mysql - 如何优化这种缓慢的MySQL查询 - 后期行查找？

我将网站转换为使用XenForo作为论坛软件，但是这个网站在MySQL表中有数百万个线程行。如果我尝试浏览一个分页的线程列表，那么我走得越远就越慢。一旦我在第10,000页，它需要将近30秒。

我的目标是改进下面的查询，可能通过使用后期行查找，以便我可以更快地运行此查询：

SELECT thread.*
    ,
    user.*, IF(user.username IS NULL, thread.username, user.username) AS username,
    NULL AS thread_read_date,
    0 AS thread_is_watched,
    0 AS user_post_count
FROM xf_thread AS thread

    LEFT JOIN xf_user AS user ON
        (user.user_id = thread.user_id)
WHERE (thread.node_id = 152) AND (thread.sticky = 0) AND (thread.discussion_state IN ('visible'))
ORDER BY thread.last_post_date DESC
LIMIT 20 OFFSET 238340

Run Time: 4.383607

Select Type    Table    Type    Possible Keys    Key    Key Len    Ref    Rows    Extra      
SIMPLE    thread    ref    node_id_last_post_date,node_id_sticky_state_last_post    node_id_last_post_date    4    const    552480    Using where      
SIMPLE    user    eq_ref    PRIMARY    PRIMARY    4    sitename.thread.user_id    1

架构：

CREATE TABLE `xf_thread` (
  `thread_id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
  `node_id` INT(10) UNSIGNED NOT NULL,
  `title` VARCHAR(150) NOT NULL,
  `reply_count` INT(10) UNSIGNED NOT NULL DEFAULT '0',
  `view_count` INT(10) UNSIGNED NOT NULL DEFAULT '0',
  `user_id` INT(10) UNSIGNED NOT NULL,
  `username` VARCHAR(50) NOT NULL,
  `post_date` INT(10) UNSIGNED NOT NULL,
  `sticky` TINYINT(3) UNSIGNED NOT NULL DEFAULT '0',
  `discussion_state` ENUM('visible','moderated','deleted') NOT NULL DEFAULT 'visible',
  `discussion_open` TINYINT(3) UNSIGNED NOT NULL DEFAULT '1',
  `discussion_type` VARCHAR(25) NOT NULL DEFAULT '',
  `first_post_id` INT(10) UNSIGNED NOT NULL,
  `first_post_likes` INT(10) UNSIGNED NOT NULL DEFAULT '0',
  `last_post_date` INT(10) UNSIGNED NOT NULL,
  `last_post_id` INT(10) UNSIGNED NOT NULL,
  `last_post_user_id` INT(10) UNSIGNED NOT NULL,
  `last_post_username` VARCHAR(50) NOT NULL,
  `prefix_id` INT(10) UNSIGNED NOT NULL DEFAULT '0',
  `sonnb_xengallery_import` TINYINT(3) DEFAULT '0',
  PRIMARY KEY (`thread_id`),
  KEY `node_id_last_post_date` (`node_id`,`last_post_date`),
  KEY `node_id_sticky_state_last_post` (`node_id`,`sticky`,`discussion_state`,`last_post_date`),
  KEY `last_post_date` (`last_post_date`),
  KEY `post_date` (`post_date`),
  KEY `user_id` (`user_id`)
) ENGINE=INNODB AUTO_INCREMENT=2977 DEFAULT CHARSET=utf8

任何人都可以帮我提高此查询的速度吗？我是一个真正的MySQL新手，但我在其他论坛软件上运行相同的数据集，而且速度要快得多 - 所以我确定有某种方式。这张表是INNODB，我认为服务器已经过优化。

如何优化这种缓慢的MySQL查询 - 后期行查找？

2 个答案: