| why not inconsistent backup [message #147122] |
Tue, 15 November 2005 19:06  |
lazycat
Messages: 57
Registered: November 2005
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Member |
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dear sir
i want to do Whole Database Backup
my database is in noARCHIVELOG mod
why i only can backup the db in consistent backup
why i can't use the inconsistent backup.
i can't know the reason in the doc
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| Re: why not inconsistent backup [message #147150 is a reply to message #147122] |
Tue, 15 November 2005 23:12  |
tarundua
Messages: 1080
Registered: June 2005
Location: India
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Senior Member |
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If i understood your question properly then you wants to ask why can't we take hot backups in NOARCHIVELOG mode.
now see this from Oracle docs,
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Oracle stops recording checkpoints to the datafiles in the tablespace when a tablespace is in backup mode. Because a block can be partially updated at the very moment that the operating system backup utility is copying it, Oracle copies whole changed data blocks into the redo stream while in backup mode. After you take the tablespace out of backup mode with the ALTER TABLESPACE ... END BACKUP or ALTER DATABASE END BACKUP statement, Oracle advances the datafile header to the current database checkpoint.
When you restore a datafile backed up in this way, the datafile header has a record of the most recent datafile checkpoint that occurred before the online tablespace backup, not any that occurred during it. As a result, Oracle asks for the appropriate set of redo log files to apply should recovery be needed. The redo logs contain all changes required to recover the datafiles and make them consistent.
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hope this explanation will help you.
[Updated on: Tue, 15 November 2005 23:12] Report message to a moderator |
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