Hey! I think the main question here is whether Flink 2.0 is going to be state backward compatible or not. If not then we need to make the upgrade right now, freeze or not. We have to decide this as a community.
If we need to preserve backward compatibility then we need to go with a much more complex solution here when upgrading Kryo to do that. Do we have a community decision somewhere related to state backward compatibility for 2.0? Cheers Gyula On Mon, Feb 24, 2025 at 3:02 AM Rui Fan <1996fan...@gmail.com> wrote: > Thanks Gyula for driving this discussion! > > +1 for upgrading kyro, I have a question about the timeline. > The flink 2.0.0 has been freezed, do we have enough time to > test if it's done in flink 2.0.0? > > Best, > Rui > > On Fri, Feb 21, 2025 at 9:55 PM Alexander Fedulov <afedu...@apache.org> > wrote: > > > Hi Gyula, > > > > Thanks for bringing up this topic! Kryo incompatibility with newer > > Java versions is a major issue that needs to be addressed, and in my > > opinion, Flink 2.0 provides a great opportunity to introduce this > > change. > > > > My understanding is that state compatibility was not a strict goal > > during 2.0 development. However, I’ve heard mentions that it might > > actually be compatible after all. > > > > From this perspective: > > definitely +1 on upgrading Kryo. The decision to invest additional > > effort in maintaining compatibility should depend on whether all other > > changes have preserved compatibility guarantees. If Kryo is the only > > breaking change, then ensuring compatibility might be worth > > considering. > > > > Best, > > Alex > > > > On Fri, 21 Feb 2025 at 06:05, Gyula Fóra <gyula.f...@gmail.com> wrote: > > > > > > Hey all! > > > > > > I would like to rekindle this discussion as it seems that it has > stalled > > > several times in the past and we are nearing the point in time where > the > > > decision has to be made with regards to 2.0. (we are already a bit late > > but > > > nevermind) > > > > > > There has been numerous requests and efforts to upgrade Kryo to better > > > support newer Java versions and Java native types. I think we can all > > agree > > > that this change is inevitable one way or another. > > > > > > The latest JIRA for this seems to be: > > > https://issues.apache.org/jira/browse/FLINK-3154 > > > > > > There is even an open PR that accomplishes this (currently in a state > > > incompatible way) but based on the discussion it seems that with some > > extra > > > complexity compatibility can even be preserved by having both the old > and > > > new Kryo versions active at the same time. > > > > > > The main question here is whether state compatibility is important for > > 2.0 > > > with this regard or we want to bite the bullet and make this upgrade > once > > > and for all. > > > > > > Cheers, > > > Gyula > > >
