6.1 事务中遇到主键冲突需要显式回滚，MySQL不需要

具体表现如下:

MYSQL行为:

[test_yhq]>select * from char_columns_4;
+----+--------+
| id | c_char |
+----+--------+
|  1 | xx |
|  4 | z  |
+----+--------+
2 rows in set (0.02 sec)
[test_yhq]>begin;
Query OK, 0 rows affected (0.01 sec)

[test_yhq]>insert into char_columns_4 values(1,'yy');
ERROR 1062 (23000): Duplicate entry '1' for key 'PRIMARY'
[test_yhq]>insert into char_columns_4 values(2,'yy');
Query OK, 1 row affected (0.00 sec)

[test_yhq]>commit;
Query OK, 0 rows affected (0.02 sec)

dble行为:

[testdb]>select * from sharding_four_node order by id;
+----+--------+-----------+
| id | c_flag | c_decimal |
+----+--------+-----------+
|  1 | 1_1    |    1.0000 |
|  2 | 2      |    2.0000 |
|  3 | 3      |    3.0000 |
+----+--------+-----------+
3 rows in set (0.28 sec)

begin;
Query OK, 0 rows affected (0.01 sec)

[testdb]>insert into sharding_four_node values(1,'1',1.0);
ERROR 1062 (23000): Duplicate entry '1' for key 'PRIMARY'
[testdb]>insert into sharding_four_node values(13,'13',13.0);
ERROR 1003 (HY000): Transaction error, need to rollback.Reason:[ errNo:1062 Duplicate entry '1' for key 'PRIMARY']
[testdb]>commit;
ERROR 1003 (HY000): Transaction error, need to rollback.Reason:[ errNo:1062 Duplicate entry '1' for key 'PRIMARY']