Re: Faster bitmaps

get a faster computer with more RAM.

there is insufficient information to make any useful suggestions, since bitcoding tends to be data specific.

"Dave Arkley" <DaveArkley_at_REMOVE.THIS.lineone.net> wrote in message news:MeCC6.528$lL5.2086_at_NewsReader...
> I've built an engine to bitmap data from a SQL server table for rapid
> analysis. Query times across 41 million rows with 58 attributes < 5
 seconds
> on a Pentium II 233. Not bad!
>
> However it takes forever to build the bitmaps. I've outlined (in
 pseudocode)
> the process I use to build the bitmaps below. The build on the above
 dataset
> takes 72 hours, anyone know of a quicker way?
>
> For each atttribute (column)
> SELECT DISTINCT Values, Count(Values)
> For each Value
> create empty bitmap
> SELECT URN Where Attribute = Value
> Turn bit on for each URN returned above
> next value
> next attribute
>
> I've got indexes on all of the high cardinality attributes, and take
 obvious
> shortcuts such as calculating the last bitmap by XORing all of the others.
 I
> need a fundamental algorithm change, not a tweak!
>
>
> Thanks in advance
> Dave Arkley
>
>
Received on Sat Apr 21 2001 - 02:36:07 CEST