[英]How can I get this MySql WordPress query to run faster?
我在WordPress中针对一些非常大的表运行以下查询。 有没有办法重新组织它,使其运行更快? 目前,这需要8秒钟,对于我的用例来说,这太慢了,我需要将其称为60万次。 wp_term_taxonomy.term_id = 18
位将是动态的,如下所示: wp_term_taxonomy.term_id = category_id
SELECT `ID` AS athlete_id, `post_title` AS athlete_name, `post_name` AS athlete_slug,
body_weight.weight, performance.speed
FROM `wp_posts`
INNER JOIN
( SELECT `post_id`, `meta_value` AS weight
FROM `wp_postmeta`
WHERE (`meta_key` = 'athlete_weight')
) body_weight ON wp_posts.ID = body_weight.post_id
INNER JOIN
( SELECT `post_id`, `meta_value` AS speed
FROM `wp_postmeta`
WHERE (`meta_key` = 'athlete_speed')
) performance ON wp_posts.ID = performance.post_id
LEFT JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id)
LEFT JOIN wp_term_taxonomy ON (wp_term_relationships.term_taxonomy_id =
wp_term_taxonomy.term_taxonomy_id)
LEFT JOIN wp_terms ON (wp_terms.term_id = wp_term_taxonomy.term_id)
WHERE wp_posts.post_status = 'publish'
AND wp_posts.post_type = 'athlete'
AND ((wp_term_taxonomy.taxonomy = 'athletics_category'
AND wp_term_taxonomy.term_id = 18)
OR (wp_terms.term_id is null)
);
由于不存在tmp表中的索引,因此使用多个JOIN
子查询的效率特别低。 (是的,5.6动态添加了一个索引,但是效率仍然较低。)
而是将JOIN插入表,而不是子查询:
SELECT ...
ms.meta_value AS speed
...
FROM ...
JOIN wp_postmeta AS ms
ON ms.post_id = wp_posts.ID
(其他同上,但使用不同的别名)
(这是为什么EAV模式令人痛苦的一个示例。)
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