Re: Extension Templates S03E11

Greg Stark <stark(at)mit(dot)edu> writes:
> On Mon, Dec 2, 2013 at 6:30 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> OK, I'll bite. I've been trying to stay out of this thread, but I
>> really *don't* understand what this patch is about. Extensions, as

Thanks!

>> they exist today, are installed from the filesystem and their contents
>> are not dumped. You're trying to create a new kind of extension which
>> is installed from the system catalogs (instead of the file system) and
>> is dumped. Why should anyone want that?

To benefit from ALTER EXTENSION … UPDATE … and \dx.

And technically the extension is not dumped, its templates are.

>> It seems that part of the answer is that people would like to be able
>> to install extensions via libpq. You could almost write a client-side
>> tool for that today just by using adminpack to write the files to the
>> server, but you'd trip over the fact that files written by adminpack
>> must be in either the data directory or the log directory. But we
>> could fix that easily enough.

Trick question: when you've implemented said client and used it for a
couple of (in-house) extensions, what do you think should happen at
pg_restore time?

Hint: in a properly designed ops model, pg_restore happens each and
every day when the unattended cron job “rebases” the QA or testing
environments from the production PITR backups, of course.

> Just tossing an idea out there. What if you could install an extension
> by specifying not a local file name but a URL. Obviously there's a
> security issue but for example we could allow only https URLs with
> verified domain names that are in a list of approved domain names
> specified by a GUC.

That's something I want to build. This time, not in core.

The model I've been thinking about involves an EVENT TRIGGER that is
fired at "ddl_command_start" for CREATE EXTENSION and prepares an
EXTENSION TEMPLATE before the command has a chance to check what's
available and install the current default version of it.

Also runs at ALTER EXTENSION … UPDATE …, of course, providing the
upgrade scripts on the fly.

Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support