Probably RelRule should not change nullability. But we have done so in
the past, and I suspect we continue to do so today. It would be
interesting to find a list of rules that do this.
Deducing that a field is never null is very useful. With that
knowledge, further optimizations become possible. S
Hi,
Can anybody clarify if RelRule should be allowed to change RelNode field
nullability?
For instance, RelOptRulesTest#testReduceNullableToNotNull has the following
SQL:
...empno + *case* when 'a' = 'a' then 1 else *null end* as newcol...
Of course, the initial type is nullable int (since the l
