If one session has a shared or exclusive lock on record R in an index, another session cannot insert

时间:2023-03-08 22:16:04
If one session has a shared or exclusive lock on record R in an index, another session cannot insert a new index 

record in the gap immediately before R in the index order. 

如果一个session 有一个共享或者排它锁在记录R上,另外的session 不能插入新的index record 在before R这个区间

Session 1:

mysql> start transaction;
Query OK, 0 rows affected (0.00 sec) mysql> select * from SmsTest where phoneNo=10 for update;
+-------+---------+-------------+--------+
| sn | phoneNo | channelType | status |
+-------+---------+-------------+--------+
| 10 | 10 | 2 | 1 |
| 45239 | 10 | 1 | 1 |
| 45252 | 10 | 1 | 1 |
+-------+---------+-------------+--------+
3 rows in set (0.01 sec) Session 2: Database changed
mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(1,1,1);
Query OK, 1 row affected (0.01 sec) mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(2,1,1);
Query OK, 1 row affected (0.00 sec) mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(3,1,1);
Query OK, 1 row affected (0.01 sec) mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(4,1,1);
Query OK, 1 row affected (0.00 sec) mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(5,1,1);
Query OK, 1 row affected (0.00 sec) mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(6,1,1);
Query OK, 1 row affected (0.00 sec) mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(7,1,1);
Query OK, 1 row affected (0.00 sec) mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(8,1,1);
Query OK, 1 row affected (0.01 sec) mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(9,1,1);
^[[A
ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction
mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(9,1,1);
ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction
mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(10,1,1); --hang mysql> insert into zjzc.SmsTest(PhoneNo,channelType,status) values(11,1,1);
Query OK, 1 row affected (0.01 sec)