Book Image

PostgreSQL 14 Administration Cookbook

By : Simon Riggs, Gianni Ciolli
5 (1)
Book Image

PostgreSQL 14 Administration Cookbook

5 (1)
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 14 allows you to scale up your PostgreSQL infrastructure. With this book, you'll take a step-by-step, recipe-based approach to effective PostgreSQL administration. This book will get you up and running with all the latest features of PostgreSQL 14 while helping you explore the entire database ecosystem. You’ll learn how to tackle a variety of problems and pain points you may face as a database administrator such as creating tables, managing views, improving performance, and securing your database. As you make progress, the book will draw attention to important topics such as monitoring roles, validating backups, regular maintenance, and recovery of your PostgreSQL 14 database. This will help you understand roles, ensuring high availability, concurrency, and replication. Along with updated recipes, this book touches upon important areas like using generated columns, TOAST compression, PostgreSQL on the cloud, and much more. By the end of this PostgreSQL book, you’ll have gained the knowledge you need to manage your PostgreSQL 14 database efficiently, both in the cloud and on-premise.
Table of Contents (14 chapters)

Knowing when a table was last used

Once you know that a table is not currently being used, the next question is, When was it last used?

Getting ready

You need to use a user with appropriate privileges.

How to do it…

PostgreSQL does not have any built-in last used information about tables, so you have to use other means to figure it out.

If you have set up a cron job to collect usage statistics, as described in the previous chapter, then it is relatively easy to find out the last date of change using a SQL query.

Other than this, there are two possibilities, neither of which give you reliable answers.

You can either look at the actual timestamps of the files that the data is stored in, or you can use the xmin and xmax system columns to find out the latest transaction ID that changed the table data.

In this recipe, we will cover the first case and focus on the date information in the table&apos...