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我有一个正在尝试优化的浏览类别查询。我以使用临时结束;在解释中使用文件排序,并且查询在具有 60,000 行的类别上很慢。如果我删除 Order By 子句,查询运行速度非常快 0.05 秒以执行 60,000 行。使用 Order By 子句,它的速度非常慢,大约 5 秒。Parts 和 Parts_Category 一样包含大约 500,000 行。

我有一个关于部件(状态、级别、仓库、更新)的组索引,称为 sort_index

在解释的顶部我有 | 全部 | 使用临时的;使用文件排序

所有其他索引都显示正常。有人可以告诉我可能是什么问题吗?我没主意了。也许我应该重新排列这个查询,以便我可以获得更好的性能?

询问。

SELECT Parts.*, Image.type, Image.width, Image.height,
(SELECT name FROM Location_State WHERE id = Parts.state_id) AS state, 
(SELECT name FROM Location_Region WHERE id = Parts.region_id) AS region, 
(SELECT start_date FROM Promotion WHERE id = Parts.promotion_id) AS promotion_start_date, 
(SELECT end_date FROM Promotion WHERE id = Parts.promotion_id) AS promotion_end_date 
FROM ( SELECT parts_id FROM Parts_Category WHERE Parts_Category.category_id = '40' 
UNION SELECT parts_id FROM Parts_Category WHERE Parts_Category.main_category_id = '40') cid 
LEFT JOIN Image ON Parts.image_id = Image.id
JOIN Parts ON Parts.id = cid.parts_id AND Parts.status = 'A'
ORDER BY Parts.level DESC, Parts.warehouse DESC, Parts.updated DESC LIMIT 0, 15
表格部件的表格结构

字段类型 Null 默认值
id int(11) 无 auto_increment
image_id int(11) 是 0
gallery_id int(11) 是 0
image_count int(3) 是 0
Promotion_id int(11) 是 0
country_id int(11) 是 NULL
state_id int(11) 是 NULL
region_id int(11) 是 NULL
city_id int(11) 是 NULL
area_id int(11) 是 NULL
更新日期时间 是 0000-00-00 00:00:00
输入日期时间 是 0000-00-00 00:00:00
续订日期 是 0000-00-00
discount_id varchar(10) 是 NULL
标题 varchar(100) 是
search_title varchar(255) 是
仓库 varchar(50) 是
url varchar(255) 是
display_url varchar(255) 是
friendly_url varchar(100) 是 NULL
说明 varchar(255) 是
关键字 varchar(1000) 是 NULL
附件文件 varchar(255) 是
attachment_caption varchar(255) 是
状态字符(1) 是
级别 tinyint(3) 是 0
全球 tinyint(1) 是 0
random_number int(11) 是 NULL
提醒 tinyint(4) 是 NULL
category_search varchar(1000) 是
video_snippet varchar(1000) 是
importID int(11) 是 0

索引

主要编号 518623
随机数索引 32201 随机数
country_id 索引 1 country_id
state_id 索引 8 state_id
region_id 索引 5 region_id
更新日期索引 1 更新日期
全球 INDEX 1 全球
友好的 URL 索引 518623 友好的 URL
Promotion_id 索引 1 Promotion_id
city_id 索引 1 city_id
area_id 索引 1 area_id
邮编索引 2790 邮编
进口 ID 索引 518623 进口 ID
image_id 索引 10 image_id

--------------
index_browse_category 索引 52
等级
地位
仓库   
更新
-----------------
关键词全文 1
描述
关键词
类别搜索


Parts_Category

id int(11) 无 auto_increment     
parts_id int(11) 否 0       
category_id int(11) 否 0       
main_category_id int(10) 否 0   

指数

初级 初级 519330 id
category_id 索引 519330 category_id
零件编号
main_category_id 索引 519330 main_category_id
零件编号





4

2 回答 2

42

尝试将您的查询重写为:

SELECT  p.*, i.type, i.width, i.height,
        (SELECT name FROM Location_State WHERE id = p.state_id) AS state, 
        (SELECT name FROM Location_Region WHERE id = p.region_id) AS region, 
        (SELECT start_date FROM Promotion WHERE id = p.promotion_id) AS promotion_start_date, 
        (SELECT end_date FROM Promotion WHERE id = p.promotion_id) AS promotion_end_date 
FROM    parts p
LEFT JOIN
        image i
ON      i.id = p.image_id
WHERE   EXISTS (
        SELECT  NULL
        FROM    Parts_Category pc
        WHERE   pc.category_id = '40'
                AND pc.parts_id = p.id
        UNION ALL
        SELECT  NULL
        FROM    Parts_Category pc
        WHERE   pc.main_category_id = '40'
                AND pc.parts_id = p.id
        )
        AND p.status = 'A'
ORDER BY
        p.status DESC, p.level DESC, p.warehouse DESC, p.updated DESC
LIMIT   15

您需要以下索引才能有效地工作:

parts (status, level, warehouse, updated) -- this one you have
parts_category (category_id, parts_id)
parts_category (main_category_id, parts_id)

更新:

我刚刚创建了这样的表:

