neilconway opened a new issue, #22761: URL: https://github.com/apache/datafusion/issues/22761
### Describe the bug For inner/left/right/full joins, estimate_join_cardinality concatenates both inputs' column statistics verbatim and never adjusts them to the estimated output cardinality: - Count-like fields (null_count, distinct_count, byte_size, sum_value) aren't scaled to the join's fan-out/selectivity, so they can be inconsistent with the output num_rows. - Outer joins don't NULL-pad the non-preserved side, even though the side-to-pad is already known (utils.rs:240-242). - Equi-join key columns aren't intersected (min/max) or NDV-bounded (min(left_ndv, right_ndv)). Related to #22743 but the general join case might be a bit more involved. ### To Reproduce _No response_ ### Expected behavior _No response_ ### Additional context _No response_ -- 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]
