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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Rollback Segment Shrinkage Question
short answer: yes, you are right, it will not shrink if no transaction
needs an additional extent.
I tested this when optimal first came out -- rollback segment did not shrink until I needed space.
Rachel
>From: Nikolay Kumanov <nkumanov_at_zgb.bg>
>Reply-To: ORACLE-L_at_fatcity.com
>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Subject: RE: Rollback Segment Shrinkage Question
>Date: Tue, 17 Oct 2000 07:35:32 -0800
>
>"Oracle concepts" manual says in chapter 4:
>
>"If a transaction needs to continue writing rollback information from one
>extent to another extent in the rollback segment, Oracle compares the
>current size of the rollback segment to the segment's optimal size. If the
>rollback segment is larger than its optimal size, and if the extents
>immediately following the extent just filled are inactive, then Oracle
>deallocates consecutive nonactive extents from the rollback segment until
>the total size of the rollback segment is equal to or close to, but not
>less
>than, its optimal size. Oracle always frees the oldest inactive extents, as
>these are the least likely to be used by consistent reads. "
>
>My question for the gurus: Does that mean that if no transactions need to
>allocate more than one extent in the RBS, it will never shrink back
>automatically?
>
>TIA,
>
>Dr. Nikolay Kumanov
>
>MIS Manager, Zeitungsgruppe Bulgarien GmbH
>47, Tsarigradsko chaussee, Sofia 1504, Bulgaria
>phone: +(359-2)4339-643, fax: +(359-2)946-1286
>mailto:nkumanov_at_zgb.bg
>
>"Show me a completely smooth operation and I'll show you someone who's
>covering mistakes. Real boats rock." - Frank Herbert, "Chapterhouse: Dune"
>
>
>
>-----Original Message-----
>Sent: Tuesday, October 17, 2000 5:21 PM
>To: Multiple recipients of list ORACLE-L
>
>
>Hi,
>
> At what point in time does a rollback segment shrink back to its
>optimal
>value?
>
>
>Bill Carle
>AT&T
>Database Administrator
>816-995-3922
>wcarle_at_att.com
>
>--
>Please see the official ORACLE-L FAQ: http://www.orafaq.com
>--
>Author: Carle, William T (Bill), NBSO
> INET: wcarle_at_att.com
>
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>Author: Nikolay Kumanov
> INET: nkumanov_at_zgb.bg
>
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Share information about yourself, create your own public profile at Received on Tue Oct 17 2000 - 11:21:28 CDT
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