RE: HOT Back up
- From: "Mercadante, Thomas F" <thomas.mercadante@xxxxxxxxxxxxxxxxx>
- To: "'gm_nirmal@xxxxxxxxx'" <gm_nirmal@xxxxxxxxx>, oracle-l@xxxxxxxxxxxxx
- Date: Thu, 30 Sep 2004 08:33:43 -0400
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@xxxxxxxxx]
Sent: Thursday, September 30, 2004 4:32 AM
To: oracle-l@xxxxxxxxxxxxx
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.
1. What will happen.
2. What will happen to that data which has been
archived.
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been archived, how that can be rollbacked and how that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.??
=====
Best Regards,
Nirmalkumar Muthukumaran.
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