MIME-Version: 1.0
References: 
 <CAPmGK16n_hcUUWuOdmeUS+w4Q6dZvTEDHb=OP=5JBzo-M3QmpQ@mail.gmail.com>
 <CAExHW5vOH-=1KhaL8S4xVVzSozvrbmbBVg97p0obwEW3sD57Cw@mail.gmail.com>
 <3660951.1741016970@sss.pgh.pa.us>
 <CAPmGK14Btk0odkH6vwBhBGjCexmmWcM_D3DG0pJtObj8k_Unag@mail.gmail.com>
 <CAExHW5vVwZdvW1Dfy3oJXVDBffJUvAwhaCw3HCSC38B1ie_H1A@mail.gmail.com>
 <CAPmGK16pn+k0tLNR8NvZdtiADpnjZPYK-HuaxwOmzHzUgTE7_A@mail.gmail.com>
 <CAPmGK14Zn9NwKPPmBrUyN9ALBJa2nv75-LOVKNBgRN=ehYnKkw@mail.gmail.com>
 <CAPmGK150ucoQy96dUu6nu5iXBxyqrPrpqR2KMZN2CCSrMq0USw@mail.gmail.com>
 <CAPmGK15AQBXTgF_8EK=AY-Q6OLmhTuQSTWittLSVrw9Rvec25g@mail.gmail.com>
 <CAPmGK14fT9_hdC40s7MWZX+-k87AvyusG0qjd6zvngEgumdNgw@mail.gmail.com>
 <CAPmGK14RxMWYmNEHcjn04ZuvqxZrbasPT+zMNdd3T2V3R9Rz2A@mail.gmail.com>
 <CAPmGK14ZTHRGPprEhzEe2TJxaCcjNVeWw6tue_gqp=9DzqYnMA@mail.gmail.com>
In-Reply-To: 
 <CAPmGK14ZTHRGPprEhzEe2TJxaCcjNVeWw6tue_gqp=9DzqYnMA@mail.gmail.com>
From: Fujii Masao <masao.fujii@gmail.com>
Date: Thu, 5 Mar 2026 12:10:50 +0900
Message-ID: 
 <CAHGQGwHjeZNppb4N7oG4vdPT1i2RY+=YRA=NUwhwYgpsjRyxfA@mail.gmail.com>
Subject: 
 =?UTF-8?Q?Re=3A_Options_to_control_remote_transactions=E2=80=99_access?=
	=?UTF-8?Q?=2Fdeferrable_modes_in_postgres=5Ffdw?=
To: Etsuro Fujita <etsuro.fujita@gmail.com>
Cc: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>,
 Tom Lane <tgl@sss.pgh.pa.us>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Archived-At: 
 <https://www.postgresql.org/message-id/CAHGQGwHjeZNppb4N7oG4vdPT1i2RY%2B%3DYRA%3DNUwhwYgpsjRyxfA%40mail.gmail.com>
Precedence: bulk

On Thu, Mar 5, 2026 at 8:52=E2=80=AFAM Etsuro Fujita <etsuro.fujita@gmail.c=
om> wrote:
>
> On Wed, Feb 25, 2026 at 7:22=E2=80=AFPM Etsuro Fujita <etsuro.fujita@gmai=
l.com> wrote:
> > This was reverted in commit 7d4667c62.  I'd like to re-propose it for
> > v19, as mentioned in [1].  Attached is a new patch, in which I added
> > to the documentation a note about login triggers executed on the
> > remote side, as discussed in [1].  Other than that, no changes.  I've
> > added this to the upcoming CF.
>
> Here is an updated version of the patch.  Changes are:
>
> * On second thought, I think the name of the variable
> top_read_only_level added to connection.c by the patch is a bit long,
> so I renamed it to top_read_only.  Does that make sense?  Other than
> that, no code changes.
> * I also added/modified some comments.
>
> Comments welcome!

I haven't yet realized the benefit from this change since I haven't
encountered issues caused by the current behavior (i.e., a remote transacti=
on
starting in read-write mode while the corresponding local transaction on
the standby is read-only).

On the other hand, this change would force any remote transaction initiated=
 by
a standby transaction to start in read-only mode, completely preventing it =
from
modifying data. Because transactions on a standby always start as read-only=
,
the remote transaction would also always be read-only under this proposal,
with no way to make it read-write.

I'm concerned that this could break certain use cases without providing
a clear benefit.

Regards,

--=20
Fujii Masao