Re: PGXS: REGRESS_OPTS=--load-language=plpgsql

On Fri, Feb 19, 2010 at 2:09 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> David Fetter <david@fetter.org> writes:
>> CREATE OR REPLACE LANGUAGE is an even bigger tar pit.
>> http://archives.postgresql.org/pgsql-hackers/2009-10/msg00386.php
>
> The reason that patch got rejected was that it was implementing
> CREATE IF NOT EXISTS --- under a false name.  The problem with
> that is summarized here:
> http://archives.postgresql.org/pgsql-patches/2008-03/msg00416.php
>
> It wouldn't be that hard to implement actual CREATE OR REPLACE
> if we decide that's the most useful solution here.  The code
> would need to be prepared to use heap_update instead of heap_insert,
> and to get rid of old dependencies, but there is plenty of precedent
> for that.
>
> The sticking point for me is still whether or not it's really a good
> idea for pg_dump to be emitting CREATE OR REPLACE LANGUAGE.  It does not
> do that for any other object type.  On the other hand, we've already
> made languages a special case in pg_dump, since it emits the abbreviated
> form of CREATE LANGUAGE in most cases rather than trying to duplicate
> the existing object definition.  Maybe there wouldn't be any bad results
> in practice.

We have all sorts of crufty hacks in pg_dump and the backend to cope
with restoration of older dumps.  Compared to some of those, this is
going to be cleaner than newfallen snow.  IMHO, anyway.

...Robert