| SESSION 1 | SESSION 2 | SESSION 3 |
| START TRANSACTION | START TRANSACTION | START TRANSACTION |
| INSERT | ||
| INSERT | ||
| INSERT | ||
| ROLLBACK | ||
| Deadlock |
解决方案：无解决方案
| SESSION 1 | SESSION 2 |
| START TRANSACTION | START TRANSACTION |
| SELECT FOR UPDATE | |
| SELECT FOR UPDATE | |
| INSERT | |
| INSERT | |
| Deadlock |
解决方案：移除 SELECT FOR UPDATE，改为扑捉 INSERT 的主键冲突的错误。
| SESSION 1 | SESSION 2 |
| START TRANSACTION | START TRANSACTION |
| DELTE WHERE a | |
| DELTE WHERE a | |
| INSERT VALUES(a) | |
| INSERT VALUES(a) | |
| Deadlock |
解决方案：先判断是否存在，存在时更新，不存在时插入
| SESSION 1 | SESSION 2 | SESSION 3 |
| START TRANSACTION | START TRANSACTION | |
| INSERT | ||
| INSERT | ||
| INSERT | ||
| COMMIT | ||
| SELECT FOR UPDATE | ||
| SELECT FOR UPDATE | ||
| Deadlock |
解决方案：将SELECT FOR UPDATE 改为 SELECT LOCK IN SHARE MODE
| SESSION 1 | SESSION 2 |
| START TRANSACTION | START TRANSACTION |
| UPDATE a | |
| UPDATE b | |
| UPDATE b | |
| UPDATE a | |
| Deadlock |
解决方案：请保持写表顺序一致-=