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Re: Dictionary-managed tablespace

From: Richard Foote <richard.foote_at_bigpond.com>
Date: Sun, 14 Jul 2002 20:21:45 +1000
Message-ID: <dacY8.34723$Hj3.104321@newsfeeds.bigpond.com>


Hi Paul,

This is how I described the setting PCTINCREASE = 1 scenario to my students:

Walking along, I come across a bloke who was repeatedly hitting his head with a hammer.

"Why are you hitting your head with the hammer ?" I asked.

"Because I want these pain killers to do me some good" he replied.

"It must still bl*&dy hurt. Are the pain killers doing any good ?" I asked.

"Yeah, it does hurt, but I think the pain killers are taking the edge off the pain".

"Ever thought about not hitting your head with the hammer" I suggested.

He gave me a puzzled look before his eyes lit up !!

Don't you just love stories with a moral :)

Richard
"Paul Brewer" <paul_at_paul.brewers.org.uk> wrote in message news:3d308905$1_2_at_mk-nntp-1.news.uk.worldonline.com...
>
> "Richard Foote" <richard.foote_at_bigpond.com> wrote in message
> news:y3RX8.33999$Hj3.102708_at_newsfeeds.bigpond.com...
> > Hi,
> >
> > Tag, my turn :)
> >
> > If all your extents are of the same size (because you set INITIAL = NEXT
> and
> > PCTINCREASE = 0) then you have *no* fragmentation (as all 'holes' left
> > behind by dropped objects are totally reused). If you have no
> fragmentation,
> > you have no need for SMON to coalesce anything (basically SMON goes on a
> > holiday to a nice Aussie beach and has a nice relaxing break :).
> >
> > PCTINCREASE = 0 is definitely the way to go and forget about SMON
> > coalescing.
> >
> > Cheers
> >
> > Richard
>
> Hi again, Richard.
>
> Agreed. And (in the days before LMT), AFAIK, this was precisely *why* SMON
> didn't bother coalescing free space in tablespaces which had a default
> PCTINCREASE = 0.
> So I've always wondered why there were some people recommending a
tablespace
> default of 1 and tables created with same initial and next, and pcti 0, so
> as to 'fool' SMON and force it to try to coalesce periodically anyway. I
> have been assuming for years (without, I admit, having got around to
> testing) that this was yet another of those absurd myths.
>
> Comments, anyone?
>
> Thanks,
> Paul
>
>
>
Received on Sun Jul 14 2002 - 05:21:45 CDT

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