如何优化此MySQL查询？数百万行

Question

我有以下查询：

SELECT 
    analytics.source AS referrer, 
    COUNT(analytics.id) AS frequency, 
    SUM(IF(transactions.status = 'COMPLETED', 1, 0)) AS sales
FROM analytics
LEFT JOIN transactions ON analytics.id = transactions.analytics
WHERE analytics.user_id = 52094 
GROUP BY analytics.source 
ORDER BY frequency DESC 
LIMIT 10

分析表有6000万行，而交易表有3M行。

EXPLAIN在此查询上运行时，我得到：

+------+--------------+-----------------+--------+---------------------+-------------------+----------------------+---------------------------+----------+-----------+-------------------------------------------------+
| # id |  select_type |      table      |  type  |    possible_keys    |        key        |        key_len       |            ref            |   rows   |   Extra   |                                                 |
+------+--------------+-----------------+--------+---------------------+-------------------+----------------------+---------------------------+----------+-----------+-------------------------------------------------+
| '1'  |  'SIMPLE'    |  'analytics'    |  'ref' |  'analytics_user_id | analytics_source' |  'analytics_user_id' |  '5'                      |  'const' |  '337662' |  'Using where; Using temporary; Using filesort' |
| '1'  |  'SIMPLE'    |  'transactions' |  'ref' |  'tran_analytics'   |  'tran_analytics' |  '5'                 |  'dijishop2.analytics.id' |  '1'     |  NULL     |                                                 |
+------+--------------+-----------------+--------+---------------------+-------------------+----------------------+---------------------------+----------+-----------+-------------------------------------------------+

我已经不知道如何优化此查询了，因为它已经非常基础了。运行此查询大约需要70秒钟。

以下是存在的索引：

+-------------+-------------+----------------------------+---------------+------------------+------------+--------------+-----------+---------+--------+-------------+----------+----------------+
|   # Table   |  Non_unique |          Key_name          |  Seq_in_index |    Column_name   |  Collation |  Cardinality |  Sub_part |  Packed |  Null  |  Index_type |  Comment |  Index_comment |
+-------------+-------------+----------------------------+---------------+------------------+------------+--------------+-----------+---------+--------+-------------+----------+----------------+
| 'analytics' |  '0'        |  'PRIMARY'                 |  '1'          |  'id'            |  'A'       |  '56934235'  |  NULL     |  NULL   |  ''    |  'BTREE'    |  ''      |  ''            |
| 'analytics' |  '1'        |  'analytics_user_id'       |  '1'          |  'user_id'       |  'A'       |  '130583'    |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'analytics' |  '1'        |  'analytics_product_id'    |  '1'          |  'product_id'    |  'A'       |  '490812'    |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'analytics' |  '1'        |  'analytics_affil_user_id' |  '1'          |  'affil_user_id' |  'A'       |  '55222'     |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'analytics' |  '1'        |  'analytics_source'        |  '1'          |  'source'        |  'A'       |  '24604'     |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'analytics' |  '1'        |  'analytics_country_name'  |  '1'          |  'country_name'  |  'A'       |  '39510'     |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'analytics' |  '1'        |  'analytics_gordon'        |  '1'          |  'id'            |  'A'       |  '56934235'  |  NULL     |  NULL   |  ''    |  'BTREE'    |  ''      |  ''            |
| 'analytics' |  '1'        |  'analytics_gordon'        |  '2'          |  'user_id'       |  'A'       |  '56934235'  |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'analytics' |  '1'        |  'analytics_gordon'        |  '3'          |  'source'        |  'A'       |  '56934235'  |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
+-------------+-------------+----------------------------+---------------+------------------+------------+--------------+-----------+---------+--------+-------------+----------+----------------+


