如何利用左连接上的大数据优化MySQL查询？_Mysql_Database_Relational Database_Left Join

如何利用左连接上的大数据优化MySQL查询？

mysql database

如何利用左连接上的大数据优化MySQL查询？,mysql,database,relational-database,left-join,Mysql,Database,Relational Database,Left Join,下面的查询返回一组用户，并且对于每一行，返回来自正在搜索的用户透视图的若干关系（id=4）每个表的行数：受信任的用户：255k facebook\u好友：1k 地址簿联系人：1.5M 朋友：70k 用户：32k 所有联接字段都已编制索引。查询需要1.1秒，这对于我们拥有的数据量来说是不可接受的。我做错了什么？我应该在多个查询中拆分并分页吗编辑1:解释结果 +----+-------------+-----------------------+-------------+---------

下面的查询返回一组用户，并且对于每一行，返回来自正在搜索的用户透视图的若干关系（id=4）

每个表的行数：

受信任的用户

：255k

facebook\u好友

：1k

地址簿联系人

：1.5M

朋友

：70k

用户

：32k

所有联接字段都已编制索引。查询需要1.1秒，这对于我们拥有的数据量来说是不可接受的。我做错了什么？我应该在多个查询中拆分并分页吗

编辑1:解释结果

+----+-------------+-----------------------+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------------------------------+---------+----------------------------------+-------+----------------------------------------------------------------------------------------------------------------------------+
| id | select_type | table                 | type        | possible_keys                                                                                                                                                               | key                                                       | key_len | ref                              | rows  | Extra                                                                                                                      |
+----+-------------+-----------------------+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------------------------------+---------+----------------------------------+-------+----------------------------------------------------------------------------------------------------------------------------+
|  1 | PRIMARY     | users                 | ALL         | PRIMARY,index_users_on_chat_id,index_users_login_facebook_id,index_users_on_login,index_users_on_parent_id,index_users_account_type,index_users_email_digest,index_users_id | NULL                                                      | NULL    | NULL                             | 31847 | Using where; Using temporary; Using filesort                                                                               |
|  1 | PRIMARY     | trusted_users         | ref         | index_trusted_users_user,index_trusted_users_trust_user                                                                                                                     | index_trusted_users_trust_user                            | 5       | messenger_dev.users.id           |     6 | Using where                                                                                                                |
|  1 | PRIMARY     | facebook_friends      | index_merge | index_facebook_friends_user,index_facebook_friends_friend                                                                                                                   | index_facebook_friends_user,index_facebook_friends_friend | 5,5     | NULL                             |     2 | Using union(index_facebook_friends_user,index_facebook_friends_friend); Using where; Using join buffer (Block Nested Loop) |
|  1 | PRIMARY     | address_book_contacts | ref         | index_address_book_contacts_owner_id,index_address_book_contacts_email                                                                                                      | index_address_book_contacts_email                         | 767     | messenger_dev.users.email_digest |     1 | Using where                                                                                                                |
|  1 | PRIMARY     | friends               | index_merge | index_friends_me_him,index_friends_me,index_friends_him                                                                                                                     | index_friends_him,index_friends_me                        | 5,5     | NULL                             |    18 | Using union(index_friends_him,index_friends_me); Using where; Using join buffer (Block Nested Loop)                        |
|  2 | SUBQUERY    | friends               | index_merge | index_friends_me_him,index_friends_me,index_friends_him                                                                                                                     | index_friends_him,index_friends_me                        | 5,5     | NULL                             |    18 | Using union(index_friends_him,index_friends_me); Using where                                                               |
+----+-------------+-----------------------+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------------------------------+---------+----------------------------------+-------+----------------------------------------------------------------------------------------------------------------------------+
6 rows in set (0,00 sec)

编辑2:表格结构

CREATE TABLE `address_book_contacts` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `email_digest` varchar(191) DEFAULT NULL,
  `code` varchar(191) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  `owner_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `index_address_book_contacts_owner_id` (`owner_id`),
  KEY `index_address_book_contacts_email` (`email_digest`)
) ENGINE=InnoDB AUTO_INCREMENT=1598109 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `trusted_users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `friend_id` int(11) DEFAULT NULL,
  `user_id` int(11) DEFAULT NULL,
  `trust_user_id` int(11) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  PRIMARY KEY (`id`),
  KEY `index_trusted_users_on_friend_id` (`friend_id`),
  KEY `index_trusted_users_user` (`user_id`),
  KEY `index_trusted_users_trust_user` (`trust_user_id`),
  CONSTRAINT `fk_rails_007c31c802` FOREIGN KEY (`trust_user_id`) REFERENCES `users` (`id`),
  CONSTRAINT `fk_rails_ca24cb4e23` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=275576 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `facebook_friends` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` int(11) DEFAULT NULL,
  `friend_user_id` int(11) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  `code` varchar(191) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `index_facebook_friends_user` (`user_id`),
  KEY `index_facebook_friends_friend` (`friend_user_id`),
  KEY `index_facebook_friends_code` (`code`(5)),
  CONSTRAINT `fk_rails_78285a074e` FOREIGN KEY (`friend_user_id`) REFERENCES `users` (`id`),
  CONSTRAINT `fk_rails_aa3ac53a81` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1149 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `friends` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `me_id` int(11) DEFAULT NULL,
  `him_id` int(11) DEFAULT NULL,
  `owner_id` int(11) DEFAULT NULL,
  `status` int(11) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  `me_status` int(11) DEFAULT '0',
  `him_status` int(11) DEFAULT '0',
  PRIMARY KEY (`id`),
  UNIQUE KEY `index_friends_me_him` (`me_id`,`him_id`),
  KEY `index_friends_me` (`me_id`),
  KEY `index_friends_him` (`him_id`),
  KEY `index_friends_owner` (`owner_id`),
  CONSTRAINT `fk_rails_9fa3474d31` FOREIGN KEY (`owner_id`) REFERENCES `users` (`id`),
  CONSTRAINT `fk_rails_d3ebb6657f` FOREIGN KEY (`him_id`) REFERENCES `users` (`id`),
  CONSTRAINT `fk_rails_fccfd1b821` FOREIGN KEY (`me_id`) REFERENCES `users` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=95724 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `account_type` varchar(191) NOT NULL,
  `firstname` varchar(191) DEFAULT NULL,
  `lastname` varchar(191) DEFAULT NULL,
  `login` varchar(191) DEFAULT NULL,
  `avatar` varchar(191) DEFAULT NULL,
  `gender` varchar(1) DEFAULT NULL,
  `locale` varchar(191) DEFAULT NULL,
  `birthdate` date DEFAULT NULL,
  `password_digest` varchar(191) DEFAULT NULL,
  `email_digest` varchar(191) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  PRIMARY KEY (`id`),
  KEY `index_users_on_login` (`login`),
  KEY `index_users_account_type` (`account_type`),
  KEY `index_users_email_digest` (`email_digest`),
  KEY `index_uses_firstname` (`firstname`),
  KEY `index_users_lastname` (`lastname`)
) ENGINE=InnoDB AUTO_INCREMENT=32516 DEFAULT CHARSET=utf8mb4;

