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)

Always knowing which user is logged in

In the preceding recipes, we just logged the value of the user variable in the current PostgreSQL session to log the current user role.

This does not always mean that this particular user was the user that was actually authenticated at the start of the session. For example, a superuser can execute the SET ROLE TO ... command to set its current role to any other user or role in the system. As you might expect, non-superusers can only assume roles that they own.

It is possible to differentiate between the logged-in role and the assumed role using the current_user and session_user session variables:

postgres=# select current_user, session_user;
current_user | session_user
-------------+--------------
postgres     | postgres 
postgres=# set role to bob;
SET
postgres=> select current_user, session_user;
current_user | session_user
-------------+--------------
bob        ...