| Bishal |
Posted: May 02, 2008 01:33:50 AM |
Total Post: 160
Joined: Apr, 2008
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This is just a discussion..I have a doubt and i need to clear that..
I am maintaining backup of my database... But there are frequent changes going on... if my database crashes then i can recover my database from the latest available backup... but the changes made after that backup won't be restored or recovered right? |
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 GOPU |
| Posted: May 02, 2008 01:36:04 AM |  |
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Total Post: 239
Joined: Apr, 2008
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I think you can apply the archives and it can be restored....
let us wait somebody to share there view regarding this...
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| Murtuja |
| Posted: May 02, 2008 01:43:56 AM | |
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Total Post: 814
Joined: Jan, 2006
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Yes,
Once we have backup and all archivelog files available then we can recover database to the point (point-in-time recovey).
Please understand concept of rollforward and roll backword so you can get answer of your all doubts.
Roll forward refers to the process Oracle goes through to apply changes contained in the redo log files (both online and archive). The database clock (as measured by the system change number) is moved forward within the blocks of the datafile that are changed within the redo log vectors. Roll forward occurs during database, tablespace or datafile recovery and during crash recovery.
Rollback is the process of undoing uncommitted database transactions. The blocks copied to the rollback segments during transactions as a copy of the block for other transaction to read. When the instance aborts, the undo information in the redo log files must be applied to the database during the roll forward process of recovery. Therefore, during recovery, the database must roll forward and roll back.
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| Bishal |
| Posted: May 02, 2008 01:52:03 AM | |
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Total Post: 160
Joined: Apr, 2008
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ya but we never take online redo log backups right? so, how can we recover database using it?
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| GOPU |
| Posted: May 02, 2008 01:55:45 AM | |
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Total Post: 239
Joined: Apr, 2008
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archives are the backups of online redolog files,So we are taking the backup of archivelogs.Using the archives we can recover the database.
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| Bishal |
| Posted: May 02, 2008 02:47:20 AM | |
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Total Post: 160
Joined: Apr, 2008
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ya.. iknow we are taking backups of archive... but if that backup was taken 2 hours back... how to recover the changes that i made in this 2 hours
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| GOPU |
| Posted: May 02, 2008 02:51:47 AM | |
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Total Post: 239
Joined: Apr, 2008
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In that 2hrs there are lots of archive will generate.Right ?
At the time of recovery we can apply that archives.
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| Bishal |
| Posted: May 02, 2008 02:57:27 AM | |
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Total Post: 160
Joined: Apr, 2008
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for that we should have our database in archival mode right?
and how do we restore from it.. i dont know... can u please tell me?
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| Bishal |
| Posted: May 02, 2008 02:57:37 AM | |
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Total Post: 160
Joined: Apr, 2008
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for that we should have our database in archival mode right?
and how do we restore from it.. i dont know... can u please tell me?
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| GOPU |
| Posted: May 02, 2008 03:05:04 AM | |
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Total Post: 239
Joined: Apr, 2008
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you should have to put the database in the archivelog mode...
Then after restoring the database, and if you go for recovery it will ask for the archives log files.
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| Bishal |
| Posted: May 02, 2008 03:06:28 AM | |
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Total Post: 160
Joined: Apr, 2008
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ok thanx gopu... i will try it out...
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