How To Fix MC819 - & & and proxy view & have different numbers of columns

SAP Error Message - Details

• Message type: E = Error

• Message class: MC - Aggregate: views, matchcodes, lock objects

• Message number: 819

• Message text: & & and proxy view & have different numbers of columns

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message MC819 - & & and proxy view & have different numbers of columns ?

  The SAP error message MC819 typically indicates a mismatch in the number of columns between a data source and a proxy view in the context of SAP BW (Business Warehouse) or SAP HANA. This error can occur during data extraction, transformation, or loading processes when the structure of the data being processed does not align with the expected structure defined in the proxy view.
  Cause:
  
  
  Schema Mismatch: The most common cause of this error is that the data source (e.g., InfoSource, DataSource, or DSO) has a different number of columns than the proxy view that is trying to access it. This can happen if:
  
  The data source has been modified (e.g., columns added or removed) without updating the corresponding proxy view.
  The proxy view was created based on an outdated version of the data source.
  
  
  
  Data Model Changes: Changes in the underlying data model, such as changes in the InfoObject definitions or the structure of the data source, can lead to this error.
  
  
  Incorrect Mapping: If there is incorrect mapping between the data source and the proxy view, it can also result in a column mismatch.
  
  
  Solution:
  
  
  Check Data Source and Proxy View: 
  
  Verify the structure of the data source and the proxy view. Ensure that they have the same number of columns and that the data types match.
  If there are discrepancies, update the proxy view to reflect the current structure of the data source.
  
  
  
  Recreate Proxy View: If the proxy view is outdated or incorrectly configured, consider recreating it based on the current data source structure.
  
  
  Update Data Model: If changes have been made to the data model, ensure that all related objects (like InfoObjects, DataSources, and transformations) are updated accordingly.
  
  
  Check for Transport Issues: If the changes were transported from one system to another (e.g., from development to production), ensure that all relevant objects were transported correctly.
  
  
  Testing: After making the necessary adjustments, test the data extraction or loading process again to ensure that the error is resolved.
  
  
  Related Information:
  
  SAP Notes: Check SAP Notes related to error MC819 for any specific patches or updates that may address this issue.
  Documentation: Review SAP BW or HANA documentation for best practices on managing data sources and proxy views.
  Transaction Codes: Use transaction codes like RSA1 (Data Warehousing Workbench) to manage and monitor data sources and InfoProviders.
  
  If the issue persists after following these steps, consider reaching out to SAP support for further assistance, providing them with detailed information about the error and the steps you have already taken.