Re: ***Bitmapped Indexing API Beta - Now Available***

Deon du Plessis wrote: > 3) THE ROUTINES OVERCOME THE PROBLEMS ASSOCIATED WITH HIGH CARDINALITY > > DATA. This is basically acheived by breaking the data into sections. > If there is no data in a particular section, a BM for that section is > not stored. E.g. A bit-map is divided into 10 sections, each > representing 10,000 bit positions, i.e. a 100,000 bit BM. If position > 1, 10,000, and 100,000 is set, only 3 - 6 bytes at most would be > required to store the BM positions. (This excludes section header > information, which is about 8 bytes for every section, i.e. 24 bytes > in the example above) So let's try out a high cardinality example. How many bits or bytes do your indexes require for a data set with 1,000,000 items present, each on average about 7-15 bits away from the last item? I'd be surprised if you needed less than 15,000,000/8 bytes. Pat