Hey there Gunnar! Are you using TwoInputNonBroadcastStreamProcessFunction <https://github.com/apache/flink/blob/538c24c8bf490eb8870c4d39c8ac5b204d3613ee/flink-datastream-api/src/main/java/org/apache/flink/datastream/api/function/TwoInputNonBroadcastStreamProcessFunction.java> ?
Is the watermark definition on the method declareWatermarks? If so, I think you may want to add defaultHandlingStrategyForward() <https://github.com/apache/flink/blob/538c24c8bf490eb8870c4d39c8ac5b204d3613ee/docs/content/docs/dev/datastream-v2/watermark.md?plain=1#L97-L105> to your builder. This will make sure the watermark is forwarded. If you want to control it by yourself, I think you have to override the onWatermark method. This is not knowledge from living it. I was just playing with something similar. Hope it helps :D Att, Pedro Mázala Be awesome On Tue, 30 Sept 2025 at 11:31, Gunnar Morling <[email protected]> wrote: > Hey all, > > Is there an example which shows the usage of watermarks with joins in the > DS V2 API? Specifically, I'd like to propagate the minimum watermark of the > two joined streams. Here's my watermark declaration: > > public static final LongWatermarkDeclaration WATERMARK_DECLARATION = > WatermarkDeclarations > .newBuilder("MY_CUSTOM_WATERMARK_IDENTIFIER") > .typeLong() > .combineFunctionMin() > .combineWaitForAllChannels(true) > .build(); > > I'm observing though that all watermarks from either side are propagated > downstream, also if there's a lower watermark on the other side. Does this > ring a bell for anyone? > > Thanks a lot, > > --Gunnar > >
