提高 SQL 查询性能

debugcn 发表于 Dev

埃布拉希米

我有一个复杂的查询，在我的机器上运行需要 700 毫秒。我发现瓶颈是ORDER BY at_firstname.value子句，但我如何使用索引来改进这一点？

SELECT 
    `e`.*
    , `at_default_billing`.`value` AS `default_billing`
    , `at_billing_postcode`.`value` AS `billing_postcode`
    , `at_billing_city`.`value` AS `billing_city`
    , `at_billing_region`.`value` AS `billing_region`
    , `at_billing_country_id`.`value` AS `billing_country_id`
    , `at_company`.`value` AS `company`
    , `at_firstname`.`value` AS `firstname`
    , `at_lastname`.`value` AS `lastname`
    , CONCAT(at_firstname.value
    , " "
    , at_lastname.value) AS `full_name`
    , `at_phone`.`value` AS `phone`
    , IFNULL(at_phone.value,"N/A") AS `telephone`
    , `e`.`entity_id` AS `id` 
FROM 
    `customer_entity` AS `e`  
LEFT JOIN 
    `customer_entity_int` AS `at_default_billing` 
    ON (`at_default_billing`.`entity_id` = `e`.`entity_id`) 
    AND (`at_default_billing`.`attribute_id` = '13')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_billing_postcode` 
    ON (`at_billing_postcode`.`entity_id` = `at_default_billing`.`value`)        
    AND (`at_billing_postcode`.`attribute_id` = '30')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_billing_city` 
    ON (`at_billing_city`.`entity_id` = `at_default_billing`.`value`) 
    AND (`at_billing_city`.`attribute_id` = '26')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_billing_region` 
    ON (`at_billing_region`.`entity_id` = `at_default_billing`.`value`) 
    AND (`at_billing_region`.`attribute_id` = '28')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_billing_country_id` 
    ON (`at_billing_country_id`.`entity_id` = `at_default_billing`.`value`) 
    AND (`at_billing_country_id`.`attribute_id` = '27')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_company` 
    ON (`at_company`.`entity_id` = `at_default_billing`.`value`) 
    AND (`at_company`.`attribute_id` = '24')  
LEFT JOIN 
    `customer_entity_varchar` AS `at_firstname` 
    ON (`at_firstname`.`entity_id` = `e`.`entity_id`) 
    AND (`at_firstname`.`attribute_id` = '5')  
LEFT JOIN 
    `customer_entity_varchar` AS `at_lastname` 
    ON (`at_lastname`.`entity_id` = `e`.`entity_id`) 
    AND (`at_lastname`.`attribute_id` = '7')  
LEFT JOIN 
    `customer_entity_varchar` AS `at_phone` 
    ON (`at_phone`.`entity_id` = `e`.`entity_id`) 
    AND (`at_phone`.`attribute_id` = '136')  
ORDER BY 
    `at_firstname`.`value` ASC LIMIT 20

这是执行计划：

查询说明：

'1','SIMPLE','e',NULL,'ALL',NULL,NULL,NULL,NULL,'19951','100.00','Using temporary; Using filesort'
'1','SIMPLE','at_default_billing',NULL,'eq_ref','UNQ_CUSTOMER_ENTITY_INT_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_INT_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_INT_ENTITY_ID,IDX_CUSTOMER_ENTITY_INT_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ENTITY_INT_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.e.entity_id,const','1','100.00',NULL
'1','SIMPLE','at_billing_postcode',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_billing_city',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_billing_region',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_billing_country_id',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_company',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_firstname',NULL,'eq_ref','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.e.entity_id,const','1','100.00',NULL
'1','SIMPLE','at_lastname',NULL,'eq_ref','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.e.entity_id,const','1','100.00',NULL
'1','SIMPLE','at_phone',NULL,'eq_ref','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.e.entity_id,const','1','100.00',NULL

