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RE: to undo or not to undo

From: Freeman Robert - IL <FREEMANR_at_tusc.com>
Date: Wed, 25 Feb 2004 10:47:48 -0600
Message-ID: <F5E885BEF9540D47A7BDC03CF1688087066D661A@tuscil_ex1>


LONG LIVE AUTOMATED UNDO!! Also, resumable space management is a much underutilized feature ....

Robert

-----Original Message-----

From: Mercadante, Thomas F
To: oracle-l_at_freelists.org
Sent: 2/25/2004 10:45 AM
Subject: RE: to undo or not to undo

Barbara,

Your steps are correct. Just one more thing - comment out the rollback_segments init.ora param. That will keep them offline when you bounce the database.

The other thing that I noticed is that the amount of Undo space that is need
is much less than what I had in Rollback's. My warehouse had over 25Gig of
Rollback space, and it's high water mark was always at 90%. I reduced it to
6 Gig and it never even approaches that limit.

You can always adjust your file size later.

Good Luck!

Tom Mercadante
Oracle Certified Professional

-----Original Message-----

From: Barbara Baker [mailto:barbarabbaker_at_yahoo.com] Sent: Wednesday, February 25, 2004 11:27 AM To: oracle-l_at_freelists.org
Subject: to undo or not to undo

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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Received on Wed Feb 25 2004 - 10:53:56 CST

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