MySQL-查询优化缓慢

问题描述

我在优化一个非常慢的prestashop SQL查询时遇到问题（MysqL需要2秒钟以上才能得到结果）。

SELECT sql_CALC_FOUND_ROWS a.`id_order`,`reference`,`total_paid_tax_incl`,`payment`,a.`date_add`                                       AS `date_add`,a.id_currency,a.id_order                                         AS id_pdf,CONCAT(LEFT(c.`firstname`,1),'. ',c.`lastname`) AS `customer`,osl.`name`                                         AS `osname`,os.`color`,carrier.`name`                                     AS `carriername`,country_lang.name                                  as cname,IF(a.valid,1,0)                                     badge_success,shop.name                                          as shop_name
FROM `ps_orders` a
         LEFT JOIN `ps_customer` c ON (c.`id_customer` = a.`id_customer`)
         INNER JOIN `ps_address` address ON address.id_address = a.id_address_delivery
         INNER JOIN `ps_country` country ON address.id_country = country.id_country
         INNER JOIN `ps_country_lang` country_lang
                    ON (country.`id_country` = country_lang.`id_country` AND country_lang.`id_lang` = 2)
         INNER JOIN `ps_carrier` carrier ON (carrier.`id_carrier` = a.`id_carrier`)
         LEFT JOIN `ps_order_state` os ON (os.`id_order_state` = a.`current_state`)
         LEFT JOIN `ps_order_state_lang` osl ON (os.`id_order_state` = osl.`id_order_state` AND osl.`id_lang` = 2)
         LEFT JOIN `ps_shop` shop ON a.`id_shop` = shop.`id_shop`
WHERE 1
  AND a.id_shop IN (1,5,3,4)
ORDER BY a.id_order DESC
LIMIT 0,50;

解释结果

CREATE TABLE `ps_orders` (
  `id_order` int(10) unsigned NOT NULL AUTO_INCREMENT,`reference` varchar(9) DEFAULT NULL,`id_shop_group` int(11) unsigned NOT NULL DEFAULT '1',`id_shop` int(11) unsigned NOT NULL DEFAULT '1',`id_carrier` int(10) unsigned NOT NULL,`id_lang` int(10) unsigned NOT NULL,`id_customer` int(10) unsigned NOT NULL,`id_cart` int(10) unsigned NOT NULL,`id_currency` int(10) unsigned NOT NULL,`id_address_delivery` int(10) unsigned NOT NULL,`id_address_invoice` int(10) unsigned NOT NULL,`current_state` int(10) unsigned NOT NULL,`secure_key` varchar(32) NOT NULL DEFAULT '-1',`payment` varchar(255) NOT NULL,`conversion_rate` decimal(13,6) NOT NULL DEFAULT '1.000000',`module` varchar(255) DEFAULT NULL,`recyclable` tinyint(1) unsigned NOT NULL DEFAULT '0',`gift` tinyint(1) unsigned NOT NULL DEFAULT '0',`gift_message` text,`mobile_theme` tinyint(1) NOT NULL DEFAULT '0',`shipping_number` varchar(64) DEFAULT NULL,`total_discounts` decimal(20,6) NOT NULL DEFAULT '0.000000',`total_discounts_tax_incl` decimal(20,`total_discounts_tax_excl` decimal(20,`total_paid` decimal(20,`total_paid_tax_incl` decimal(20,`total_paid_tax_excl` decimal(20,`total_paid_real` decimal(20,`total_products` decimal(20,`total_products_wt` decimal(20,`total_shipping` decimal(20,`total_shipping_tax_incl` decimal(20,`total_shipping_tax_excl` decimal(20,`carrier_tax_rate` decimal(10,3) NOT NULL DEFAULT '0.000',`total_wrapping` decimal(20,`total_wrapping_tax_incl` decimal(20,`total_wrapping_tax_excl` decimal(20,`round_mode` tinyint(1) NOT NULL DEFAULT '2',`round_type` tinyint(1) NOT NULL DEFAULT '1',`invoice_number` int(10) unsigned NOT NULL DEFAULT '0',`delivery_number` int(10) unsigned NOT NULL DEFAULT '0',`invoice_date` datetime NOT NULL,`delivery_date` datetime NOT NULL,`valid` int(1) unsigned NOT NULL DEFAULT '0',`date_add` datetime NOT NULL,`date_upd` datetime NOT NULL,`client_message` text,`ac_processed` tinyint(1) DEFAULT '0',`twilio` tinyint(1) DEFAULT NULL,`stop_sync` int(1) NOT NULL DEFAULT '0',`moloni_internal` tinyint(1) DEFAULT '0',`moloni_offers` tinyint(1) DEFAULT '0',`bonus_credited_at` datetime DEFAULT NULL,`Feedback_survey_sent_at` timestamp NULL DEFAULT NULL,PRIMARY KEY (`id_order`),KEY `reference` (`reference`),KEY `id_customer` (`id_customer`),KEY `id_cart` (`id_cart`),KEY `invoice_number` (`invoice_number`),KEY `id_carrier` (`id_carrier`),KEY `id_lang` (`id_lang`),KEY `id_currency` (`id_currency`),KEY `id_address_delivery` (`id_address_delivery`),KEY `id_address_invoice` (`id_address_invoice`),KEY `id_shop_group` (`id_shop_group`),KEY `current_state` (`current_state`),KEY `id_shop` (`id_shop`),KEY `date_add` (`date_add`)
) ENGINE=InnoDB AUTO_INCREMENT=185578 DEFAULT CHARSET=utf8

我发现，如果同时删除 sql_CALC_FOUNDS_ROWS和order by子句，则执行时间将从2秒减少到250ms。

这是来自Prestashop的查询...不确定我是否可以删除 sql_CALC_FOUND_ROWS及其影响。

如何优化此查询？

解决方法

这能给出正确的计数吗？

SELECT COUNT(*) FROM a
    WHERE a.id_shop IN (1,5,3,4)

如果是，则使用SELECT FOUND_ROWS()中的。

这是否给您想要的a行？

SELECT a.id FROM a
    WHERE a.id_shop IN (1,4)
    ORDER BY a.id_order DESC
    LIMIT 0,50;

将这两个索引添加到a：

INDEX(id_shop,id_order),INDEX(id_order)

以上查询是否在合理的时间内运行？

如果是，请执行类似的操作

SELECT ...
    FROM ( the query above,with the ORDER BY and LIMIT )
    JOIN a  USING(id)   -- "self join"
    and the rest of the joins
    ORDER BY a.id_order DESC;

请提供SHOW CREATE TABLE ps_orders 文字而不是图片。

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