On 2020-Nov-26, Kyotaro Horiguchi wrote: > This shares RI_ConstraintInfo cache by constraints that shares the > same parent constraints. But you forgot that the cache contains some > members that can differ among partitions. > > Consider the case of attaching a partition that have experienced a > column deletion.
I think this can be solved easily in the patch, by having ri_BuildQueryKey() compare the parent's fk_attnums to the parent; if they are equal then use the parent's constaint_id, otherwise use the child constraint. That way, the cache entry is reused in the common case where they are identical. I would embed all this knowledge in ri_BuildQueryKey though, without adding the new function ri_GetParentConstOid. I don't think that function meaningful abstraction value, and instead it would make what I suggest more difficult.
