Re: Non-superuser subscription owners

On Tue, Nov 30, 2021 at 12:56 AM Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
>
> On Mon, 2021-11-29 at 09:43 +0530, Amit Kapila wrote:
> > The first reason is that way it would be consistent with what we can
> > see while doing the operations from the backend.
>
> Logical replication is not interactive, so it doesn't seem quite the
> same.
>
> If you have a long running INSERT INTO SELECT or COPY FROM, the
> permission checks just happen at the beginning. As a user, it wouldn't
> surprise me if logical replication was similar.
>
> > operation. Another reason is to make behavior predictable as users
> > can
> > always expect when exactly the privilege change will be reflected and
> > it won't depend on the number of changes in the transaction.
>
> This patch does detect ownership changes more quickly (at the
> transaction boundary) than the current code (only when it reloads for
> some other reason). Transaction boundary seems like a reasonable time
> to detect the change to me.
>
> Detecting faster might be nice, but I don't have a strong opinion about
> it and I don't see why it necessarily needs to happen before this patch
> goes in.
>

I think it would be better to do it before we allow subscription
owners to be non-superusers.

> Also, do you think the cost of doing maybe_reread_subscription() per-
> tuple instead of per-transaction would be detectable?
>

Yeah, it is possible that is why I suggested in one of the emails
above to allow changing the owners only for disabled subscriptions.

--
With Regards,
Amit Kapila.