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Thread: Locally managed tablespaces

  1. #1
    Join Date
    Jan 2000
    Posts
    5

    Question



    Hi gurus,

    I was wondering if someone is using locally managed tablespaces
    in a VLDB production environment ( from 40-60Gb up to 3-4 terabytes,
    about 400-5000 tables , 100-2000 tablespaces), because I cannot simulate and perform
    tests with this feature in a large environment.
    Any problems or suggestions with LMT?

    Thanks in advance

    Paolo


  2. #2
    Join Date
    Apr 2000
    Location
    roma
    Posts
    131
    LMT do not use the data dictionary to track free space and extent allocation,they buy itself maintain info for blocks or sets of blocks contained within.. so you may have a higher performance. They also eliminate the need to periodically coalesce free space...will go well for temporary tablespaces for es...

  3. #3
    Join Date
    Nov 2000
    Location
    greenwich.ct.us
    Posts
    9,092
    I know of several DBA's that will ONLY have LMT in their databases (except, of course, for system). They claim huge performance increases with growing databases.
    Jeff Hunter

  4. #4
    Join Date
    Feb 2001
    Posts
    389
    Few limitations with LMT:

    1) Minimum datafile size is 64K.
    2)While creating datafile, be sure of extent policy.
    3)Do not drop in read only mode.
    4)Rollback segments are first created on dictionary tablespace and then coverted to LMT, besure compatible parameter is 8.1.6.
    otherwise, Full export will give u problems.
    5)Next extent,pctincrease parameters do not work.
    6) Cannot change next parameteronce objects are created.


    Take Care
    GP

  5. #5
    Join Date
    Jun 2000
    Location
    Madrid, Spain
    Posts
    7,447
    for point 4, you first create a dummy RBS if you dont have any RBS, once you have a dummy RBS you can create a LMT for your *REAL* RBS. You dont need to convert
    for point 5 and 6, these are not limitations these are features. When the extent size is uniform there is not point alter object´s storage and with LMT we get uniform extent sizes

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