On Tue, May 22, 2012 at 10:56 AM, Josh Berkus <josh@agliodbs.com> wrote:
> I'm not arguing that we don't have users who would like interdatabase
> queries, especially when they port applications from MySQL or MSSQL. We
> have a lot of such users. However, we *also* have a lot of users who
> would like to treat separate databases as virtual private instances of
> Postgres, and there's no way to satisfy both goals. We have to choose
> one route or the other.
I think the idea that a physical machine where catalogs are physically
(shared-everything) co-located is one that will not stand for long as
part of a useful contract between a user and the database. I'd really
like to avoid an extra tier of functionality that exists only for
databases that happen to land on the same physical machine.
I think any inter-database feature should work identically between two
databases across a network as two machines on one machine/cluster.
Transparent optimizations to deal with the special case of physical
co-location are not contrary to that contract, but I don't have a
sense of how important those optimizations would be before getting a
lot of the usability issues figured out. Right now, it seems to me
that getting interdatabase usability feeling better is already pretty
hard.
--
fdr