MySQL Enterprise Backup 8.4 Release Notes
The --exec-when-locked option of
mysqlbackup lets you specify a command
(together with the desired command arguments) to run near the
end of the backup while the database's non-InnoDB tables are
still locked. This command can copy or create additional files
in the backup directory. For example, you can use this option to
back up MEMORY tables with the
mysqldump command, storing the output in the
backup directory. To delay any redirection or variable
substitution until the command is executed, enclose the entire
option value within single quotes.