neilconway opened a new pull request, #22700:
URL: https://github.com/apache/datafusion/pull/22700
## Which issue does this PR close?
- Closes #22699
## Rationale for this change
`stats_cartesian_product` computes the total byte size of a cross join as:
```rust
let total_byte_size = left_stats
.total_byte_size
.multiply(&right_stats.total_byte_size)
.multiply(&Precision::Exact(2));
```
This is wrong (e.g., it multiples two byte-size values together). The
correct formula is "left-num-rows * right-size-in-bytes + right-num-rows *
left-size-in-bytes", since the left side is repeated once per row on the right,
and vice versa.
## What changes are included in this PR?
* Fix total byte size formula for cross join
* Update expected SLT results
## Are these changes tested?
Yes; covered by existing tests.
## Are there any user-facing changes?
No.
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