Create the partition keys in a Stream data set when your custom load balancer for Stream data sets is unavailable or busy.

If the Stream data set feeds event data to an Event Strategy rule, you can define only a single partition key for that data set. That partition key must be the same as the event key that is defined in the Real-Time Data shape on the Event Strategy form. Otherwise, when you run the Data Flow, it fails.

An active Data Flow rule that references a Stream data set with least one partition key defined continues processing when nodes are added or removed from the cluster, for example, as a result of node failure or an intentional change in the node topology. However, any data that was not yet processed on the failed or disconnected node is lost.