Re: advisory locks and permissions

"Merlin Moncure" <mmoncure(at)gmail(dot)com> writes:
> On 9/22/06, Jim C. Nasby <jim(at)nasby(dot)net> wrote:
>> This is why I suggested we set aside some range of numbers that should
>> not be used. Doing so would allow adding a better-managed
>> numbering/naming scheme in the future.

> the whole point about advisory locks is that the provided lock space
> is unmanaged.

I think we forgot to document that the lock space is per-database; also,
wouldn't it be a good idea to specifically recommend that advisory locks
be used only in databases that are used just by one application, or a
few cooperating applications? The lack of any permissions checks makes
them fairly unsafe in databases that are used by multiple users.

I don't actually have a problem with the lack of security checks or
key range limitations --- I see advisory locks as comparable to large
objects, which are likewise permissions-free. It's an optional feature
and you just won't use it in databases where permission constraints are
a critical need. The thing that's bothering me is the relative ease of
accidental DoS to applications in *other* databases in the same cluster.

regards, tom lane