| alter tablespace begin backup [message #405878] |
Sat, 30 May 2009 19:00  |
tjay
Messages: 37
Registered: September 2008
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Hi
Assume user managed backup, not rman.
Why should we copy the datafiles after
"alter tablespace begin backup"..
What does this statement do?
Does it locks the datafiles to avoid IO,or avoid increasing checkpoint SCN of the datafile.
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| Re: alter tablespace begin backup [message #405891 is a reply to message #405884] |
Sun, 31 May 2009 03:20  |
tjay
Messages: 37
Registered: September 2008
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Member |
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During online backup:
"alter tablespace begin backup"
The checpoint scn of the datafiles do not change.
What is the main purpose of this?
and in this state I can perform transactions to the tablepsace.
Are these transactions recorded in redo(not in datafiles) and performed recovery after "alter tablespace end backup"
[Updated on: Sun, 31 May 2009 03:21] Report message to a moderator |
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| Re: alter tablespace begin backup [message #405933 is a reply to message #405922] |
Mon, 01 June 2009 00:24 |
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Michel Cadot
Messages: 68716
Registered: March 2007
Location: Saint-Maur, France, https...
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Senior Member
Account Moderator |
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| tjay wrote on Mon, 01 June 2009 01:37 | You told me that:
"It causes whole database block to be written to the REDO log"
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It does not mean the data are not *also* written to datafiles, they may be.
The ONLY points that change with "begin backup" are the 2 points I already mentioned (did I already say that?).
Regards
Michel
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