Book Image

PostgreSQL 10 Administration Cookbook - Fourth Edition

By : Simon Riggs, Gianni Ciolli
Book Image

PostgreSQL 10 Administration Cookbook - Fourth Edition

By: Simon Riggs, Gianni Ciolli

Overview of this book

PostgreSQL is a powerful, open source database management system with an enviable reputation for high performance and stability. With many new features in its arsenal, PostgreSQL 10 allows users to scale up their PostgreSQL infrastructure. This book takes a step-by-step, recipe-based approach to effective PostgreSQL administration. Throughout this book, you will be introduced to these new features such as logical replication, native table partitioning, additional query parallelism, and much more. You will learn how to tackle a variety of problems that are basically the pain points for any database administrator - from creating tables to managing views, from improving performance to securing your database. More importantly, the book pays special attention to topics such as monitoring roles, backup, and recovery of your PostgreSQL 10 database, ensuring high availability, concurrency, and replication. By the end of this book, you will know everything you need to know to be the go-to PostgreSQL expert in your organization.
Table of Contents (14 chapters)

Finding unused indexes

Selecting the correct set of indexes for a workload is known to be a hard problem. It usually involves trial and error by developers and DBAs to get a good mix of indexes.

Tools for identifying slow queries exist, and many SELECT statements can be improved by the addition of an index.

What many people forget is to check whether the mix of indexes remains valuable over time, which is something for the DBA to investigate and optimize.

How to do it...

PostgreSQL keeps track of each access against an index. We can view that information and use it to see whether an index is unused, as follows:

postgres=# SELECT schemaname, relname, indexrelname, idx_scan FROM pg_stat_user_indexes ORDER BY idx_scan;
schemaname...