Rollup is a general transformation component introduced in CloverETL version 2.8. It serves as an executor of rollup transformations written in Java or CTL. Basically, rollup transformations are used to process groups of data records. Each group consisting of M data records may be used to output N different data records. The number of output data records is determined at runtime within the rollup transformation. If no group key is defined, all input data records belong to a single group.