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RE: Extent allocation

From: Elliott, Patrick <Patrick.Elliott_at_bestbuy.com>
Date: Thu, 08 Feb 2001 12:26:04 -0800
Message-ID: <F001.002AF93C.20010208122608@fatcity.com>

Is the tablespace you are creating this table in a Locally Managed Tablespace? If so, then initial and next extents will be ignored.

> -----Original Message-----
> From: Shakeel Qureshi [SMTP:msklq_at_yahoo.com]
> Sent: Thursday, February 08, 2001 1:35 PM
> To: Multiple recipients of list ORACLE-L
> Subject: RE: Extent allocation
>
> Hi Paul,
>
> I created an object with initial_extent 128K and it
> took 13 blocks. I then created the same object with
> 208K and still it took 13 blocks. My db_block size is
> 16K. I tested this on 8.1.5 and 8.1.6 and they both
> behave the same.
>
>
> TIA,
>
> Shakeel Qureshi
> squrehi_at_barpoint.com
> --- Paul Baumgartel <PaulB_at_instipro.com> wrote:
> > It is a big clue. Oracle rounds to multiples of 5
> > extents to prevent the
> > existence of a free extent of fewer than 5 blocks,
> > which is unlikely to be
> > usable.
> >
> >
> >
> > Paul Baumgartel
> > InstiPro, Inc.
> > paul.baumgartel_at_instipro.com
> > 212 813-0829 x103 (office)
> > 917 549-4717 (mobile)
> >
> > -----Original Message-----
> > Sent: Wednesday, February 07, 2001 4:26 PM
> > To: Multiple recipients of list ORACLE-L
> >
> >
> >
> > Hi -
> >
> > I am confused now about how oracle actually
> > determines the size an extent
> > should be. I have db_block_size set at 8192 and
> > have defined a tablespace
> > (and tables) at initial and next extents of 128K.
> > When I do a show
> > parameter db_file_multiblock_read_count it says 8.
> > Therefore I thought 128K
> > would be a good number, since it is a multiple of
> > these numbers.
> >
> > However, when I check my extent sizes, I see that
> > each extent contains 10
> > blocks which is 160K.
> >
> > I remember reading an article some time ago about
> > how oracle actually
> > determines what it thinks the extent size should be.
> > Does anyone know of an
> > article like this, or can anyone explain to me why
> > it chose a different
> > extent size?
> >
> > By the way, I looked at several tables and the one
> > common thing I noticed is
> > that the number of blocks allocated seems to be a
> > multiple of 5 - ie. some
> > are 5 blocks, some 10, some 20, etc. I don't know
> > if that's coincidence or
> > a big clue to the whole thing
> >
> > Lisa
> >
> >
>
>
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> --
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> --
> Author: Shakeel Qureshi
> INET: msklq_at_yahoo.com
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Elliott, Patrick
  INET: Patrick.Elliott_at_bestbuy.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
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Received on Thu Feb 08 2001 - 14:26:04 CST

Original text of this message

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