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


PostgreSQL exploits MVCC to enable high concurrent access to the underlying data, and this means that every transaction perceives a snapshot of the data while the system keeps different versions of the same tuples. Sooner or later, invalid tuples will be removed and the storage space will be reclaimed. On one hand, MVCC provides better concurrency, but on the other hand, it requires extra effort to reclaim the storage space once transactions no longer reference dead tuples. PostgreSQL provides VACUUM with this aim and also has a background process named autovacuum to periodically and non-invasively reclaim storage space and keep the system clean and healthy.

In order to improve I/O and reliability, PostgreSQL stores data in a journal written sequentially, the WAL. The WAL is split into segments, and at particular time intervals, named checkpoints, all the dirty data in memory is forced to a specified position in the storage and WAL segments are recycled.

In this chapter, you have...