我有一个名为usr_data的表格，其中包含40,000左右的记录，我希望通过连接中的选择与用户的组织数据（大约1000条记录）连接，显然这非常慢（最多150秒）。< / p>
我想知道是否有任何方法可以加快速度？不幸的是，这是加入中子选择的最快查询。
我的查询
SELECT usr_data.usr_id,usr_data.login,orgus.title FROM usr_data
LEFT JOIN (
SELECT object_reference.ref_id,rbac_ua.usr_id,object_data.obj_id,object_data.title
FROM rbac_ua
JOIN rbac_fa ON rbac_fa.rol_id = rbac_ua.rol_id
JOIN object_reference ON rbac_fa.parent = object_reference.ref_id
JOIN object_data ON object_data.obj_id = object_reference.obj_id
JOIN object_data role ON role.obj_id = rbac_ua.rol_id
WHERE object_data.type = 'orgu') as orgus on orgus.usr_id = usr_data.usr_id
WHERE usr_data.usr_id > 0 AND usr_data.login <> "anonymous"
查询描述
+------+-------------+------------------+--------+-----------------------+---------+---------+--------------------------------+------+--------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+-------------+------------------+--------+-----------------------+---------+---------+--------------------------------+------+--------------------------+
| 1 | SIMPLE | usr_data | range | PRIMARY,i1_idx | PRIMARY | 4 | NULL | 8148 | Using where |
| 1 | SIMPLE | rbac_ua | ref | PRIMARY,i1_idx,i2_idx | PRIMARY | 4 | ildCPC.usr_data.usr_id | 2 | Using where; Using index |
| 1 | SIMPLE | rbac_fa | ref | PRIMARY,i1_idx | PRIMARY | 4 | ildCPC.rbac_ua.rol_id | 1 | Using where; Using index |
| 1 | SIMPLE | role | eq_ref | PRIMARY | PRIMARY | 4 | ildCPC.rbac_ua.rol_id | 1 | Using index |
| 1 | SIMPLE | object_reference | eq_ref | PRIMARY,i1_idx | PRIMARY | 4 | ildCPC.rbac_fa.parent | 1 | Using where |
| 1 | SIMPLE | object_data | eq_ref | PRIMARY,i1_idx | PRIMARY | 4 | ildCPC.object_reference.obj_id | 1 | Using where |
+------+-------------+------------------+--------+-----------------------+---------+---------+--------------------------------+------+--------------------------+
usr_data table
+----------------------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------------------+---------------+------+-----+---------+-------+
| usr_id | int(11) | NO | PRI | 0 | |
| login | varchar(80) | YES | MUL | NULL | |
| passwd | varchar(80) | YES | | NULL | |
| firstname | varchar(32) | YES | | NULL | |
| lastname | varchar(32) | YES | | NULL | |
| title | varchar(32) | YES | | NULL | |
| gender | char(1) | YES | | m | |
| email | varchar(80) | YES | | NULL | |
usr_data索引
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| usr_data | 0 | PRIMARY | 1 | usr_id | A | 29354 | NULL | NULL | | BTREE | | |
| usr_data | 1 | i1_idx | 1 | login | A | 29354 | NULL | NULL | YES | BTREE | | |
| usr_data | 1 | i1_idx | 2 | passwd | A | 29354 | NULL | NULL | YES | BTREE | | |
| usr_data | 1 | i2_idx | 1 | ext_account | A | 2 | NULL | NULL | YES | BTREE | | |
| usr_data | 1 | i2_idx | 2 | auth_mode | A | 4 | NULL | NULL | YES | BTREE | | |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
我试图在LEFT JOIN中为那个SELECT创建一个临时表，但它并没有真正加快它的速度，查询目前需要150秒，右键加入会使其降低到约1秒。 （这是较小的表格。）
select * from object_data where type = 'orgu' returns 1058 rows.
