問題：昨天線上出現報錯導致一個功能無法執行，查詢日誌發現是mysql的死鎖問題。
分析問題：其實解決問題最大的難點在於分析問題找到出現問題出現在哪裡，這個過程花費的時間和思考是最多的，而使用程式碼解決問題反而很快速。
（1）報錯日誌如下：
2021-10-09 18:59:04] local.INFO: RobotAuction-SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction (SQL: select id, cash, freeze, area_id from users where users.id in (2634, 2662, 2672, 2673, 2675, 2685, 2808, 2811, 2818, 2834, 2869, 2886, 2926, 2961, 2962, 2981, 3066, 3080, 3124, 3131, 3135) and users.deleted_at is null for update)-669
從報錯日誌上去檢視msyql的死鎖日誌，再結合業務上的可能的操作進行分析
（2）死鎖日誌：
2021-10-09 18:59:04 0x150d81d79700
* (1) TRANSACTION:
TRANSACTION 385220, ACTIVE 0 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 11 lock struct(s), heap size 1136, 19 row lock(s)
MySQL thread id 1376113, OS thread handle 23147762767616, query id 23440050 localhost 127.0.0.1 lpt Sending data
select `id`, `cash`, `freeze`, `area_id` from `users` where `users`.`id` in (2634, 2662, 2672, 2673, 2675, 2685, 2808, 2811, 2818, 2834, 2869, 2886, 2926, 2961, 2962, 2981, 3066, 3080, 3124, 3131, 3135) and `users`.`deleted_at` is null
for update(1) WAITING FOR THIS LOCK TO BE GRANTED: 【1】持有id = 2675的鎖，等待id = 3124 的事務鎖
RECORD LOCKS space id 191 page no 14 n bits 120 index PRIMARY of table lpt.users trx id 385220 lock_mode X locks rec but not gap waiting
Record lock, heap no 49 PHYSICAL RECORD: n_fields 52; compact format; info bits 0
** 省略部分
* (2) TRANSACTION:
TRANSACTION 385219, ACTIVE 0 sec starting index read
mysql tables in use 1, locked 1
7 lock struct(s), heap size 1136, 3 row lock(s), undo log entries 6
MySQL thread id 1376112, OS thread handle 23147757147904, query id 23440106 localhost 127.0.0.1 lpt statistics
select `id`, `cash` from `users` where `users`.`id` = 2675 and `users`.`deleted_at` is null limit 1 for update(2) HOLDS THE LOCK(S): 【2】持有id=3124的鎖
RECORD LOCKS space id 191 page no 14 n bits 120 index PRIMARY of table lpt.users trx id 385219 lock_mode X locks rec but not gap
Record lock, heap no 49 PHYSICAL RECORD: n_fields 52; compact format; info bits 0
** 省略部分
(2) WAITING FOR THIS LOCK TO BE GRANTED: 【3】等待 id = 2675的資料釋放鎖
RECORD LOCKS space id 191 page no 6 n bits 120 index PRIMARY of table lpt.users trx id 385219 lock_mode X locks rec but not gap waiting
Record lock, heap no 32 PHYSICAL RECORD: n_fields 52; compact format; info bits 0
** 省略部分
* WE ROLL BACK TRANSACTION (1) 【4】選擇開銷小的進行回滾，選擇了事務（1），對照前面的任務未執行，回滾了
問題所在：
1、使用的鎖都是排他鎖
2、這典型的加鎖順序不同造成的死鎖
3、分析過程【1】【2】【3】【4】
解析辦法
1、通過分析業務，調整業務上的順序來解決 ✔
2、通過表鎖來解決，卻會犧牲效能並且不能使用索引 ×