L1 Level Questions

1. What is performance tuning in Oracle?

   • Explain the concept of performance tuning and its importance in Oracle databases.

2. What are some common performance issues in Oracle databases?

   • List typical performance problems such as slow queries, high CPU usage, and contention.

3. What is the role of the Oracle Optimizer?

   • Describe how the Oracle Optimizer works and its purpose in query performance.

4. What are Execution Plans and how do you obtain them?

   • Explain what an execution plan is and how to obtain it using EXPLAIN PLAN or DBMS_XPLAN.DISPLAY.

5. What is an index and how does it improve query performance?

   • Define an index and explain how it can enhance the performance of queries.

6. What are some types of indexes in Oracle?

   • List and describe different types of indexes such as B-tree, Bitmap, and Function-based indexes.

7. How do you gather statistics in Oracle?

   • Explain the purpose of gathering statistics and the basic command to gather statistics on a table.

8. What is the purpose of the tkprof utility?

   • Describe what tkprof is and how it is used in performance tuning.

9. How do you monitor the performance of an Oracle database?

   • Discuss basic tools and views such as AWR, ADDM, and V$ views used for monitoring performance.

10. What is a SQL trace and how do you enable it?

    • Explain what SQL tracing is and provide the basic commands to enable and disable it.

L2 Level Questions

1. How do you interpret an execution plan?

   • Describe how to read and understand the output of an execution plan.

2. What is the difference between soft parsing and hard parsing in Oracle?

   • Explain the concepts of soft parsing and hard parsing and their impact on performance.

3. What are bind variables and why are they important?

   • Define bind variables and discuss their benefits in preventing SQL injection and improving performance.

4. How do you use the Automatic Workload Repository (AWR) for performance tuning?

   • Describe the purpose of AWR and how to use it for identifying performance issues.

5. What is the Automatic Database Diagnostic Monitor (ADDM) and how does it assist in performance tuning?

   • Explain what ADDM is and how it provides recommendations for tuning.

6. How do you optimize a query that performs poorly?

   • Discuss the steps and considerations involved in optimizing a poorly performing query.

7. What are some common wait events and how do you address them?

   • List common wait events and describe strategies to mitigate them.

8. How do you manage and tune memory components in Oracle?

   • Explain how to configure and optimize memory components such as the SGA and PGA.

9. What is partitioning and how can it improve performance?

   • Describe the concept of partitioning and its benefits for query performance.

10. How do you use the SQL Performance Analyzer (SPA)?

    • Explain the purpose of SPA and the steps to use it for tuning SQL performance.

L3 Level Questions

1. Explain the impact of parallel execution on performance and how to configure it.

   • Discuss how parallel execution works and the considerations for configuring it to improve performance.

2. How do you perform advanced troubleshooting using ASH (Active Session History)?

   • Describe the use of ASH for in-depth performance analysis and troubleshooting.

3. What are histograms and how do they affect query optimization?

   • Explain the purpose of histograms in Oracle statistics and how they influence the optimizer.

4. How do you approach performance tuning in a multi-tenant (CDB/PDB) environment?

   • Discuss the challenges and strategies for performance tuning in a multi-tenant architecture.

5. What are materialized views and how do they help in performance tuning?

   • Define materialized views and explain how they can be used to improve query performance.

6. How do you tune a RAC (Real Application Clusters) environment for optimal performance?

   • Describe the specific considerations and techniques for tuning performance in an Oracle RAC environment.

7. How do you use Oracle Enterprise Manager for performance tuning?

   • Explain how Oracle Enterprise Manager can be leveraged for monitoring, diagnosing, and tuning database performance.

8. What are adaptive query optimization features in Oracle, and how do they enhance performance?

   • Discuss adaptive features like adaptive plans, adaptive statistics, and their impact on query performance.

9. How do you handle and optimize large data loads in Oracle?

   • Provide strategies for efficiently loading and processing large volumes of data, including the use of direct path loads and parallel processing.

10. What are some best practices for indexing strategy in a high-transactional database?

    • Outline best practices for creating and managing indexes in a database with high transaction rates to maintain optimal performance.