Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: Increase the size of rollback segments

Re: Increase the size of rollback segments

From: Howard J. Rogers <howardjr_at_www.com>
Date: Mon, 16 Oct 2000 20:37:43 +1000
Message-ID: <39eacce2@news.iprimus.com.au>

Well, we'll have to agree to disagree. I see nothing wrong with letting the rollback segments rip during the day, and manually shrinking them at the dead of night, when no-one gives a damn, with a manual shrink command, suitably chron'd of course. Disk space is cheap (or should be considered so), and I hate to see anything get between me and my transaction, however "trivial" it might be.

I agree with sizing for the general case.

Regards
HJR

--
--------------------------------------------------------------------------
Opinions expressed are my own, and not those of Oracle Corporation
Oracle DBA Resources:               http://www.geocities.com/howardjr2000
--------------------------------------------------------------------------

"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message
news:971618594.24915.0.nnrp-08.9e984b29_at_news.demon.co.uk...

>
> I have to disagree with you on this point.
> In well-structured system, the optimum rollback
> size is the smallest size that you can get away
> with that does not result in frequent small extends
> and shrinks of rollback segments.
>
> However, there are often cases where you expect
> an occasional , but not predictably timed, transaction
> to demand an excessive amount of rollback. In this case,
> the optimum strategy is to set the optimal at the 'steady
> state' figure, and allow the rollback segment to shrink
> automatically some time after the major transaction
> completes.
>
> The only alternatives are to code the transaction to
> acquire the same rollback segment every time(nasty),
> or to code the transaction to find and shrink the extended
> rollback segment as its last step (just as nasty), or get
> the dba to keep checking the database and shrink the
> segment manually (nastiest of all).
>
>
> --
>
> Jonathan Lewis
> Yet another Oracle-related web site: http://www.jlcomp.demon.co.uk
>
> Howard J. Rogers wrote in message <39e7a664$1_at_news.iprimus.com.au>...
> >Why avoid dropping them? There's no point. Create a new one first, then
> >drop the old ones. Incidentally, Optimal is a very bad idea (it will
cause
> >shrinking just exactly when you don't want it to happen: when a new
> >transaction is looking to acquire new rollback blocks).
> >

> >
>
>
Received on Mon Oct 16 2000 - 05:37:43 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US