binlog_format为statement时的同步问题

binlog_format设置为statement时，从机采用与主机执行同样语句的方式同步。

这时不同的函数就会有不同的影响

双机A机:

mysql> set binlog_format=statement;
Query OK, 0 rows affected (0.00 sec)

mysql> update test set d = now() where id =1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from test;
+----+---------------------+
| id | d                   |
+----+---------------------+
|  1 | 2015-03-10 04:55:57 |
+----+---------------------+
1 row in set (0.00 sec)

mysql> select sysdate();
+---------------------+
| sysdate()           |
+---------------------+
| 2015-03-10 04:56:17 |
+---------------------+
1 row in set (0.00 sec)

双主B机

mysql> select * from test;
+----+---------------------+
| id | d                   |
+----+---------------------+
|  1 | 2015-03-10 04:55:57 |
+----+---------------------+
1 row in set (0.00 sec)

mysql> select sysdate();
+---------------------+
| sysdate()           |
+---------------------+
| 2015-03-10 09:19:14 |
+---------------------+
1 row in set (0.00 sec)

此时AB数据一样。

改用sysdate()
A机

mysql> update test set d = sysdate() where id =1;
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 1

mysql> select * from test;
+----+---------------------+
| id | d                   |
+----+---------------------+
|  1 | 2015-03-10 04:56:34 |
+----+---------------------+
1 row in set (0.00 sec)

B机

mysql> select * from test;
+----+---------------------+
| id | d                   |
+----+---------------------+
|  1 | 2015-03-10 09:19:24 |
+----+---------------------+
1 row in set (0.00 sec)

可以看到B机更新成了本地时间，这时数据不一致了。

因此一般为了数据一致会把参数设成row

两台机子都设置如下

mysql> set binlog_format=row;
Query OK, 0 rows affected (0.00 sec)

A机

mysql> update test set d = sysdate() where id =1;
Query OK, 1 row affected (0.03 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from test;
+----+---------------------+
| id | d                   |
+----+---------------------+
|  1 | 2015-03-10 05:02:44 |
+----+---------------------+
1 row in set (0.00 sec)

B机

mysql> select * from test;
+----+---------------------+
| id | d                   |
+----+---------------------+
|  1 | 2015-03-10 05:02:44 |
+----+---------------------+
1 row in set (0.00 sec)

可以看到这时结果一致了