优化MySQL查询，使用子查询； MariaDB 快得多

Question

我有以下查询（带子查询）：

SELECT  ROUND(SUM(cb.points)) AS points
    FROM  clients_bonuses cb
    WHERE  cb.cb_year = 2016
      AND  cb.account_id IN (
        SELECT  CONCAT('85500/',uc.contract)
            FROM  users_contracts uc , users_details ud
            WHERE  ud.id=uc.users_details_id
              AND  uc.platform_id = 1
              AND  ud.id=6  )

在我的本地 MySQL 服务器 (10.1.9-MariaDB) 上运行得很好 (0.2 秒 )，但是，在我的生产 MySQL 上服务器 (5.5.46-0ubuntu0.14.04.2) 需要 35 秒。完成。

我的本地数据库是生产数据库的精确副本，硬件配置仅视频适配器不同（本地有内置英特尔显卡）。

我的问题是 - 问题的原因可能是什么？我可以（以及如何）优化这个查询吗？

解释上述查询的结果（注意FirstMatch(cb); Using join buffer (flat, BNL join)中的差异）

（生产服务器）：

"id"    "select_type"   "table" "type"  "possible_keys" "key"   "key_len"   "ref"   "rows"  "Extra"
"1" "PRIMARY"   "cb"    "ALL"   \N  \N  \N  \N  "394886"    "Using where"
"2" "DEPENDENT SUBQUERY"    "ud"    "const" "PRIMARY"   "PRIMARY"   "4" "const" "1" "Using index"
"2" "DEPENDENT SUBQUERY"    "uc"    "ALL"   \N  \N  \N  \N  "12243" "Using where"

（本地机器）：

"id"    "select_type"   "table" "type"  "possible_keys" "key"   "key_len"   "ref"   "rows"  "Extra"
"1" "PRIMARY"   "ud"    "const" "PRIMARY"   "PRIMARY"   "4" "const" "1" "Using index"
"1" "PRIMARY"   "cb"    "ALL"   \N  \N  \N  \N  "394537"    "Using where"
"1" "PRIMARY"   "uc"    "ALL"   \N  \N  \N  \N  "12238" "Using where; FirstMatch(cb); Using join buffer (flat, BNL join)"

表（由于这个编辑器，从 table 列名称中删除引号）：

users_contracts

CREATE TABLE users_contracts ( id INT(11) UNSIGNED NOT NULL AUTO_INCREMENT, users_details_id INT(11) NOT NULL DEFAULT '0', platform_id INT(11) NOT NULL DEFAULT '0', contract VARCHAR(20) NOT NULL DEFAULT '', createdon TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', createdby INT(11) NOT NULL DEFAULT '0', updatedon TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', updatedby INT(11) NOT NULL DEFAULT '0', portfolio_id INT(11) NULL DEFAULT NULL, PRIMARY KEY (id) ) COLLATE='cp1251_general_ci' ENGINE=MyISAM AUTO_INCREMENT=13617;
clients_bonuses

CREATE TABLE clients_bonuses ( id INT(11) UNSIGNED NOT NULL AUTO_INCREMENT, account_id VARCHAR(255) NOT NULL DEFAULT '', bi_id INT(11) NOT NULL DEFAULT '0', cb_year YEAR NOT NULL DEFAULT '0000', cb_month TINYINT(1) NOT NULL DEFAULT '0', cb_day TINYINT(1) NOT NULL DEFAULT '0', bonus DECIMAL(10,4) NOT NULL DEFAULT '0.0000', amount DECIMAL(20,4) NOT NULL DEFAULT '0.0000', points DECIMAL(20,4) NOT NULL DEFAULT '0.0000', month_lots DECIMAL(10,4) NOT NULL DEFAULT '0.0000', PRIMARY KEY (id) ) COLLATE='cp1251_general_ci' ENGINE=MyISAM AUTO_INCREMENT=395015;
users_details

