On Tue, 20 Aug 2024 at 19:02, David G. Johnston <david.g.johns...@gmail.com> wrote: > So basically my proposal amounted to making every update a "major version > update" and changing the behavior surrounding NegotiateProtocolVersion so it > applies to major version differences. I'll stand by that change in > definition. The current one doesn't seem all that useful anyway, and as we > only have a single version, definitely hasn't been materially implemented. > Otherwise, at some point a client that knows both v3 and v4 will exist and > its connection will be rejected instead of downgraded by a v3-only server > even though such a downgrade would be possible. I suspect we'd go ahead and > change the rule then - so why not just do so now, while getting rid of the > idea that minor versions are a thing.
If we decide to never change the format of the StartupMessage again (which may be an okay thing to decide). Then I agree it would make sense to update the existing supported servers ASAP to be able to send back a NegotiateProtocolVersion message if they receive a 4.x StartupMessage, and the server only supports up to 3.x. However, even if we do that, I don't think it makes sense to start using the 4.0 version straight away. Because many older postgres servers would still throw an error when receiving the 4.x request. By using a 3.x version we are able to avoid those errors in the existing ecosystem. Basically, I think we should probably wait ~5 years again until we actually use a 4.0 version. i.e. I don't see serious benefits to using 4.0. The main benefit you seem to describe is: "it's theoretically cleaner to use major version bumps". And there is a serious downside: "seriously breaking the existing ecosystem". > I suppose we could leave minor versions for patch releases of the main server > version - which still leaves the first new feature of a release incrementing > the major version. That would be incidental to changing how we handle major > versions. Having a Postgres server patch update change the protocol version that the server supports sounds pretty scary to me.
