I heard of it some place. that is try to have three different
tablespaces. One for large table, one for medium size table and third
for small tables. Each of these tablespaces can have their own extent
sizes. Large having large extent size. Medium can have medium size
extents and same for small tablespace. Each tablespace can still have
uniform extent size. So depending on the table size you can choose
which tablespace they will go in and thus save yourself from over
allocating the space.
- DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM> wrote:
> Sundeep
> Oops, egg on my face. Reading too fast, seeing one word and thinking
> another. My understanding from "Stop Defragmenting and Start Living"
> was
> that uniform extents was the direction Oracle was heading. The
> problem with
> autoallocate is that you can end up with fragmented tablespaces and
> therefore have to reorganize them from time to time. You end up with
> free
> spaces of varying sizes. With uniform extents you can't have
> fragmentation
> because all the extents are exactly the same size. The down side is
> that
> you may waste a bit more space because a small table may have more
> space
> allocated than it needs. Also you must get beyond the myth that a
> good table
> is all in one extent. Based on the above, I opted for uniform extents
> and
> have been pleased with the results. However, if someone has some
> strong
> arguments for autoallocate, I would be interested in hearing them.
> Hopefully
> this time I have responded to your question. Let me know.
>
> I went to http://www.google.com and searched for Oracle Autoallocate.
> Here
> is a link I found:
>
> http://www.jlcomp.demon.co.uk/ch_08.html
> With autoallocate tablespaces, you may get a fairly random scattering
> of
> 64K, 1MB, 8MB or 64MB depending on the demand and the current state
> of the
> tablespace.
>
> Dennis Williams
> DBA
> Lifetouch, Inc.
> dwilliams_at_lifetouch.com
>
> -----Original Message-----
> Sent: Tuesday, March 26, 2002 2:46 PM
> To: Multiple recipients of list ORACLE-L
>
>
> Dennis,
>
> I mentioned Autoallocate and not autoextend. I have
> been using LMTs for over a year now but only with
> UNIFORM extent sizes. I am not sure if I am ready to
> handover space management to Oracle (via Autoallocate
> which is being foisted upon me as a panecea of all
> ills) least I have evaluated the pros and cons. The
> stuff in Manual and technet I have reveiwed so far
> doesn't give you enough information like how much
> space is wated in Autoallocate vs Uniform extent
> sizes. How does Oracle decide to allocate an extent
> for an Insert or an Update in Autoallocate option and
> how does it decide on the extent size?
>
> So far I have looked at SQLRef, Concepts manual and
> technet. Any other pointers?
>
> TIA
> Sundeep
>
>
>
> --- DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM> wrote:
> > Sundeep - Start by reading the classic paper "How to
> > Stop Defragmenting and
> > Start Living" at this link:
> >
> http://www.dbatoolbox.com/WP2001/spacemgmt/defrag.htm
> >
> > Actually, autoallocate and uniform extents work very
> > well together. But you
> > need to understand the concepts behind them first.
> > And make sure your
> > application doesn't use up all your disk space if
> > you autoallocate.
> > Dennis Williams
> > DBA
> > Lifetouch, Inc.
> > dwilliams_at_lifetouch.com
> >
> >
> > -----Original Message-----
> > Sent: Tuesday, March 26, 2002 12:54 PM
> > To: Multiple recipients of list ORACLE-L
> >
> >
> > Can someone point me to good reading material on
> > this
> > subject. Is one better than the other for
> > performance
> > and manageability?
> >
> > Syntactically the autoallocate is shorter and seems
> > to
> > be more hands off (does that mean worry free also?).
> >
> >
> >
> > TIA
> >
> >
> > =====
> >
> > Sundeep Maini
> > Consultant
> > Currently on Assignement at Marshfield Clinic WI
> > mainis_at_mfldclin.edu
> >
> > __________________________________________________
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> > http://www.orafaq.com
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> > Author: sundeep maini
> > INET: sundeep_maini_at_yahoo.com
> >
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>
> =====
>
> Sundeep Maini
> Consultant
> Currently on Assignement at Marshfield Clinic WI
> mainis_at_mfldclin.edu
>
> __________________________________________________
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> Yahoo! Movies - coverage of the 74th Academy Awards®
> http://movies.yahoo.com/
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: sundeep maini
> INET: sundeep_maini_at_yahoo.com
>
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
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Mohammed Shakir
CompuSoft, Inc.
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(732) 257-6001 (Home)
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Received on Tue Mar 26 2002 - 20:53:18 CST
