Re: pg_tablespace.spclocation column removed in 9.2

On Mon, Jun 25, 2012 at 3:46 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Pavel Golub <pavel(at)microolap(dot)com> writes:
>> I'm aware of problems caused by this hard coded column. My proposal is
>> to convert pg_tablespace to system view may be?
>
> It's not that easy to make a 100% backwards compatible view for a system
> catalog.  The main sticking point is the OID column; see recent problems
> with pg_roles' OID column for an example.  On the whole I don't think
> renaming pg_tablespace and inserting a mostly-compatible view would be
> a net advance.
>
> More generally, I don't see that this particular incompatibility in
> the system catalogs is worse than many others that we've perpetrated.

I'd say it's a lot less bad than some others. At least for this one
you can reasonably connect and figure it out. There was the changes
for database config, I think, which made at least pgadmin break even
before it managed to connect properly. (It got the connection in the
libpq sense, but not in the pgadmin sense).

Bottom line is, any admin tool will *always* have to have to know
about the specific versions and have code to deal with being able to
run different queries on different versions anyway. And this one is
trivial to reimplement with a different query, compared to most
others.

Yes, if we had a set of those stable-system-views that people keep
asking for every now and then, this is one of the few changes that
they *would* actually help with. But there would still be changes that
even those couldn't deal with, because they simply can't know the
future...

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/