Re: running logical replication as the subscription owner

On Mon, Mar 27, 2023 at 6:08 PM Jelte Fennema <postgres(at)jeltef(dot)nl> wrote:
> Attached is an updated version of your patch with what I had in mind
> (admittedly it needed one more line than "just" the return to make it
> work). But as you can see all previous tests for a lowly privileged
> subscription owner that **cannot** SET ROLE to the table owner
> continue to work as they did before. While still downgrading to the
> table owners role when the subscription owner **can** SET ROLE to the
> table owner.
>
> Obviously this needs some comments explaining what's going on and
> probably some code refactoring and/or variable renaming, but I hope
> it's clear what I meant now: For high privileged subscription owners,
> we downgrade to the permissions of the table owner, but for low
> privileged ones we care about permissions of the subscription owner
> itself.

Hmm. This is an interesting idea. A variant on this theme could be:
what if we made this an explicit configuration option?

I'm worried that if we just try to switch users and silently fall back
to not doing so when we don't have enough permissions, the resulting
behavior is going to be difficult to understand and troubleshoot. I'm
thinking that maybe if you let people pick the behavior they want that
becomes more comprehensible. It's also a nice insurance policy: say
for the sake of argument we make switch-to-table-owner the new
default. If that new behavior causes something to happen to somebody
that they don't like, they can always turn it off, even if they are a
highly privileged user who doesn't "need" to turn it off.

--
Robert Haas
EDB: http://www.enterprisedb.com