Re: Streaming Replication vs Logical

On Sat, Oct 12, 2024 at 07:01:31AM +0200, Laurenz Albe wrote:
> 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".
> >
> > Probably this is historical: at first physical replication was the
> > only kind of streaming we had.
> >
> > 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 documentation
> that speak of physical vs. logical replication, while most places use the
> term "streaming replication" for physical replication. I myself consequently
> speak of "streaming replication" vs. "logical replication", even though both
> stream data. The protocol section of the documentation describes the
> "streaming replication protocol" and the "logical streaming replication protocol".
>
> This is confusing, and I am also sometimes confused in the way you described
> above.
>
> I think the mess is too well established to be really cleaned up. But adding
> some clarity is a good thing, so +1.

I don't think our current setup is sustainable so I think it does need
to be cleaned up. Also, physical/logical replication slots also needs
help, I think.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

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