查看mysql是否有锁

SHOW ENGINE INNODB STATUS;

-- 事务1
START TRANSACTION;
SELECT * FROM users WHERE id = 1 LOCK IN SHARE MODE;

-- 事务2
START TRANSACTION;
UPDATE users SET name = 'new_name' WHERE id = 1;

SHOW ENGINE INNODB STATUS;

---TRANSACTION 281475200388544, ACTIVE 3 sec updating or deleting
3 lock struct(s), heap size 1136, 2 row lock(s), undo log entries 1
MySQL thread id 12345, OS thread handle 0x7f8d9e0f1700, query id 67890 localhost root updating
UPDATE users SET name = 'new_name' WHERE id = 1
------- TRX HAS BEEN WAITING 3 SEC FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 18 page no 3 n bits 72 index `PRIMARY` of table `test`.`users` trx id 281475200388544 lock_mode X locks rec but not gap waiting
Record lock, heap no 3 PHYSICAL RECORD: n_fields 5; compact format; info bits 0
 0: len 4; hex 80000001; asc     ;;
 1: len 6; hex 00000000000a; asc       ;;
 2: len 7; hex 000000002f0d0c; asc     /  ;;
 3: len 4; hex 80000001; asc     ;;
 4: len 4; hex 80000001; asc     ;;