MySQL version 5.7 versus MySQL version 8.

MySQL is an open-source relational database management system widely used in the software industry. It is developed by Oracle Corporation and has been used for more than two decades. Over the years, MySQL has undergone many changes and improvements, with new versions released periodically. In this article, we will discuss the differences between
MySQL version 5.7 and MySQL version 8.

Performance:

MySQL 8 has improved performance over MySQL 5.7. This is mainly because of the following factors:

a) The InnoDB storage engine has been improved with a new lock-free algorithm called “persistent memory atomic transactions”. This has significantly improved the performance of large-scale transactions.

b) The MySQL optimizer has also been improved, resulting in better query performance. The new optimizer also has better support for subqueries, joins, and other complex queries.

c) The performance schema has been improved, making it easier to identify and troubleshoot performance issues.

Security:

MySQL 8 has several security enhancements over MySQL 5.7. These include:

a) Password policy: MySQL 8 has a new password policy that enforces stronger password requirements for all users.

b) Encrypted connections: MySQL 8 supports encrypted connections by default, whereas in MySQL 5.7, encrypted connections had to be enabled manually.

c) Secure user account management: MySQL 8 has improved user account management, with support for roles and improved password management.

JSON:

MySQL 8 has better support for JSON than MySQL 5.7. This is important because JSON is becoming increasingly popular for data storage and exchange. MySQL 8 has improved JSON functions, making it easier to work with JSON data.

Data Dictionary:

MySQL 8 has a new data dictionary that stores all metadata in a centralized location. This makes it easier to manage metadata, especially when dealing with large-scale databases.

General improvements:

MySQL 8 has several general improvements over MySQL 5.7, including:

a) Atomic Data Definition Language (DDL): MySQL 8 supports atomic DDL, which means that changes to the database schema can be made without locking the entire table.

Persistent memory atomic transactions (PMAT) is a feature introduced in MySQL version 8 that enhances the performance of transactions in InnoDB storage engine. PMAT is a lock-free algorithm designed to ensure that concurrent transactions can work on the same data without blocking each other. This improves the scalability and throughput of large-scale transaction processing in MySQL.

Before the introduction of PMAT, InnoDB storage engine relied on the traditional locking mechanism to ensure the consistency of data during transactions. This meant that when a transaction acquired a lock on a data item, other transactions had to wait until the lock was released before they could access that data. This could lead to contention and slowdowns in high-concurrency environments.

With PMAT, InnoDB storage engine employs a new algorithm that allows transactions to work on the same data item concurrently without blocking each other. The algorithm relies on the use of atomic instructions provided by the hardware to ensure that transactions are executed atomically and in isolation. This means that transactions are either committed or rolled back entirely, with no intermediate states allowed.

The use of atomic instructions provided by the hardware ensures that transactions can be executed with minimal overhead, resulting in improved performance and throughput. PMAT also reduces the likelihood of deadlocks and contention, which can occur in traditional locking mechanisms.

In summary, Persistent memory atomic transactions is a feature in MySQL 8 that enhances the performance of transaction processing in the InnoDB storage engine. It allows concurrent transactions to work on the same data item without blocking each other, resulting in improved scalability and throughput. The use of atomic instructions provided by the hardware ensures that transactions are executed atomically and in isolation, reducing the likelihood of deadlocks and contention.

b) Window Functions: MySQL 8 has added support for window functions, which makes it easier to perform complex calculations and analysis.

c) Improved caching: MySQL 8 has improved caching, making it faster to retrieve frequently accessed data.

In conclusion, MySQL 8 is a significant improvement over MySQL 5.7, with better performance, security, and support for JSON. It also has several general improvements that make it easier to manage large-scale databases. If you are currently using MySQL 5.7, it is worth considering upgrading to MySQL 8 to take advantage of these improvements.