]
> Kevin Kempter <cs_dba@consistentstate.com> writes:
> > we have a few not null constraints we want to drop on very large tables.
> > Unfortunately the drop's are taking hours. Is there a way to drop a not
> > null constraint via the system catalogs?
>
> Dropping a NOT NULL constraint is a trivial operation. The problem is
> probably that you are blocked waiting to get a lock on the table.
> Look for idle-in-transaction sessions that are holding locks on the
> target table.
>
> regards, tom lane
thanks