Article: Transferring SQL Execution Plans in Oracle 19c

Performance tuning is a critical responsibility for Oracle database administrators, ensuring that SQL queries run efficiently across various environments. This guide details how to copy an SQL execution plan from one Oracle 19c database to another, a practical solution when a query performs inconsistently across environments.

Why Copying SQL Execution Plans is Crucial

Imagine a scenario where a query runs efficiently in a staging environment but performs poorly in production. In such cases, transferring the execution plan can resolve performance issues without the need to modify the SQL code. This approach can save time and effort while maintaining query integrity across different databases.

Steps to Copy SQL Execution Plans in Oracle 19c

• Identify the SQL Statement: Begin by identifying the SQL statement for which you want to copy the execution plan. This could be a complex query that is not performing optimally in the target database.

• Generate the Execution Plan: Use the `DBMS_XPLAN.DISPLAY_CURSOR` function to generate the execution plan for the identified SQL statement in the source database. This function provides a detailed breakdown of the steps involved in executing the query.

• Export the Execution Plan: Once you have the execution plan, export it using tools like SQL Developer or by querying the `V$SQL_PLAN` view. This step ensures that you have a clear record of the execution plan that needs to be transferred.

• Transfer the Plan to the Target Database: To transfer the execution plan to the target database, you can use tools like Data Pump or manually execute the `EXPLAIN PLAN FOR` statement in the target database with the execution plan obtained from the source.

• Verify and Implement: Finally, verify that the execution plan has been successfully copied to the target database by checking the plan using `DBMS_XPLAN.DISPLAY_CURSOR` in the target environment. Implement the copied plan and monitor the query performance to ensure improvements.

Conclusion

Copying SQL execution plans from one Oracle 19c database to another is a valuable technique in performance tuning, especially when dealing with queries that exhibit varying performance across environments. By following the outlined steps, database administrators can streamline the process of optimizing query performance without the need for extensive code modifications.

In conclusion, mastering the art of transferring execution plans can significantly enhance the efficiency and reliability of SQL queries in Oracle databases, ultimately leading to improved performance and user satisfaction.