我已经阅读了其他相关问题,但由于它的结构,我的独特之处。
我的应用程序存储了大约10,000多个用户,其中的配置文件由许多参数(性别,体重,身高,头发颜色,眼睛颜色,舞蹈技能等等)定义,等等,大概有100个属性,比如说。
应用程序使用这些属性构建过滤器表单。用户使用此表单过滤数据库,因此构建一个包含许多子查询的查询,每个查询对应一个使用的过滤器。
问题是使用超过8-9个过滤器,引擎会崩溃成很长的响应(我必须在等待30米后终止进程。)
所以,这是数据库的结构
表def_attributes (这里是属性定义)
表utilizatori (用户定义,现在只使用列激活)
表val_atribute (存储每个用户的属性值)
例如,这是一个由Filtering表单构建的查询,它延迟了:
SELECT DISTINCT Q1.user_id
FROM (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 45
AND attr_value IN ( 'Actor', 'Actor Amator' )) Q1
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 46
AND Floor(Datediff(Curdate(), attr_value) / 365) >= '20') Q2
ON Q1.user_id = Q2.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 46
AND Floor(Datediff(Curdate(), attr_value) / 365) <= '50') Q3
ON Q2.user_id = Q3.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 47
AND attr_value IN ( 'feminin', 'masculin' )) Q4
ON Q3.user_id = Q4.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 102
AND attr_value IN ( 'African', 'Asiatic', 'Caucazian', 'Metis' )) Q5
ON Q4.user_id = Q5.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 103
AND attr_value >= 1) Q6
ON Q5.user_id = Q6.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 103
AND attr_value <= 200) Q7
ON Q6.user_id = Q7.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 104
AND attr_value >= 10) Q8
ON Q7.user_id = Q8.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 104
AND attr_value <= 150) Q9
ON Q8.user_id = Q9.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 107
AND attr_value IN ( 'Albastri', 'Caprui', 'Heterocrom', 'Verzi' )) Q10
ON Q9.user_id = Q10.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 108
AND attr_value IN ( 'Blond', 'Brunet', 'Castaniu', 'Roscat', 'Saten' )) Q11
ON Q10.user_id = Q11.user_id
INNER JOIN (SELECT DISTINCT val_atribute.user_id
FROM val_atribute
WHERE attr_id = 109
AND attr_value IN ( 'Calvitie', 'Lung', 'Mediu', 'Scurt', 'Zero' )) Q12
ON Q11.user_id = Q12.user_id
INNER JOIN (SELECT DISTINCT utilizatori.id
FROM utilizatori
WHERE activ = 1) Q13
ON Q12.user_id = Q13.id
GROUP BY user_id
Q2正在计算AGE,因为Weonly属性[出生日期]和过滤器Q2要年龄&gt; 20。
最后一个查询(此处为Q13)始终是来自Table utilizatori的活跃用户。
我认为这是笛卡尔进展的问题但是 问题:我如何重新制作查询以使其更快? 非常感谢你!
编辑/问题已解决:
根据Gordon Linoff的大力帮助,我使用相同的过滤器构建了正确的查询:
SELECT u.id
FROM utilizatori u
WHERE EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 45
AND attr_value IN ( 'Actor', 'Actor Amator' ))
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 46
AND Floor(Datediff(Curdate(), attr_value) / 365) >= 20)
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 46
AND Floor(Datediff(Curdate(), attr_value) / 365) <= 50)
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 47
AND attr_value IN ( 'feminin', 'masculin' ))
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 102
AND attr_value IN ( 'African', 'Asiatic', 'Caucazian', 'Metis' ))
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 103
AND attr_value >= 1)
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 103
AND attr_value <= 200)
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 104
AND attr_value >= 10)
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 104
AND attr_value <= 150)
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 107
AND attr_value IN ( 'Albastri', 'Caprui', 'Heterocrom', 'Verzi' ))
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 108
AND attr_value IN ( 'Blond', 'Brunet', 'Castaniu', 'Roscat', 'Saten' ))
AND EXISTS (SELECT 1
FROM val_atribute va
WHERE va.user_id = u.id
AND va.attr_id = 109
AND attr_value IN ( 'Calvitie', 'Lung', 'Mediu', 'Scurt', 'Zero' ))
AND activ = 1
现在查询大约需要0.0015秒才能运行。
答案 0 :(得分:1)
MySQL中的子查询存在问题 - select distinct
使事情变得更糟。您正在使用and
连接子查询。我建议使用exists
构建相同的逻辑。
所以:
select u.*
from users u
where exists (select 1
from val_atribute va
where va.user_id = u.user_id and
va.attr_id = 45 and
va.attr_value in ( 'Actor', 'Actor Amator' )
) and
exists (select 1
from val_atribute va
where va.user_id = u.user_id and
va.attr_id = 46 and
Floor(Datediff(Curdate(), va.attr_value) / 365) >= 20) Q2
) and
. . .
此版本的查询可以利用val_attribute(user_id, attr_id, attr_value)
上的索引。它应该更快,并具有更好的可扩展性。
答案 1 :(得分:1)
这是臭名昭着的低效EAV架构设计的变种。
到目前为止,最佳解决方案(在本课题中)涉及utilizatori
的全表扫描,其中有许多探针进入属性表(val_atribute
)进行过滤。
为了提高效率,val_atribute
需要PRIMARY KEY(user_id, attr_id)
。不,这两列上的单独索引不就好了。
为了提高效率,您需要提取小个常用使用的属性并添加索引。这应该避免全表扫描(10K用户,加上大量的属性查找),将其减少到一小部分。