升级到5.7 cpu后，盒的利用率急剧增加。当我们检查了最常用的查询之一时，我们发现它在5.7中花费了更多时间。粘贴升级前后查询的解释结果
升级mysql 5.6.27之前
explain
SELECT * from `shipments`
LEFT OUTER JOIN `orders` ON `orders`.`id` = `shipments`.`order_id`
LEFT OUTER JOIN `users` `pickup_users` ON `orders`.`pickup_user_id` = `pickup_users`.`id`
LEFT OUTER JOIN `users` `drop_users` ON `orders`.`drop_user_id` = `drop_users`.`id`
LEFT OUTER JOIN `merchants` ON `orders`.`source_id` = `merchants`.`id`
LEFT OUTER JOIN `users` `source_users` ON `merchants`.`user_id` = `source_users`.`id`
LEFT OUTER JOIN `user_addresses` `pickup_user_address` ON `orders`.`pickup_user_address_id` = `pickup_user_address`.`id`
LEFT OUTER JOIN `user_addresses` `drop_user_address` ON `orders`.`drop_user_address_id` = `drop_user_address`.`id`
LEFT OUTER JOIN `driver_queues` `driver_queues` ON `orders`.`id` = `driver_queues`.`order_id`
WHERE `pickup_user_address`.`city_id` = 10
ORDER BY `shipments`.`id` DESC
LIMIT 20 ;
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+---------------------+--------+------------------------------------------------+----------------------------------------+---------+-------------------------------------------+---------+---------------------------------+
| 1 | SIMPLE | pickup_user_address | ref | PRIMARY,index_user_addresses_on_city_id | index_user_addresses_on_city_id | 4 | const | 1156876 | Using temporary; Using filesort |
| 1 | SIMPLE | orders | ref | PRIMARY,index_orders_on_pickup_user_address_id | index_orders_on_pickup_user_address_id | 5 | carthero_prod.pickup_user_address.id | 7 | Using index condition |
| 1 | SIMPLE | drop_user_address | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.orders.drop_user_address_id | 1 | NULL |
| 1 | SIMPLE | shipments | ref | index_shipments_on_order_id | index_shipments_on_order_id | 5 | carthero_prod.orders.id
| 1 | NULL |
| 1 | SIMPLE | driver_queues | ref | index_driver_queues_on_order_id | index_driver_queues_on_order_id | 5 | carthero_prod.orders.id | 1 | NULL |
| 1 | SIMPLE | pickup_users | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.orders.pickup_user_id | 1 | NULL |
| 1 | SIMPLE | drop_users | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.orders.drop_user_id | 1 | NULL |
| 1 | SIMPLE | merchants | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.orders.source_id | 1 | NULL |
| 1 | SIMPLE | source_users | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.merchants.user_id | 1 | NULL |
+----+-------------+---------------------+--------+------------------------------------------------+----------------------------------------+---------+-------------------------------------------+---------+---------------------------------+
升级到5.7.21后
explain
SELECT * from `shipments`
LEFT OUTER JOIN `orders` ON `orders`.`id` = `shipments`.`order_id`
LEFT OUTER JOIN `users` `pickup_users` ON `orders`.`pickup_user_id` = `pickup_users`.`id`
LEFT OUTER JOIN `users` `drop_users` ON `orders`.`drop_user_id` = `drop_users`.`id`
LEFT OUTER JOIN `merchants` ON `orders`.`source_id` = `merchants`.`id`
LEFT OUTER JOIN `users` `source_users` ON `merchants`.`user_id` = `source_users`.`id`
LEFT OUTER JOIN `user_addresses` `pickup_user_address` ON `orders`.`pickup_user_address_id` = `pickup_user_address`.`id`
LEFT OUTER JOIN `user_addresses` `drop_user_address` ON `orders`.`drop_user_address_id` = `drop_user_address`.`id`
LEFT OUTER JOIN `driver_queues` `driver_queues` ON `orders`.`id` = `driver_queues`.`order_id`
WHERE `pickup_user_address`.`city_id` = 10
ORDER BY `shipments`.`id` DESC
LIMIT 20 ;
+----+-------------+---------------------+------------+--------+------------------------------------------------+---------------------------------+---------+---------------------------------------------+----------+----------+----------------------------------------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+---------------------+------------+--------+------------------------------------------------+---------------------------------+---------+---------------------------------------------+----------+----------+----------------------------------------------+
| 1 | SIMPLE | orders | NULL | ALL | PRIMARY,index_orders_on_pickup_user_address_id | NULL | NULL | NULL | 24079764 | 100.00 | Using where; Using temporary; Using filesort |
| 1 | SIMPLE | pickup_users | NULL | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.orders.pickup_user_id | 1 | 100.00 | NULL |
| 1 | SIMPLE | drop_users | NULL | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.orders.drop_user_id | 1 | 100.00 | NULL |
| 1 | SIMPLE | merchants | NULL | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.orders.source_id | 1 | 100.00 | NULL |
| 1 | SIMPLE | pickup_user_address | NULL | eq_ref | PRIMARY,index_user_addresses_on_city_id | PRIMARY | 4 | carthero_prod.orders.pickup_user_address_id | 1 | 10.83 | Using where |
| 1 | SIMPLE | source_users | NULL | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.merchants.user_id | 1 | 100.00 | NULL |
| 1 | SIMPLE | drop_user_address | NULL | eq_ref | PRIMARY | PRIMARY | 4 | carthero_prod.orders.drop_user_address_id | 1 | 100.00 | NULL |
| 1 | SIMPLE | driver_queues | NULL | ref | index_driver_queues_on_order_id | index_driver_queues_on_order_id | 5 | carthero_prod.orders.id | 1 | 100.00 | NULL |
| 1 | SIMPLE | shipments | NULL | ref | index_shipments_on_order_id | index_shipments_on_order_id | 5 | carthero_prod.orders.id | 1 | 100.00 | NULL |
+----+-------------+---------------------+------------+--------+------------------------------------------------+---------------------------------+---------+---------------------------------------------+----------+----------+----------------------------------------------+