Re: Rollback extents

From: D.Y. <dyou98_at_aol.com>
Date: 28 Jun 2002 13:04:49 -0700
Message-ID: <f369a0eb.0206281204.869d310@posting.google.com>

"Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk> wrote in message news:<3d1c17a8$0$227$ed9e5944_at_reading.news.pipex.net>...
> "D.Y." <dyou98_at_aol.com> wrote in message
> news:f369a0eb.0206271902.6a3d8692_at_posting.google.com...
> > "Steve Ashmore" <sashmore_at_neonramp.com> wrote in message
> news:<uhmv3r9c783o00_at_corp.supernews.com>...
> > > That is what I get for working on this at 5AM.
> > >
> > > Nologging is of course for used to suspend redo generation.
> > >
> > > Interesting though. If you do a direct load insert
> > > you can still issue a rollback and at least some
> > > rollback information is generated. I was playing with this today.
> > >
> >
> > DMLs all generate redo, because they can all be rolled back unless you

                      ^^^^

I meant undo. Hit the send button before I wanted to send it out. That's the kind of mistake you make late at night.

> > set autocommit to true. I have yet to see an exception.
>
> This is true, but how much rollback is a different question.
>

...
> SQL> insert /*+ append */ into nl_objects select * from nl_objects;
>
> 232680 rows created.
>
> SQL> select used_urec,used_ublk
> 2 from v$transaction;
>
> USED_UREC USED_UBLK
> ---------- ----------
> 1 1
>

True. Different DMLs use undo space differently. The fact that APPEND always puts data in previously unused space suggests it could be using undo space the same way as create table, and your test seems to verify that.

>
> --
> Niall Litchfield
> Oracle DBA
> Audit Commission UK
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Received on Fri Jun 28 2002 - 15:04:49 CDT