[FLINK-3336] Add Rescale Data Shipping for DataStream
This is the Javadoc of DataStream.rescale() that describes the behaviour: Sets the partitioning of the {@link DataStream} so that the output elements are distributed evenly to a subset of instances of the next operation in a round-robin fashion. The subset of downstream operations to which the upstream operation sends elements depends on the degree of parallelism of both the upstream and downstream operation. For example, if the upstream operation has parallelism 2 and the downstream operation has parallelism 4, then one upstream operation would distribute elements to two downstream operations while the other upstream operation would distribute to the other two downstream operations. If, on the other hand, the downstream operation has parallelism 2 while the upstream operation has parallelism 4 then two upstream operations will distribute to one downstream operation while the other two upstream operations will distribute to the other downstream operations. In cases where the different parallelisms are not multiples of each other one or several downstream operations will have a differing number of inputs from upstream operations.
Showing
想要评论请 注册 或 登录