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
Credits
About the Author
About the Reviewer
www.Packtpub.com
Customer Feedback
Preface

Optimizing foreign table access


If you read the end of the previous recipe, you might assume we don't recommend that you use foreign tables at all. However, we would like to reassure you that foreign tables are not all doom and gloom. To prove it, we're going to use a disarmingly simple technique to optimize them: views.

It's true that PostgreSQL foreign data wrappers cannot combine queries for multiple tables on the same server. Provided we have access to the remote server, we can rectify this situation by creating a view to encapsulate the core of the query we want to perform. We can do this because PostgreSQL only knows the name of remote objects, not their composition. We can take advantage of this and use views to force remote joins.

In this recipe, we will describe how to use a remote view in place of a foreign table.

Getting ready

As we will be using the pgbench_accounts foreign table in this recipe, please follow all the previous recipes before proceeding.

How to do it...

For this recipe...