[Bizgres-general] A bitmap index access method is available in bizgres CVS tip

[Mark Kirkwood]

Luke Lonergan wrote:
> Mark,
> 
> On 12/19/05 7:37 PM, "Mark Kirkwood" <markir at paradise.net.nz> wrote:
> 
>>I didn't post results for creation time, but here they are (compared
>>bizgres to *itself* this time). I've included the resulting index sizes too:
>>btree :
>>   val2  154 s, 160M    # 100 distinct
>>
>>bitmap:
>>   val2  224 s, 550M    # 100 distinct
>>
>>So creation takes *longer* in the bitmap case - perhaps the integer data
>>is the reason (let's see what happens when I try characters).
> 
> 
> Yes - this all looks pretty yucky.  One thing I want to look at is the word
> size and optimality of our bitmap compression scheme.  I presume you are
> using an even distribution of values?  That is certainly a worst-case
> situation, having basically no bitmap compression as it is an RLE-based
> scheme.

Yeah, the val0-2 are uniformly distributed - should have said that 
*first*, sorry.

cheers

Mark