How Oracle Closes open Archive log _oracle

to see if an Oracle database is in archive mode
Sql> select Name,log_mode from V$database;

NAME Log_mode
------------------ ------------------------
TEST Noarchivelog

Sql> Archive Log List
Database log mode No Archive mode
Automatic Archival Disabled
Archive Destination Use_db_recovery_file_dest
Oldest online log sequence 80157
Current log sequence 80163

Edit Archive mode for this section configuration database
1. Change non-archive mode to archive mode:
1) sql> Conn/as sysdba (database connected as DBA)
2) sql> shutdown immediate; (Close database now)
3 sql> Startup Mount (start the instance and load the database but not open)
4) sql> ALTER DATABASE archivelog; (Change the database to archive mode)
5) sql> ALTER DATABASE open; (Open database)
6) sql> alter system archive log start; (Automatic archiving enabled)
7) Sql> exit (exit)

Do a full backup, because the backup log generated in the non-archived log mode is not available for archive mode. This step is not very important!
2. Change archive mode to non-archive mode:
1) Sql>shutdown normal/immediate;
2) Sql>startup MOUNT;
3) Sql>alter DATABASE Noarchivelog;
4) Sql>alter DATABASE OPEN;
3. Filing of related commands
Archive log stop;
Archive log start;
Archive log list;

Show parameters;
Show Parameters Log_archive_start;
Show Parameters log_archive_max_process; #归档进程数
alter system set LOG_ARCHIVE_MAX_PROCESS=5; #将归档进程数改为5
SELECT * from V$bgprocess; #检察后台进程