Oracle SQL Tuning with Oracle SQLTXPLAINOracle SQL Tuning with SQLTXPLAIN is a practical guide to SQL tuning the way Oracle's own experts do it, using a freely downloadable tool called SQLTXPLAIN. Using this simple tool you'll learn how to tune even the most complex SQL, and you'll learn to do it quickly, without the huge learning curve usually associated with tuning as a whole.
Firmly based in real world problems, this book helps you reclaim system resources and avoid the most common bottleneck in overall performance, badly tuned SQL. You'll learn how the optimizer works, how to take advantage of its latest features, and when it's better to turn them off. Quickly tune any SQL statement no matter how complex. Build and tune test cases without affecting production. Use the latest tuning features with confidence. What you’ll learn How and why complex SQL goes wrong When statistics are crucial and when they are not How and when the tuning facilities of the database can help or hinder When to tune and when not to tune Which steps in an execution plan are crucial to performance How the optimizer works out the execution plan Who this book is forOracle SQL Tuning with SQLTXPLAIN is ideal for everyone who deals with SQL and SQL tuning. Both developers and DBA's will benefit from learning how to use the SQLTXPLAIN tool along with the problem solving approach described in this book. Table of Contents1. Introduction to SQLTXPLAIN2. The Cost-Based Optimizer Environment 3. How Object Statistics Can Make Your Execution Plan Wrong 4. How Skewness Can Make Your Execution Times Variable 5. Troubleshooting Query Transformations 6. Forcing Execution Plans Through Profiles 7. Adaptive Cursor Sharing 8. Dynamic Sampling and Cardinality Feedback 9. Using SQLTXPLAIN with Data Guard Physical Standby Databases 10. Comparing Execution Plans 11. Building Good Test Cases 12. Using XPLORE to Investigate Unexpected Plan Changes 13. Trace Files, TRCANLZR, and Modifying SQLT Behavior 14. Running a Health Check 15. The Final Word 16. Appendix A. Installing SQLTXPLAIN 17. Appendix B. The CBO Parameters (11.2.0.1) 18. Appendix C: Tool Configuration Parameters
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Contents
Chapter 1 Introduction to SQLTXPLAIN | 1 |
Chapter 2 The CostBased Optimizer Environment | 17 |
Chapter 3 How Object Statistics Can Make Your Execution Plan Wrong | 39 |
Chapter 4 How Skewness Can Make Your Execution Times Variable | 53 |
Chapter 5 Troubleshooting Query Transformations | 71 |
Chapter 6 Forcing Execution Plans Through Profiles | 93 |
Chapter 7 Adaptive Cursor Sharing | 111 |
Chapter 8 Dynamic Sampling and Cardinality Feedback | 129 |
Chapter 9 Using SQLTXPLAIN with Data Guard Physical Standby Databases | 147 |
Chapter 10 Comparing Execution Plans | 163 |
Chapter 11 Building Good Test Case s | 177 |
Chapter 12 Using XPLORE to Investigate Unexpected Plan Changes | 205 |
Chapter 13 Trace Files TRCANLZR and Modifying SQLT behavior | 231 |
About the Technical Reviewer | xvii |
Acknowledgments | xix |
Foreword | xx |