bitmap indexes

[sathya1212]

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

[julian]

Replace the proper schema name in the code below and rin it:

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;
/

[sathya1212]

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...

[julian]

Why don't you create the index first and then check the sizes....