Book Image

Mastering PostgreSQL 13 - Fourth Edition

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 13 - Fourth Edition

By: Hans-Jürgen Schönig

Overview of this book

Thanks to its reliability, robustness, and high performance, PostgreSQL has become one of the most advanced open source databases on the market. This updated fourth edition will help you understand PostgreSQL administration and how to build dynamic database solutions for enterprise apps with the latest release of PostgreSQL, including designing both physical and technical aspects of the system architecture with ease. Starting with an introduction to the new features in PostgreSQL 13, this book will guide you in building efficient and fault-tolerant PostgreSQL apps. You’ll explore advanced PostgreSQL features, such as logical replication, database clusters, performance tuning, advanced indexing, monitoring, 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. The book also covers transactions, locking, and indexes, and shows you how to improve performance with query optimization. You’ll also focus on how to manage 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 get the most out of your database by executing advanced administrative tasks.
Table of Contents (15 chapters)

Understanding basic locking

In this section, you will learn about basic locking mechanisms. The goal is to understand how locking works in general and how to get simple applications right.

To show you how things work, we will create a simple table. For demonstrative purposes, I will add one row to the table using a simple INSERT command:

test=# CREATE TABLE  t_test (id int);  
CREATE TABLE 
test=# INSERT INTO t_test VALUES (0); INSERT 0 1

The first important thing is that tables can be read concurrently. Many users reading the same data at the same time won't block each other. This allows PostgreSQL to handle thousands of users without any problems.

The question now is what happens if reads and writes occur at the same time? Here is an example. Let's assume that the table contains one row and its id = 0:

Transaction 1

Transaction 2

BEGIN;

BEGIN;

UPDATE t_test SET id = id + 1 RETURNING *;

User will see 1

SELECT * FROM t_test;

User will see 0

...