Re: PCTFREE & PCTUSED

I would agree with everything except #5 (increasing PCTINCREASE for growth). Most thinking today seems to be to set INITIAL and NEXT to the same size, and PCTINCREASE to zero. With those settings, all extents will be the same size and thus all empty spaces created by deletion of an extent will be the exact size to receive a new extent, making Oracle's internal space management much simpler. If PCTINCREASE
> zero, each additional extent allocation is larger than the previous.
Not only does this make it more difficult for Oracle to find a place to put the extent, it gets you into a situation where there is plenty of space for the DATA, but not enough space for the extent being requested.

If you expect a high amount of insert activity, increase MAXEXTENTS, buy DASD, and try to get the user to define some resonable retention criteria.

In article <38C7983A.7682_at_btinternet.com>,   High.Flight_at_btinternet.com wrote:
> Here you go :-
>
> J wrote:
> >
> > I have some questions about the usage of PCTFREE & PCTUSED. Hope
 anyone can
> > give me the answer along with the explanation.
> > T.I.A
> >
> > Vurley
> >
> > =============================================
> > Q: Which parameter reserves the more space for future updates
> >
> > 1. high PCTINCREASE
> > 2. high PCTFREE ** CORRECT **
> > 3. high INITIAL
> > 4. high PCTUSED
> >
> > Q: Row migration is a result of
> >
> > 1. high PCTFREE
> > 2. low PCTFREE ** CORRECT **
> > 3. high PCTUSED
> > 4. low PCTUSED
> >
> > Q: If the space usage parameters are set to the default clause,
 which change
> > could cause higher processing costs because blocks will be
 considered
> > free more often.
> >
> > A. raising PCTUSED ** CORRECT **
> > B. raising PCTFREE
> > C. lowering PCTUSED
> > D. lowering PCTFREE
> >
> > Q : Which setting for the storage parameter should you use if
 tables are
> > updated very infrequently
> >
> > 1. low PCTUSED
> > 2. high PCTUSED
> > 3. low PCTFREE ** CORRECT **
> > 4. high PCTFREE
> >
> > Q : If your table grows significantly, which storage parameter
 should you
> > increase
> >
> > 1. MAXEXTENTS
> > 2. PCTINCREASE ** CORRECT **
> > 3. PCTFREE
> > 4. PCTUSED
> >
> > Q: Which parameter value should you use if tables have frequent
 inserts and
> > deletes
> >
> > 1. low PCTUSED ** CORRECT ** (I think - reason :- lowers
 freelist processing?)
> > 2. high PCTUSED
> > 3. low PCTFREE
> > 4. high PCTFREE
> >
> > Q: You are creating the LINE_ITEM table that will experience
 extensive
> > insert activity.
> > Which space utilization parameter setting is most appropriate for
 the table?
> >
> > A. low PCTUSED
> > B. low PCTFREE
> > C. high PCTUSED
> > D. high PCTFREE ** CORRECT **
>

--
Ed Stevens
(Opinions are not necessarily those of my employer)


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