Warning!
Recently, Jean-François Gagné opened a bug on bug.mysql.com #115517; unfortunately, the bug is now private.
However, the bug looks quite serious. We at Percona have performed several tests and opened the issue PS-9306 to investigate the problem.
In short, what happens is that if you create a large number of tables, like 10000, the mysql daemon will crash at restart.
Currently, we have identified that the following versions are affected:
MySQL 8.0.38
MySQL 8.4.1
MySQL 9.0.0
We have not yet identified the root cause or a workaround. As such, we suggest that all users do not adopt any of the MySQL versions mentioned until a fix is released.
If you want to test it yourself, just install one of the mentioned MySQL versions and run a script like the one used in our issue PS-9306.
The gradual rollout of the rollout slot-6 for the package cl-MySQL80@8.0.38-1 was paused due to an upstream bug in MySQL 8.0.38.
According to the article from Percona: https://www.percona.com/blog/do-not-upgrade-to-any-version-of-mysql-after-8-0-37/
if you create a large number of tables, like 10000, the MySQL daemon will crash at restart.
The server will not start after encountering this issue.
A workaround that can be applied to the server with cl-MySQL80 upgraded to 8.0.38 is to downgrade the cl-MySQL80 version back to 8.0.37:
yum downgrade cl-MySQL*
We are waiting for an upstream fix for this issue.
We apologize for the inconvenience.