Re: Best/Only way to change RBS initial/minextents

"Howard J. Rogers" <howardjr2000_at_yahoo.com.au> wrote in message news:miLm9.45024$g9.128459_at_newsfeeds.bigpond.com...

...snip...

>
> You're doing it hard. What you want to do is to avoid segment growth or
> shrinkage. Optimal encourages shrinkage (hence, don't set it). And trying
to
> create pretty, perfectly-formed, small rollback segments is likewise an
> encouragement to growth. If you can spare the disk space, create them all
> quite large: say, 6 extents of 8Mb each. If you want your OCP, then 20
> extents is the right number -and I'd still say they should be each 8Mb
big.

... Snip...

> Question 5: What's 1Gb divided by 6 extents? Er, er, er... damn I wished I
> passed A level Maths!... er, 180K. Or thereabouts.
>
> Therefore: create rollback segement RBS01 storage (initial 180K next 180K
> minextents 6) tablespace RBS;
>

Hi Howard,

I agree pretty well agree with what you've said/recommended except I have a question about the above 6 extents suggestion.

Why 6 ? Why not 5, or 8, or indeed 20 extents ?

Personally I usually go for 10 in that 10 is an easier number to use in any calculations, so 10 x 100M (as my maths is always questionable at the best of times ;) It also gives the RBS plenty of time to work it's way around in case of blocking transactions (900M) and increasing in nice healthy chucks (100M) to avoid excessive allocations if necessary.

Just curious where you come up with 6 ?

Cheers

Richard Received on Wed Oct 02 2002 - 19:23:40 CDT