Why does the leaf node of InnoDB non-primary key index structure store the primary key value instead of storing the data address like the MyiSAM index?

1. Maintain consistency. When the database table performs DML operations, the page address of the same row of records will change, because the non-primary key index saves the value of the primary key, and there is no need to change it;

2. Save storage space, follow-up supplements, the reason is not clear

Reference link: https://blog.csdn.net/a1_HelloWord/article/details/104341349