How To Fix RSDD817 - Hierarchy not unique. Check aggregate not possible

SAP Error Message - Details

• Message type: E = Error

• Message class: RSDD - Message class for data manager

• Message number: 817

• Message text: Hierarchy not unique. Check aggregate not possible

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message RSDD817 - Hierarchy not unique. Check aggregate not possible ?

  The SAP error message RSDD817, which states "Hierarchy not unique. Check aggregate not possible," typically occurs in the context of SAP BW (Business Warehouse) when there is an issue with the hierarchy structure in your data model. This error indicates that the system has encountered multiple hierarchies that are not uniquely identifiable, which prevents the aggregation process from proceeding.
  Causes:
  
  Duplicate Hierarchies: There may be multiple hierarchies defined for the same characteristic, leading to ambiguity in the data model.
  Incorrect Hierarchy Assignment: A characteristic may be assigned to more than one hierarchy, causing conflicts.
  Hierarchy Structure Issues: The hierarchy may not be properly structured, or there may be inconsistencies in the hierarchy nodes.
  Data Inconsistencies: There may be inconsistencies in the data that are causing the hierarchy to be interpreted as non-unique.
  
  Solutions:
  
  
  Check Hierarchy Definitions:
  
  Go to the hierarchy maintenance transaction (e.g., RSH1) and review the hierarchies defined for the characteristic in question.
  Ensure that there are no duplicate hierarchies and that each hierarchy is uniquely identifiable.
  
  
  
  Review Characteristic Assignment:
  
  Check the assignment of characteristics to hierarchies. Make sure that each characteristic is assigned to only one hierarchy at a time.
  
  
  
  Validate Hierarchy Structure:
  
  Use the hierarchy display transaction (e.g., RSH2) to visualize the hierarchy structure. Look for any inconsistencies or duplicate nodes that may be causing the issue.
  
  
  
  Rebuild Hierarchies:
  
  If necessary, consider rebuilding the hierarchy from scratch to ensure that it is correctly defined and structured.
  
  
  
  Check Aggregates:
  
  Review the aggregates that are defined for the InfoObject. Ensure that they are correctly set up and that they reference the correct hierarchy.
  
  
  
  Data Consistency Check:
  
  Run data consistency checks to identify any issues with the data that may be affecting the hierarchy.
  
  
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as RSH1 (Hierarchy Maintenance), RSH2 (Hierarchy Display), and RSA1 (Data Warehousing Workbench) for managing hierarchies and aggregates.
  SAP Notes: Check SAP Notes for any known issues or patches related to this error message. SAP frequently updates its knowledge base with solutions for common problems.
  Documentation: Refer to SAP BW documentation for best practices on managing hierarchies and aggregates.
  
  By following these steps, you should be able to identify and resolve the issue causing the RSDD817 error message in your SAP BW environment.