Effective in version 10.2.2, you can preview hierarchical data within a mapping in the Developer tool. Previewing hierarchical data helps to design and debug big data mappings.
You can choose sources and transformations as preview points in a mapping that contain the following hierarchical types:
Hierarchical data preview is available for technical preview. Technical preview functionality is supported but is unwarranted and is not production-ready. Informatica recommends that you use these features in non-production environments only.