InnoDB Tablespace Duplicate Check Threads (and EBS Volumes for MySQL Startup with Many Tables)

In the last weeks / months, I have been working on understanding / improving MySQL startup with many tables.  I already wrote five posts on the subject, they are listed below.  In this post, I use the knowledge we gained in the previous two posts to show the interest of tuning InnoDB Tablespace Duplicate Check Threads, making startup 30% in one case (2:28 vs. 3:33) and 5% in another (5:33 vs. 5:53).

Problematic Improved Offline Mode Error in MySQL 9

I am writing this quick post to share what I think is a problematic new behavior of Offline Mode in MySQL 9.  Basically, the new default behavior in MySQL 9 is to write the username of the user which set offline_mode to ON.  I think this behavior has not been considered from a security point of view because it leaks a root username in the error message presented to the users.