Re: pg_upgrade libraries check

On Tue, May 29, 2012 at 01:46:28PM -0400, Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > I assumed I could just have pg_upgrade create and drop the extension in
> > the new database to make sure it works.  In the JSON backpatch case, the
> > extension file would just do nothing, as has already been suggested.
> 
> It seems like checking for the control file being present should be
> sufficient.  I don't think it's part of pg_upgrade's job description to
> test whether the new installation is broken.  And we don't really want
> it cluttering the new installation with dead objects right off the bat
> (could cause OID issues or LSN issues, for instance).

True.  I just wasn't sure the control file method was fool-proof enough.

> > In fact, can we identify right now if a function is used only by an
> > extension?
> 
> ITYM is the function defined by an extension, and the answer to that is
> "look in pg_depend".

So is this something I should be exploring, or not worth it at this
time?  It would allow changing the names of extension shared object
files, but right now I don't know anyone doing that, so I am not sure of
the value of the change.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +