Starting from MySQL 8.1, the official has implemented new version models: MySQL Innovation and Long Term Support (LTS). According to the introduction, the quality of both has reached a level suitable for production environments. The difference is that if you want to try out the latest features and improvements, and enjoy keeping up with the latest technology, then the innovative version of MySQL may be the most suitable for you. This version is very suitable for developers and DBAs working in fast-paced development environments, with high-level automated testing and modern continuous integration technology that can achieve faster upgrade cycles. If your environment needs to maintain a fixed behavior, then LTS version is your best choice. These versions only include necessary fixes, thus reducing the risk of database software behavior changes. The deletion function in MySQL 9.0 The following features are outdated and have been removed in MySQL 9.0. If there are alternative solutions displayed in the MySQL update instructions, you should update the application and use them. For MySQL 8.4 applications that use the deletion feature in MySQL 9.0, when copying from a MySQL 8.4 source to a MySQL 9.0 replica, statements may fail to execute or may have different effects on the source and replica. To avoid such issues, applications that use the features removed in MySQL 9.0 should be modified to avoid these problems and alternative solutions should be used as much as possible. Introduction to mysql_native_massword Starting from MySQL 8.0.4, the default authentication plugin for MySQL has been changed from mysql_native_password to cachind_sha_2 password. Correspondingly, libmysqlclient also uses cachind_sha_2password as the default authentication mechanism. Actually, since MySQL 5.6, a more secure authentication mechanism has been introduced: the ha256_ password authentication plugin. It uses a salted password for multiple rounds of SHA256 hashing (thousands of rounds of hashing, harder to brute force crack) to ensure more secure hash value conversion. However, establishing secure connections and multiple rounds of hash encryption are time-consuming. Although it has higher security, the verification speed is not fast enough. MySQL attempts to combine the advantages of both. So a new authentication plugin caching.sha_2password was introduced in MySQL version 8.0.3 as an alternative to sha256_ password. Based on sha256_ password, improvements were made to address both security and performance issues. At the same time, sha256password will exit the tide of the times. MySQL is expected to remove it in future versions. It is recommended to change the MySQL account used for authentication to caching.sha_2password. In fact, MySQl has long wanted to replace the mysql_native_massword plugin in version 8.0, and in version 9.0, it directly removed the mysql_native_massword feature. I actually informed everyone in advance.