Code: 9001, Message: Max connect timeout reached while reaching hostgroup %d after %llums
Code: 9002, Message: Max connect failure while reaching hostgroup %d
Code: 9003, Message: Command not supported
Code: 9004, Message: Backend Offline Detected
Code: 9006, Message: Connection is locked to hostgroup X but trying to reach hostgroup Y
Error descriptions
9004: ProxySQL error code 9004 indicates that a backend server is determined to be offline before attempting to use a connection. This means ProxySQL has detected the backend’s unavailability through other means, rather than by receiving an error during a connection attempt.