Re: Disable All Logins

[Georgi Kodinov]

Several tricks can be employed to the effect. See https://dev.mysql.com/doc/refman/8.0/en/connection-interfaces.html for some ideas.
One way would be to set max_connections to 1.
This will allow 1 "regular" connection and 1 connection for users with CONNECTION_ADMIN or SUPER.
max_connections is dynamic so you can do a SET GLOBAL for it.
Once you get into that state you can then safely kill all sessions and go on.

Another trick is to set a https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_init_connect command that throws a SQL error.
This will cause all future connections to fail at connect. It's also dynamic so you can do a SET GLOBAL.

Georgi "Joro" Kodinov
MySQL SrvGen team lead
Plovdiv, Bulgaria