| UNDO in parameter file [message #534814] |
Fri, 09 December 2011 06:28  |
abhi_sri
Messages: 20
Registered: September 2010
Location: India
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Junior Member |
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Hello,
I have a question ragarding undo tablespace.
I want to ask that why only undo tablespace information we need to specify in parameter file. We do not specify any other tablespace information. Not even for temporary tablespace. Then why we need to give undo tablespace name while instance is creating.
Thank in advance.
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| Re: UNDO in parameter file [message #534818 is a reply to message #534816] |
Fri, 09 December 2011 07:17  |
John Watson
Messages: 8929
Registered: January 2010
Location: Global Village
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Senior Member |
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To complete the answer, your default temporary tablespace is an attribute of the database, not of the instance. So you set it in the controlfile rather than with a parameter:
alter database default temporary tablespace temp;
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| Re: UNDO in parameter file [message #535106 is a reply to message #534818] |
Mon, 12 December 2011 04:04 |
abhi_sri
Messages: 20
Registered: September 2010
Location: India
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Junior Member |
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Hello,
Thanks for these informative replies. My question was - why only undo tablespace require an entry in parameter file.
If we talk about temporary tablespace, we can have multiple temporary tablespaces in database but only one should by & must be default. I can understand that all other tablespaces information require at the time of mounting the database by controlfile. But why UNDO tablespace required to specify in parameter file. Why it is require to let instance know that this will be the UNDO tablespace. We can register it at the time of mounting the database like other tablespace.
Thank in advance for all your favours.
Regards
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| Re: UNDO in parameter file [message #535113 is a reply to message #535106] |
Mon, 12 December 2011 04:15 |
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Michel Cadot
Messages: 68641
Registered: March 2007
Location: Nanterre, France, http://...
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Senior Member
Account Moderator |
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Michel Cadot wrote on Fri, 09 December 2011 13:36Because only one can be current at each time but you can create several.
Regards
Michel
All UNDO tablespaces are visible, only ONE can be active so you have to tell Oracle which one.
All other kind of tablespaces are visible AND active.
Regards
Michel
[Updated on: Mon, 12 December 2011 04:17] Report message to a moderator |
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| Re: UNDO in parameter file [message #535150 is a reply to message #535106] |
Mon, 12 December 2011 07:06 |
John Watson
Messages: 8929
Registered: January 2010
Location: Global Village
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Senior Member |
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I think you are consideribng only the simple single instance environment. In a RAC, every instance must use a different undo tablespace. How could you manage that without an instance paramerer set uniquely for each instance?
You might also want to look at 11.2, where if you do not specify the undo_tablespace parameter, each instance that starts will take the next currently unused undo tablespace.
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