Message-ID: <186ddb32d1f5e6bc46fdd6546fcc225a4d2dc3b6.camel@cybertec.at>
Subject: Re: How to Handle Sequences in Logical Bi-Directional Replication
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: PGSQL DBA <pgsqldba.1987@gmail.com>, pgsql-admin@lists.postgresql.org
Date: Thu, 13 Jun 2024 09:15:43 +0200
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On Thu, 2024-06-13 at 09:23 +0800, PGSQL DBA wrote:
> I am reaching out to seek your guidance and expertise on handling sequenc=
es
> in a bi-directional logical replication setup.
>=20
> I am planning to set up two PostgreSQL-16 database servers with logical b=
i-directional
> replication, using the `origin=3Dnone` configuration. In this setup, my a=
pplication will
> be connecting to either of the database servers for DML operations.

You will have to resolve conflicts manually.

> Given this scenario, I am looking for the best practices to handle sequen=
ce values to
> ensure consistency and avoid conflicts. Specifically, I would like to und=
erstand:
>=20
> 1. How to configure sequences to avoid duplicate values in both database =
servers.

On server 1:

  CREATE TABLE tab (
     id bigint BENERATED ALWAYS AS IDENTITY (START 1 INCREMENT 2)
               PRIMARY KEY,
     ...
  );

On server 2:

  CREATE TABLE tab (
     id bigint BENERATED ALWAYS AS IDENTITY (START 2 INCREMENT 2)
               PRIMARY KEY,
     ...
  );

Yours,
Laurenz Albe