This book provides a practical guide to Oracle’s diagnostic triad: AWR, ASH, and ADDM. It teaches you how to read the reports produced by these tools and how to go beyond formatted reports by querying the underlying diagnostic views directly with SQL. This direct-query approach gives you incredible flexibility and enables targeted analysis with great precision.

Built on decades of consulting experience, this book provides practical scripts and real-world cases that demonstrate a repeatable diagnostic workflow. Start with AWR to understand the overall performance landscape and identify symptoms. Use ASH to validate hypotheses and drill down to precise root causes at the session, SQL, or object level. Use ADDM as a supplementary source of guidance to support and refine the investigation.

What You Will Learn

• Interpret the mechanics behind AWR snapshots, ASH sampling, and ADDM findings.
• Detect anomalies by focusing on a few key sections instead of reading the entire AWR report.
• Measure overall database health using AWR, ASH, and ADDM reports.
• Query raw ASH, AWR, and ADDM view data directly with SQL.
• Leverage AWR, ASH, and ADDM together to troubleshoot Oracle performance issues.
• Develop a reusable SQL toolkit for Oracle performance diagnostics.

Who This Book Is For:

Database administrators, consultants, and system architects who need practical, evidence-based Oracle performance diagnostics using ASH, AWR and ADDM, suitable for intermediate-to-advanced readers

Yuan Yao has been working with Oracle databases since 1990. Most of his career has been spent as a database consultant, helping clients troubleshoot complex issues, optimize performance, and architect large-scale database systems for enterprise environments. He currently serves as Chief DBA at Scutech, a leading data management company in China with a client base exceeding 20,000.

Yuan holds more than 20 Oracle certifications, including Oracle Certified Master (OCM) versions 10g through 19c. He has been honored as an Oracle ACE and a Huawei Cloud Most Valuable Professional. Additionally, he is the inventor of two computer patents and the recipient of two ministerial-level awards. He is the author of MySQL 8.0 Operations and Optimization (Tsinghua University Press), a widely referenced guide among Chinese database professionals.