表结构：

CREATE TABLE `customer_entity_varchar` (
  `value_id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'Value Id',
  `entity_type_id` smallint(5) unsigned NOT NULL DEFAULT '0' COMMENT 'Entity Type Id',
  `attribute_id` smallint(5) unsigned NOT NULL DEFAULT '0' COMMENT 'Attribute Id',
  `entity_id` int(10) unsigned NOT NULL DEFAULT '0' COMMENT 'Entity Id',
  `value` varchar(255) DEFAULT NULL COMMENT 'Value',
  PRIMARY KEY (`value_id`),
  UNIQUE KEY `UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID` (`entity_id`,`attribute_id`),
  KEY `IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_TYPE_ID` (`entity_type_id`),
  KEY `IDX_CUSTOMER_ENTITY_VARCHAR_ATTRIBUTE_ID` (`attribute_id`),
  KEY `IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID` (`entity_id`),
  KEY `IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE` (`entity_id`,`attribute_id`,`value`),
  CONSTRAINT `FK_CSTR_ENTT_VCHR_ATTR_ID_EAV_ATTR_ATTR_ID` FOREIGN KEY (`attribute_id`) REFERENCES `eav_attribute` (`attribute_id`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `FK_CSTR_ENTT_VCHR_ENTT_TYPE_ID_EAV_ENTT_TYPE_ENTT_TYPE_ID` FOREIGN KEY (`entity_type_id`) REFERENCES `eav_entity_type` (`entity_type_id`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `FK_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_CUSTOMER_ENTITY_ENTITY_ID` FOREIGN KEY (`entity_id`) REFERENCES `customer_entity` (`entity_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=131094 DEFAULT CHARSET=utf8 COMMENT='Customer Entity Varchar';

穿刺者

截至目前，您的查询是：

首先执行所有左外连接。
然后ORDERing 行。
然后LIMITing 行。

我会首先执行严格需要的外连接，然后排序和限制（减少到 20 行），最后我会执行所有其余的外连接。简而言之，我会这样做：

首先执行最小左外连接。也就是说，只有两个表。
然后ORDERing 行。
然后LIMITing 行。这最多产生 20 行。
执行所有其余的外部联接。在这一点上，这不再是数千行，而是只有 20 行。

此更改应该会大大减少“唯一键查找”的执行次数。修改后的查询将如下所示：

select
  e.*
  , `at_default_billing`.`value` AS `default_billing`
  , `at_billing_postcode`.`value` AS `billing_postcode`
  , `at_billing_city`.`value` AS `billing_city`
  , `at_billing_region`.`value` AS `billing_region`
  , `at_billing_country_id`.`value` AS `billing_country_id`
  , `at_company`.`value` AS `company`
  , `at_lastname`.`value` AS `lastname`
  , CONCAT(firstname
  , " "
  , at_lastname.value) AS `full_name`
  , `at_phone`.`value` AS `phone`
  , IFNULL(at_phone.value,"N/A") AS `telephone`
from ( -- Step #1: joining customer_entity with customer_entity_varchar
SELECT 
    `e`.*
    , `at_firstname`.`value` AS `firstname`
    , `e`.`entity_id` AS `id` 
FROM 
    `customer_entity` AS `e`  
LEFT JOIN 
    `customer_entity_varchar` AS `at_firstname` 
    ON (`at_firstname`.`entity_id` = `e`.`entity_id`) 
    AND (`at_firstname`.`attribute_id` = '5')  
ORDER BY -- Step #2: Sorting (the bare minimum)
    `at_firstname`.`value` ASC 
LIMIT 20 -- Step #3: Limiting (to 20 rows)
) e
LEFT JOIN -- Step #4: Performing all the rest of outer joins (only few rows now)
    `customer_entity_int` AS `at_default_billing` 
    ON (`at_default_billing`.`entity_id` = `e`.`entity_id`) 
    AND (`at_default_billing`.`attribute_id` = '13')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_billing_postcode` 
    ON (`at_billing_postcode`.`entity_id` = `at_default_billing`.`value`)        
    AND (`at_billing_postcode`.`attribute_id` = '30')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_billing_city` 
    ON (`at_billing_city`.`entity_id` = `at_default_billing`.`value`) 
    AND (`at_billing_city`.`attribute_id` = '26')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_billing_region` 
    ON (`at_billing_region`.`entity_id` = `at_default_billing`.`value`) 
    AND (`at_billing_region`.`attribute_id` = '28')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_billing_country_id` 
    ON (`at_billing_country_id`.`entity_id` = `at_default_billing`.`value`) 
    AND (`at_billing_country_id`.`attribute_id` = '27')  
LEFT JOIN 
    `customer_address_entity_varchar` AS `at_company` 
    ON (`at_company`.`entity_id` = `at_default_billing`.`value`) 
    AND (`at_company`.`attribute_id` = '24')  
LEFT JOIN 
    `customer_entity_varchar` AS `at_lastname` 
    ON (`at_lastname`.`entity_id` = `e`.`entity_id`) 
    AND (`at_lastname`.`attribute_id` = '7')  
LEFT JOIN 
    `customer_entity_varchar` AS `at_phone` 
    ON (`at_phone`.`entity_id` = `e`.`entity_id`) 
    AND (`at_phone`.`attribute_id` = '136')

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