Re: 9i multi cache buffer

"Mark Townsend" <markbtownsend_at_attbi.com> wrote in message news:B9FAE621.283B%markbtownsend_at_attbi.com...
> in article jmbB9.77282$g9.218121_at_newsfeeds.bigpond.com, Howard J. Rogers
at
> howardjr2000_at_yahoo.com.au wrote on 11/15/02 10:59 AM:
>
> > My troubles start when Oracle introduces a new feature (such as multiple
> > blocksizes or ASSM) which then get touted as the latest cure-all and
hence
> > get implemented without due consideration.
>
> We never, ever, ever intended multiple blocksizes to be used primarily as
a
> performance enhancement - it was done to make transportable tablespaces
easy
> to use between an OLTP and DW system, where the 'in use' blocksizes may
> vary. And then, the aim is that you would use it only to stage the moved
> data, and then merge or CTAS into the actual warehouse data.

Exactly what I posted originally. That was my understanding, too, and that's the context in which I would want make initial use of the feature.

>
> As a side note, during the original inhouse discussion of the feature,it
was
> mentioned that multiple blocksizes did also have some performance tuning
> advantages - unfortunately, this then became over emphazised in the
training
> and the doc, and has fast become another Oracle myth. This situation has
now
> been reversed, and newer updates to the doc and training deliberately
under
> emphasize the performance value of this feature.
>

Yup. Obviously it *might* have a role to play in tuning. Peripherally. And it shouldn't be discounted that it could make a difference. But it shouldn't be promoted either. Absolutely agree.

> The reality is that for most workloads (and I'd dare to say all customer
> workloads), the performance benefits from multiple block sizes will not
make
> a significant impact, and in fact, I doubt would be measurable at all.
>
> Hopefully this will close this thread (as it did the one that went through
> Oracle about 6 months ago on this same topic)
>

Not when you have the likes of Jonathan and Geoff saying it might make a difference it won't!

(But I sorta wish it would, for sure).

Regards
HJR
>
>
>
Received on Fri Nov 15 2002 - 21:59:47 CST