How To Fix DB6123 - Number of lock waits per hour

SAP Error Message - Details

• Message type: E = Error

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

• Message number: 123

• Message text: Number of lock waits per hour

What causes this issue?

All wait situations are included here, including
<DS:NA.DB6115>Deadlocks</> and <DS:NA.DB6121>Lock timeouts</>. In
general, these are the situations in which an application (and
therefore also a work process) must wait for another applications
(another work process) to be able to execute further commands.

System Response

Reduction of performance

How to fix this error?

You should perform a more detailed analysis of the applications (who is
locking, what is locked?), if the system develops performance
bottlenecks due to wait situations occurring too frequently. In this
context, note also the note of lock escalations, as these can also lead
to lock situations.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message DB6123 - Number of lock waits per hour ?

  The SAP error message DB6123 indicates that the number of lock waits per hour has exceeded a predefined threshold. This situation typically arises in database systems when multiple transactions are trying to access the same data concurrently, leading to contention and delays.
  Cause:
  
  High Contention for Resources: Multiple transactions are trying to access the same database records simultaneously, leading to lock waits.
  Long-Running Transactions: If transactions take a long time to complete, they can hold locks for extended periods, causing other transactions to wait.
  Inefficient Queries: Poorly optimized SQL queries can lead to longer execution times and increased lock contention.
  Database Configuration: Inadequate database configuration settings for handling concurrent transactions can exacerbate lock waits.
  Application Logic: Inefficient application logic that leads to unnecessary locking of resources.
  
  Solution:
  
  Analyze Lock Waits: Use database monitoring tools to analyze which transactions are causing lock waits. Identify the specific tables and rows involved.
  Optimize Queries: Review and optimize SQL queries to ensure they run as efficiently as possible. Use indexes where appropriate to speed up data access.
  Reduce Transaction Duration: Break long-running transactions into smaller, more manageable units of work. This can help reduce the time locks are held.
  Increase Lock Timeout: If appropriate, consider increasing the lock timeout settings in the database to allow transactions to wait longer before failing.
  Review Application Logic: Ensure that the application logic is designed to minimize locking. For example, avoid locking resources unnecessarily or holding locks for longer than needed.
  Database Configuration: Review and adjust database configuration settings to better handle concurrent transactions. This may include tuning parameters related to locking and transaction management.
  Implement Retry Logic: In the application, implement retry logic for transactions that fail due to lock waits, allowing them to attempt execution again after a short delay.
  
  Related Information:
  
  Monitoring Tools: Use SAP transaction codes like SM12 (to view locks) and SM21 (to view system logs) to monitor and analyze lock situations.
  Database-Specific Tools: Depending on the database (e.g., Oracle, SQL Server, HANA), use specific monitoring tools to analyze lock contention and performance.
  SAP Notes: Check SAP Notes for any known issues or patches related to lock waits and performance tuning.
  Performance Tuning: Regularly perform database performance tuning and maintenance to ensure optimal operation.
  
  By addressing the underlying causes of lock waits and implementing the suggested solutions, you can reduce the occurrence of the DB6123 error and improve overall system performance.