Re: How to remove data from disk

sandell_at_pacbell.net (Bruce) wrote in message news:<595024a5.0405061514.5f256b15_at_posting.google.com>...
> I have a table with some sensitive customer data in it. I am now
> keeping all the data in another table, and encrypting it. I want to
> get rid of the original unencrypted data and be sure that it is no
> longer anywhere on disk. Should I drop the table, or first delete the
> rows and then clear the redo logs? I'm not sure how to know if the
> data is actually physically deleted from disk, or if it's still there,
> but just in blocks that get marked as available. Any guidance would
> be greatly appreciated.
>
> Thanks,
> Bruce

I composed a great answer to this on Friday, but google lost it, silly me I was cutting and pasting from an x-window before things scrolled off and didn't copy the google window before hitting the post button. Anyways, it demonstrated that you can grep the datafiles for particular data after deleting rows.

So the answer is, you must write over all rows before deleting, since you never know when oracle is going to deign to re-use the segments, and you must switch logfiles more than once to actually get the rewrites to disk.

Then you must burn all your backup tapes.

Don't forget to include version and platform information on questions.

jg

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