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Home -> Community -> Mailing Lists -> Oracle-L -> 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
>
>
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Shakeel Qureshi INET: msklq_at_yahoo.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Thu Feb 08 2001 - 13:47:16 CST
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