TODO idea - implicit constraints across child tables with a common column as primary key (but obviously not a shared index)

If you have a table with a bunch of children, and these children all
have a primary key which is generated from the same sequence, assuming
that you're partitioning based on date (ie, this is a transaction
record table), it would be nice if the planner could spot that all
tables have a primary key on a column used as a join condition, check
the min / max to see if there is overlap between tables, then apply
CBE as if constraints existed.

This strikes me as a pretty common situation, certainly we're seeing
it here.

Andrew