haohuaijin opened a new issue, #25794:
URL: https://github.com/apache/datafusion/issues/25794
### Describe the bug
Integer multiplication overflow can produce false-empty filter statistics.
The following reproduction uses TINYINT to demonstrate the issue with small
values.
For columns containing `(0, -3)` and `(20, 7)`, `a * b < -100` correctly
returns `(20, 7, -116)`, but the filter statistics report `Rows=Inexact(0)`,
exact NULL bounds, and `Distinct=Exact(0)` for both input columns.
### To Reproduce
Use a Parquet destination that does not already exist.
```sql
SET datafusion.execution.target_partitions = 1;
SET datafusion.execution.collect_statistics = true;
SET datafusion.explain.show_statistics = true;
COPY (
SELECT a::TINYINT AS a, b::TINYINT AS b
FROM (VALUES (0, -3), (20, 7)) AS t(a, b)
) TO '/tmp/df_mul_wrap.parquet' STORED AS PARQUET;
CREATE EXTERNAL TABLE mul_wrap STORED AS PARQUET
LOCATION '/tmp/df_mul_wrap.parquet';
SELECT a, b, a * b AS x FROM mul_wrap WHERE a * b < -100;
EXPLAIN SELECT a, b FROM mul_wrap WHERE a * b < -100;
```
Query result:
```text
a b x
20 7 -116
```
Filter statistics include:
```text
Rows=Inexact(0), Bytes=Inexact(0)
For both input columns:
Min=Exact(Int8(NULL))
Max=Exact(Int8(NULL))
Distinct=Exact(0)
```
### Expected behavior
Statistics should remain conservative rather than infer an empty result. The
returned rows are correct; this reproduction demonstrates a statistics error,
including exact-empty column statistics, rather than just an inaccurate
row-count estimate.
### Additional context
Reproduced with DataFusion CLI 55.1.0 at
`e2ca7f38051744b2010cf09b80db8e9dfa4b5d38`.
Multiplication inference discards an overflow-generated unbounded endpoint
when combining the ranges `[0, 20]` and `[-3, 7]`, producing `[-60, 0]` and
excluding the actual wrapped value `-116`. The issue is in the shared
multiplication interval logic, rather than a TINYINT-specific implementation.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
