Write optimized queries. This book helps you write queries that perform fast and deliver results on time. You will learn that query optimization is not a dark art practiced by a small, secretive cabal of sorcerers. Any motivated professional can learn to write efficient queries from the get-go and capably optimize existing queries. You will learn to look at the process of writing a query from the database engine’s point of view, and know how to think like the database optimizer.

The book begins with a discussion of what a performant system is and progresses to measuring performance and setting performance goals. It introduces different classes of queries and optimization techniques suitable to each, such as the use of indexes and specific join algorithms. You will learn to read and understand query execution plans along with techniques for influencing those plans for better performance. The book also covers advanced topics such as the use of functions and procedures, dynamic SQL, and generated queries. All of these techniques are then used together to produce performant applications, avoiding the pitfalls of object-relational mappers.

This second edition includes new examples using Postgres 15 and the newest version of the PostgresAir database. It includes additional details and clarifications about advanced topics, and covers configuration parameters in greater depth. Finally, it makes use of advancements in NORM, using automatically generated functions.

You will:

• Identify optimization goals in OLTP and OLAP systems
• Read and understand PostgreSQL execution plans
• Distinguish between short queries and long queries
• Choose the right optimization technique for each query type
• Identify indexes that will improve query performance
• Optimize full table scans
• Avoid the pitfalls of object-relational mapping systems
• Optimize the entire application rather than just database queries

Table of Contents

Chapter 1: Why Optimize?

Chapter 2: Theory: Yes, We Need It!

Chapter 3: Even More Theory: Algorithms

Chapter 4: Understanding Execution Plans

Chapter 5: Short Queries and Indexes

Chapter 6: Long Queries and Full Scans

Chapter 7: Long Queries: Additional Techniques

Chapter 8: Optimizing Data Modification

Chapter 9: Design Matters

Chapter 10: What About Configuration Parameters?

Chapter 11: Application Development and Performance

Chapter 12: Functions

Chapter 13: Dynamic SQL

Chapter 14: Avoiding the Pitfalls of Object-Relational Mapping

Chapter 15: More Complex Filtering and Search

Chapter 16: Ultimate Optimization Algorithm

Chapter 17: Conclusion

About the Authors

Henrietta Dombrovskaya is a database researcher and developer with over 40 years of academic and industrial experience. She holds a PhD in Computer Science from the University of Saint Petersburg, Russia. At present, she is a Database Architect at DRW Holdings, Chicago, Illinois. She is an active member of the PostgreSQL community, a frequent speaker at the PostgreSQL conference, and the local organizer of the Chicago PostgreSQL User Group. Her research interests are tightly coupled with practice and are focused on developing efficient interactions between applications and databases.

Boris Novikov's experience includes leading post-graduate research groups and advising dozens of PhD students, while partnering and collaborating with industrial clients. His research interests are in the broad area of information management and include design, development, and tuning of databases, applications, and database management systems (DBMSs). He also has interests in distributed scalable systems for stream processing and analytics..

Anna Bailliekova is Senior Data Engineer at UrbanFootprint, where she works on data platform tools and cloud ops for geospatial applications. Previously, she worked in data engineering at Zendesk, and held a variety of DBA and BI roles at Epic. Her writing can be found in the newsletter Better Streets MKE. She received her undergraduate degree with College Honors in Political Science and Computer Science from Knox College in Galesburg, Illinois.