docker run -d --rm --name mysql -e MYSQL_ROOT_HOST=localhost -e MYSQL_ALLOW_EMPTY_PASSWORD=yes mysql:8.0.13@sha256:b7f7479f0a2e7a3f4ce008329572f3497075dc000d8b89bac3134b0fb0288de8
docker exec -ti mysql bash
# in the container
mysql -e "CREATE USER IF NOT EXISTS 'testuser'@'%' IDENTIFIED BY 'testuser' WITH MAX_CONNECTIONS_PER_HOUR 3;"
mysql -utestuser -ptestuser -e "SHOW DATABASES" > /dev/null
mysql -utestuser -ptestuser -e "SHOW DATABASES" > /dev/null
mysql -utestuser -ptestuser -e "SHOW DATABASES" > /dev/null
# = "ERROR 1226 (42000): User 'testuser' has exceeded the 'max_connections_per_hour' resource (current value: 3)"
mysql -e "ALTER USER 'testuser'@'%' WITH MAX_CONNECTIONS_PER_HOUR 10;"
mysql -utestuser -ptestuser -e "SHOW DATABASES" > /dev/null
# = works again
exit
# outside the container
docker kill mysql

# Now try the same experiment with
docker run -d --rm --name mysql -e MYSQL_ROOT_HOST=localhost -e MYSQL_ALLOW_EMPTY_PASSWORD=yes mariadb:10.2.19@sha256:8263e0a4a69ee6defdea16c48ed2c2243f086a5fed3febb2d062e6e938dc7c96

root@82eff92299fd:/# mysql -utestuser -ptestuser -e "SHOW DATABASES" > /dev/null
ERROR 1226 (42000): User 'testuser' has exceeded the 'max_connections_per_hour' resource (current value: 3)
root@82eff92299fd:/# mysql -e "USE mysql; SELECT host, user, max_user_connections, max_connections FROM user;"
+-----------+----------+----------------------+-----------------+
| host      | user     | max_user_connections | max_connections |
+-----------+----------+----------------------+-----------------+
| localhost | root     |                    0 |               0 |
| %         | testuser |                    0 |              10 |
+-----------+----------+----------------------+-----------------+