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)

Using psql variables

In the previous recipe, you learned how to use the ON_ERROR_STOP variable. Here, we will show you how to work with any variable, including user-defined ones.

Getting ready

As an example, we will create a script that takes a table name as a parameter. We will keep it simple because we just want to show how variables work.

For instance, we might want to add a text column to a table and then set it to a given value. So, we must write the following lines in a file called vartest.sql:

ALTER TABLE mytable ADD COLUMN mycol text;
UPDATE mytable SET mycol = 'myval';

The script can be run as follows:

psql -f vartest.sql

How to do it…

We change vartest.sql as follows:

\set tabname mytable
\set colname mycol
\set colval 'myval'
ALTER TABLE :tabname ADD COLUMN :colname text;
UPDATE :tabname SET :colname = :'colval';

How it works…

What do these changes mean? We have defined...