1, Oracle 19c alarm log

2020-01-19 20:40:26.193000 +08:00
Warning: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE has been deprecated.
Warning: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE has been deprecated.
alter database recover managed standby database using current logfile disconnect from session

The alarm indicates that USING CURRENT LOGFILE has been discarded. Fortunately, a lot of Oracle commands are backward compatible, and there will be no problem in the original execution mode.

2, How to use official documents

To start apply services on a physical standby database, ensure the physical standby database is started and mounted and then start Redo Apply.

Start apply services on a physical standby database as follows:

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE;
This also automatically enables real-time apply provided the standby database is configured with a standby redo log and is in ARCHIVELOG mode.
--stay Oracle 12c Start real-time application automatically in the future, and the standby database needs to be configured standby redo log And open the archive log.

Redo Apply can be run either as a foreground session or as a background process. 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;
--In the future, use the above command to start the real-time application process, and you can also tap fewer commands, which is very good.
or

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING ARCHIVED LOGFILE 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 command does not disconnect the current SQL session.

Three, summary
1. When you are not too busy, look at the alarm log of the database. There will always be new discoveries.
2. It's good to read the official documents for half an hour every day, especially the new version, and learn more English.