Book Image

Mastering PostgreSQL 9.6

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 9.6

By: Hans-Jürgen Schönig

Overview of this book

PostgreSQL is an open source database used for handling large datasets (Big Data) and as a JSON document database. It also has applications in the software and web domains. This book will enable you to build better PostgreSQL applications and administer databases more efficiently. We begin by explaining the advanced database design concepts in PostgreSQL 9.6, along with indexing and query optimization. You will also see how to work with event triggers and perform concurrent transactions and table partitioning, along with exploring SQL and server tuning. We will walk you through implementing advanced administrative tasks such as server maintenance and monitoring, replication, recovery and high availability, and much more. You will understand the common and not-so-common troubleshooting problems and how you can overcome them. By the end of this book, you will have an expert-level command of the advanced database functionalities and will be able to implement advanced administrative tasks with PostgreSQL.
Table of Contents (14 chapters)
Free Chapter
PostgreSQL Overview

Understanding and fixing joins

Joins are an important thing; everybody needs them on a regular basis. Consequently, joins are also relevant to maintaining or achieving good performance. To ensure that you can write good joins, I have decided to include a section about joining into this book.

Getting joins right

Before we dive into optimizing joins, it is important to take a look at some of the most common problems arising with joins and which should ring alarm bells to you.

Here is an example:

test=# CREATE TABLE a (aid int); 
test=# CREATE TABLE b (bid int);
test=# INSERT INTO a VALUES (1), (2), (3);
test=# INSERT INTO b VALUES (2), (3), (4);

In the next example, you will see a simple outer join:

test=# SELECT * FROM...