Re: to undo or not to undo
- From: Kirtikumar Deshpande <kirtikumar_deshpande@xxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Wed, 25 Feb 2004 10:31:06 -0800 (PST)
Barbara,
I always kept these activities separate.
Migrate to 9i first.
Keep the old RBS after migrating to 9i for a new days, monitored them using
v$transaction,
v$rollstat to assist in sizing of undo tablespace and scheduled downtime to do:
1. Remove old rbs, and associated tablespace(s).
2. Create undo tablespace
3. Change init.ora file
And then restart the DB. This way all the new undo segments will start from
USN # 1. I just
prefer it that way to avoid any confusion (in the minds of my backup DBAs as to
what happened to
USN #1-40, for example).
4. Monitor undo usage, and adjust undo_retention for just a few hours, at
most, and then adjust
the undo tablespace size.
I have not had any problems. But again we do not have a tonne of (thousands
of) concurrent
transactions. Dan Fink has some horror stories when # of xactions reaches very
high...
Thanks for the kind words about my presentation at RMOUG..
Regards,
- Kirti
--- Barbara Baker <barbarabbaker@xxxxxxxxx> wrote:
> Howdy, list.
> For those of you who migrated a database from 8i to
> 9i, did you move convert to undo tablespace
> immediately? Did you run for awhile still using
> rollback segments then convert later? Any gotcha's?
>
> I cannot find a concise doc on how to change over.
> (I'm using notes from Kirti's excellent RMOUG
> presentation on "Understanding Automatic Undo.." but
> I've already forgotten stuff.)
>
> Here are the steps I know. What I do not know is when
> to remove my rollback segments. If I add the undo
> params to init then bounce the db, can I then offline
> the rbs segs and tablespace after I come back up? Or
> do I offline them before I bounce the db?
>
> Anyone know of a doc that outlines this stuff?
> Thanks for any help.
> Solaris 9 Oracle 9.2.0.4
> Barb
>
> (here's what I think I need to do)
>
> Changing Rollback Segments to Undo
>
> set compatible 9.0.0 in init (currently 8.1.7.4)
>
> create undo tablespace
> create undo tablespace undotbs1
> datafile '/class17db/u01/undotbs1.dbf'
> size 500m;
>
> insert init parameters
> undo_management=AUTO
> undo_retention=10800
> undo_tablespace=UNDOTBS1
> undo_suppress_errors=TRUE
>
> shut down and restart database
>
>
>
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