mysql - #1071 - 指定的 key 太长；最大 key 长度为 767 字节

Question

我用这个 SQL 查询来创建一个表:

CREATE TABLE IF NOT EXISTS `local_sysDB`.`hashtags` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `hashtag` VARCHAR(255) NOT NULL COMMENT 'hashtag must be unique. Must be saved without #',
  `accountId` INT NULL,
  `startTracking` DATETIME NOT NULL COMMENT 'When tracking of the hashtag start',
  `endTracking` DATETIME NOT NULL COMMENT 'When tracking of the hashtag ends',
  `channelInstagram` TINYINT(1) NOT NULL DEFAULT 1,
  `channelTwitter` TINYINT(1) NOT NULL DEFAULT 1,
  `channelYoutube` TINYINT(1) NOT NULL DEFAULT 1,
  `postLimit` INT NOT NULL,
  `suspendOnLimit` TINYINT(1) NOT NULL DEFAULT 1,
  `created` TIMESTAMP NOT NULL DEFAULT NOW(),
  `updated` TIMESTAMP NULL ON UPDATE CURRENT_TIMESTAMP,
  `approveBeforeView` TINYINT(1) NOT NULL DEFAULT 0 COMMENT 'If account should approve posts before being displayed public',
  `suspended` TINYINT(1) NOT NULL DEFAULT 0,
  `InstagramSubscriptionId` INT(10) UNSIGNED NULL,
  `deleted` TINYINT(1) NULL DEFAULT 0 COMMENT 'if hashtag is marked for deletion',
  `collectedPosts` BIGINT(50) UNSIGNED NULL DEFAULT 0,
  PRIMARY KEY (`id`),
  UNIQUE INDEX `hashtags_hashtag` (`hashtag` ASC)  KEY_BLOCK_SIZE=255,
  INDEX `hashtags_accounts_accountId` (`accountId` ASC),
  INDEX `hashtag_trackingDate` (`startTracking` ASC, `endTracking` ASC),
  INDEX `hashtag_collectedPosts` (`collectedPosts` ASC),
  INDEX `hashtag_updated` (`updated` ASC),
  FULLTEXT INDEX `hashtag_search` (`hashtag` ASC),
  CONSTRAINT `hashtags_accounts_accountId`
    FOREIGN KEY (`accountId`)
    REFERENCES `local_sysDB`.`accounts` (`id`)
    ON DELETE CASCADE
    ON UPDATE CASCADE)
ENGINE = InnoDB
ROW_FORMAT = COMPRESSED
KEY_BLOCK_SIZE = 16;

当我尝试运行此程序时，出现以下错误:

SQL-query:

CREATE TABLE IF NOT EXISTS `local_sysDB`.`hashtags` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `hashtag` VARCHAR(255) NOT NULL COMMENT 'hashtag must be unique. Must be saved without #',
  `accountId` INT NULL,
  `startTracking` DATETIME NOT NULL COMMENT 'When tracking of the hashtag start',
  `endTracking` DATETIME NOT NULL COMMENT 'When tracking of the hashtag ends',
  `channelInstagram` TINYINT(1) NOT NULL DEFAULT 1,
  `channelTwitter` TINYINT(1) NOT NULL DEFAULT 1,
  `channelYoutube` TINYINT(1) NOT NULL DEFAULT 1,
  `postLimit` INT NOT NULL,
  `suspendOnLimit` TINYINT(1) NOT NULL DEFAULT 1,
  `created` TIMESTAMP NOT NULL DEFAULT NOW(),
  `updated` TIMESTAMP NULL ON UPDATE CURRENT_TIMESTAMP,
  `approveBeforeView` TINYINT(1) NOT NULL DEFAULT 0 COMMENT 'If account should approve posts before being displayed public',
  `suspended` TINYINT(1) NOT NULL DEFAULT 0,
  `InstagramSubscriptionId` INT(10) UNSIGNED NULL,
  `deleted` TINYINT(1) NULL DEFAULT 0 COMMENT 'if hashtag is [...]

MySQL meldt: Documentatie

#1071 - Specified key was too long; max key length is 767 bytes

我已经发现它与 this 有关。 :

767 bytes is the stated prefix limitation for InnoDB tables - its 1,000 bytes long for MyISAM tables.

According to the response to this issue, you can get the key to apply by specifying a subset of the column rather than the entire amount. IE:

ALTER TABLE mytable ADD UNIQUE ( column1(15), column2(200) ); Tweak as you need to get the key to apply, but I wonder if it would be worth it to review your data model regarding this entity to see if there's improvements that would allow you to implement the intended business rules without hitting the MySQL limitation.

我尝试向索引添加长度，但 MySQL Workbench 不断将它们重置为 0。 我想知道是否还有其他原因导致此问题，或者是否有其他方法来解决此问题。

Answer 1

我刚刚学到了一种解决方法...获取 5.5.14 或 5.6.3(或更高版本)，执行此处指示的 SET，并使用 DYNAMIC 或 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)