On Thu, 2011-07-07 at 23:21 -0700, Darren Duncan wrote: > I think an even better way to support this is would be based on Postgres having > support for directly using multiple databases within the same SQL session at > once, as if namespaces were another level deep, the first level being the > databases, the second level the schemas, and the third level the schema objects. > > Kind of like what the SQL standard defines its catalog/schema/object namespaces. > > This instead of needing to use federating or that contrib module to use multiple > Pg databases of the same cluster at once. > > Under this scenario, we make the property of a database being read-only or > read-write for the current SQL session associated with a database rather than > the whole SQL session. A given transaction can read from any database but can > only make changes to the ones not read-only. > > Also, the proper way to do temporary tables would be to put them in another > database than the main one, where the whole other database has the property of > being temporary. > > Under this scenario, there would be separate system catalogs for each database, > and so the ones for read-only databases are read-only, and the ones for other > databases aren't. > > Then the system catalog itself fundamentally isn't more complicated, per > database, and anything extra to handle cross-database queries or whatever, if > anything, is a separate layer. Code that only deals with a single database at > once would be an optimized situation and perform no worse than it does now. One challenge that jumps to mind here is that an Oid would need to become a pair (catalog, oid). Even if the end result isn't much more complex, getting there is not trivial. > See also how SQLite works; this "mount" being analogous to their "attach". I'm not sure SQLite is the best example. It has a radically different architecture. Regards, Jeff Davis -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