DROP TABLE IF EXISTS `test`.`image`;
CREATE TABLE  `test`.`image` (
  `id` int(11) NOT NULL,
  `type` int(11) NOT NULL,
  `width` int(11) NOT NULL,
  `height` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `test`.`location_region`;
CREATE TABLE  `test`.`location_region` (
  `id` int(11) NOT NULL,
  `name` varchar(20) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `test`.`location_state`;
CREATE TABLE  `test`.`location_state` (
  `id` int(11) NOT NULL,
  `name` varchar(20) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `test`.`parts`;
CREATE TABLE  `test`.`parts` (
  `id` int(11) NOT NULL,
  `status` char(1) NOT NULL,
  `level` int(11) NOT NULL,
  `warehouse` int(11) NOT NULL,
  `updated` int(11) NOT NULL,
  `state_id` int(11) NOT NULL,
  `region_id` int(11) NOT NULL,
  `promotion_id` int(11) NOT NULL,
  `image_id` int(11) NOT NULL DEFAULT '1',
  PRIMARY KEY (`id`),
  KEY `status` (`status`,`level`,`warehouse`,`updated`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `test`.`parts_category`;
CREATE TABLE  `test`.`parts_category` (
  `id` int(11) NOT NULL,
  `parts_id` int(11) NOT NULL,
  `category_id` int(11) NOT NULL,
  `main_category_id` int(11) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `ix_pc_cat_parts` (`category_id`,`parts_id`),
  KEY `ix_pc_main_parts` (`main_category_id`,`parts_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `test`.`promotion`;
CREATE TABLE  `test`.`promotion` (
  `id` int(11) NOT NULL,
  `start_date` datetime NOT NULL,
  `end_date` datetime NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

并用样本数据填充它们:

INSERT
INTO    parts
SELECT  id,
        CASE WHEN RAND() < 0.1 THEN 'A' ELSE 'B' END,
        RAND() * 100,
        RAND() * 100,
        RAND() * 100,
        RAND() * 50,
        RAND() * 50,
        RAND() * 50,
        RAND() * 50
FROM    t_source
LIMIT 500000;
INSERT
INTO    parts_category
SELECT  id,
        id,
        RAND() * 100,
        RAND() * 100
FROM    t_source
LIMIT 500000;
INSERT
INTO    location_state
SELECT  id, CONCAT('State ', id)
FROM    t_source
LIMIT 1000;
INSERT
INTO    location_region
SELECT  id, CONCAT('Region ', id)
FROM    t_source
LIMIT 1000;
INSERT
INTO    promotion
SELECT  id,
        '2009-07-22' - INTERVAL RAND() * 5 - 20 DAY,
        '2009-07-22' - INTERVAL RAND() * 5 DAY
FROM    t_source
LIMIT 1000;

上面的查询运行30 milliseconds并产生以下计划:

1, 'PRIMARY', 'p', 'ref', 'status', 'status', '3', 'const', 107408, 'Using where'
1, 'PRIMARY', 'i', 'eq_ref', 'PRIMARY', 'PRIMARY', '4', 'test.p.image_id', 1, ''
6, 'DEPENDENT SUBQUERY', 'pc', 'ref', 'ix_pc_cat_parts', 'ix_pc_cat_parts', '8', 'const,test.p.id', 1, 'Using index'
7, 'DEPENDENT UNION', 'pc', 'ref', 'ix_pc_main_parts', 'ix_pc_main_parts', '8', 'const,test.p.id', 1, 'Using index'
, 'UNION RESULT', '<union6,7>', 'ALL', '', '', '', '', , ''
5, 'DEPENDENT SUBQUERY', 'Promotion', 'eq_ref', 'PRIMARY', 'PRIMARY', '4', 'test.p.promotion_id', 1, ''
4, 'DEPENDENT SUBQUERY', 'Promotion', 'eq_ref', 'PRIMARY', 'PRIMARY', '4', 'test.p.promotion_id', 1, ''
3, 'DEPENDENT SUBQUERY', 'Location_Region', 'eq_ref', 'PRIMARY', 'PRIMARY', '4', 'test.p.region_id', 1, ''
2, 'DEPENDENT SUBQUERY', 'Location_State', 'eq_ref', 'PRIMARY', 'PRIMARY', '4', 'test.p.state_id', 1, ''

如您所见,不temporary,不filesort,一切都非常快。

为了帮助你,我只需要看看你的表是如何定义的。

于 2009-07-22T15:04:45.817 回答
1

约翰,问题是您的查询是从派生表中选择的。派生表无法从您的索引中受益。尝试按如下方式更新您的查询:

SELECT
  Parts.*,
  Image.type, Image.width, Image.height,
  Location_State.name AS state,
  Location_Region.name AS region,
  Promotion.start_date AS promotion_start_date,
  Promotion.end_date AS promotion_end_date
FROM Parts
LEFT JOIN Image ON Parts.image_id = Image.id
LEFT JOIN Location_State ON Parts.state_id = Location_State.id
LEFT JOIN Location_Region ON Parts.state_id = Location_Region.id
LEFT JOIN Promotion ON Parts.promotion_id = Promotion.id
INNER JOIN Parts_Category ON (Parts_Category.category_id = 40 OR Parts_Category.main_category_id = 40)
WHERE Parts.status = 'A'
GROUP BY Parts.id
ORDER BY Parts.level DESC, Parts.warehouse DESC, Parts.updated DESC LIMIT 0, 15

请注意,如果您的 Location_State、Location_Region、Promotion 表不需要 LEFT JOIN,请改用 INNER JOIN。它可能会表现得更好。

为了进一步帮助优化此查询,请提供以下信息:

SHOW CREATE TABLE Parts;

如果我提供的重写查询与您的示例相同(应该),那么还提供:

EXPLAIN <my query here>\G
于 2009-07-22T15:28:30.660 回答