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)

Placing query output into psql variables

It is also possible to store some values produced by a query into variables, for instance to reuse them later in other queries.

In this recipe we demonstrate this approach with a concrete example.

Getting ready

In recipe Controlling automatic database maintenance of Chapter 9, Regular Maintenance, we describe VACUUM, showing that it runs regularly on each table based on the number of rows that might need vacuuming ("dead rows"). VACUUM will run if that number exceeds a given threshold, which by default is just above 20% of the row count.

In this recipe we create a script that picks the table with the largest number of dead rows, and runs VACUUM on it.