Re: Bitmapped Indexes, Anyone?

Stephen--

We're doing a warehouse application and bit-mapped indexes are critical to our operation. Couple of cautions. There's a known problem linking to Oracle tables with a BMI defined on it: you can't. However, you can make the link and then create the index. Also, although the marketing literature said "BMI's in 7.3" you actually need 7.3.2.3 (I think that's it) before they are actually there.

That said, they're GREAT for query performance--sometimes order-of-magnitude speedups. Plus, they're much SMALLER than normal ones, plus you can combine them in any order at query time so the number of separate indexes you need in an ad-hoc query environment is smaller.

There's some docco---about 20 pages--in the Server Tuning Guide (I think that's where.)

Good luck

Martin Smith

(PS--I'm not the DBA so my knowledge is hereby almost exhausted.)

>
> Stephen Turner wrote:
> >
> > I've read in several press releases, magazine articles and books
> > about a mystical new feature of Oracle 7.3, the bitmapped index.
> > I even saw a description of how to create one of these elusive
> > creatures <CREATE BITMAP INDEX BM_IDX ON TAB_NAME (COLUMN); >
> >
> > However, none of our 7.3 documentation seems to refer to these
> > objects and I can't issue the above statement in SQL*Plus.
> >
> > Has anyone out there created such indexes with 7.3 & if so how?
> > Is there a server option which is needed?
> >
> > We are running Oracle 7.3.2.
> >
> > Thanks,
> > Steve Turner.
>
Received on Sat Jun 14 1997 - 00:00:00 CDT