Re: bitmap index with nosort

Offline -

I'm sure you already know this, but technically they are stored in a tree format, loosely speaking as an IOT with columns:

    {column values(s)}, starting rowid, ending rowid, {string of bits}

where the {string of bits} is the 'data' component of the IOT, and the rest is the 'primary key'.

In principle there is no reason why the NOSORT option shouldn't apply to bitmap indexes. I would guess that in practice because the sorting requirement is so small compared to the bitmap generation strategy, no-one has bothered to put the code in place.

Jonathan Lewis
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-----Original Message-----
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Date: 13 March 2002 08:44

|Sinardy :
|
|It is expected behavior only. Bit map indexes are not stored in a
tree
|format and sorting will have no impact.
|Have a look at bit map concepts in Oracle Documentation.
|
|
|Best Regards,
|K Gopalakrishnan
|Bangalore, INDIA
|

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