Hi Weijie! Thank you for the proposal.
I have some initial questions to start the discussion: 1. What is the semantics of the usesStates method? When is it called? Can the used state change dynamically at runtime? Can the logic depend on something computed in open(..) for example? Currently state access is pretty dynamic in Flink and I would assume many jobs create states on the fly based on some required logic. Are we planning to address these use-cases? Are we planning to support deleting/dropping states that are not required anymore? 2. Get state now returns an optional, but you mention that: " If you want to get a state that is not declared or has no access, Option#empty is returned." I think if a state is not declared or otherwise cannot be accessed, an exceptions must be thrown. We cannot confuse empty value with something inaccessible. 3. The RedistributionMode enum sounds a bit strange to me, as it doesn't actually specify a mode of redistribution. It feels more like a flag. Can we simply have an Optional<RedistributionStrategy> instead? 4. BroadcastStates are currently very limited by only Map-like states, and the new interface also enforces that. Can we remove this limitation? If not, should broadcastState declaration extend mapstate declaration? Cheers, Gyula Cheers Gyuka On Wed, Mar 6, 2024 at 11:18 AM weijie guo <guoweijieres...@gmail.com> wrote: > Hi devs, > > I'd like to start a discussion about FLIP-433: State Access on > DataStream API V2 > [1]. This is the third sub-FLIP of DataStream API V2. > > > After FLIP-410 [2], we can already write a simple stateless job using the > DataStream V2 API. But as we all know, stateful computing is Flink's trump > card. In this FLIP, we will discuss how to declare and access state on > DataStream API V2 and we manage to avoid some of the shortcomings of V1 in > this regard. > > You can find more details in this FLIP. Its relationship with other > sub-FLIPs can be found in the umbrella FLIP > [3]. Looking forward to hearing from you, thanks! > > > Best regards, > > Weijie > > > [1] > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-433%3A+State+Access+on+DataStream+API+V2 > > [2] > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-410%3A++Config%2C+Context+and+Processing+Timer+Service+of+DataStream+API+V2 > > [3] > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-408%3A+%5BUmbrella%5D+Introduce+DataStream+API+V2 >