看起来MySQL没有为

用户

表选择任何可用标记

首先，运行

分析表用户

，然后重新运行

EXPLAIN

命令。第一个

行

单元格的值现在是否大大低于31847？如果是这样，你的问题应该得到解决

如果没有，则运行

优化表用户

，然后重新运行

EXPLAIN

命令。第一个

行

单元格的值现在是否大大低于31847？如果是这样，你的问题应该得到解决

如果这两个步骤都不起作用，请尝试将

使用索引（主）

或

使用索引（用户id）

添加到查询的

部分之后
希望这有帮助 这些似乎对我都不起作用：（我在问题中添加了表创建。
CREATE TABLE `address_book_contacts` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `email_digest` varchar(191) DEFAULT NULL,
  `code` varchar(191) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  `owner_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `index_address_book_contacts_owner_id` (`owner_id`),
  KEY `index_address_book_contacts_email` (`email_digest`)
) ENGINE=InnoDB AUTO_INCREMENT=1598109 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `trusted_users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `friend_id` int(11) DEFAULT NULL,
  `user_id` int(11) DEFAULT NULL,
  `trust_user_id` int(11) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  PRIMARY KEY (`id`),
  KEY `index_trusted_users_on_friend_id` (`friend_id`),
  KEY `index_trusted_users_user` (`user_id`),
  KEY `index_trusted_users_trust_user` (`trust_user_id`),
  CONSTRAINT `fk_rails_007c31c802` FOREIGN KEY (`trust_user_id`) REFERENCES `users` (`id`),
  CONSTRAINT `fk_rails_ca24cb4e23` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=275576 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `facebook_friends` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` int(11) DEFAULT NULL,
  `friend_user_id` int(11) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  `code` varchar(191) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `index_facebook_friends_user` (`user_id`),
  KEY `index_facebook_friends_friend` (`friend_user_id`),
  KEY `index_facebook_friends_code` (`code`(5)),
  CONSTRAINT `fk_rails_78285a074e` FOREIGN KEY (`friend_user_id`) REFERENCES `users` (`id`),
  CONSTRAINT `fk_rails_aa3ac53a81` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1149 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `friends` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `me_id` int(11) DEFAULT NULL,
  `him_id` int(11) DEFAULT NULL,
  `owner_id` int(11) DEFAULT NULL,
  `status` int(11) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  `me_status` int(11) DEFAULT '0',
  `him_status` int(11) DEFAULT '0',
  PRIMARY KEY (`id`),
  UNIQUE KEY `index_friends_me_him` (`me_id`,`him_id`),
  KEY `index_friends_me` (`me_id`),
  KEY `index_friends_him` (`him_id`),
  KEY `index_friends_owner` (`owner_id`),
  CONSTRAINT `fk_rails_9fa3474d31` FOREIGN KEY (`owner_id`) REFERENCES `users` (`id`),
  CONSTRAINT `fk_rails_d3ebb6657f` FOREIGN KEY (`him_id`) REFERENCES `users` (`id`),
  CONSTRAINT `fk_rails_fccfd1b821` FOREIGN KEY (`me_id`) REFERENCES `users` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=95724 DEFAULT CHARSET=utf8mb4;

CREATE TABLE `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `account_type` varchar(191) NOT NULL,
  `firstname` varchar(191) DEFAULT NULL,
  `lastname` varchar(191) DEFAULT NULL,
  `login` varchar(191) DEFAULT NULL,
  `avatar` varchar(191) DEFAULT NULL,
  `gender` varchar(1) DEFAULT NULL,
  `locale` varchar(191) DEFAULT NULL,
  `birthdate` date DEFAULT NULL,
  `password_digest` varchar(191) DEFAULT NULL,
  `email_digest` varchar(191) DEFAULT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL,
  PRIMARY KEY (`id`),
  KEY `index_users_on_login` (`login`),
  KEY `index_users_account_type` (`account_type`),
  KEY `index_users_email_digest` (`email_digest`),
  KEY `index_uses_firstname` (`firstname`),
  KEY `index_users_lastname` (`lastname`)
) ENGINE=InnoDB AUTO_INCREMENT=32516 DEFAULT CHARSET=utf8mb4;