bitmap indexes
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Thread: bitmap indexes

  1. #1
    Join Date
    Aug 2001
    Location
    bangalore,india
    Posts
    17

    Cool

    hi guys,

    how do u estimate the size of an bitmap index i.e the initial extent of it.
    ex: cust table --- 350000 recoreds
    index column --- marital_status varchar2(1)

    so,what should be the initial size of the index...
    any sites or links available regarding this....

    thanx

  2. #2
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
    Posts
    3,938
    Replace the proper schema name in the code below and rin it:

    Code:
    declare
    tot_blocks number;
    tot_bytes number;
    unused_blocks number;
    unused_bytes number;
    lufid number;
    lubid number;
    lub number;
    begin
    dbms_space.unused_space(
    'REPLACE_ME_WITH_THE_SCHEMA_NAME',
    'marital_status','INDEX',
    tot_blocks,
    tot_bytes,
    unused_blocks,
    unused_bytes,
    lufid,
    lubid,
    lub);
    dbms_output.put_line('total_blocks :'||tot_blocks);
    dbms_output.put_line('total_bytes :'||tot_bytes);
    dbms_output.put_line('unused_blocks :'||unused_blocks);
    dbms_output.put_line(' The file ID of the last extent which contains data:'||lufid);
    dbms_output.put_line(' The block ID of the last extent which contains data :'||lubid);
    dbms_output.put_line(' The last block within this extent which contains data :'||lub);
    end;
    /

  3. #3
    Join Date
    Aug 2001
    Location
    bangalore,india
    Posts
    17
    HI...JULIAN THANKX,

    the script u have given works for an already existing index ,but in my case i am going to create the index for the first time...



  4. #4
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
    Posts
    3,938
    Why don't you create the index first and then check the sizes....

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