Re: dblink get_connect_string() passes FDW option "updatable" to the connect string, connection fails.

>
> The dblink docs recommend using dblink_fdw as the FDW for this purpose,
> which would only accept legal connstr options. However, I can see the
> point of using a postgres_fdw server instead, and considering that
> dblink isn't actually enforcing use of any particular FDW type, it seems
> like the onus should be on it to be more wary of what the options are.
>

I have to admit, this was the first I'd heard of dblink_fdw. I'm glad it
exists, though. And yes, I'd like to be able to use postgres_fdw entries
because there's value in knowing that the connection for your ad-hoc SQL
exactly matches the connection used for other FDW tables.

> It looks like this might be fairly easy to fix by having
> get_connect_string() use is_valid_dblink_option() to check each
> option name, and silently ignore options that are inappropriate.
>

From what I can tell, it is very straightforward, the context oids are set
up just a few lines above where the new is_valid_dblink_option() calls
would be.

I'm happy to write the patch, for both v10 and any back-patches we feel are
necessary. However, I suspect with a patch this trivial that reviewing
another person's patch might be more work for a committer than just doing
it themselves. If that's not the case, let me know and I'll get started.