MySQL 5.7で追加されたALTER TABLE .. RENAME INDEX

5.7.5が来る前に、5.7.4までのおさらい。

mysql57> SHOW CREATE TABLE t1\G
*************************** 1. row ***************************
       Table: t1
Create Table: CREATE TABLE `t1` (
  `num` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `val` varchar(32) DEFAULT NULL,
  UNIQUE KEY `num` (`num`),
  KEY `org_index` (`val`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

mysql57> ALTER TABLE t1 RENAME INDEX org_index TO renamed_index;
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql57> SHOW CREATE TABLE t1\G
*************************** 1. row ***************************
       Table: t1
Create Table: CREATE TABLE `t1` (
  `num` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `val` varchar(32) DEFAULT NULL,
  UNIQUE KEY `num` (`num`),
  KEY `renamed_index` (`val`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

これで、index_hogehoge_01なんて情報量ゼロのインデックスを見つけてもすぐに直せますね！

http://dev.mysql.com/doc/refman/5.7/en/alter-table.html