The StepContext and StepExecution provide access to metrics recorded for a chunk step. The spec does not describe how this is handled in a partitioned step, but since you have no way to get metrics for an individual partition you might assume these step-level metrics are aggregated across the partitions. The spec should say that and perhaps provide a way to get to partition metrics. Although..if you ask the StepContext for metrics from within a partition you probably get the metrics for that partition. Again..spec should clarify how this is supposed to work.
The StepContext and StepExecution provide access to metrics recorded for a chunk step. The spec does not describe how this is handled in a partitioned step, but since you have no way to get metrics for an individual partition you might assume these step-level metrics are aggregated across the partitions. The spec should say that and perhaps provide a way to get to partition metrics. Although..if you ask the StepContext for metrics from within a partition you probably get the metrics for that partition. Again..spec should clarify how this is supposed to work.