| hot backup [message #308365] |
Mon, 24 March 2008 02:35  |
sheldon1982
Messages: 59
Registered: February 2008
Location: india
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hi Experts,
some days before i went for an intervier asked me the question that when we put database in backup mode why lots of redo get generated i said because during backup mode datafile header get freezed this may be the reason. he does not seems satisfied with my answer.
so could any body explain me the same?
Thanks,
Sheldon
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| Re: hot backup [message #308376 is a reply to message #308372] |
Mon, 24 March 2008 03:01  |
sheldon1982
Messages: 59
Registered: February 2008
Location: india
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ok
was not knowing i thought its an interview so i must give it a rate so everybody can voew it and learn otherwise you can see i have never given rate to any of my question.
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| Re: hot backup [message #308378 is a reply to message #308365] |
Mon, 24 March 2008 03:12 |
varu123
Messages: 754
Registered: October 2007
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Senior Member |
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When datafile is in backup mode,oracle copies the first modified block to the redo log files.
When the same block is modified again ,only the modified part is copied.
Since DML continues as normal,lots of redo blocks are copied to the redo files and hence lots of redo is generated.
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| Re: hot backup [message #308383 is a reply to message #308365] |
Mon, 24 March 2008 03:18 |
varu123
Messages: 754
Registered: October 2007
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Senior Member |
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| Quote: | i told him the same answer he told me
why lots of redo get generated.
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Then you should have told him again.
BTW, the answer is not so simple as it looks.
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| Re: hot backup [message #308386 is a reply to message #308383] |
Mon, 24 March 2008 03:25 |
sheldon1982
Messages: 59
Registered: February 2008
Location: india
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Member |
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i told him that when we take the tablespace in backup mode
datafile header get freezed and scn number stops updating
this may be the reason he does not seem satisfied after this reply.
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| Re: hot backup [message #308400 is a reply to message #308398] |
Mon, 24 March 2008 03:54 |
sheldon1982
Messages: 59
Registered: February 2008
Location: india
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Member |
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my fisrt reply was the same which you posted but when he asked me again then my reply was the one which i wrote now.
so i think i was right.
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| Re: hot backup [message #308411 is a reply to message #308407] |
Mon, 24 March 2008 04:20 |
Frank
Messages: 7901
Registered: March 2000
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Senior Member |
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| varu123 wrote on Mon, 24 March 2008 10:07 | Post other questions also.
They might be useful to others.
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How would other users benefit from that?
So they can learn the answers to these questions, in order to pose themselves as more experienced or expert than they really are?
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| Re: hot backup [message #308418 is a reply to message #308365] |
Mon, 24 March 2008 04:46 |
varu123
Messages: 754
Registered: October 2007
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Senior Member |
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| Quote: | So they can learn the answers to these questions, in order to pose themselves as more experienced or expert than they really are?
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Just by mugging up some inaccurate answers.
I don't think so.
I take it as a reason to look in to the docs.
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