サポート終了後の MySQL 8.0 から 8.4 へのアップグレード

SELECT user, host, plugin
FROM mysql.user
WHERE plugin = 'mysql_native_password';

ALTER USER 'app'@'%' IDENTIFIED WITH caching_sha2_password BY 'new-password';

CREATE USER 'legacy'@'%' IDENTIFIED WITH mysql_native_password BY 'pw';

ERROR 1524 (HY000): Plugin 'mysql_native_password' is not loaded

-- Both fail on 8.4: the variables no longer exist
SELECT @@default_authentication_plugin;
SELECT @@expire_logs_days;

ERROR 1193 (HY000): Unknown system variable 'default_authentication_plugin'

mysqlcheck -u root -p --all-databases --check-upgrade

mysqldump -u root -p --all-databases --events --routines --triggers > pre84_backup.sql

SELECT VERSION();