Book Image

Mastering PostgreSQL 15 - Fifth Edition

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 15 - Fifth Edition

By: Hans-Jürgen Schönig

Overview of this book

Starting with an introduction to the newly released features of PostgreSQL 15, this updated fifth edition will help you get to grips with PostgreSQL administration and how to build dynamic database solutions for enterprise apps, including designing both physical and technical aspects of the system. You'll explore advanced PostgreSQL features, such as logical replication, database clusters, advanced indexing, and user management to manage and maintain your database. You'll then work with the PostgreSQL optimizer, configure PostgreSQL for high speed, and move from Oracle to PostgreSQL. Among the other skills that the book will help you build, you’ll cover transactions, handling recursions, working with JSON and JSONB data, and setting up a Patroni cluster. It will show you how to improve performance with query optimization. You'll also focus on managing network security and work with backups and replication while exploring useful PostgreSQL extensions that optimize the performance of large databases. By the end of this PostgreSQL book, you’ll be able to use your database to its utmost capacity by implementing advanced administrative tasks with ease.
Table of Contents (16 chapters)

Understanding PostgreSQL index types

So far, only binary trees have been discussed. However, in many cases, B-trees are just not enough. Why is that? As we’ve already discussed in this chapter, B-trees are basically based on sorting. The <, <=, =, >=, and > operators can be handled using B-trees. The trouble is that not every data type can be sorted in a useful way. Just imagine a polygon. How would you sort these objects in a useful way? Sure, you can sort by the area covered, its length, and so on, but doing this won’t allow you to find them using a geometric search.

The solution to this problem is to provide more than just one index type. Each index will serve a special purpose and do exactly what is needed. The following six index types are available (as of PostgreSQL 10.0):

test=# SELECT * FROM pg_am;
  oid | amname |       amhandler      | amtype
------+--------+-------...