Book Image

Mastering PostgreSQL 10

Book Image

Mastering PostgreSQL 10

Overview of this book

PostgreSQL is an open source database used for handling large datasets (big data) and as a JSON document database. This book highlights the newly introduced features in PostgreSQL 10, and shows you how you can build better PostgreSQL applications, and administer your PostgreSQL database more efficiently. We begin by explaining advanced database design concepts in PostgreSQL 10, 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, high availability, and much more. You will understand 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 advanced database functionalities and will be able to implement advanced administrative tasks with PostgreSQL 10.
Table of Contents (15 chapters)

Working with PostgreSQL transactions

PostgreSQL provides you with a highly advanced transaction machinery that offers countless features to developers and administrators alike. In this section, it is time to look at the basic concept of transactions.

The first important thing to know is that in PostgreSQL, everything is a transaction. If you send a simple query to the server, it is already a transaction. Here is an example:

test=# \x 
Expanded display is on. 
test=# SELECT now(), now();

now | now
-------------------------------+------------------------------
2017-08-24 16:03:27.174253+02 | 2017-08-24 16:03:27.174253+02
(1 row)

In this case, the SELECT statement will be a separate transaction. If the same command is executed again, different timestamps will be returned.

Keep in mind that the now() function will return the transaction...