Re: Extension Templates S03E11

On 12/02/2013 05:34 AM, Stephen Frost wrote:
> * Jeff Davis (pgsql(at)j-davis(dot)com) wrote:
>> I see where you're coming from, but after some thought, and looking at
>> the patch, I think we really do want a catalog representation for (at
>> least some) extensions.
>
> Perhaps I'm missing something- but we already *have* a catalog
> representation for every extension that's ever installed into a given
> database. A representation that's a heck of a lot better than a big
> text blob.

Right. I think Jeff was thinking of a catalog representation for
extensions that haven't been installed yet, but are available in the
system and could be installed with CREATE EXTENSION foo. I wouldn't mind
having a catalog like that. Even without any of this extension template
stuff, it would be handy to have a view that lists all the extensions
available in the filesystem.

>> 2. When 9.4 gets released, we need some solid advice for extension
>> authors. If they have a native shared library, I assume we just tell
>> them to keep using the file-based templates. But if they have a SQL-only
>> extension, do we tell them to port to the in-catalog templates? What if
>> they port to in-catalog templates, and then decide they just want to
>> optimize one function by writing it in native code? Do they have to port
>> back? What should the authors of SQL-only extensions distribute on PGXN?
>> Should there be a migration period where they offer both kinds of
>> templates until they drop support for 9.3?
>
> This is one of the main things that I think Heikki was trying to drive
> at with his comment- we really don't *want* to make extension authors
> have to do anything different than what they do today. With an external
> tool, they wouldn't need to and it would just be two different ways for
> an extension to be installed into a given database. In the end though,
> if we're telling people to 'port' their extensions, then I think we've
> already lost.

Exactly.

There should be no difference between file-based extensions and
catalog-based extensions. It's just two different ways to install the
same extension. The extension author doesn't need to care about that,
it's the DBA that decides which method to use to install it.

I'm going to object loudly to any proposal that doesn't meet that criteria.

- Heikki