测试一下11gr2的active dataguard

首先与原来10g一样，standby 跟上主库的归档，

Media Recovery Waiting for thread 1 sequence 278 (in transit)

然后在standby以只读打开后，启动日志恢复。

SQL> recover managed standby database cancel;
Media recovery complete.
SQL> alter database open read only;

Database altered.

SQL> recover managed standby database disconnect using current logfile;
Media recovery complete.

主库创建一个表

SQL> create table t as select * from adult;

Table created.

SQL> select * from t;

USERNAME USERPWD
------------------------------ ------------------------------
laogao3232 321456
hello world
tiany 22596

马上到备库查，不需要switch logfile：

SQL> select * from t;

USERNAME USERPWD
------------------------------ ------------------------------
laogao3232 321456
hello world
tiany 22596

主库delete一行

SQL> delete from t where username='tiany';

1 row deleted.
到备库查：

SQL> select * from t;

USERNAME USERPWD
------------------------------ ------------------------------
laogao3232 321456
hello world
tiany 22596

主库commit后，在备库查

SQL> select * from t;

USERNAME USERPWD
------------------------------ ------------------------------
laogao3232 321456
hello world

从这里看，小事务时主备基本上是实时的，压力大的时候可以测试一下，可能会有所延迟。