Oracle checks the main library, physical and snapshot backup libraries through views and alarm logs
Main library action master database information standby database information whether to enable redo threads
Alert log
V$thread
Alert log
Show database role, protection mode, protection level, switch status, quick enable, failure conversion information v$databasev$database add and delete redo log filegroup
Alert log
V$log
The status field of v$logfile
Alert log controls the creation of files
Alert log
Alert log
Changes in the state of the tablespace
V$recover_file
Dba_tablespace
Alert log
V$recover_file
Dba_tablespace
Add or delete data files or tablespaces
Dba_data_files
Alert log
V$datafile
Alert log
Rename data file
V$datafile
Alert log
V$datafile
Alert log
Unlogged or unrestored operation
V$datafile
V$database
Alert log
Monitor redo transmission
V$archive_dest_status
V$archived_log
V$archived_dest
Alert log
V$archived_log
Alert log
Issue open resetlogs or clear unarchived logfiles statements
Alert log
Alert log
Modify initialization parameters
Alert log
Alert log
Use the following statement to obtain the current role, protection mode, protection level, switch status, quick enable, and failure transition information of the master and slave database.
Select protection_mode, protection_level, database_role role, switchover_status from v$database
Get fast-start failover statu
Select fs_failover_status "fsfo status", fs_failover_current_target target, fs_failover_threshold threshold, fs_failover_observer_present "observer present" from v$database
Get the redo application and transfer status on the physical repository
Select process, status, thread#, sequence#, block#, blocks from v$managed_standby
Query archive log file information and historical archive information
Select thread#, sequence#, first_change#, next_change# from vested archived logon select thread#, sequence#, first_change#, next_change# from v$log_history
View event information about DG written to alert log
Select message from v$dataguard_status
Check the status of the transfer of the main library redo log to the target side, and SCN represents the system change number of the last redo log applied on the standby library.
Select dest_id, applied_scn from v$archive_dest where target='standby'
