IMPORT/LMT'S/EXTENT SIZE - Please discuss
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Thread: IMPORT/LMT'S/EXTENT SIZE - Please discuss

  1. #1
    Join Date
    Aug 2000
    Posts
    236
    Dba's,

    I have anlyzed my existing DB which uses dictionary managed tablespaces and found initial extent sizes ranging from 40 - 100Mb (for different tables of course) which I find too much.

    Both DBA_TABLES and DBA_EXTENTS show one extent allocated to the table of size 40 - 100MB

    I am pllaning a reorg and testing the use of LMT's. I ceated a LMT with uniform allocation of 512K extents.

    After import, I analyzed my tables again and guess what?

    DBA_TABLES show an initial extent size of 40 - 100 MB (original).

    DBA_EXTENTS show an number of extents allocated of uniform size 512K.

    Why is this discrepancy and what is right? And how do I achieve smaller extent sizes for my segments?

    Thanks,
    Nizar

  2. #2
    Join Date
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    greenwich.ct.us
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    When you specify your INITIAL and NEXT extent values for an object, Oracle is smart enough to go out and allocate that much space in 512K chunks.
    Jeff Hunter
    marist89@yahoo.com
    http://marist89.blogspot.com/
    Get Firefox!
    "I pledge to stop eating sharks fin soup and will not do so under any circumstances."

  3. #3
    Join Date
    Apr 2001
    Location
    Louisville KY
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    I am trying to learn about LMT's. (Old dog.......)

    When you did your import did it go to the LMT or the DMT?

    I though Oracle ignored initial and next sizes for LMT's?
    Joseph R.P. Maloney, CSP,CDP,CCP
    'The answer is 42'

  4. #4
    Join Date
    Feb 2001
    Posts
    389
    It depends how u created ur LMT, if u specified uniform extent then ORacle
    respects ur table storage clause and shall allocate extents
    equal to or round off to ur initial extent in multiples of uniform extent
    size specified at tablespace level.

  5. #5
    Join Date
    Aug 2000
    Posts
    236
    Marist,
    Please clear me on this.

    Yes - My object has storage parameters of initial 100M.

    My LMT has uniform extent allocation of 512 K.

    Are you saying that during the import process when Oracle creates that table, 200 extents of 512 K are allocated. And this is what DBA_EXTENTS reports.

    And DBA_Tables report 100M because initially 100M space is allocated for the table.

    Is this right?

    Thanks,

    Nizar

  6. #6
    Join Date
    Nov 2000
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    greenwich.ct.us
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    9,092
    Originally posted by nabaig
    Are you saying that during the import process when Oracle creates that table, 200 extents of 512 K are allocated. And this is what DBA_EXTENTS reports.

    Yup.


    And DBA_Tables report 100M because initially 100M space is allocated for the table.
    You got it.
    Jeff Hunter
    marist89@yahoo.com
    http://marist89.blogspot.com/
    Get Firefox!
    "I pledge to stop eating sharks fin soup and will not do so under any circumstances."

  7. #7
    Join Date
    Aug 2000
    Posts
    236
    Jeff,

    Thanks a ton.

    Nizar.

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