Re: support for CREATE MODULE

Nathan Bossart <nathandbossart(at)gmail(dot)com> writes:
> On Fri, Feb 04, 2022 at 05:12:43PM -0500, Tom Lane wrote:
>> On the whole I'm kind of allergic to inventing an entire new concept
>> that has as much overlap with extensions as modules seem to. I'd
>> rather try to understand what functional requirements we're missing
>> and see if we can add them to extensions. Yeah, we won't end up being
>> bug-compatible with Oracle's feature, but that's not a project goal
>> anyway --- and where we have tried to emulate Oracle closely, it's
>> often not worked out well (poster child: to_date).

> If I'm understanding correctly, you are suggesting that CREATE MODULE would
> be more like creating an extension without a control file, installation
> script, etc. Objects would be added aѕ members with something like ALTER
> MODULE ADD, and members could share properties such as access control. And
> this might be possible to do by enhancing CREATE EXTENSION instead of
> creating a new catalog, dependency type, etc.

> I think this could be a nice way to sidestep the naming resolution problems
> discussed upthread while still allowing folks to group objects together in
> some meaningful way. Also, while it might be nice to have separate CREATE
> EXTENSION and CREATE MODULE commands, perhaps they would use roughly the
> same code paths behind the scenes.

Hm. If the functional requirement is "group objects without needing
any out-in-the-filesystem infrastructure", then I could see defining
a module as being exactly like an extension except there's no such
infrastructure --- and hence no concept of versions, plus pg_dump
needs to act differently. That's probably enough semantic difference
to justify using a separate word, even if we can share a lot of
code infrastructure.

regards, tom lane