Your job reads from a file using a Sequential File stage running sequentially. You are using a Transformer stage following the Sequential File stage to format the data in some of the columns. What is the default (Auto) partitioning method?

When a sequential stage feeds into a parallel stage with Auto partitioning, DataStage defaults to Round Robin. This evenly distributes the sequential stream across available partitions without requiring a key. Random would also distribute but is not the default for Auto. Hash and Same require specific conditions (key column or existing partitioning) that don't apply when coming from sequential.