Chapter08Configuring the Database Archiving Mode

NOARCHIVELOG Mode

Implications of NOARCHIVELOG Mode

• If a tablespace becomes unavaliable because of a failure,you cannot continue to operate the database until the tablespace has been dropped or the entire database has been restored from backups.

Auto and Manual Archiving

oracle server有归档模式与非归档模式之分，如果是归档模式，又分自动归档模式和手动归档模式；

archive log的启动与关闭

• 查看archive 状态信息命令
  • archive log list
• 启动archive log
  • alter system archive log start to '/u01/admin/denver/archdest';
• 停止archive log
  • alter system archive log stop;
• 手动归档
  • alter system archive log current;
• 异常排查

SQL> alter system set log_archive_start=true scope=both; 
alter system set log_archive_start=true scope=both
                 *
ERROR at line 1:
ORA-02095: specified initialization parameter cannot be modified

ALTER SYSTEM ARCHIVE LOG

Option	Description
THREAD	Specifies thread containing the redo log file group to be achived (for Oracle Parallel Server)
SEQUENCE	Archives the online redo log file group identified by the log sequence number
CHANGE	Archives based upon the SCN
GROUP	Archives the online redo log file group
CURRENT	Archives the current redo log file group of the specified thread
LOGFILE	Archives the redo log file group with members identied by filename
NEXT	Archives the oldest online redo log file group that has not been archived
ALL	Archives all online redo log file groups from the specified thread that are full but have not been archived.
START	Enables automatic archiving of redo log file groups
TO	Specifies the location to which the redo log file group is archived
STOP	Disables automatic archiving of redo log file groups

问题跟踪：执行了alter system archive log stop;命令之后，Automatic archival 还是Enabled，这是为什么？

SQL> alter system archive log stop;

System altered.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     10
Next log sequence to archive   12
Current log sequence           12