Drop columns without ORA-30036: unable to extend segment ... UNDO_TBS

Question

Hello folks, I've a table with 290 million-rows (big enought to be a headache sometimes). And this is my problem, I must drop 21 columns of this table... So, I did
ALTER TABLE <table_name> DROP (column1, column2, ...., column21);
But I got an ORA-30036: unable to extend segment by 8 in undo tablespace "UNDO_TBS". And I don't want to extend this tablespace.
There is any operation that doesn't use UNDO space???
To Use this is a valid option?
ALTER TABLE <table_name> SET UNUSED COLUMN <column_name>;
ALTER TABLE <table_name> DROP UNUSED COLUMNS;
Thanks.
Martin

Answer 1

Etbin,
DBMS_REDEFINITION offers some interesting features, among the most important one is probably the "online" redefinition option, but it doesn't do any magic behind the scenes. You'll have a copy of your original table (called the "interim" table) while performing the redefinition so I thought it makes sense to mention that due to the fact that the table we talk about probably consumes a significant amount of space.
It'll will also consume a significant amount of resources to perform the copy of this particular table. What is meant by "original table redefined and the interim table statistics" is that you apply whatever statistics to the interim table while performing the redefinition. The interim table actually becomes the "original" table when completing the redefinition, the two tables are basically "swapped" and you have to finally drop the "interim" table, which also indicates that there are two tables allocating space while performing the redefinition.
I didn't mean to offend you in any way, I just thought it would be good to know about the implications of using DBMS_REDEFINITION.
Regards,
Randolf
Oracle related stuff blog:
http://oracle-randolf.blogspot.com/
SQLTools++ for Oracle (Open source Oracle GUI for Windows):
http://www.sqltools-plusplus.org:7676/
http://sourceforge.net/projects/sqlt-pp/