CREATE TABLE vacation_notification ( 
    on_vacation varchar(255) NOT NULL, 
    notified varchar(255) NOT NULL, 
    notified_at timestamp NOT NULL default now(), 
    CONSTRAINT vacation_notification_pkey PRIMARY KEY(on_vacation, notified), 
    FOREIGN KEY (on_vacation) REFERENCES vacation(email) ON DELETE CASCADE 
)  ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci TYPE=InnoDB COMMENT='Virtual Vacation Notifications';


#1005 - Can't create table './postfix/vacation_notification.frm' (errno: 150) 


After: SHOW ENGINE INNODB STATUS;

I get a bunch of stuff and

~SNIP~

Cannot resolve table name close to:
(email) ON DELETE CASCADE
)  ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci TYPE=InnoDB COMMENT='Virtual Vacation Notifications'

~SNIP~