If you have a 1MB rollback segment, it may be
recycled several times without being written to
disc. If you have a 100MB rollback segment
then you will probably write the whole thing
out before you get round to recycling it.
--
Jonathan Lewis
Yet another Oracle-related web site: http://www.jlcomp.demon.co.uk
Howard J. Rogers wrote in message <39ec377a_at_news.iprimus.com.au>...
>Can you explain what the IO cost is? Cos I can't think of one.
>
>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:971718991.1058.0.nnrp-08.9e984b29_at_news.demon.co.uk...
>>
>> The problem isn't one of space - like you, I am quite happy
>> to 'waste' empty space to make administration more straightforward.
>> In the case of rollback segments, though, there is an I/O cost
>> to large rollback segments that can be avoided by keeping the
>> rollback segments at the optimal size.
>>
>> --
>>
>> Jonathan Lewis
>> Yet another Oracle-related web site: http://www.jlcomp.demon.co.uk
Received on Tue Oct 17 2000 - 13:40:29 CDT
