Hi Folks, I would like to finally agree on a plan for implementing side inputs in Flink. There has already been an attempt to come to consensus [1], which resulted in two design documents. I tried to consolidate those two and also added a section about implementation plans. This is the resulting FLIP: https://cwiki.apache.org/confluence/display/FLINK/FLIP-17+Side+Inputs+for+DataStream+API
In terms of semantics I tried to go with the minimal viable solution. The part that needs discussing is how we want to implement this. I outlined three possible implementation plans in the FLIP but what it boils down to is that we need to introduce some way of getting several inputs into an operator/task. Please have a look at the doc and let us know what you think. Best, Aljoscha [1] https://lists.apache.org/thread.html/797df0ba066151b77c7951fd7d603a8afd7023920d0607a0c6337db3@1462181294@%3Cdev.flink.apache.org%3E
