Re: DROP COLUMN uses rollback?

When you go from 'unused' to clearing the columns out, you might want to look at:

alter table XXX move nologging;

which will recreate the table with the columns present, unavailable, but null - reclaiming most of the space with very little undo and redo. And/or

alter table XXX
drop unused columns
checkpoint 1000;

which issues an internal commit every 1000 cleaned rows, and therefore limits the amount of undo used at any instant. (Of course, as a series of small transactions, this may cause other long-running processes to hit a 1555 error).

--
Jonathan Lewis
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Stephen B wrote in message ...


>That makes perfect sense...thank you!

>I'm familiar with the UNUSED option, but I'll need to free up the space

>eventually...this particular database is in development

>and will ultimately be deployed accross the country...unfortunately space

is


>a consideration in deployment.

>

>Thank you especially Howard, for taking the time to clearly delineate why

>this particular type of DDL requires rollback.

>