Pessimistic Locking
Introduction When applying Pessimistic Locking, it means that the system is always defensive and assumes that "There will certainly be other people accessing to modify this row at the same time as me, so it is best to set up a barrier to lock this row right from the reading phase ( SELECT ) to reserve the spot." All types of Row-level Locks such as FOR SHARE, FOR KEY SHARE, FOR NO KEY UPDATE, FOR UPDATE in PostgreSQL are pure tools of the Pessimistic Locking mindset. Detail In the previous article, we explored Row-level locks and their characteristics. Now, I will guide you through its specific use cases when applied in a system like E-commerce. First, let us create the tables and seed data as follows. This is a simple schema to illustrate how to apply Pessimistic locking to solve problems, rather than being as comprehensive as a real-world production system. CREATE TABLE customers ( id INT PRIMARY KEY , name VARCHAR ( 100 ), phone VARCHAR ( 20 ), loyalty_p...