Re: Locks on FK Tables From Partitioning

Aaron Sipser <ajsipser(at)gmail(dot)com> writes:
> I am fairly confused about the locks generated by some partitioning code I
> am using. The setup is that we have a partitioned table (call it P), and it
> has a foreign key constraint to another table F. I'm trying to figure out
> why when I add partitions to P, it seems that a lock is also taken on F.

Addition of a foreign key constraint implies adding triggers to both sides
of the FK. Adding a new partition also adds a child foreign key
constraint, which I'm pretty sure requires its own trigger. So the F
table is going to need whatever lock strength is involved in CREATE
TRIGGER. I don't recall offhand what we use, but it would at least need
to block operations that might fire such a trigger.

regards, tom lane