How To Fix /SDF/DB6121 - Number of lock timeouts per hour

SAP Error Message - Details

• Message type: E = Error

• Message class: /SDF/DB6 -

• Message number: 121

• Message text: Number of lock timeouts per hour

Self-Explanatory Message

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Smart SAP Assistant

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

  The SAP error message /SDF/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 may not be optimized for the workload, leading to increased lock contention.
  Application Logic: Inefficient application logic that leads to unnecessary locking of resources.
  
  Solution:
  
  Analyze Lock Contention: Use transaction codes like SM12 (to view locks) and SM21 (to check system logs) to identify which transactions are causing the lock timeouts.
  Optimize Transactions: Review and optimize long-running transactions to ensure they complete as quickly as possible. This may involve breaking them into smaller units of work.
  Improve Query Performance: Analyze and optimize SQL queries to reduce execution time. Use transaction codes like ST05 (SQL Trace) to identify slow queries.
  Adjust Lock Timeout Settings: If appropriate, consider increasing the lock timeout settings in the database configuration. However, this should be done cautiously, as it may mask underlying issues.
  Review Application Logic: Ensure that the application logic is designed to minimize locking. For example, avoid locking resources unnecessarily and consider using optimistic locking where appropriate.
  Database Tuning: Work with your database administrator to tune the database settings for better performance and reduced contention.
  Monitor and Alert: Set up monitoring and alerting for lock timeouts to proactively address issues before they impact users.
  
  Related Information:
  
  SAP Notes: Check SAP Notes related to lock timeouts and performance tuning for specific recommendations and patches.
  Performance Monitoring Tools: Utilize SAP's performance monitoring tools (like ST03N) to analyze workload and identify bottlenecks.
  Database Documentation: Refer to the documentation for your specific database (e.g., HANA, Oracle, SQL Server) for best practices on managing locks and optimizing performance.
  
  By addressing the underlying causes of lock contention and optimizing both the application and database configurations, you can reduce the occurrence of lock timeouts and improve overall system performance.