For every selected record, the task loads all the parent records to maintain referential integrity. You can configure relationship behavior to select child records from an object.

Consider that there are two objects Account and Contact. Account is the parent object, and Contact is the child object of Account. You can apply filter on the Account object or the Contact object. You can either use the default path that the task selects or configure the path. The number of paths traversed is minimal with the default path selection.

The number of subset rows is not the sum of all target rows that the task loads. The subset estimates show the number of unique records that are selected from all the relationships and loaded to target.