Comment 3 for bug 1189633

Here's another bit of evidence, this is pre-migration 23:

# mysql -ukeystone -pkeystone -e "show create table credential;" keystone

| credential | CREATE TABLE `credential` (
  `id` varchar(64) NOT NULL,
  `user_id` varchar(64) NOT NULL,
  `project_id` varchar(64) DEFAULT NULL,
  `blob` text NOT NULL,
  `type` varchar(255) NOT NULL,
  `extra` text,
  PRIMARY KEY (`id`),
  KEY `user_id` (`user_id`),
  KEY `project_id` (`project_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 |

Whereas on a system with InnoDB:

| credential | CREATE TABLE `credential` (
  `id` varchar(64) NOT NULL,
  `user_id` varchar(64) NOT NULL,
  `project_id` varchar(64) DEFAULT NULL,
  `blob` text NOT NULL,
  `type` varchar(255) NOT NULL,
  `extra` text,
  PRIMARY KEY (`id`),
  KEY `user_id` (`user_id`),
  KEY `project_id` (`project_id`),
  CONSTRAINT `credential_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `user` (`id`),
  CONSTRAINT `credential_ibfk_2` FOREIGN KEY (`project_id`) REFERENCES `project` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |