我有一张大约10k行的表格。我在sql下运行但是需要花费太多时间(~4秒):
SELECT
ID, post_date, post_title, post_name, pc.post_view,
t.name AS post_category,
pm2.meta_value AS post_image
FROM wp_posts p
INNER JOIN wp_term_relationships tr ON p.ID = tr.object_id
INNER JOIN wp_term_taxonomy tt ON tr.term_taxonomy_id = tt.term_taxonomy_id AND tt.taxonomy='category'
INNER JOIN wp_terms t ON tt.term_id = t.term_id AND (t.name='My Posts' OR t.name='HOT posts')
LEFT JOIN post_counter pc ON p.ID = pc.post_id
LEFT JOIN wp_postmeta pm ON pm.post_id = p.ID AND pm.meta_key = '_thumbnail_id'
LEFT JOIN wp_postmeta pm2 ON pm.meta_value = pm2.post_id AND pm2.meta_key = '_wp_attached_file'
WHERE p.post_status = 'publish' AND p.post_type = 'post'
ORDER BY FIELD(t.name, 'HOT posts', 'My Posts'), post_date DESC
LIMIT 14
如果我删除“按post_date排序”,一切都很好。运行只需0.05秒。
我在CREATE INDEX和ADD INDEX中添加了一些索引(我不知道它们之间有什么区别):
CREATE INDEX ix_type_date ON wp_posts (post_type, post_date)
ALTER TABLE wp_posts ADD INDEX ix_status_type_date (post_status,post_type,post_date)
然后将这些索引与USE INDEX和FORCE INDEX一起使用(我也不知道它们之间有什么区别):
...FROM wp_posts p USE INDEX (ix_type_date)...
OR
...FROM wp_posts p FORCE INDEX (ix_status_type_date)...
我仍然记录,但加载时间增加到7-8秒。
真的需要你的帮助! 先谢谢!
修改
表的结构
ID bigint(20) No
post_author bigint(20) No 0
post_date datetime No 0000-00-00 00:00:00
post_date_gmt datetime No 0000-00-00 00:00:00
post_content longtext No
post_title text No
post_excerpt text No
post_status varchar(20) No publish
comment_status varchar(20) No open
ping_status varchar(20) No open
post_password varchar(255) No
post_name varchar(200) No
to_ping text No
pinged text No
post_modified datetime No 0000-00-00 00:00:00
post_modified_gmt datetime No 0000-00-00 00:00:00
post_content_filtered longtext No
post_parent bigint(20) No 0
guid varchar(255) No
menu_order int(11) No 0
post_type varchar(20) No post
post_mime_type varchar(100) No
comment_count bigint(20) No 0
答案 0 :(得分:0)
你想要"热门帖子"首先,然后"我的帖子"?并且可能会少于14个Hotties,并且有很多"我的帖子"?
一个笨拙的解决方案是
( SELECT ... name='HOT posts' ORDER BY post_date DESC LIMIT 14 )
UNION ALL
( SELECT ... name='My Posts' ORDER BY post_date DESC LIMIT 14 )
ORDER BY field(...), post_date DESC LIMIT 14
请注意,有可能快速找到每个类别的最新14个,然后快速重新排列28以获得所需的14个。
对于多对多表格,请参阅here了解如何改善其效果。 (默认WP效率很低。)
如果您需要进一步讨论,请提供EXPLAIN SELECT ...
和SHOW CREATE TABLE
。