Book Image

Mastering PostgreSQL 12 - Third Edition

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 12 - Third Edition

By: Hans-Jürgen Schönig

Overview of this book

Thanks to its reliability, robustness, and high performance, PostgreSQL has become the most advanced open source database on the market. This third edition of Mastering PostgreSQL helps you build dynamic database solutions for enterprise applications using the latest release of PostgreSQL, which enables database analysts to design both physical and technical aspects of system architecture with ease. Starting with an introduction to the newly released features in PostgreSQL 12, this book will help you build efficient and fault-tolerant PostgreSQL applications. You’ll thoroughly examine the advanced features of PostgreSQL, including logical replication, database clusters, performance tuning, monitoring, and user management. You’ll also work with the PostgreSQL optimizer, configure PostgreSQL for high speed, and understand how to move from Oracle to PostgreSQL. As you progress through the chapters, you’ll cover transactions, locking, indexes, and how to optimize queries for improved performance. Additionally, you’ll learn how to manage network security and explore backups and replications while understanding useful PostgreSQL extensions to help you in optimizing the performance of large databases. By the end of this PostgreSQL book, you’ll be able to get the most out of your database by implementing advanced administrative tasks effortlessly.
Table of Contents (18 chapters)
Free Chapter
1
Section 1: Basic Overview
4
Section 2: Advanced Concepts

Writing your own aggregates

In this book, you will learn about most of the on-board functions provided by PostgreSQL. However, what SQL provides might not be enough for you. The good news is that it is possible to add your own aggregates to the database engine. In this section, you will learn how that can be done.

Creating simple aggregates

For this example, the goal is to solve a very simple problem. If a customer takes a taxi, they usually have to pay for getting in the taxi—for example, 2.50. Now, let's assume that for each kilometer, the customer has to pay 2.20. The question now is, what is the total price of a trip? 

Of course, this example is simple enough to solve without a custom...