03) Briefly describe how you can obtain redo log group and member information? (10 Points)
04) Briefly describe why you need to archived redo log files? (10 Points)
05) Briefly describe how archived redo log file works? (10 Points)Answer:Oracle allows the optional archiving of filled groups of online redo log files, which creates archived (offline) redo logs. The archiving of filled groups has two key advantages relating to database backup and recovery options:A database backup, together with online and archived redo logfiles, guarantees that all committed transactions can be recovered in the event of an operating system or disk failure.Online backups, taken while the database is open and in normal system use, can be used if an archived log is kept permanently.If you cannot afford to lose any data in your database in the event of a disk failure, an archived log must be present. However, the archiving of filled online redo log files can requirethe database administrator to perform extra administrative operations.f an Oracle database is operated in ARCHIVELOG mode, the archiving of the online redo log is enabled. Information in a database control file indicates that a group of filled online redo log files cannot be reused by LGWR until the group is archived. A filled group is immediately available to theprocess performing the archiving once a log switch occurs (when a group becomes inactive); the process performing the archiving does not have to wait for the checkpoint of a log switch to complete before it can access the inactive group for archiving.If a database is operating in ARCHIVELOG mode, the database administrator can manually archive the filled groups of inactive
online redo log files, as necessary, whether or not automatic archiving is enabled or disabled. If automatic archiving is disabled, the database administrator is responsible for archiving all filled groups.For most systems, automatic archiving is chosen because the administrator does not have to watch for a group to become inactive and available for archiving. Furthermore, if automatic archiving is disabled and manual archiving is not performed fast enough, database operation can be suspended temporarilywhenever LGWR is forced to wait for an inactive group to
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- Summer '19
- Oracle Database, Redo log, log file