Book Image

PostgreSQL High Availability Cookbook - Second Edition

By : Shaun Thomas
Book Image

PostgreSQL High Availability Cookbook - Second Edition

By: Shaun Thomas

Overview of this book

Databases are nothing without the data they store. In the event of a failure - catastrophic or otherwise - immediate recovery is essential. By carefully combining multiple servers, it’s even possible to hide the fact a failure occurred at all. From hardware selection to software stacks and horizontal scalability, this book will help you build a versatile PostgreSQL cluster that will survive crashes, resist data corruption, and grow smoothly with customer demand. It all begins with hardware selection for the skeleton of an efficient PostgreSQL database cluster. Then it’s on to preventing downtime as well as troubleshooting some real life problems that administrators commonly face. Next, we add database monitoring to the stack, using collectd, Nagios, and Graphite. And no stack is complete without replication using multiple internal and external tools, including the newly released pglogical extension. Pacemaker or Raft consensus tools are the final piece to grant the cluster the ability to heal itself. We even round off by tackling the complex problem of data scalability. This book exploits many new features introduced in PostgreSQL 9.6 to make the database more efficient and adaptive, and most importantly, keep it running.
Table of Contents (18 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback

Listing PgBouncer server connections

PgBouncer provides an administration console to view pool status or control the service. For now, we will focus on viewing the list of server connections that PgBouncer maintains. These connections are held for distribution to database clients as necessary, and they can tell us much more about the health of the pool. Let's explore the PgBouncer console a bit.

Getting ready

We need to know how to connect to PgBouncer instead of PostgreSQL, so check the Connect to PgBouncer recipe for a refresher. In this section, we will use something known as a pseudo-database. When in use, PgBouncer reserves the database name pgbouncer for its own internal purposes to access its administration console. This database does not actually exist, but it will still connect from the perspective of our PostgreSQL client.

In the highly unlikely event that the pgbouncer database actually exists within your PostgreSQL installation, we recommend renaming it to avoid confusion.

How to...