+----------------+-------------+-------------------+---------------+-------------------+------------+--------------+-----------+---------+--------+-------------+----------+----------------+
|    # Table     |  Non_unique |      Key_name     |  Seq_in_index |    Column_name    |  Collation |  Cardinality |  Sub_part |  Packed |  Null  |  Index_type |  Comment |  Index_comment |
+----------------+-------------+-------------------+---------------+-------------------+------------+--------------+-----------+---------+--------+-------------+----------+----------------+
| 'transactions' |  '0'        |  'PRIMARY'        |  '1'          |  'id'             |  'A'       |  '2436151'   |  NULL     |  NULL   |  ''    |  'BTREE'    |  ''      |  ''            |
| 'transactions' |  '1'        |  'tran_user_id'   |  '1'          |  'user_id'        |  'A'       |  '56654'     |  NULL     |  NULL   |  ''    |  'BTREE'    |  ''      |  ''            |
| 'transactions' |  '1'        |  'transaction_id' |  '1'          |  'transaction_id' |  'A'       |  '2436151'   |  '191'    |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'transactions' |  '1'        |  'tran_analytics' |  '1'          |  'analytics'      |  'A'       |  '2436151'   |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'transactions' |  '1'        |  'tran_status'    |  '1'          |  'status'         |  'A'       |  '22'        |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'transactions' |  '1'        |  'gordon_trans'   |  '1'          |  'status'         |  'A'       |  '22'        |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
| 'transactions' |  '1'        |  'gordon_trans'   |  '2'          |  'analytics'      |  'A'       |  '2436151'   |  NULL     |  NULL   |  'YES' |  'BTREE'    |  ''      |  ''            |
+----------------+-------------+-------------------+---------------+-------------------+------------+--------------+-----------+---------+--------+-------------+----------+----------------+

根据建议，在添加任何额外索引之前简化了两个表的架构，因为这并不能改善情况。

CREATE TABLE `analytics` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` int(11) DEFAULT NULL,
  `affil_user_id` int(11) DEFAULT NULL,
  `product_id` int(11) DEFAULT NULL,
  `medium` varchar(45) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `source` varchar(45) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `terms` varchar(1024) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `is_browser` tinyint(1) DEFAULT NULL,
  `is_mobile` tinyint(1) DEFAULT NULL,
  `is_robot` tinyint(1) DEFAULT NULL,
  `browser` varchar(45) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `mobile` varchar(45) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `robot` varchar(45) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `platform` varchar(45) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `referrer` varchar(255) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `domain` varchar(45) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `ip` varchar(255) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `continent_code` varchar(10) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `country_name` varchar(100) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `city` varchar(100) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  KEY `analytics_user_id` (`user_id`),
  KEY `analytics_product_id` (`product_id`),
  KEY `analytics_affil_user_id` (`affil_user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=64821325 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE `transactions` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `transaction_id` varchar(255) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `user_id` int(11) NOT NULL,
  `pay_key` varchar(50) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `sender_email` varchar(255) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `amount` decimal(10,2) DEFAULT NULL,
  `currency` varchar(10) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `status` varchar(50) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `analytics` int(11) DEFAULT NULL,
  `ip_address` varchar(46) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `session_id` varchar(60) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `eu_vat_applied` int(1) DEFAULT '0',
  PRIMARY KEY (`id`),
  KEY `tran_user_id` (`user_id`),
  KEY `transaction_id` (`transaction_id`(191)),
  KEY `tran_analytics` (`analytics`),
  KEY `tran_status` (`status`)
) ENGINE=InnoDB AUTO_INCREMENT=10019356 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

如果以上无法进一步优化。关于汇总表的任何实施建议都将非常有用。我们正在AWS上使用LAMP堆栈。上面的查询正在RDS（m1.large）上运行。

Answer 1

我将创建以下索引（b树索引）：

analytics(user_id, source, id) 
transactions(analytics, status)

这与戈登的建议不同。

索引中列的顺序很重要。

您要按特定条件进行过滤analytics.user_id，因此该字段必须是索引中的第一个字段。然后，您按分组analytics.source。为避免source以此排序，索引的下一个字段应该是。您还参考analytics.id，因此最好将此字段作为索引的一部分，放在最后。MySQL是否能够只读取索引而不接触表？我不知道，但是测试起来很容易。

索引transactions必须以开头analytics，因为它会在中使用JOIN。我们还需要status。

SELECT 
    analytics.source AS referrer, 
    COUNT(analytics.id) AS frequency, 
    SUM(IF(transactions.status = 'COMPLETED', 1, 0)) AS sales
FROM analytics
LEFT JOIN transactions ON analytics.id = transactions.analytics
WHERE analytics.user_id = 52094 
GROUP BY analytics.source 
ORDER BY frequency DESC 
LIMIT 10