A physical backup is a low-level backup that's taken during the normal operations of the database cluster. Here, low-level means that the backup is somehow performed "externally" inside the backup cluster; that is, at the filesystem level.
As you already know from Chapter 10, Users, Roles, and Database Security, the database cluster requires both the data files contained in PGDATA/base and the write-ahead logs (WALs) contained in PGDATA/wal, as well as a few other files, to make the cluster work properly. The main concept, however, is that the data files and the WALs can make the cluster self-healing and recover from a crash. Hence, a physical backup performs a copy of all the cluster files and then, when the restore is required, it simulates a database crash and makes the cluster self-heal with the WALs in place.
The reason why physical backups are important is that they allow us to effectively clone a cluster, starting from the files it is...
Learn PostgreSQL
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Learn PostgreSQL
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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.
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Current Title:
Learn PostgreSQL
Table of Contents (27 chapters)
Preface
Section 1: Getting Started
Free Chapter
Introduction to PostgreSQL
Getting to Know Your Cluster
Managing Users and Connections
Section 2: Interacting with the Database
Basic Statements
Advanced Statements
Window Functions
Server-Side Programming
Triggers and Rules
Partitioning
Section 3: Administering the Cluster
Users, Roles, and Database Security
Transactions, MVCC, WALs, and Checkpoints
Extending the Database - the Extension Ecosystem
Indexes and Performance Optimization
Logging and Auditing
Backup and Restore
Configuration and Monitoring
Section 4: Replication
Physical Replication
Logical Replication
Section 5: The PostegreSQL Ecosystem
Useful Tools and Extensions
Toward PostgreSQL 13
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