From: Chris Travers [mailto:chris.travers@adjust.com]
> For example a competitor of yours could copy the relevant pieces of the
> PostgreSQL code, refactor this into a library, and then use it as a
> derivative work and this would be entirely within the copyright license.
> They could then license that library out, and you could not use your patents
> or copyrights to stop them. As such, a patent license would probably be
> very similar from a business perspective to a global public grant even though
> the two strike me as something which might not offer protection in the case
> of a clean-room implementation.
>
> I certainly wouldn't be opposed to accepting patents where a license was
> granted to the PostgreSQL Global Developer Group and the community as a
> whole to make full use of the patents in any way covered by the copyright
> license of PostgreSQL (i.e where any use that involves utilizing the
> copyright license for PostgreSQL extends to the patents in question). But
> I am not sure that a business case would be able to be made for releasing
> any patents under such a license since it means that for anyone else, using
> the patents even in commercial software becomes trivial and enforcement
> would become very difficult indeed.
It looks like you are right in that we can't restrict the use of patents in PostgreSQL code to PostgreSQL-based
software... Re-reading Apache License 2.0, it doesn't have any restriction either. But, like Apache License, I think
thepatents can be useful to prevent litigation.
Regards
Takayuki Tsunakawa