How To Fix DB6121 - Number of lock timeouts per hour

SAP Error Message - Details

• Message type: E = Error

• Message class: DB6 - DB6: Alert Monitoring and Alert Configuration

• Message number: 121

• Message text: Number of lock timeouts per hour

What causes this issue?

You can set the time that an application waits for a lock in the
database configuration parameter LOCKTIMEOUT. After this wait time
expires, the system resets the waiting transaction.

System Response

Resetting a transaction is performance-critical. The actual cause of
the problem is often an application problem, in that an application
locks for too long.

How to fix this error?

We recommend the following procedure:
Identify the applications that hold the locks.
If the parameter LOCKTIMEOUT is too small, adjust it.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message DB6121 - Number of lock timeouts per hour ?

  The SAP error message DB6121 indicates that the number of lock timeouts per hour has exceeded a predefined threshold. This typically occurs in environments where multiple transactions are trying to access the same database records simultaneously, leading to contention and lock timeouts.
  Cause:
  
  High Concurrency: Multiple users or processes are trying to access the same data simultaneously, leading to lock contention.
  Long-Running Transactions: Transactions that take a long time to complete can hold locks for extended periods, increasing the likelihood of timeouts for other transactions.
  Inefficient Queries: Poorly optimized queries can lead to longer execution times, which can exacerbate locking issues.
  Database Configuration: The database settings for lock timeouts may be too low for the workload being processed.
  Application Logic: Inefficient application logic that leads to unnecessary locking or delays in releasing locks.
  
  Solution:
  
  Analyze Lock Contention: Use transaction monitoring tools to identify which transactions are causing lock contention. Tools like SAP's transaction SM12 (for lock entries) and SM21 (for system logs) can be helpful.
  Optimize Queries: Review and optimize SQL queries to ensure they run efficiently and do not hold locks longer than necessary.
  Adjust Lock Timeout Settings: If appropriate, consider increasing the lock timeout settings in the database configuration to allow for longer wait times before a timeout occurs.
  Review Transaction Logic: Analyze the application logic to ensure that transactions are as short as possible and that locks are released promptly.
  Batch Processing: If applicable, consider implementing batch processing to reduce the number of concurrent transactions that access the same data.
  Database Tuning: Work with your database administrator to tune the database for better performance and to handle concurrent access more effectively.
  
  Related Information:
  
  SAP Notes: Check SAP Notes related to DB6121 for specific recommendations or patches that may address the issue.
  Monitoring Tools: Utilize SAP's monitoring tools (like ST03N for workload analysis) to get insights into transaction performance and locking behavior.
  Database Documentation: Refer to the documentation for your specific database (e.g., Oracle, SQL Server, HANA) for best practices on managing locks and optimizing performance.
  
  By addressing the underlying causes of lock timeouts and optimizing both the application and database configurations, you can reduce the occurrence of the DB6121 error and improve overall system performance.