Re: Oracle Myths

Pascal Byrne wrote:
>
> "Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk> wrote in message news:<3ce21b71$0$8510$ed9e5944_at_reading.news.pipex.net>...
> > PCTIncrease should be as small as possible but non-zero to minimize
> > tablespace fragmentation.1% is a good value (from my OCP course notes though
> > not necessarily given by the tutor!)
>
> I've seen this quoted in a recent paper by Michael R. Ault (author of
> "Oracle8i Administration and Management"). The reason given was that
> SMON will not coalesce free space if PCTINCREASE is zero. Is this
> definitly a myth?
>
> -Pascal

I like to think of it like this...

1. Take a wooden house
2. Smash it to pieces with a hammer (ie its now "fragmented")
3. Get some nails
4. Use the hammer to put the house back to together ("defragment")

Voila! We can now proclaim that a hammer is an effective defragmentation device.

pctincrease is the same. You set to 1 (which causes fragmentation more often than now), and then claim that setting it to 1 will solve the very problem that they've just caused.

hth
connor

-- 
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Connor McDonald

http://www.oracledba.co.uk

"Some days you're the pigeon, some days you're the statue..."