Vlad Khorsun wrote:

>>>> Alex Peshkov wrote:
>>>>
>>>>
>>>>> First problem. Currently external engines access is actively developed by
>>>>> the project. Looks like very soon we will be able access virtually any
>>>>> file format using ODBC. Would not extending of external tables be just a
>>>>> duplication of our efforts in that direction?
>>>>>
>>>>>
>>>> Yes, and in two different ways.
>>>>
>>>> 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.
But very good performance to import data on the database is not always
necessary.

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.


Adriano