Feedback-ID: ia2694551:Fastmail
Date: Thu, 14 Mar 2024 15:21:46 +0100
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Shlok Kyal <shlok.kyal.oss@gmail.com>
Cc: Andrew Atkinson <andyatkinson@gmail.com>, 
	Peter Smith <smithpb2250@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Add publisher and subscriber to glossary documentation.
Message-ID: <202403141421.gkawed227diy@alvherre.pgsql>
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On 2024-Mar-14, Shlok Kyal wrote:

> Andrew Atkinson wrote:
>
> > Anyway, hopefully these examples show “node” and “database” are
> > mixed and perhaps others agree using one consistently might help the
> > goals of the docs.
> 
> For me the existing content looks good, I felt let's keep it as it is
> unless others feel differently.

Actually it's these small terminology glitches that give me pause.  If
we're going to have terms that are interchangeable (in this case "node"
and "database"), then they should be always interchangeable, not just in
some unspecified cases.  Maybe the idea of using "node" (which sounds
like something that's instance-wide) is wrong for logical replication,
which is necessarily something that happens database-locally.

Then again, maybe defining "node" as something that exists at a
database-local level when used in the context of logical replication is
sufficient.  In that case, it would be better to avoid defining it as a
synonym of "instance".  Then the terms are not always interchangeable,
but it's clear when they are and when they aren't.

"Node: in <glossterm>replication</>, each of the endpoints to which or
from which data is replicated.  In the context of physical replication,
each node is an instance.  In the context of logical replication, each
node is a database".

Does that make sense?

I'd also look at altering "Primary" and "Standby" so that it's clearer
that they're about physical replication, and don't mention "database"
anymore, since that's the wrong level.  Maybe turn them into "Primary
(node)" and "Standby (node)" instead.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/