On Dec 6, 2010, at 11:36 AM, Tom Lane wrote:
> There's a difference between whether an extension as such is considered
> to belong to a schema and whether its contained objects do. We can't
> really avoid the fact that functions, operators, etc must be assigned to
> some particular schema.
Right, of course.
> It seems not particularly important that
> extension names be schema-qualified, though --- the use-case for having
> two different extensions named "foo" installed simultaneously seems
> pretty darn small. On the other hand, if we were enforcing that all
> objects contained in an extension belong to the same schema, it'd make
> logistical sense to consider that the extension itself belongs to that
> schema as well. But last I heard we didn't want to enforce such a
> restriction.
Okay.
> I believe what the search_path substitution is actually about is to
> provide a convenient shorthand for the case that all the contained
> objects do indeed live in one schema, and you'd like to be able to
> select that schema at CREATE EXTENSION time. Which seems like a useful
> feature for a common case. We've certainly heard multiple complaints
> about the fact that you can't do that easily now.
Yes, it *is* useful. But what happens if I have
SET search_path = whatever;
In my extension install script, and someone executes CREATE EXTENSION FOO WITH SCHEMA bar; Surprise! Everything is in
whatever,not in bar.
> BTW, I did think of a case where substitution solves a problem we don't
> presently have any other solution for: referring to the target schema
> within the definition of a contained object. As an example, you might
> wish to attach "SET search_path = @target_schema@" to the definition of
> a SQL function in an extension, to prevent search-path-related security
> issues in the use of the function. Without substitution you'll be
> reduced to hard-wiring the name of the target schema.
You lost me. :-(
David