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)

Restricting users to only one session each

If resources need to be closely controlled, you may wish to restrict users so that they can only connect to the server once, at most. The same technique can be used to prevent connections entirely for that user.

How to do it...

We can restrict users to only one connection using the following command:

postgres=# ALTER ROLE fred CONNECTION LIMIT 1;
ALTER ROLE

This will then cause any additional connections to receive the following error message:

FATAL: too many connections for role "fred".

You can eliminate this restriction by setting the value to -1.

It's possible to set the limit to zero or any positive integer. You can set this to a number other than max_connections...