Re: [v9.4] row level security

On Wed, Sep 4, 2013 at 11:22 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> The same mechanism will prevent UPDATE and DELETE from seeing any rows
>> the user shouldn't be able to touch.
>
> No, it won't, because we don't support direct update/delete on views
> (and if you look, you'll notice the auto-updatable-view stuff doesn't
> think a security-barrier view is auto-updatable).
>
> AFAICT, to deal with update/delete the RLS patch needs to constrain order
> of qual application without the crutch of having a separate level of
> subquery; and it's that behavior that I have zero confidence in, either
> as to whether it works as submitted or as to our odds of not breaking it
> in the future.

I don't really see why.  AIUI, the ModifyTable node just needs to get
the right TIDs.  It's not like that has to be stacked directly on top
of a scan; indeed, in cases like UPDATE .. FROM and DELETE .. USING it
already isn't.  Maybe there's some reason why the intervening level
can be a Join but not a  SubqueryScan, but if so I'd expect we could
find some way of lifting that limitation without suffering too much
pain.

-- 
Robert Haas
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