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From Emmanuel Lécharny <elecha...@gmail.com>
Subject Re: Mavibot Partition
Date Sun, 03 Nov 2013 05:16:34 GMT
Le 11/3/13 3:32 AM, Kiran Ayyagari a écrit :
> On Sun, Nov 3, 2013 at 4:09 AM, Emmanuel Lécharny <elecharny@gmail.com>wrote:
>
>> Hi,
>>
>> today, I investigated the way the Mavibot Partition is implemented, wrt
>> to the modifications I've made those past month. There are a few missing
>> parts, I'm afraid.
>>
>> First of all, we aren't counting correctly. When we add a <key, value>
>> tuple, we should increment the counter regardless the fact the key
>> exists or not. In other words, we count tuples, not keys. That's easy to
>> fix.
>>
>> I think we should count the tuples, say we have a filter
> (&(cn=x)(sn=y))
>
> and 'cn' index has: x -> 1,2,3,4,5,6,7
> 'sn' index has: y -> 2,5
>
> then the optimizer will pick up the predicate with less number of candidates
> which is 'sn' here based on the count of tuples, if we count only keys
> then this optimization will not work

Absolutely. I fixed the code to count tuples, not keys.


-- 
Regards,
Cordialement,
Emmanuel Lécharny
www.iktek.com 


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