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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Rollback segments not shrinking
Rollback segments do NOT shrink automatically when another rollback segment needs space.
A rollback segment will shrink (and ONLY if OPTIMAL is set) if and only if *it* needs to extend. so manual shrinks work fine, but automatic shrinks only happen when the extended rollback segment needs to extend again. It's a performance hit -- Oracle determines it needs more space in that rollback segment, then determines that it can shrink it, shrinks it and then extends it.
MUCH better to size the rollback segments appropriately so that they do not need to extend frequently. If you can't, set up a batch job to manually shrink the rollback segments at a time of YOUR choosing.
Rachel
>On Thu, 05 Apr 2001 09:16:17
> Nicoll, Iain (metering) wrote:
> >Can anyone tell me why we would get "unable to extend" errors in rollback
> >but the segments will shrink when done manually - I thought that rollback
> >segments would shrink when not used if another rollback segment needed
>the
> >extents.
> >
> >We're way back on 7.3.4 on Solaris.
> >
> >Cheers
> >
> >Iain Nicoll
> >--
> >Please see the official ORACLE-L FAQ: http://www.orafaq.com
> >--
> >Author: Nicoll, Iain (metering)
> > INET: iain.nicoll_at_calanais.com
> >
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-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Rachel Carmichael INET: carmichr_at_hotmail.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Tue Apr 10 2001 - 15:58:23 CDT
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