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Subject: Re: Non-superuser subscription owners
From: Mark Dilger <mark.dilger@enterprisedb.com>
In-Reply-To: 
 <CAA4eK1KdsoVCpregR8BymGfwhp38WnnX5hP-ZLdynZS78E2ZRQ@mail.gmail.com>
Date: Tue, 7 Dec 2021 06:55:51 -0800
Cc: Jeff Davis <pgsql@j-davis.com>,
 Andrew Dunstan <andrew@dunslane.net>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>,
 Robert Haas <robertmhaas@gmail.com>
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To: Amit Kapila <amit.kapila16@gmail.com>
Archived-At: 
 <https://www.postgresql.org/message-id/8BADB085-239C-4572-847D-99AA1DB84E36%40enterprisedb.com>
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> On Dec 7, 2021, at 2:29 AM, Amit Kapila <amit.kapila16@gmail.com> =
wrote:
>=20
> Okay, let me try to explain again. Following is the text from docs
> [1]: " (a) To create a subscription, the user must be a superuser. (b)
> The subscription apply process will run in the local database with the
> privileges of a superuser. (c) Privileges are only checked once at the
> start of a replication connection. They are not re-checked as each
> change record is read from the publisher, nor are they re-checked for
> each change when applied.
>=20
> My understanding is that we want to improve what is written as (c)
> which I think is the same as what you mentioned later as "Fix the
> current bug wherein subscription changes are applied with superuser
> force after the subscription owner has superuser privileges revoked.".
> Am I correct till here? If so, I think what I am suggesting should fix
> this with the assumption that we still want to follow (b) at least for
> the first patch.

Ok, that's a point of disagreement.  I was trying to fix both (b) and =
(c) in the first patch.

> One possibility is that our understanding of the
> first problem is the same but you want to allow apply worker running
> even when superuser privileges are revoked provided the user with
> which it is running has appropriate privileges on the objects being
> accessed by apply worker.

Correct, that's what I'm trying to make safe.

> We will talk about other points of the roadmap you mentioned once our
> understanding for the first one matches.

I am happy to have an off-list phone call with you, if you like.

=E2=80=94
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company