Re: Pg_upgrade and toast tables bug discovered

On Thu, Jul 10, 2014 at 10:46:30AM -0400, Robert Haas wrote:
> > Agreed. I am now thinking we could harness the code that already exists
> > to optionally add a TOAST table as part of ALTER TABLE ADD COLUMN. We
> > would just need an entry point to call it from pg_upgrade, either via an
> > SQL command that checks (and hopefully doesn't do anything else), or a C
> > function that does it, e.g. VACUUM would be trivial to run on every
> > database, but I don't think it tests that; is _could_ in binary_upgrade
> > mode. However, the idea of having a C function plug into the guts of
> > the server and call internal functions makes me uncomforable.
>
> Well, pg_upgrade_support's charter is basically to provide access to
> the guts of the server in ways we wouldn't normally allow; all that
> next-OID stuff is basically exactly that. So I don't think this is
> such a big deal. It needs to be properly commented, of course.

If you look at how oid assignment is handled, it is done in a very
surgical way, i.e. pg_upgrade_support sets a global variable, and the
variable triggers different behavior in a CREATE command. This change
would be far more invasive than that.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ Everyone has their own god. +