Book Image

Learn PostgreSQL

By : Luca Ferrari, Enrico Pirozzi
Book Image

Learn PostgreSQL

By: Luca Ferrari, Enrico Pirozzi

Overview of this book

PostgreSQL is one of the fastest-growing open source object-relational database management systems (DBMS) in the world. As well as being easy to use, it’s scalable and highly efficient. In this book, you’ll explore PostgreSQL 12 and 13 and learn how to build database solutions using it. Complete with hands-on tutorials, this guide will teach you how to achieve the right database design required for a reliable environment. You'll learn how to install and configure a PostgreSQL server and even manage users and connections. The book then progresses to key concepts of relational databases, before taking you through the Data Definition Language (DDL) and commonly used DDL commands. To build on your skills, you’ll understand how to interact with the live cluster, create database objects, and use tools to connect to the live cluster. You’ll then get to grips with creating tables, building indexes, and designing your database schema. Later, you'll explore the Data Manipulation Language (DML) and server-side programming capabilities of PostgreSQL using PL/pgSQL, before learning how to monitor, test, and troubleshoot your database application to ensure high-performance and reliability. By the end of this book, you'll be well-versed with the Postgres database and be able to set up your own PostgreSQL instance and use it to build robust solutions.
Table of Contents (27 chapters)
Section 1: Getting Started
Section 2: Interacting with the Database
Section 3: Administering the Cluster
Section 4: Replication
Section 5: The PostegreSQL Ecosystem

Exploring the pg_trgm extension

In previous chapters, we talked about query optimization and indexing. When we talked about indexing, we learned how to make our queries faster through the use of indices. However, B-tree indices do not index all types of operations. Now let's consider textual data types (char, varchar, or text). We have seen that the B-tree, using the varchar_pattern_ops opclass, is able to index like operations only as regards the 'search%' type queries, but it is not able to index queries with a where condition of the '%search' or 'search%' type:

  1. Before diving into our example, let's do set enable_seqscan to 'off' in order to force PostgreSQL to use any index if it exists. We need to do this because, in our example case, PostgreSQL would always use sequential scanning, because we have less data in our table and all data that is present in the table is stored on a single page:
db_source=# set enable_seqscan to &apos...