oracle 10g dataguard 测试

1、备库只读打开

备库现在是mount状态，不能查询数据。可以把它open read only;如果read only，备库就只能查询，并且不再应用日志。

备库操作：

SQL> recover managed standby database cancel;
SQL> alter database open read only;

此时就可以查询数据，看主库最新的数据是否可以在备库查到。

如果需要继续应用日志，需要关闭数据库，启动到mount状态，重新应用日志。

2、主备切换

切换顺序，把主切换成从；再把从切换成主

主切换成从

SQL> select database_role,switchover_status from v$database;
DATABASE_ROLE    SWITCHOVER_STATUS
---------------- --------------------
PRIMARY          SESSIONS ACTIVE
SQL> alter database commit to switchover to physical standby with session shutdown;
SQL> shutdown immediate
SQL> startup nomount
SQL> alter database mount standby database;
SQL> recover managed standby database disconnect from session;
SQL> select database_role,switchover_status from v$database;
DATABASE_ROLE    SWITCHOVER_STATUS
---------------- --------------------
PHYSICAL STANDBY SESSIONS ACTIVE

从切换成主

SQL> select database_role,switchover_status from v$database;
DATABASE_ROLE    SWITCHOVER_STATUS
---------------- --------------------
PHYSICAL STANDBY TO PRIMARY
SQL> alter database commit to switchover to primary with session shutdown;
SQL> shutdown immediate
SQL> startup
SQL> select database_role,switchover_status from v$database;
DATABASE_ROLE    SWITCHOVER_STATUS
---------------- --------------------
PRIMARY          TO STANDBY

也可以按照上边的步骤重新切换回去。

3、逻辑standby

物理standby：通过redo apply来恢复进行同步

逻辑standby：通过sql apply来恢复进行同步

逻辑standby可以在open状态下完成数据同步，它的物理结构可以不一致

逻辑standby的实现：通过物理standby转换成逻辑standby

备库关闭日志应用

SQL> alter database recover managed standby database cancel;

生成记录的元数据信息到 redo log

主库运行

SQL> exec dbms_logstdby.build

备库操作

SQL> alter database recover to logical standby std;
SQL> shutdown immediate
SQL> startup mount
SQL> select member from v$logfile;
SQL> alter database open resetlogs;
SQL> alter database start logical standby apply immediate;
SQL> select database_role from v$database;
DATABASE_ROLE
----------------
LOGICAL STANDBY

查看逻辑standby的当前的归档日志应用情况

主库：

SQL> alter system switch logfile;

System altered.

SQL> select max(sequence#) from v$archived_log;

MAX(SEQUENCE#)
--------------

备库：

SQL> select sequence#,first_change#,next_change#,timestamp,applied from dba_logstdby_log;

SEQUENCE# FIRST_CHANGE# NEXT_CHANGE# TIMESTAMP      APPLIED
---------- ------------- ------------ -------------- ----------------
49        463066       463602 26-3月 -16     CURRENT
50        463602       463613 26-3月 -16     CURRENT

4、逻辑standby切换

切换前的检查

切换前一定要检查下日志是否同步正常

相互sqlplus sys/sys@test as sysdba连接下，是否都能够连通。

主库准备转换为备库

SQL> alter database prepare to switchover to logical standby;

Database altered.

SQL> select switchover_status from v$database;

SWITCHOVER_STATUS
--------------------
PREPARING SWITCHOVER

注：取消准备ALTER DATABASE PREPARE TO SWITCHOVER CANCEL;

备库准备转换为主库

SQL> alter database prepare to switchover to primary;

Database altered.

SQL> select switchover_status from v$database;

SWITCHOVER_STATUS
--------------------
PREPARING SWITCHOVER

再次检查主库的状态

SQL> select switchover_status from v$database;

SWITCHOVER_STATUS
--------------------
TO LOGICAL STANDBY

转换主库为逻辑standby

SQL> alter database commit to switchover to logical standby;

Database altered.

再次检查逻辑standby状态

SQL> select switchover_status from v$database;

SWITCHOVER_STATUS
--------------------
TO PRIMARY

转换逻辑standby为主库

SQL> alter database commit to switchover to primary;

Database altered.

启用新逻辑standby的sql应用（别执行错库了）

SQL> alter database start logical standby apply;

Database altered.

5、其他

停止逻辑standby应用

SQL> alter database stop logical standby apply;

Database altered.

standby同步问题排查

SQL> column EVENT_TIME format a10
SQL> column EVENT_TIMESTAMP format a20
SQL> column STATUS format a40
SQL> select EVENT_TIME,EVENT_TIMESTAMP,STATUS from dba_logstdby_events  order by event_time desc;

EVENT_TIME EVENT_TIMESTAMP      STATUS
---------- -------------------- ----------------------------------------
28-3月 -16 28-3月 -16 03.02.30. ORA-16111: log mining and apply setting
573734 下午          up

28-3月 -16 28-3月 -16 03.02.30. Apply LWM 540429, HWM 540429, SCN 540434
597606 下午

28-3月 -16 28-3月 -16 11.37.51. ORA-16128: User initiated stop apply suc
578547 上午          cessfully completed

28-3月 -16 28-3月 -16 11.35.58. ORA-16226: DDL skipped due to lack of su
963554 上午          pport

EVENT_TIME EVENT_TIMESTAMP      STATUS
---------- -------------------- ----------------------------------------

28-3月 -16 28-3月 -16 11.33.30. ORA-16111: log mining and apply setting
624892 上午          up

26-3月 -16 26-3月 -16 05.19.42. ORA-16128: User initiated stop apply suc
056570 下午          cessfully completed

26-3月 -16 26-3月 -16 02.34.53. ORA-16111: log mining and apply setting
643625 下午          up

7 rows selected.