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Home -> Community -> Mailing Lists -> Oracle-L -> RE: HOT Back up
Nirmal,
It's simple really. Read up on UNDO or Rollback Segments. This is where the rollback information is being stored. It has nothing to do with the Redo Logs. And also has nothing to do with putting a tablespace in Hot Backup mode. It all works the same.
Good Luck!
Tom Mercadante
Oracle Certified Professional
-----Original Message-----
From: Nirmal Kumar M [mailto:gm_nirmal_at_yahoo.com]
Sent: Thursday, September 30, 2004 4:32 AM
To: oracle-l_at_freelists.org
Subject: HOT Back up
HI,
Suppose u have 300 GB database with 3 Redo log groups having each 100 MB of redo log files.
Now u have started taking HOTBACKUP, by putting a tablespace in backup mode.
When backup is going on , same time big transactions are also going on and suppose a transaction fills 300 MB of redolog buffers.
as per Oracle conecpts, LGWR will write to redo log files. Suppose it has written 100MB of Redo buffer to 1st log file and on LOG Switch it starts writing to 2nd LOG file and archive the 1st LOG file and on another log switch it starts writing on 3rd log file and archive the 2nd log file.
Kindly note, the same transaction(which fills 300MB of redo buffers) is still running(means not completed).
and now, I rollback the transaction.
One DBA said the whole transaction will be
rollbacked, when
we issue ROLLBACK command.
3. But here the question is how the data which has been archived, how that can be rollbacked and how that can be removed from Archived files.??
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