>>>>> One would be through selectable Java procedures, using any (or ODBC)
>>>>> JDBC driver. It will be read-only.
>>>>>
>>
>> Its performance killer, as for me.
>
> What I can say about performance is that external (C++ or Java)
> selectable procedure is not very slow. One could also use (for example)
> a CSV/XML/etc library and completely bypass JDBC or ODBC drivers. Of
> course, it will not have the same performance as an internal solution.

Of course

> But very good performance to import data on the database is not always
> necessary.

Really ? :)

> Anyway, I'm not against internal support. But instead of more ifs and
> switches, we should define a plugin interface for external tables and
> implement them.

Plugins is a good thing. The hard part is to define good clear interface... as usual ;)

Regards,
Vlad