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From: Chao Li <[email protected]>
To: Dilip Kumar <[email protected]>
Cc: Amit Kapila <[email protected]>
Cc: Postgres hackers <[email protected]>
Subject: Re: Improve logical replication usability when tables lack primary keys
Date: Mon, 15 Dec 2025 11:35:36 +0800
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAFiTN-ucvk8JOiLvjii6VXar6nYJvCQDgzp8_4v55yweUmzdzw@mail.gmail.com>
References: <CAEoWx2mMorbMwjKbT4YCsjDyL3r9Mp+z0bbK57VZ+OkJTgJQVQ@mail.gmail.com>
	<CAA4eK1+UL6wVDNzkpHjA7RVLD_8AkrP2tu+RvQ2h5AUjyEe+-Q@mail.gmail.com>
	<[email protected]>
	<CAFiTN-ucvk8JOiLvjii6VXar6nYJvCQDgzp8_4v55yweUmzdzw@mail.gmail.com>



> On Dec 15, 2025, at 11:28, Dilip Kumar <[email protected]> wrote:
> 
> On Tue, Nov 11, 2025 at 6:11 PM Chao Li <[email protected]> wrote:
>> 
>> Hi Amit,
>> 
>> Thanks for asking.
>> 
>>> On Nov 11, 2025, at 19:18, Amit Kapila <[email protected]> wrote:
>>> 
>>> On Mon, Nov 10, 2025 at 1:36 PM Chao Li <[email protected]> wrote:
>>>> 
>>>> * BACKGROUND
>>>> 
>>>> This requirement comes from several users operating large deployments, particularly in HIS (Hospital Information Systems). The situation can be summarized as follows:
>>>> 
>>>> - A central DB operations team maintains the main database and configures logical replication for all tables.
>>>> - Multiple third-party application vendors are allowed to create new tables in that database.
>>>> - Some of these newly created tables lack a primary key. Since logical replication with `REPLICATION IDENTITY DEFAULT` requires a primary key, such tables silently fail to replicate.
>>>> - The DB operations team must then spend significant effort identifying the affected tables and correcting them manually.
>>>> 
>>> 
>>> Can you share an example of how we silently fail to replicate? Won't
>>> in such cases UPDATE/DELETE will anyway raise an ERROR?
>>> 
>> 
>> Yes, UPDATE/DELETE will fail. That’s the easy case to expose the error. Actually my patch will allow the update/delete.
>> 
>> However, some tables, like dictionary tables, they are important, but don’t have much update/delete, they may silently fail to replicate.
> 
> But other than UPDATE/DELETE for what operation we need RI, I mean
> INSERT would work without any RI and UPDATE/DELETE will fail on the
> publisher itself without setting RI, so can you explain the exact case
> where it will silently fail to replicate?
> 
> -- 
> Regards,
> Dilip Kumar
> Google

Hi Dilip,

Thanks for asking. When fallback to FULL, UPDATE/DELETE will be allowed in the publisher side. In my first email, attached v1 patch is a PoC that has implemented the logic.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/

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