由 macro 发布于: 2001-03-01 18:49

Decide if Archiving of the Redo log files should be enabled

NOARCHIVELOG Mode

In this mode ,the online redo log files are overwritten each time an online redo log file is filled,and log switches occur.LGWR will not overwrite a redo log group until the checkpoint for that group is completed.

ARCHIVELOG Mode

If the database is configured to run in ARCHIVELOG mode,inactive groups of filled online redo log files must be archived . Because all changes made to the database are recorded in the online redo log files,the database administrator can use the physical backup and the archived online redo log files to recover the database without losing any committed data.

There are two ways in which online redo log files can be archived:
1.Manually
2.Automatically

The LOG_ARCHIVE_START initialization parameter indicate whether archiving should be automatic or manual when the instance starts up.

1.TRUE indicates that archiving is automatic,ARCn will initiate archiving of the filled log group at every log switch.

2.FALSE,the default value,indicates that the database administrator will archive filled redo log files manaully.The database administrator must manually execute a command each time he or she wants to archived an online redo log file.All or specific online redo log files can be archived manually.
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谢谢你抽时间看我的发言，

Macro Zeng

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