# pyflink.datastream.data_stream.DataStream.rescale#

- DataStream.rescale() pyflink.datastream.data_stream.DataStream [source]#
Sets the partitioning of the 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. If, on the other hand, the downstream 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 one or several downstream operations will have a differing number of inputs from upstream operations.

- Returns
The DataStream with rescale partitioning set.