Re: SQL/MED - core functionality

On 28.12.2010 05:16, Robert Haas wrote:
> On Sat, Dec 25, 2010 at 11:52 PM, Robert Haas<robertmhaas(at)gmail(dot)com> wrote:
> In fact, basically all you can do with CREATE FOREIGN TABLE is set column
> names, types, and whether they're NOT NULL. But I think that's enough
> to get started.

Even NOT NULL seems questionable. It might be interesting for the
planner, but our cost estimates of remote queries are pretty bogus
anyway. We can't enforce the NULLness of remote data, so I don't think
we should allow NOT NULL, and should always choose plans that are safe
if there are NULLs after all.

> - I removed all of the changes related to adding a HANDLER option to
> foreign data wrappers. I think that stuff properly belongs in the
> "fdw scan" patch. Instead, what I've done here is just prohibit
> foreign data wrappers from being used in queries. I'm generally
> pretty negative on syntax-only patches, but then foreign data wrappers
> have been basically syntax-only for two releases, and I think there's
> a good chance that if we get the syntax patch in soon we'll actually
> be able to make it work before we run out of time. So I'm feeling
> like it might be OK in this case, especially because even with all the
> trimming down I've done here, this is still a very big patch.

+1, now that we have a patch for the rest of the feature as well.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com