我的SQL查詢非常慢（60秒），任何人有想法改進？

Question

我的查詢很慢。我在3個表格之間搜索。 Se_movies = 80000條記錄，se_movie_contenttags = 1.6 mil記錄，se_movie_description標籤-200000條記錄

兩個簡化查詢。

OR - 慢

SELECT SQL_NO_CACHE count(movie_id) 
FROM se_movies LEFT JOIN se_users ON se_movies.movie_user_id=se_users.user_id 
LEFT JOIN 
( 
    SELECT did , cid , ifnull(cid,did) as uid FROM (SELECT tag_object_id AS did FROM se_movie_descriptiontags WHERE tag_name IN ('dog')) AS dtag 
    LEFT JOIN (SELECT tag_object_id AS cid FROM se_movie_contenttags WHERE tag_name IN ('dog')) AS ctag 
    ON dtag.did=ctag.cid 
UNION 
    SELECT did , cid , ifnull(cid,did) as uid FROM (SELECT tag_object_id AS did FROM se_movie_descriptiontags WHERE tag_name IN ('dog')) AS dtag 
    RIGHT JOIN (SELECT tag_object_id AS cid FROM se_movie_contenttags WHERE tag_name IN ('dog')) AS ctag 
    ON dtag.did=ctag.cid 
) 
AS tagobjects ON se_movies.movie_id=tagobjects.uid 
WHERE (se_movies.movie_title LIKE '%dog%') **OR** ( (cid IS NOT NULL or did IS NOT NULL) and uid IS NOT NULL) 

AND - 快速

SELECT SQL_NO_CACHE count(movie_id) 
FROM se_movies LEFT JOIN se_users ON se_movies.movie_user_id=se_users.user_id 
LEFT JOIN 
( 
    SELECT did , cid , ifnull(cid,did) as uid FROM (SELECT tag_object_id AS did FROM se_movie_descriptiontags WHERE tag_name IN ('dog')) AS dtag 
    LEFT JOIN (SELECT tag_object_id AS cid FROM se_movie_contenttags WHERE tag_name IN ('dog')) AS ctag 
    ON dtag.did=ctag.cid 
UNION 
    SELECT did , cid , ifnull(cid,did) as uid FROM (SELECT tag_object_id AS did FROM se_movie_descriptiontags WHERE tag_name IN ('dog')) AS dtag 
    RIGHT JOIN (SELECT tag_object_id AS cid FROM se_movie_contenttags WHERE tag_name IN ('dog')) AS ctag 
    ON dtag.did=ctag.cid 
) 
AS tagobjects ON se_movies.movie_id=tagobjects.uid 
WHERE (se_movies.movie_title LIKE '%dog%') **AND** ( (cid IS NOT NULL or did IS NOT NULL) and uid IS NOT NULL) 

每一個單獨

(se_movies.movie_title LIKE '%dog%') - around 300 
(cid IS NOT NULL or did IS NOT NULL) and uid IS NOT NULL - return 595 

，但它是快，如果任何人他們返回大約50或更少。

基本上如果任何關鍵字具有在上述各標籤和電影表標題500 ...它需要60秒

否則2.3秒。

有沒有更好的方法？

我知道u能這兩個... 之間和其他的東西做UNION ...

搜索 - 冠軍OR（或CONTENTTAG desctag）

問題是查詢的太多變化...

是否問題在做或者如果數據在兩個不同的表中？無論如何加快它們？

謝謝。

系統 - mysql apache2 php5 ubuntu - 亞馬遜aws。

解釋 enter link description here

解決它BY

SELECT SQL_NO_CACHE計數（movie_id） FROM se_movies LEFT JOIN se_users ON se_movies.movi​​e_user_id = se_users.user_id INNER JOIN （SELECT tag_object_id AS movieid FROM se_movie_contenttags WHERE tag_name IN（'dog'） UNION SELECT tag_object_id AS movieid FROM se_movie_descriptiontags WHERE tag_name IN（'dog'） UNION SELECT s1.movi​​e_id AS movieid FROM se_movies爲S1 WHERE s1.movi​​e_title LIKE '％狗％' UNION SELECT s2.movi​​e_id AS movieid FROM se_movies爲S2 WHERE s2.movi​​e_desc LIKE '％狗％' ） AS tagobjects ON se_movies.movi​​e_id = tagobjects.movi​​eid

。5秒

Answer 1

如果se_movie_descriptiontags和se_movie_contenttags包含對(movie_id, tag)並且要包括具有一定標籤的所有電影，我將取代tagobjects在線視圖：

SELECT `tag_object_id` AS `uid` FROM `se_movie_descriptiontags` 
WHERE `tag_name` IN ('dog') 
UNION 
SELECT `tag_object_id` FROM `se_movie_contenttags` 
WHERE `tag_name` IN ('dog') 

這個查詢將返回電影IDS在se_movie_descriptiontags和se_movie_contenttags表中的任何一個或兩個都有標籤'dog'。然後你可以在主查詢中刪除OR ((cid IS NOT NULL OR did IS NOT NULL) AND uid IS NOT NULL)。

最終的完整的查詢將是：

SELECT SQL_NO_CACHE count(movie_id) 
FROM 
    se_movies LEFT JOIN 
    se_users ON se_movies.movie_user_id=se_users.user_id INNER JOIN 
    ( 
     SELECT `tag_object_id` AS `uid` FROM `se_movie_descriptiontags` 
     WHERE `tag_name` IN ('dog') 
     UNION 
     SELECT `tag_object_id` FROM `se_movie_contenttags` 
     WHERE `tag_name` IN ('dog') 
    ) AS tagobjects ON se_movies.movie_id=tagobjects.uid 
WHERE (se_movies.movie_title LIKE '%dog%') 

另外請注意，單獨(se_movies.movie_title LIKE '%dog%')是性能殺手，因爲它無法通過在movie_title列使用索引進行優化，肯定會引起表掃描。這主要是由於條件以通配符開始的事實。對於這種情況，我建議查看MySQL的全文搜索功能。