| how to drop a column in a huge table [message #519007] |
Mon, 08 August 2011 20:34  |
andy huang
Messages: 498
Registered: July 2011
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Senior Member |
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Dear all,
I want to drop a column in a huge table which contain about 420,000,000 rows,i use the alter table drop coumn command to execute,and found it takes a long time and generate huge redo.
Is there any quickly way to drop a column in a huge table?
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| Re: how to drop a column in a huge table [message #519010 is a reply to message #519009] |
Mon, 08 August 2011 20:53  |
andy huang
Messages: 498
Registered: July 2011
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Senior Member |
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Hi,
1) CREATE VIEW without the column. The method is not drop the column really.
2) alter column UNUSED The method is not drop the column really also.
3) DBMS_REDEFINITION The method can drop the column,but i think it will take a long time to create mv for base table .
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| Re: how to drop a column in a huge table [message #519030 is a reply to message #519010] |
Tue, 09 August 2011 01:09 |
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Michel Cadot
Messages: 68643
Registered: March 2007
Location: Nanterre, France, http://...
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Senior Member
Account Moderator |
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I'd set the column as UNUSED and then really drop it during a maintenance window.
If you have none, then use there is no other way then to use dbms_redifinition.
Regards
Michel
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