src/scalar.rs:342:22

While there is unlikely to be a big usecase for this, it would be nice for completeness sake. At the very least we should add a proper error message rather than a panic

Reproducer:

echo "true" > /tmp/foo.csv
 ./target/debug/datafusion-cli

> CREATE EXTERNAL TABLE t (a boolean) STORED AS CSV LOCATION '/tmp/foo.csv';

0 rows in set. Query took 0 seconds.
> select count(distinct a) from t;

thread 'tokio-runtime-worker' panicked at 'Unexpected DataType for list', datafusion/src/scalar.rs:342:22
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
ArrowError(ExternalError(Canceled))

Issue Links

• is a clone of: ARROW-12312 [Rust][DataFusion] COUNT DISTINCT does not support for `Float64`