On Mon, Nov 14, 2011 at 11:48 AM, Nikhil Sontakke
<nikhil.sontakke@enterprisedb.com> wrote:
>> If all you need to do is lock a schema, you can just call
>> LockDatabaseObject(NamespaceRelationId, namespace_oid, 0,
>> AccessShareLock); there's no need to fake up an objectaddress just to
>> take a lock. But I think that's not really all you need to do,
>> because somebody could drop the namespace between the time that you
>> decide what OID to lock and the time you acquire the lock. So I think
>> you need something like what we did in RangeVarGetRelid(). See
>> attached patch.
>
> Thanks Robert. But currently there are very few callers of
> RangeVarGetAndCheckCreationNamespace() function. For the sake of
> completeness we will have to introduce a call to this function while
> creating all other objects too.
Well, RangeVarGetAndCheckCreationNamespace is only (and can only) be
used for relations. To get similar protection for other object types,
we'd need to add a similar logic elsewhere. I haven't looked at where
it would need to go.
In fact, I think that the technique demonstrated here (which was
pioneered by Noah Misch) is actually quite general, and there are
probably a lot of places where we need to be doing it but currently
are not. So it's probably going to take a while to get this
completely nailed down, but we can keep chipping away at it.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company