### 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.
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.
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