"Dave Page" <dpage@xxxxxxxxxxx> writes: > On Tue, May 27, 2008 at 2:06 PM, Justin Clift <justin@xxxxxxxxxxxx> wrote: >> I'm trying to point out that - PG is a database system - and MS may have >> just been granted a patent for a fundamental part of it. > I don't think it's a major issue. Even if MS do think we infringe on > the patent it would be laughable for them to try to do anything about > it given that our rules implementation has provably existed in a > leading FOSS project for a decade or more. Right --- if in fact PG's rules infringe, then the patent is invalid because we are prior art. After scanning the claims, though, most of this is about access-rights enforcement; which is something that rules *could* be used for but it's not their sole or main purpose. What it seems a whole lot closer to is Veil or SEPostgres. I think those projects have reason to be very afraid. In fact, I suspect that the originally submitted version of SEPostgres does infringe the patent, and that code is not old enough to be prior art. The part of the patch that looks like this patent to me is the part that enforces row-level access checks by adding constraints to a querytree's WHERE clause. I had already suggested to KaiGai-san that he get rid of that in favor of low-level checks in the executor, but the need to avoid an M$ patent makes it even more important ... regards, tom lane