dataguard 日志的应用

1、实时应用日志是11g物理dataguard的特性， Real-Time Apply ，也叫adg


物理standby实时应用日志：
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE 
逻辑standby 实时应用日志：
ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE 

Real-time apply requires a standby database that is configured with a standby redo log and that is in ARCHIVELOG mode.
LOG_ARCHIVE_DEST_n   initialization parameter to delay applying archived redo log files to the standby database.
By default, there is no time delay. If you specify the DELAY attribute without specifying a value, then the default delay interval is 30 minutes.


2、停止实时应用日志
物理standby停止实时应用日志：
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE NODELAY;
逻辑standby停止实时应用日志：
SQL> ALTER DATABASE START LOGICAL STANDBY APPLY NODELAY;






3、物理standby 应用日志
 To start Redo Apply in the foreground, issue the following SQL statement:


SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE;
If you start a foreground session, control is not returned to the command prompt until recovery is canceled by another session.


To start Redo Apply in the background, include the DISCONNECT keyword on the SQL statement. For example:


SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;
This statement starts a detached server process and immediately returns control to the user. While the managed recovery process is performing recovery in the background, the foreground process that issued the RECOVER statement can continue performing other tasks. This does not disconnect the current SQL session.


To start real-time apply, include the USING CURRENT LOGFILE clause on the SQL statement. For example:


SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE;


4、物理standby停止应用日志
                        SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;


5、逻辑standby 应用日志
SQL> ALTER DATABASE START LOGICAL STANDBY APPLY;


6、逻辑standby停止应用日志
SQL> ALTER DATABASE STOP LOGICAL STANDBY APPLY;




7、监控物理standby
SQL> SELECT PROTECTION_MODE, PROTECTION_LEVEL,  DATABASE_ROLE ROLE, SWITCHOVER_STATUS  FROM V$DATABASE


SQL> SELECT FS_FAILOVER_STATUS "FSFO STATUS",  FS_FAILOVER_CURRENT_TARGET TARGET,  FS_FAILOVER_THRESHOLD THRESHOLD, 
FS_FAILOVER_OBSERVER_PRESENT "OBSERVER PRESENT"  FROM V$DATABASE;


查看物理备库日志进程的状态：
SQL> SELECT PROCESS, STATUS, THREAD#, SEQUENCE#, BLOCK#, BLOCKS FROM V$MANAGED_STANDBY;

备库查询，从主库接收的日志
SQL> SELECT THREAD#, SEQUENCE#, FIRST_CHANGE#,  NEXT_CHANGE# FROM V$ARCHIVED_LOG;

显示归档日志的历史
SQL> SELECT THREAD#, SEQUENCE#, FIRST_CHANGE#, NEXT_CHANGE# FROM V$LOG_HISTORY;

显示写入日志或者进程的消息
SQL> SELECT MESSAGE FROM V$DATAGUARD_STATUS;

显示传输地址的状态：
SQL> SELECT DEST_ID, APPLIED_SCN FROM V$ARCHIVE_DEST WHERE TARGET='STANDBY';


8监控逻辑standby