Book Image

PostgreSQL High Performance Cookbook

By : Chitij Chauhan, Dinesh Kumar
Book Image

PostgreSQL High Performance Cookbook

By: Chitij Chauhan, Dinesh Kumar

Overview of this book

PostgreSQL is one of the most powerful and easy to use database management systems. It has strong support from the community and is being actively developed with a new release every year. PostgreSQL supports the most advanced features included in SQL standards. It also provides NoSQL capabilities and very rich data types and extensions. All of this makes PostgreSQL a very attractive solution in software systems. If you run a database, you want it to perform well and you want to be able to secure it. As the world’s most advanced open source database, PostgreSQL has unique built-in ways to achieve these goals. This book will show you a multitude of ways to enhance your database’s performance and give you insights into measuring and optimizing a PostgreSQL database to achieve better performance. This book is your one-stop guide to elevate your PostgreSQL knowledge to the next level. First, you’ll get familiarized with essential developer/administrator concepts such as load balancing, connection pooling, and distributing connections to multiple nodes. Next, you will explore memory optimization techniques before exploring the security controls offered by PostgreSQL. Then, you will move on to the essential database/server monitoring and replication strategies with PostgreSQL. Finally, you will learn about query processing algorithms.
Table of Contents (19 chapters)
PostgreSQL High Performance Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Control bloat using transaction age


In this recipe, we will be discussing how to control the generation of dead tuples using the snapshot threshold setting.

Getting ready

In earlier versions of PostgreSQL, the old version of a tuple could be visible to the snapshot until the transaction was completed. Once the tuple was not visible to any of the active transactions, then it would be removed logically by the autovacuum process. Also, we cannot limit the age of a transaction snapshot as we can in other database management systems. If we can restrict the age of a transaction, then we can prevent generating multiple versions of the tuples by throwing the snapshot too old error. This means that, if a transaction holds a set of tuples that were modified some time ago, then that transaction should not progress further. In PostgreSQL 9.6, we can achieve this by configuring the old_snapshot_threshold parameter.

How to do it...

To demonstration this feature, let us execute the following query and then...