自从我开始使用 MariaDB 10 以来，我就遇到了这个问题。查询花费太多时间。使用 MySql 5.5，他们最多需要一分钟才能获得结果集，但使用 MariaDB，我什至在 20 分钟后都看不到结果集。
这个系统运行在Magento 1.7.0.2上，但是这个问题与Magento无关，所以我没有在Magento部分下创建它。
我的服务器管理员说“服务器上一切都很好，查询在 RAM 上运行，当该查询开始运行时，CPU 利用率为 100%，如果您想改进它，您需要更改查询或增加 CPU 功率。 ”。但我很确定这与 MariaDB 和/或数据库服务器设置有关。
如果有人以前遇到过此类问题，请指导我找到正确的路径。
这是应运行以获取用于创建提要的数据的最大查询之一。
SELECT `e`.*, `at_status`.`value` AS `status`, `at_visibility`.`value` AS
`visibility`, `at_quality_score`.`value` AS `quality_score`,
`at_exportable_for_idealo`.`value` AS `exportable`,
`stock`.`qty`, `stock`.`is_in_stock`, `stock`.`manage_stock`,
`stock`.`use_config_manage_stock`, `stock`.`min_qty`,
`stock`.`min_sale_qty`, MAX(DISTINCT request_path) AS `request_path`,
`cpsl`.`parent_id`, `categories`.*, `categories_parent`.*,
GROUP_CONCAT(DISTINCT categories_index.category_id) AS `categories_ids`,
`price_index`.`min_price`, `price_index`.`max_price`,
`price_index`.`tier_price`, `price_index`.`final_price` FROM
`catalog_product_entity` AS `e`
INNER JOIN `catalog_product_website` AS `product_website` ON
product_website.product_id = e.entity_id AND product_website.website_id =
'1'
INNER JOIN `catalog_product_entity_int` AS `at_status` ON
(`at_status`.`entity_id` = `e`.`entity_id`) AND (`at_status`.`attribute_id`
= '96') AND (`at_status`.`store_id` = 0)
INNER JOIN `catalog_product_entity_int` AS `at_visibility` ON
(`at_visibility`.`entity_id` = `e`.`entity_id`) AND
(`at_visibility`.`attribute_id` = '102') AND (`at_visibility`.`store_id` =
0)
INNER JOIN `catalog_product_entity_varchar` AS `at_quality_score` ON
(`at_quality_score`.`entity_id` = `e`.`entity_id`) AND
(`at_quality_score`.`attribute_id` = '313') AND
(`at_quality_score`.`store_id` = 0)
INNER JOIN `catalog_product_entity_int` AS `at_exportable_for_idealo` ON
(`at_exportable_for_idealo`.`entity_id` = `e`.`entity_id`) AND
(`at_exportable_for_idealo`.`attribute_id` = '353') AND
(`at_exportable_for_idealo`.`store_id` = 0)
LEFT JOIN `cataloginventory_stock_item` AS `stock` ON
stock.product_id=e.entity_id
LEFT JOIN `core_url_rewrite` AS `url` ON url.product_id=e.entity_id AND
url.target_path NOT LIKE '%category%' AND is_system=1 AND ISNULL(options)
AND url.store_id=1
LEFT JOIN `catalog_product_super_link` AS `cpsl` ON
cpsl.product_id=e.entity_id
LEFT JOIN `catalog_category_product` AS `categories` ON
categories.product_id=e.entity_id
LEFT JOIN `catalog_category_product` AS `categories_parent` ON
categories_parent.product_id=cpsl.parent_id
LEFT JOIN `catalog_category_product_index` AS `categories_index` ON
((categories_index.category_id=categories.category_id AND
categories_index.product_id=categories.product_id) OR
(categories_index.category_id=categories_parent.category_id AND
categories_index.product_id=categories_parent.product_id )) AND
categories_index.store_id=1
LEFT JOIN `catalog_product_index_price` AS `price_index` ON
price_index.entity_id=e.entity_id AND customer_group_id=0 AND
price_index.website_id=1 WHERE (at_status.value = '1') AND (`e`.`type_id`
IN('simple')) AND (at_visibility.value IN('1')) AND (`e`.`attribute_set_id`
IN('19', '13', '4')) AND ((at_quality_score.value = 'A')) AND
((at_status.value = '1')) AND ((at_exportable_for_idealo.value = '1'))
正如我所说，即使 20 分钟后我也看不到结果!没有抛出异常，没有 sql 错误日志，没有 php 错误日志，什么也没有。即使我直接在 PhpMyAdmin 上运行它，结果也是完全相同的。
提前致谢。
最佳答案
我没有遇到此类问题，但我确信如果您使用子查询编写联接，那么它会优化
而不是这个
内部连接 catalog_product_website AS product_website ON
Product_website.product_id = e.entity_id AND Product_website.website_id =
'1'
这样写
内连接
(从catalog_product_website中选择*
Product_website.website_id = '1') 作为临时值
开
temp.product_id = e.entity_id
如果您在所有联接中更改此设置，则执行查询所需的时间会更少。
关于mysql - MariaDB 上的查询非常非常慢，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34335259/