How To Fix DMC_GENERAL121 - Structure &1 could not be locked

SAP Error Message - Details

• Message type: E = Error

• Message class: DMC_GENERAL - MWB: General Messages

• Message number: 121

• Message text: Structure &1 could not be locked

What causes this issue?

This usually happens if several parallel-running jobs are creating
conversion objects simulaneously. It might happen that two objects refer
to the same DDIC structures of the sender or receiver system (for
example, two tables use the same includes). In order to prevent
potential problems with the DDIC activation of shadow structures in the
central system, a logical lock must be acquired by the job that
processes the objects. If this lock can't be obtained in a due time
interval, the processing of the corresponding conversion object is
stopped. The object is set to "error" state and the system proceeds with
the processing of the next object.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Repeat the creation of the conversion objects. Usually the problem
disappears if the processing is repeated.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message DMC_GENERAL121 - Structure &1 could not be locked ?

  The SAP error message DMC_GENERAL121 indicates that a specific structure (denoted by &1) could not be locked. This typically occurs in the context of data management and can be related to various scenarios, such as data migration, data replication, or data processing tasks.
  Causes:
  
  Concurrent Access: Another user or process is currently accessing or modifying the structure, preventing your session from obtaining a lock.
  Long-Running Transactions: A transaction that is taking too long to complete may hold the lock longer than expected.
  System Performance Issues: High system load or performance issues can lead to delays in lock acquisition.
  Configuration Issues: Incorrect configuration settings in the system may lead to locking issues.
  Database Locks: Locks at the database level may also prevent access to the structure.
  
  Solutions:
  
  Check for Active Sessions: Use transaction codes like SM12 (to view and manage locks) to check if there are any active sessions holding locks on the structure. If you find any unnecessary locks, you may need to terminate those sessions (with caution).
  Wait and Retry: If the lock is held by a legitimate process, you may need to wait for that process to complete and then retry your operation.
  Optimize Long-Running Transactions: If you identify that a specific transaction is taking too long, investigate and optimize it to reduce the time it holds the lock.
  System Monitoring: Monitor system performance and resource usage to identify any bottlenecks that may be causing delays in lock acquisition.
  Review Configuration: Ensure that your system configuration is set up correctly for the operations you are performing. Consult with your SAP Basis team if necessary.
  Database Administration: If the issue persists, consult with your database administrator to check for any database-level locks or issues.
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with transaction codes like SM12 (lock entries), SM21 (system log), and ST22 (dump analysis) to diagnose issues.
  SAP Notes: Check the SAP Support Portal for any relevant SAP Notes that may address this specific error or provide additional troubleshooting steps.
  Documentation: Review SAP documentation related to data management and locking mechanisms to better understand how locks are handled in your specific context.
  
  If the problem continues after trying the above solutions, it may be beneficial to engage SAP support for further assistance.