Re: UPDATE run check constraints for affected columns only

hi.

We cache ri_CheckConstraintExprs in ExecConstraints and must initialize them all
if different actions like INSERT and UPDATE, happen together in a query.
Both INSERT and UPDATE need to use these ri_CheckConstraintExprs.
Invoke INSERT AND UPDATE together can happen within MERGE command. We confirm
it's a MERGE operation by checking that resultRelInfo->ri_MergeActions is not
NIL. See ExecMergeNotMatched and ExecMergeMatched.

For cross-partition updates (ExecCrossPartitionUpdate), the operation splits
into an INSERT and DELETE, we can treat it as a single action.

--
jian
https://www.enterprisedb.com/