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user1368644 wrote:I can't see any reason to do that
I need to drop a column in a table (Oracle Version is 9iR2). This table contains approximately 2 000 000 000 records, each record is about 41 bytes length.
The column I need to drop represents un varchar(10), i.e. about 25% of a line size.
Because this operation is going to be very long, I would like to ask for the best way to proceed :
- should I previously set all values to null before the drop ?
- should I drop indexes on the table (there are 5 bitmap indexes but none on the column to drop).this should not be necessary if the indexes do not contain the column to be dropped
- should I set some specific values to TEMP_TBS or UNDO_TBS before I proceed ?Not sure.
- are there any other tips to know to achieve this goal ?There are actually a couple of ways do do this. You can drop the column in place, or cheat by copying the old table to a new one withouth the column. The sheer size of your table probably makes the second method impractical, not to mention having to recreate indexes, triggers, etc.
Hope this will help you...1 person found this helpful
Thank you for the link.
It is exactly what i was looking for.