insert 加的锁

?INSERT sets an exclusive lock on the inserted row. This lock is an index-record lock, not a next-key lock (that is, there is no gap lock) and 

does not prevent other sessions from inserting into the gap before the inserted row


INSERTS 设置一个排他锁在插入的记录,锁是一个Index-record lock, 不是一个next-key lock （也就是说,没有一个gap锁）

不会阻止其他会话插入到之前插入值之前的区间




mysql> show create table SmsTestG;
*************************** 1. row ***************************
       Table: SmsTest
Create Table: CREATE TABLE `SmsTest` (
  `sn` int(11) NOT NULL AUTO_INCREMENT COMMENT '自增编号',
  `phoneNo` int(16) NOT NULL,
  `channelType` int(11) DEFAULT NULL COMMENT '通道识别',
  `status` tinyint(4) NOT NULL COMMENT '短信转态,1.发送成功,2.发送失败,3.发送异常',
  PRIMARY KEY (`sn`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='短信发送成功记录表'
1 row in set (0.00 sec)

ERROR: 
No query specified


mysql> select * from SmsTest;
+----+---------+-------------+--------+
| sn | phoneNo | channelType | status |
+----+---------+-------------+--------+
|  1 |       1 |           2 |      1 |
|  2 |       2 |           2 |      1 |
|  3 |       3 |           2 |      1 |
|  4 |       4 |           2 |      1 |
|  5 |       5 |           2 |      1 |
|  6 |       6 |           2 |      1 |
|  7 |       7 |           2 |      1 |
|  8 |       8 |           2 |      1 |
|  9 |       9 |           2 |      1 |
| 10 |      10 |           1 |      1 |
| 16 |      16 |           2 |      1 |
| 17 |      17 |           2 |      1 |
| 18 |      18 |           1 |      1 |
| 19 |      19 |           1 |      1 |
| 20 |      20 |           2 |      1 |
+----+---------+-------------+--------+
15 rows in set (0.00 sec)


Session 1:

mysql> start transaction;
Query OK, 0 rows affected (0.00 sec)

mysql> insert into SmsTest values(15,15,1,1);
Query OK, 1 row affected (0.00 sec)




Session 2:
mysql> start transaction;
Query OK, 0 rows affected (0.00 sec)

mysql> delete from SmsTest where sn=8;
Query OK, 1 row affected (0.00 sec)

mysql> delete from SmsTest where sn=9;
Query OK, 1 row affected (0.00 sec)

mysql> delete from SmsTest where sn=10;
Query OK, 1 row affected (0.00 sec)

mysql> delete from SmsTest where sn=11;
Query OK, 0 rows affected (0.00 sec)

mysql> delete from SmsTest where sn=12;
Query OK, 0 rows affected (0.00 sec)

mysql> delete from SmsTest where sn=13;
Query OK, 0 rows affected (0.00 sec)

mysql> delete from SmsTest where sn=14;
Query OK, 0 rows affected (0.00 sec)

mysql> delete from SmsTest where sn=15;  --hang