CREATE TABLE users_details ( id INT(11) UNSIGNED NOT NULL AUTO_INCREMENT, email VARCHAR(100) NOT NULL DEFAULT '', phone VARCHAR(32) NULL DEFAULT NULL, interest TINYINT(1) NOT NULL DEFAULT '0', contact TINYINT(1) NOT NULL DEFAULT '0', instrument TINYINT(1) NOT NULL DEFAULT '0', instrument1 TINYINT(1) NOT NULL DEFAULT '0', comments TEXT NOT NULL, reminder TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', reminder1 TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', last_accessed TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', dealer INT(11) NOT NULL DEFAULT '0', dealer1 INT(11) NOT NULL DEFAULT '0', real_client TINYINT(1) NOT NULL DEFAULT '0', real_client_meta TINYINT(1) NOT NULL DEFAULT '0', real_client_bgtrader TINYINT(1) NOT NULL DEFAULT '0', real_client_bmpro TINYINT(1) NOT NULL DEFAULT '0', advmails TINYINT(1) NOT NULL DEFAULT '0', analysis_status TINYINT(4) NULL DEFAULT '0', real_client_date TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', real_client_meta_date TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', real_client_bgtrader_date TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', real_client_bmpro_date TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', reg_status TINYINT(1) NOT NULL DEFAULT '0', password VARCHAR(100) NOT NULL DEFAULT '', real_name VARCHAR(100) NOT NULL DEFAULT '', date_of_first_points TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', trader_points INT(11) NOT NULL DEFAULT '0', metatrader_points INT(11) NOT NULL DEFAULT '0', bgtrader_points INT(11) NOT NULL DEFAULT '0', bmpro_points INT(11) NOT NULL DEFAULT '0', vps_status TINYINT(1) NOT NULL DEFAULT '0', vps_username VARCHAR(50) NOT NULL DEFAULT '', vps_password VARCHAR(50) NOT NULL DEFAULT '', vps_start_date TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00', metatrader5_points INT(11) NOT NULL DEFAULT '0', mt_points INT(11) NOT NULL DEFAULT '0', reminder_from INT(11) NOT NULL DEFAULT '0', reminder_mt4 DATE NULL DEFAULT NULL, taken_bonus DATE NOT NULL DEFAULT '0000-00-00', taken_bonus_from DATE NOT NULL DEFAULT '0000-00-00', experience INT(11) NOT NULL DEFAULT '0', invalid_phone TINYINT(4) NOT NULL DEFAULT '0', invalid_email TINYINT(4) NOT NULL DEFAULT '0', number_of_calls INT(11) NOT NULL DEFAULT '0', last_call DATETIME NULL DEFAULT NULL, PRIMARY KEY (id), UNIQUE INDEX email (email), INDEX users_details_email (email(30)) ) COLLATE='cp1251_general_ci' ENGINE=InnoDB AUTO_INCREMENT=63820;

Answer 1

您应该将 ud.id=uc.users_details_id AND uc.platform_id = 1 AND ud.id=6 从 WHERE 移动到 INNER JOIN

为了让它正常工作，为 uc.users_details_id 添加 INDEX ud.id 是主键，因此它已经被编入索引。

Answer 2

IN ( SELECT ... ) 优化不佳。

将其变成 JOIN 可能会使聚合膨胀 (SUM)。

FROM ( SELECT ... ) 消除了 IN 问题，但存在 'inflate' 问题的风险。

所以，EXISTS ( SELECT * ... ) 可能是最佳答案：

SELECT  ROUND(SUM(cb.points)) AS points
    FROM  clients_bonuses cb
    WHERE  cb.cb_year = 2016
      AND  EXISTS 
      ( SELECT  *
            FROM  users_contracts uc
            JOIN  users_details ud  ON  ud.id = uc.users_details_id
            WHERE  uc.platform_id = 1
              AND  ud.id=6
              AND  CONCAT('85500/', uc.contract) = cb.account_id 
      )

您可以从中受益：

users_contracts : INDEX(users_details_id, platform_id) -- in either order
clients_bonuses : INDEX(cb_year, account_id, points)  -- in that order

看来您可以通过摆脱 users_details:

来进一步加快速度

SELECT  ROUND(SUM(cb.points)) AS points
    FROM  clients_bonuses cb
    WHERE  cb.cb_year = 2016
      AND  EXISTS 
      ( SELECT  *
            FROM  users_contracts uc
            WHERE  uc.platform_id = 1
              AND  uc.users_details_id = 6
              AND  CONCAT('85500/', uc.contract) = cb.account_id 
      )

这些公式可能适用于 MySQL/MariaDB 自 4.1 以来的所有变体。

优化MySQL查询，使用子查询； MariaDB 快得多

Optimise MySQL query, which uses sub-query; MariaDB much faster

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