Message-ID: <2c392993640661b817c5c779f6aaf44c103510bf.camel@cybertec.at>
Subject: Re: Streaming Replication vs Logical
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Paul A Jungwirth <pj@illuminatedcomputing.com>,
	pgsql-docs@lists.postgresql.org
Date: Sat, 12 Oct 2024 07:01:31 +0200
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On Fri, 2024-10-11 at 15:53 -0700, Paul A Jungwirth wrote:
> Our docs seem to contrast "streaming replication" to logical, but
> these are not really opposites. Sometimes when they say "streaming"
> they mean "physical".
>=20
> Probably this is historical: at first physical replication was the
> only kind of streaming we had.
>=20
> Personally this has caused me a lot of confusion. For example,
> recently when I read "Synchronous replication (see Section 26.2.8) is
> only supported on replication slots used over the streaming
> replication interface," I took it to mean synchronous replication only
> worked for physical replication, not logical.

What you are saying makes a lot of sense, and improving some of this
is a good thing.

Our current trminology is a mess.  There are some places in the documentati=
on
that speak of physical vs. logical replication, while most places use the
term "streaming replication" for physical replication.  I myself consequent=
ly
speak of "streaming replication" vs. "logical replication", even though bot=
h
stream data.  The protocol section of the documentation describes the
"streaming replication protocol" and the "logical streaming replication pro=
tocol".

This is confusing, and I am also sometimes confused in the way you describe=
d
above.

I think the mess is too well established to be really cleaned up.  But addi=
ng
some clarity is a good thing, so +1.

Yours,
Laurenz Albe