Re: Rollback performance and delete

The rollback segment contains changes to data *and* any indexes involved.

Hth,

Sybrand Bakker, Oracle DBA

"Allen" <allen.brost_at_motorola.com> wrote in message news:3A06DE5D.30933844_at_motorola.com...
> I have looked through the Oracle documenation to understand exactly what
 the
> rollback segment is doing during a DELETE and I am still a little confused
 with
> the results I am finding.
>
> I am doing a delete of a large table. The table is 5G. I am deleting
 about 1G
> of the the table.
>
> I have created a large rollback segment to handle the transaction and I
 have set
> the size of the rollback segment to about 2G. I figured that this should
 be
> plenty. When I do the delete, I see the rollback segment grow to 5G. I
 don't
> understand this. I thought the rollback segment held all of the original
 rows
> before the change. If this is so, then I would expect to see about 1G in
 the
> segment. It seems like Oracle is copying everything in the table to the
> rollback segment. Anyone know why?
>
> - Allen
>
Received on Mon Nov 06 2000 - 15:35:30 CST