Re: Unlogged Deletes in Oracle

Peter Nolan wrote:

> Seems kind of
> strange that all deletes should be logged like this and no option
> being available to turn it off...

Well, you can. As I said, there's a totally unsupported, potentially catastrophic, extraordinary method of doing it. But you'd best have a cold backup beforehand, and be prepared to restore it in its entirety if anything at all goes wrong with your database whilst it's in use. If you're interested and don't already know what I'm talking about, mail me.

But think about it logically. If you could ever (ordinarily) suppress redo generation for deletes, and there was some sort of failure, how would Oracle ever know which records in a table should have been deleted and which not? We'll have to wait for dbms_mindreading before that can be resolved!

Compare that, for example, with creating an index: if that ever goes wrong, you can drop it and re-create it as often as you want, and the end result will always be a functional index.

Redo suppression for things which cannot plausibly be re-created or re-performed via any other mechanism must inevitably result in an unrecoverable database. So that's why you have no option to turn it off.

Regards
HJR Received on Tue Nov 30 2004 - 12:04:02 CST