Re: Bitmap index thoughts

On Wed, Dec 27, 2006 at 10:16:54PM +1100, Gavin Sherry wrote:
> On Wed, 27 Dec 2006, Heikki Linnakangas wrote:
> > But actually I'm not convinced we need to worry about efficient storage
> > of small bitmaps at all. The typical use case for bitmap indexes is
> > large tables with small number of distinct values, and the problem
> > doesn't really arise in that scenario. Let's keep it simple for now, we
> > can enhance it in later releases.
> The scenario I'm concerned about is where a sales data base, say, has
> 100,000 products. However, only 500 or 1000 products are popular. They
> dominate, say >99% of the sales. The other 99,900 products consume a
> little bit over 8K each for very little benefit :-(.
> This is pretty contrived but it seem real world enough...

Seems like a good candidate for CREATE INDEX WHERE :-)

I wonder what would happen if somebody implemented automatic index
exclusion conditions after use of an INDEX proved to be in the realm
of the worst case scenario? :-)

Cheers,
mark

--
mark(at)mielke(dot)cc / markm(at)ncf(dot)ca / markm(at)nortel(dot)com __________________________
. . _ ._ . . .__ . . ._. .__ . . . .__ | Neighbourhood Coder
|\/| |_| |_| |/ |_ |\/| | |_ | |/ |_ |
| | | | | \ | \ |__ . | | .|. |__ |__ | \ |__ | Ottawa, Ontario, Canada

One ring to rule them all, one ring to find them, one ring to bring them all
and in the darkness bind them...

http://mark.mielke.cc/