Mysql -----------------+--+

应用Wilson Hauck提供的修复程序后更新了解释。查询速度降至~0.005秒

| id | select_type | table          | type  | possible_keys | key           | key_len | ref              | rows | Extra                       |
|----|-------------|----------------|-------|---------------|---------------|---------|------------------|------|-----------------------------|
| 1  | PRIMARY     | <derived2>     | ALL   | NULL          | NULL          | NULL    | NULL             | 966  | Using where; Using filesort |
| 1  | PRIMARY     | t1             | ref   | activity_date | activity_date | 5       | t2.activity_date | 1    |                             |
| 2  | DERIVED     | wp_ap_activity | range | activity_q_id | activity_q_id | 8       | NULL             | 966  | Using index condition       |

| id |选择|类型|类型|可能的|键|键|列|参考|行|额外|
|----|-------------|----------------|-------|---------------|---------------|---------|------------------|------|-----------------------------|
|1 | PRIMARY | | ALL | NULL | NULL | NULL | NULL | NULL | 966 |使用where；使用文件排序|
|1 |主要| t1 |参考|活动|日期|活动|日期| 5 | t2.活动|日期| 1 ||
|2 |派生| wp | U ap |活动|范围|活动| q | id |活动| q | id | 8 |空| 966 |使用索引条件|

你的

解释

根本不可能完全相同，请看行尾。第二个查询的注释中有BNL，这意味着块嵌套循环处理（总是很慢）。必须避免

您需要在每个表的

activity\u date

上建立索引

从MySQL命令提示符运行，

显示wp\u ap\u活动的索引都将重建索引，使其成为当前索引

将查询更改为
选择SQL\u NO\u CACHE………
进行测试，以避免使用查询缓存结果，并从每个查询的第二次和第三次执行中再次获取要比较的计时

请告诉我们您的结果。
您是否做了
解释
？@user3783243否-这是一个WordPress应用程序，但问题与WP或PHP无关，我已更新了标记。请从两台服务器发布表的CREATE语句。使用
SHOW CREATE TABLE wp\u ap\u activity
@Jay Blanchard我在上面添加了解释结果。这两个表的查询速度完全相同。@Pail Spiegel在上面添加了
SHOW CREATE TABLE
结果。在activity_date上添加索引将查询速度从~6秒提高到~0.005秒，令人难以置信。非常感谢@Albion索引是您高速访问的门票。免责声明：我是我的个人资料、网络个人资料中提到的网站的内容作者，在那里我们有免费的实用程序脚本下载，以帮助进行性能调整。请访问我们。
CREATE TABLE `wp_ap_activity` (
 `activity_id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
 `activity_action` varchar(45) NOT NULL,
 `activity_q_id` bigint(20) unsigned NOT NULL,
 `activity_a_id` bigint(20) unsigned DEFAULT NULL,
 `activity_c_id` bigint(20) unsigned DEFAULT NULL,
 `activity_user_id` bigint(20) unsigned NOT NULL,
 `activity_date` timestamp NULL DEFAULT NULL,
 PRIMARY KEY (`activity_id`),
 KEY `activity_q_id` (`activity_q_id`),
 KEY `activity_a_id` (`activity_a_id`),
 KEY `activity_user_id` (`activity_user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=113657 DEFAULT CHARSET=utf8mb4

+----+-------------+----------------+-------+---------------+---------------+---------+------+--------+-------------------------------------------------+--+
| id | select_type | table          | type  | possible_keys | key           | key_len | ref  | rows   | Extra                                           |  |
+----+-------------+----------------+-------+---------------+---------------+---------+------+--------+-------------------------------------------------+--+
| 1  | PRIMARY     | <derived2>     | ALL   | NULL          | NULL          | NULL    | NULL | 970    | Using temporary; Using filesort                 |  |
+----+-------------+----------------+-------+---------------+---------------+---------+------+--------+-------------------------------------------------+--+
| 1  | PRIMARY     | t1             | ALL   | NULL          | NULL          | NULL    | NULL | 109514 | Using where; Using join buffer (flat, BNL join) |  |
+----+-------------+----------------+-------+---------------+---------------+---------+------+--------+-------------------------------------------------+--+
| 2  | DERIVED     | wp_ap_activity | range | activity_q_id | activity_q_id | 8       | NULL | 970    | Using index condition                           |  |
+----+-------------+----------------+-------+---------------+---------------+---------+------+--------+-------------------------------------------------+--+

+----+-------------+----------------+------------+-------+---------------+---------------+---------+---------------------------+-------+----------+----------------------------------------------+--+
| id | select_type | table          | partitions | type  | possible_keys | key           | key_len | ref                       | rows  | filtered | Extra                                        |  |
+----+-------------+----------------+------------+-------+---------------+---------------+---------+---------------------------+-------+----------+----------------------------------------------+--+
| 1  | PRIMARY     | t1             | NULL       | ALL   | NULL          | NULL          | NULL    | NULL                      | 20270 | 100.00   | Using where; Using temporary; Using filesort |  |
+----+-------------+----------------+------------+-------+---------------+---------------+---------+---------------------------+-------+----------+----------------------------------------------+--+
| 1  | PRIMARY     | <derived2>     | NULL       | ref   | <auto_key0>   | <auto_key0>   | 5       | helpdesk.t1.activity_date | 10    | 100.00   | Using index                                  |  |
+----+-------------+----------------+------------+-------+---------------+---------------+---------+---------------------------+-------+----------+----------------------------------------------+--+
| 2  | DERIVED     | wp_ap_activity | NULL       | range | activity_q_id | activity_q_id | 8       | NULL                      | 970   | 100.00   | Using index condition                        |  |
+----+-------------+----------------+------------+-------+---------------+---------------+---------+---------------------------+-------+----------+----------------------------------------------+--+

| id | select_type | table          | type  | possible_keys | key           | key_len | ref              | rows | Extra                       |
|----|-------------|----------------|-------|---------------|---------------|---------|------------------|------|-----------------------------|
| 1  | PRIMARY     | <derived2>     | ALL   | NULL          | NULL          | NULL    | NULL             | 966  | Using where; Using filesort |
| 1  | PRIMARY     | t1             | ref   | activity_date | activity_date | 5       | t2.activity_date | 1    |                             |
| 2  | DERIVED     | wp_ap_activity | range | activity_q_id | activity_q_id | 8       | NULL             | 966  | Using index condition       |