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

How PostgreSQL handles persistency and consistency: WALs

In the previous sections, you have seen how to interact with explicit transactions, and most notably how PostgreSQL executes every single statement within a transaction.

PostgreSQL goes to a lot of effort internally to ensure that consolidated data on storage reflects the status of the committed transactions. In other words, data can be considered consolidated only if the transaction that produced (or modified) it has been committed. But this also means that, once a transaction has been committed, its data is "safe" on storage, no matter what happens in the future.

PostgreSQL manages transactions and data consolidations by means of Write-Ahead Logs (WALs). This section introduces you to the concept of WALs and their use within PostgreSQL.

Write-Ahead Logs (WALs)

Before we dig into the details, it is required to briefly explain how PostgreSQL internally handles data. Tuples are stored in mass storage – usually, a...