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Tuesday, March 5, 2013

How to check RECOVER MANAGED STANDBY DATABASE real time apply?



### On Standby: Delayed apply or Real time apply?


SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DELAY 60 disconnect; -- apply delayed for 60 minutes.

Database altered.

SQL> SELECT RECOVERY_MODE FROM V$ARCHIVE_DEST_STATUS;

RECOVERY_MODE
-----------------------
MANAGED
IDLE
IDLE
IDLE
...


SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE disconnect; -- Realtime apply

Database altered.

SQL> SELECT RECOVERY_MODE FROM V$ARCHIVE_DEST_STATUS; 

RECOVERY_MODE
-----------------------
MANAGED REAL TIME APPLY
IDLE
IDLE
IDLE
...



-- no time delay
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT; 

-- no time delay
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE NODELAY DISCONNECT;

-- 60 minutes delay
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DELAY 60 DISCONNECT;

-- real time apply
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT;


--- Note: -----------------------------------------------------------------------------------

By default, apply services wait for the full archived redo log file to arrive on the standby database before applying it to the standby database.

If the real-time apply feature is enabled, apply services can apply redo data as it is received, without waiting for the current standby redo log file to be archived.