Notes in-line
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Regards
Jonathan Lewis
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The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
"Richard Foote" <richard.foote_at_bigpond.com> wrote in message
news:gghdb.126259$bo1.14654_at_news-server.bigpond.net.au...
>
> However, IMHO, you uniform sizes don't make much sense.
>
> Because it suggests that if you have a (say) table in the 1M
tablespace but
> it grows and becomes 100M in size (or 100 extents) then it really
should
> have gone in the 8M tablespace (else why have it). By having uniform
sizes
> that are only a magnitude of 10 or so different, it suggests that
anything
> substantially more than 10 extents is undesirable. And we both know
what
> rubbish that is.
>
> So why such a tiny magnitude of difference ?
>
> I can see why you're leaning towards autoallocate ....
>
The argument I have in favour of picking a few sizes for
uniform is that I don't like to see status reports that are
longer than a few lines. One of my reasons for choosing
a particular extent size for an object is that if it is a growing
object, I want to see a report showing that my predictions
about the rate of growth are correct - any incorrect prediction
should be taken as a performance threat.
By choosing an extent size that corresponds to a
growth rate of about one extent per month, I can
get a report of 'what grew last night' or 'what grew
this week' that is only a few lines, so that anything
growing too rapidly stands out quite quickly.
Having a short-list where the change in magnitude
is relatively small makes it quite easy to hit the
target of roughly one extent per month.
Received on Sun Sep 28 2003 - 11:10:14 CDT
