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


Up until now, we've performed a great deal of preliminary work. We know the proper settings, we can create replicas in our sleep, and have all the skills necessary to troubleshoot and fix a misbehaving server or two. Yet we're still missing one critical element to truly achieve high availability: automation.

Many of the recipes in previous chapters cover utilities that are almost automated. We learned how to combine PgBouncer and pgpool in the Chapter 3, Pooling Resources, for example. The Replication chapter got us even further, giving us the necessary tools to maintain a veritable army of alternate servers for primary substitution at a moment's notice.

But we still need manual intervention. We don't want a central point of failure, so pgpool and PgBouncer must run on all candidate servers. Only one of these is writable, so we have a virtual IP address or CNAME that needs to be reassigned to a promoted replica. Given three PostgreSQL servers, the best stack we could produce with...