Hi Flink users, I'm struggling with some basic concept and would appreciate some help. I have 2 Input streams, one is fast event stream and one is slow changing dimension. They have the same key and I use CoProcessFunction to store slow data in state and enrich fast data from this state. Everything works as expected.
Before I start processing fast streams on first run, I would like to completely initialise state. I though it could be done in open(), but I don't understand how it will be re-distributed across parallel operators. Another alternative would be to create custom source and push all slow dimension data downstream, but I could not find how to hold processing fast data until state is initialised. I realise that FLIP-17 (Side Inputs) is what I need, but is there some other way to implement it now ? Thanks, Maxim.
