Annotating datasets without redundant copying

Disclosed embodiments are methods, apparatuses, and computer-readable media for annotating distributed data without redundant data copying. In one embodiment, a method is disclosed comprising reading a raw dataset, the raw dataset comprising a first set of columns and a first set of rows; generating an annotation dataset, the annotation dataset comprising a second set of columns and a second set of rows; assigning row identifiers to each row in the second set of rows, the row identifiers aligning the second set of rows with the first set of rows based on the underlying storage of the raw dataset and annotation dataset; and writing the annotation dataset to a distributed storage medium.