Horton

Re: Improve logical replication usability when tables lack primary keys

Chao Li <li.evan.chao@gmail.com>

View thread
From: Chao Li <li.evan.chao@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Postgres hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-11-11T12:40:39Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Add the notion of REPLICA IDENTITY for a table.

Hi Amit,

Thanks for asking.

> On Nov 11, 2025, at 19:18, Amit Kapila <amit.kapila16@gmail.com> wrote:
> 
> On Mon, Nov 10, 2025 at 1:36 PM Chao Li <li.evan.chao@gmail.com> 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.

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