Acabei de aprender uma solução alternativa... Obtenha 5.5.14 ou 5.6.3 (ou posterior), faça os SETs indicados aqui e use DYNAMIC ou COMPRESSED:
SET GLOBAL innodb_file_per_table = ON,
innodb_file_format = Barracuda,
innodb_large_prefix = ON;
CREATE TABLE so29676724 (
`id` INT NOT NULL AUTO_INCREMENT,
`hashtag` VARCHAR(255) NOT NULL COMMENT 'hashtag must be unique. Must be saved without #',
PRIMARY KEY (`id`),
UNIQUE INDEX `hashtags_hashtag` (`hashtag` ASC)
)
ENGINE = InnoDB
DEFAULT CHARACTER SET utf8mb4
ROW_FORMAT = COMPRESSED;
SHOW CREATE TABLE so29676724\G
mysql> CREATE TABLE so29676724 (
-> `id` INT NOT NULL AUTO_INCREMENT,
-> `hashtag` VARCHAR(255) NOT NULL COMMENT 'hashtag must be unique. Must be saved without #',
-> PRIMARY KEY (`id`),
-> UNIQUE INDEX `hashtags_hashtag` (`hashtag` ASC)
-> )
-> ENGINE = InnoDB
-> DEFAULT CHARACTER SET utf8mb4
-> ROW_FORMAT = COMPRESSED;
Query OK, 0 rows affected (0.09 sec)
