我在应用程序的“自定义仪表板”上有一些查询,其中一个查询需要10-12秒才能执行。使用EXPLAIN我可以看到为什么它很慢,但我不知道该怎么做。这是查询:
SELECT person.PersonID,FullName,Furigana,qualdate FROM person
INNER JOIN (
SELECT pq.PersonID,MAX(ContactDate) AS qualdate FROM person pq
INNER JOIN contact cq ON pq.PersonID=cq.PersonID
WHERE cq.ContactTypeID IN (22,26,45) GROUP BY pq.PersonID
) qual ON person.PersonID=qual.PersonID
LEFT OUTER JOIN (
SELECT pe.personID,MAX(ContactDate) AS elimdate FROM person pe
INNER JOIN contact ce ON pe.PersonID=ce.PersonID WHERE ce.ContactTypeID IN (25,31,30,41,23,42,2,33,35,29,12)
GROUP BY pe.PersonID
) elim ON qual.PersonID=elim.PersonID
LEFT OUTER JOIN (
SELECT po.personID FROM person po
INNER JOIN percat pc ON po.PersonID=pc.PersonID WHERE pc.CategoryID=38
) overseas ON qual.PersonID=overseas.PersonID
WHERE (elimdate IS NULL OR qualdate > elimdate)
AND qualdate < CURDATE()-INTERVAL 7 DAY
AND overseas.PersonID IS NULL
ORDER BY qualdate
以下是EXPLAIN结果:
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 5447 Using where; Using temporary; Using filesort
1 PRIMARY <derived3> ALL NULL NULL NULL NULL 5565 Using where
1 PRIMARY <derived4> ALL NULL NULL NULL NULL 9 Using where; Not exists
1 PRIMARY person eq_ref PRIMARY PRIMARY 4 qual.PersonID 1
4 DERIVED pc ref PRIMARY,CategoryID CategoryID 4 8
4 DERIVED po eq_ref PRIMARY PRIMARY 4 kizuna_misa.pc.PersonID 1 Using index
3 DERIVED pe index PRIMARY PRIMARY 4 NULL 5964 Using index
3 DERIVED ce ref PersonID,ContactTypeID PersonID 4 kizuna_misa.pe.PersonID 1 Using where
2 DERIVED pq index PRIMARY PRIMARY 4 NULL 5964 Using index
2 DERIVED cq ref PersonID,ContactTypeID PersonID 4 kizuna_misa.pq.PersonID 1 Using where
我确定EXPLAIN的第一行显示问题(与类似的查询相比,看起来第二行不是太慢),但我不知道如何修复它。我已经在连接中出现的每一列都有索引,但由于这些表是<derived2>
等,我猜索引是无关紧要的。
目标(因为对于不熟悉我的应用程序和架构的人来说可能并不明显)是一个后续的tickler列表 - 如果其中一个#22/26/45联系人已经发生但没有做任何响应(其中一个其他几个联系人或通过类别转让指定该人在海外),然后该人应在等待一周后出现在列表中以供跟进。子查询比这些混乱的连接更容易编写和理解,但是我无法检查日期的顺序(并且子查询通常也很慢)。
MySQL版本是5.0.95(是的,我知道......)。虽然SHOW CREATE TABLE
中的大部分字段都不相关,但这里涉及的三个表格person
为CREATE TABLE `contact` (
`ContactID` int(11) unsigned NOT NULL auto_increment,
`PersonID` int(11) unsigned NOT NULL default '0',
`ContactTypeID` int(11) unsigned NOT NULL default '0',
`ContactDate` date NOT NULL default '0000-00-00',
`Description` text,
PRIMARY KEY (`ContactID`),
KEY `ContactDate` (`ContactDate`),
KEY `PersonID` (`PersonID`),
KEY `ContactTypeID` (`ContactTypeID`)
) ENGINE=MyISAM AUTO_INCREMENT=16901 DEFAULT CHARSET=utf8
CREATE TABLE `percat` (
`PersonID` int(11) unsigned NOT NULL default '0',
`CategoryID` int(11) unsigned NOT NULL default '0',
PRIMARY KEY (`PersonID`,`CategoryID`),
KEY `CategoryID` (`CategoryID`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8
CREATE TABLE `person` (
`PersonID` int(11) unsigned NOT NULL auto_increment,
`FullName` varchar(100) NOT NULL default '',
`Furigana` varchar(100) NOT NULL default '',
`Sex` enum('','M','F') character set ascii NOT NULL default '',
`HouseholdID` int(11) unsigned NOT NULL default '0',
`Relation` varchar(6) character set ascii NOT NULL default '',
`Title` varchar(6) NOT NULL default '',
`CellPhone` varchar(30) character set ascii NOT NULL default '',
`Email` varchar(70) character set ascii NOT NULL default '',
`Birthdate` date NOT NULL default '0000-00-00',
`Country` varchar(30) NOT NULL default '',
`URL` varchar(150) NOT NULL default '',
`Organization` tinyint(1) NOT NULL default '0',
`Remarks` text NOT NULL,
`Photo` tinyint(1) NOT NULL default '0',
`UpdDate` date NOT NULL default '0000-00-00',
PRIMARY KEY (`PersonID`),
KEY `Furigana` (`Furigana`),
KEY `FullName` (`FullName`),
KEY `Email` (`Email`),
KEY `Organization` (`Organization`,`Furigana`)
) ENGINE=MyISAM AUTO_INCREMENT=6063 DEFAULT CHARSET=utf8
:
SELECT
p.PersonID,
FullName,
Furigana,
(SELECT MAX(ContactDate) FROM contact cq
WHERE cq.PersonID=p.PersonID
AND cq.ContactTypeID IN (22,26,45))
AS qualdate,
(SELECT MAX(ContactDate) FROM contact ce
WHERE ce.PersonID=p.PersonID
AND ce.ContactTypeID IN (25,31,30,41,23,42,2,33,35,29,12))
AS elimdate
FROM person p
WHERE (elimdate IS NULL OR qualdate > elimdate)
AND qualdate < CURDATE()-INTERVAL 7 DAY
AND NOT EXISTS (SELECT * FROM percat WHERE CategoryID=38 AND percat.PersonID=p.PersonID)
ORDER BY qualdate
我试图实现Rick James关于将子选项放在字段列表中的建议(我甚至不知道这是可能的),如下所示:
#1054 - Unknown column 'elimdate' in 'where clause'
但它抱怨: <template is="dom-repeat" items="{{response.0.sentence}}">
<div style="display: inline; postition: realative;">
<span>{{item.word}}></span>
</div>
</template>
根据文档,WHERE子句在字段列表之前被解释,所以这种方法不起作用。
答案 0 :(得分:1)
你有一个有趣的查询。我不确定最好的解决方案是什么。这是两个猜测:
计划A
INDEX(qualdate)
可能有所帮助。请提供SHOW CREATE TABLE
。
这种结构优化得很差:
FROM ( SELECT ... )
JOIN ( SELECT ... )
在您的情况下,overseas
应该变成JOIN
,而不是子选择。另外两个应该变成一种不同的依赖子查询:
SELECT ...,
( SELECT MAX(...) ... ) AS qualdate,
( SELECT MAX(...) ... ) AS elimdate
FROM ...
您运行的是哪个版本的MySQL?
计划B
如果可行,将它们折叠到子查询中,以便它们生成更少的行,从而减少外部查询的工作量。 (每个子查询一个)
elimdate IS NOT NULL
qualdate < CURDATE()-INTERVAL 7 DAY
overseas.PersonID IS NOT NULL
也许NULL
测试适用于LEFT
,此建议可能不适用。