mysql - WordPress 查询时间慢

Question

我正在 MU wordpress 网站上工作，我在查询中遇到问题，执行时间太长。

SELECT wp_posts.* FROM wp_posts 
INNER JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id) 
INNER JOIN wp_term_taxonomy ON (wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id) 
INNER JOIN wp_terms ON (wp_term_taxonomy.term_id = wp_terms.term_id) 
WHERE 1=1 AND wp_posts.blog_id = '1'
AND wp_term_taxonomy.taxonomy = 'post_tag' 
AND wp_terms.slug IN ('rate') 
AND wp_posts.post_type = 'post' 
AND (wp_posts.post_status = 'publish') 
GROUP BY wp_posts.ID 
ORDER BY wp_posts.post_date DESC 
LIMIT 0, 20

这个查询是由wordpress执行的，执行需要30-40秒，这太长了。

• wp_posts:4,00,000 行
• wp_terms:2,50,000 行
• wp_term_relationship:2,30,000 行
• wp_term_taxonomy:2,60,000 行

我已经对(使用的)列建立了索引。

Answer 1

尝试解释如下。

将以下内容粘贴到 phpmyadmin 并执行它:-

EXPLAIN SELECT wp_posts.* FROM wp_posts 
INNER JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id) 
INNER JOIN wp_term_taxonomy ON (wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id) 
INNER JOIN wp_terms ON (wp_term_taxonomy.term_id = wp_terms.term_id) 
WHERE 1=1 AND wp_posts.blog_id = '1'
AND wp_term_taxonomy.taxonomy = 'post_tag' 
AND wp_terms.slug IN ('rate') 
AND wp_posts.post_type = 'post' 
AND (wp_posts.post_status = 'publish') 
GROUP BY wp_posts.ID 
ORDER BY wp_posts.post_date DESC 
LIMIT 0, 20

然后复制结果并将其粘贴到您原来的问题中。它将提供哪些表中使用了哪些键等详细信息。