Re: New MS patent: sounds like PG db rules

Tom Lane wrote:
> "Dave Page" <dpage(at)pgadmin(dot)org> writes:
>> On Tue, May 27, 2008 at 2:06 PM, Justin Clift <justin(at)salasaga(dot)org> 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 ...

Yes, I've changed the originally submitted version of SE-PostgreSQL.
The latest version of its implementation does not have any feature
to modify given queries. All of low-level checks are moved to hard
wired hooks in ExecScan().

http://code.google.com/p/sepgsql/source/browse/trunk/sepgsql/src/backend/executor/execScan.c#144

BTW, I may have to backport the feature for v8.4 into v8.3/v8.2
based SE-PostgreSQL... :(
--
KaiGai Kohei <kaigai(at)kaigai(dot)gr(dot)jp>