Ronan Dunklau <rdunklau@gmail.com> writes:
> It is possible to create a user mapping on a server and drop said server in
> two concurrent transactions, and have both succeed.
There are lots of hazards of this sort, since we generally don't try to
lock database objects other than tables when doing DDL. I can't get
particularly excited about this one compared to the rest. We could try
to extend the table-locking protocols to apply to all object types ...
but from here, the amount of work and complexity involved seems far out
of proportion to the benefit.
regards, tom lane