On 20/10/2020 11:58, Peter Eisentraut wrote:
While working on another patch, I figured adding a select_common_typmod() to go along with select_common_type() and select_common_collation() would be handy. Typmods were previously combined using hand-coded logic in several places, and not at all in other places. The logic in select_common_typmod() isn't very exciting, but it makes the code more compact and readable in a few locations, and in the future we can perhaps do more complicated things if desired.
Makes sense.
There might have been a tiny bug in transformValuesClause() because while consolidating the typmods it does not take into account whether the types are actually the same (as more correctly done in transformSetOperationTree() and buildMergedJoinVar()).
Hmm, it seems so, but I could not come up with a test case to reach that codepath. I think you'd need to create two types in the same typcategory, but with different and incompatible typmod formats.
The patch also adds typmod resolution for hypothetical ordered-set aggregate arguments. I couldn't come up with a test case that would tickle that codepath either, but it seems like a sensible change. You might want to mention it in the commit message though.
- Heikki