SHOW CREATE TABLE rbac_ua
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| rbac_ua | CREATE TABLE `rbac_ua` (
`usr_id` int(11) NOT NULL DEFAULT '0',
`rol_id` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`usr_id`,`rol_id`),
KEY `i1_idx` (`usr_id`),
KEY `i2_idx` (`rol_id`),
KEY `rol_id` (`rol_id`,`usr_id`),
KEY `rol_usr` (`rol_id`,`usr_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci ROW_FORMAT=DYNAMIC |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
SHOW CREATE TABLE rbac_fa
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| rbac_fa | CREATE TABLE `rbac_fa` (
`rol_id` int(11) NOT NULL DEFAULT '0',
`parent` int(11) NOT NULL DEFAULT '0',
`assign` char(1) COLLATE utf8_unicode_ci DEFAULT NULL,
`protected` char(1) COLLATE utf8_unicode_ci DEFAULT 'n',
PRIMARY KEY (`rol_id`,`parent`),
KEY `i1_idx` (`parent`),
KEY `parent` (`parent`,`rol_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci ROW_FORMAT=DYNAMIC |
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
SHOW CREATE TABLE object_data
+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| object_data | CREATE TABLE `object_data` (
`obj_id` int(11) NOT NULL DEFAULT '0',
`type` char(4) COLLATE utf8_unicode_ci DEFAULT 'none',
`title` char(255) COLLATE utf8_unicode_ci DEFAULT NULL,
`description` char(128) COLLATE utf8_unicode_ci DEFAULT NULL,
`owner` int(11) NOT NULL DEFAULT '0',
`create_date` datetime DEFAULT NULL,
`last_update` datetime DEFAULT NULL,
`import_id` char(50) COLLATE utf8_unicode_ci DEFAULT NULL,
PRIMARY KEY (`obj_id`),
KEY `i1_idx` (`type`),
KEY `i2_idx` (`title`),
KEY `i4_idx` (`import_id`),
FULLTEXT KEY `i3_idx` (`title`,`description`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci ROW_FORMAT=DYNAMIC |
+-------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SHOW CREATE TABLE object_reference
+------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| object_reference | CREATE TABLE `object_reference` (
`ref_id` int(11) NOT NULL DEFAULT '0',
`obj_id` int(11) NOT NULL DEFAULT '0',
`deleted` datetime DEFAULT NULL,
PRIMARY KEY (`ref_id`),
KEY `i1_idx` (`obj_id`),
KEY `i2_idx` (`deleted`),
KEY `obj_id` (`obj_id`,`ref_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci ROW_FORMAT=DYNAMIC |
+------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
如果我遗漏了任何有用的信息，请告诉我。
先谢谢。
答案 0 :(得分：2)
通过删除子选择并使用连接，您应该能够提高性能。首先处理子选择，生成一个临时表，这是一个很大的性能。
SELECT
usr_data.usr_id,
usr_data.login,
object_data.title,
object_reference.ref_id,
rbac_ua.usr_id,
object_data.obj_id,
object_data.title
FROM usr_data
LEFT JOIN rbac_ua
ON rbac_ua.usr_id = usr_data.usr_id
JOIN rbac_fa ON rbac_fa.rol_id = rbac_ua.rol_id
JOIN object_reference ON rbac_fa.parent = object_reference.ref_id
JOIN object_data ON object_data.obj_id = object_reference.obj_id
JOIN object_data role ON role.obj_id = rbac_ua.rol_id
WHERE
object_data.type = 'orgu' AND
usr_data.usr_id > 0 AND
usr_data.login <> "anonymous"
答案 1 :(得分：1)
通过使用LEFT JOIN，您需要一个大型结果集，其中包含与您的WHERE usr_data whatever子句匹配的每个项目的行。即使查询规划器做得很好，也需要时间来推送您的客户端软件。
usr_data.usr_id > 0似乎是多余的，因为您的usr_id列似乎是一个自动增量列。所有值都是零以上吗？
该子选择绝对是一场表现难题。
先生。我想，Thrasher很接近。问题是在LEFT JOIN子句中提到WHERE ed表的列：将LEFT JOIN转换为直JOIN。
试试看你是否得到了合适的结果。我不明白你的架构，所以这里有一点猜测。
SELECT usr_data.usr_id, usr_data.login, object_data.title
FROM usr_data
LEFT JOIN rbac_ua ON rbac_ua.usr_id = usr_data.usr_id
LEFT JOIN rbac_fa ON rbac_fa.rol_id = rbac_ua.rol_id
LEFT JOIN object_reference ON rbac_fa.parent = object_reference.ref_id
LEFT JOIN object_data ON object_data.obj_id = object_reference.obj_id
AND object_data.type = 'orgu'
LEFT JOIN object_data role ON role.obj_id = rbac_ua.rol_id
WHERE usr_data.login <> 'anonymous'
注意object_data.type = 'orgu'子句中ON的结果。 （是的，ON子句可以包含与WHERE子句相同的内容！）这使得它不会使LEFT JOIN成为直的JOIN。
我不确定这一行的重点。
LEFT JOIN object_data role ON role.obj_id = rbac_ua.rol_id
该表似乎不会对您的结果集产生影响。
答案 2 :(得分：1)
从EXPLAIN，我发现优化工具认为“LEFT”没有影响。所以它删除了它。然后它决定“派生表”可以变成JOIN。你可以完成所有这些。
但是，性能方面的真正问题是过滤的重要部分是type = 'orgu'，但是它隐藏在'last'表中。
（此后我猜是因为每个表缺少SHOW CREATE TABLE。并且DESCRIBE不是描述性广告SHOW CREATE。）
让我们来看看：
SELECT ud.usr_id, ud.login, od.title
FROM object_data AS od
JOIN object_reference AS r ON od.obj_id = r.obj_id
JOIN rbac_fa AS rfa ON rfa.parent = r.ref_id
JOIN rbac_ua AS rua ON rfa.rol_id = rua.rol_id
JOIN usr_data AS ud ON ud.usr_id = rua.usr_id
-- unnec?: JOIN object_data role ON role.obj_id = rua.rol_id
WHERE od.type = 'orgu'
AND ud.usr_id > 0
AND ud.login <> "anonymous"
在添加以下索引之后，我认为它更有效。如果type = 'orgu'具有足够的选择性，可能就是这种情况。
请注意，role除了验证给定obj_id的角色确实存在外，不会向查询添加任何内容。
需要索引，以便 启动 {/ 1}}：
type = 'orgu'如果这没有帮助，请提供结果的object_data: INDEX(type)
object_reference: INDEX(obj_id, ref_id) -- (covering, too)
rbac_fa: INDEX(parent, rol_id) -- (covering, too)
rbac_ua: INDEX(rol_id, usr_id) -- (covering, too)
。并告诉我们EXPLAIN SELECT ...有多少行有type = orgu。