How To Fix W#511 - External lock while locking lock object &2 and key &3 &4

SAP Error Message - Details

• Message type: E = Error

• Message class: W# -

• Message number: 511

• Message text: External lock while locking lock object &2 and key &3 &4

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

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Smart SAP Assistant

• What is the cause and solution for SAP error message W#511 - External lock while locking lock object &2 and key &3 &4 ?

  The SAP error message W#511 indicates that there is an issue with acquiring a lock on a specific lock object. This typically occurs when a program or transaction attempts to lock a resource that is already locked by another process. Here’s a breakdown of the cause, potential solutions, and related information for this error:
  Cause:
  
  Concurrent Access: The most common cause of this error is that another transaction or program is currently holding a lock on the same object and key. SAP uses locks to ensure data consistency during updates.
  Long-Running Transactions: If a transaction takes too long to complete, it may hold onto locks longer than expected, causing other transactions to fail when they try to acquire the same lock.
  Deadlocks: In some cases, a deadlock situation may arise where two or more transactions are waiting for each other to release locks, leading to this error.
  Lock Table Overflow: If the lock table is full, new lock requests may be denied, leading to this error.
  
  Solutions:
  
  Wait and Retry: If the error is due to a temporary lock, waiting for a few moments and then retrying the operation may resolve the issue.
  Identify Lock Holders: Use transaction codes like SM12 (Display and Delete Locks) to identify which user or process is holding the lock. You can then decide whether to wait for it to release or take action to terminate it if necessary.
  Optimize Long Transactions: Review the code or process that is holding the lock for an extended period. Optimize it to ensure that locks are held for the shortest time possible.
  Increase Lock Table Size: If the lock table is frequently full, consider increasing its size. This can be done by adjusting the profile parameters in the SAP system.
  Check for Deadlocks: Use transaction SM21 (System Log) to check for any deadlock situations and analyze the logs to understand the cause.
  Code Review: If the error is occurring in custom code, review the locking logic to ensure that locks are being managed correctly.
  
  Related Information:
  
  Lock Objects: In SAP, lock objects are defined in the Data Dictionary (SE11) and are used to manage concurrent access to database records.
  Lock Management: Understanding how SAP handles locks can help in troubleshooting. Locks can be exclusive (write locks) or shared (read locks).
  Transaction Codes:
  
  SM12: To view and manage locks.
  SM21: To view system logs for error analysis.
  SE11: To view and manage lock objects.
  
  
  
  If the issue persists after trying the above solutions, it may be necessary to involve your SAP Basis team or consult SAP support for further assistance.