Re: About Oracle Bitmap Index...

Stanley wrote:

> I create many Bitmap Indices on all attributes of a table which has
> about 100 attributes(A1~A100). I query data and use hint on it, when
> the Where clause including some of attributes of A1 to A50, it is good
> to work, but when the Where clause including some of attributes of A51
> to A100, it's performance will
> be very poor, why ???
>
> Oracle version : 9.0.1.0.0
> O.S : Windows XP
> RAM : 1G
> HD : 10G
>
> Create table sample :
>
> CREATE TABLE "FUZZY"."FEMALE_BI" (
>
> "RID" ROWID NOT NULL,
> "AB1_1" NUMBER(1, 0) NOT NULL,
> :
> "AB1_100" NUMBER(1, 0) NOT NULL)
>
> Create Bitmap Index sample :
>
> Create Bitmap Index B11 on Female_BI (AB1_1) TABLESPACE FB_INDEX
> STORAGE ( INITIAL 1000K);
> :
> Create Bitmap Index B1100 on Female_BI(AB1_100) TABLESPACE FB_INDEX
> STORAGE ( INITIAL 1000K);
Please please tell me you did not create a table with a column of type ROWID. Please!

Have you invested any time in researching when to use, and when not to indexes? Especially bitmap indexes? What you posted looks like the poster-child for a bad example.

--
Daniel Morgan
http://www.outreach.washington.edu/extinfo/certprog/oad/oad_crs.asp
damorgan_at_x.washington.edu
(replace 'x' with a 'u' to reply)