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Home -> Community -> Mailing Lists -> Oracle-L -> RE: to undo or not to undo
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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