On Tue, Nov 18, 2003 at 02:31:03PM -0800, Sailesh Krishnamurthy wrote:
> Another thing I toyed with was having an implementation of a
> Tid-List-Fetch .. sorting a TID-list from an index and fetching the
> records of the relation off the sorted list for better IO
> performance. AFAICT something like this isn't present yet .. can pgsql
> do this already ?
Nope. In fact it's on the TODO list. I think people call it "bitmap
indexes", the idea being that the TID list is represented as a "sparse
bitmap" (go ask some JPEG hacker what that means).
Extra points if multiple bitmaps can be ANDed and ORed, to allow using
multiple indexes simultaneously ...
--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
Oh, oh, las chicas galacianas, lo harán por las perlas,
¡Y las de Arrakis por el agua! Pero si buscas damas
Que se consuman como llamas, ¡Prueba una hija de Caladan! (Gurney Halleck)