Re: ALTER EXTENSION UPGRADE, v3

On Thu, Feb 3, 2011 at 12:38 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Florian Pflug <fgp@phlo.org> writes:
>> I fully agree. The extension infrastructure should provide basic support
>> for upgrades, not every kind of bell and whistle one could possible think of.
>
> Maybe somewhere around here we should stop and ask why we are bothering
> with any of this.  The original idea for an extension concept was that
> (1) some collection of objects could be designated as a module
> (2) pg_dump would be taught to dump "LOAD MODULE foo" instead of the
> individual objects
> (3) the way you'd do an upgrade is to dump and reload into a database
> that has available a newer definition of the module's content.
>
> Given that pg_upgrade is now considered a supported piece of the system,
> ISTM that most real-world upgrade scenarios will be accomplished with
> pg_upgrade relying on provision (3).  It looks to me like we're talking
> about adding a large amount of complication --- both for the core
> database and for module authors --- in order to provide a duplicate
> solution for that.  Why should we bother?  Especially, why should we
> bother in version 1 of the feature?  This could all be added later if
> we determine there's really sufficient demand, but right now we have
> no experience to show whether there is demand or not.

I think you can pretty much take it to the bank that there will be
demand.  This is an important, real-world problem.

That having been said, I'm not 100% convinced that the main extensions
patch is ready for prime-time, and I'm even less convinced that the
upgrade patch is anywhere the point where we want to commit to it
long-term.  So I would have no qualms about punting it out to 9.2.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company