Book Image

Mastering PostgreSQL 9.6

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 9.6

By: Hans-Jürgen Schönig

Overview of this book

PostgreSQL is an open source database used for handling large datasets (Big Data) and as a JSON document database. It also has applications in the software and web domains. This book will enable you to build better PostgreSQL applications and administer databases more efficiently. We begin by explaining the advanced database design concepts in PostgreSQL 9.6, along with indexing and query optimization. You will also see how to work with event triggers and perform concurrent transactions and table partitioning, along with exploring SQL and server tuning. We will walk you through implementing advanced administrative tasks such as server maintenance and monitoring, replication, recovery and high availability, and much more. You will understand the common and not-so-common troubleshooting problems and how you can overcome them. By the end of this book, you will have an expert-level command of the advanced database functionalities and will be able to implement advanced administrative tasks with PostgreSQL.
Table of Contents (14 chapters)
Free Chapter
PostgreSQL Overview

Understanding basic locking

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

To show how things work, a simple table can be created. For demonstration purposes, I will add one row to the table:

test=# CREATE TABLE t_test (id int); 
test=# INSERT INTO t_test VALUES (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 problems.

Multiple users can read the same data at the same time without blocking each other.

The question now is: what happens if reads and writes occur at the same time? Here is an example:

Transaction 1

Transaction 2



UPDATE t_test SET id = id + 1 RETURNING *;
User will...