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From Emmanuel Lecharny <elecha...@gmail.com>
Subject Re: [ApacheDS] [JDBM Partition] Why it's a BAD idea to store the Entry + DN in the master table
Date Thu, 07 Aug 2008 07:49:43 GMT
Howard Chu wrote:
> Emmanuel Lecharny wrote:
>> Alex Karasulu wrote:
>>> Hi all,
>>>
>> Hi Alex,
>>> The ServerEntry stores the DN of the entry.  I think this is good 
>>> for better
>>> code organization.  However, storing the entry together with it's DN 
>>> into
>>> the master table is a very bad idea.  The DN should instead be 
>>> managed in
>>> the NDN and DN indices.
>>>
>> I think you are wrong. Storing the DN within the entyr is a very good
>> idea (tm) :)
>
> For what it's worth, in my experience Alex is right. OpenLDAP's 
> back-hdb can do subtree renames in O(1) time. It's the only LDAP 
> implementation in the world that can do this, and it's partly because 
> we don't store the DNs with the rest of the entry data. back-hdb is 
> also the fastest at searches too, and that's just a matter of 
> balancing cache demands...
Apache DS 1.0 was also able to do ModifyDN in O(1) :)

All the profiling sessions I did last year shown that, for ADS, storing 
DN outside the entry was costing more than storing them within the 
entry. We will do more tests :)

The good thing is that we can move back to have the DN stored outside 
the DN easily, the hard part was to define the Entry class and use it 
all over the server !

Let's evaluate both solution, and pick the one which is the fastest ! 
(and whoever is right or wrong does not matter, as soon as we have a 
faster server :)

Thanks Howard, as usual, your insights are always good to have ! (when 
you will hate Java less, let us know, we have a warm and comfortable 
place for you at Directory :)

-- 
--
cordialement, regards,
Emmanuel L├ęcharny
www.iktek.com
directory.apache.org



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