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From Emmanuel Lecharny <elecha...@gmail.com>
Subject Re: [Studio] Using JDBM for secondary cache
Date Wed, 02 Apr 2008 21:55:55 GMT

>
>     I also think that the switch from the old DN/RDN implementation to
>     the shared-ldap LdapDN/Rdn implementation costs some memory. We
>     should consider to do some test for performance and memeory
>     consumtion.
>
>
> Oh that's not good.  We need to cleanup that code anyway so might be 
> good to work in some optimization. 
>
> Emmanuel had a good idea at some point to build a simple parser for 
> DNs along with a simpler LdapDN class for handling most general 
> cases.  If this parser fails then another corner-case parser continues 
> where the first left off.
The idea was to consider that a DN is using only ASCII chars. If not, 
throw an exception, and use the standard parser. This can save some 
cycles, that's for sure.
>
> All these crazy and complicated corner cases like with multi-attribute 
> Rdns and character issues cost more memory. 
No. In no case. It costs time, not memory. We don't store anything but 
Strings.
> They can then be handled by this special DN parser with it's resective 
> special LdapDN object that has additional structures for handling 
> these the tracking of these complex DNs.
>
> If 99% of the time the simple LDAP DNs are used with smaller 
> footprint, then we can reduce complexity and memory usage, while 
> increasing performance.  This will have an impact for both ApacheDS 
> and Studio.
Depending on which side we are handling DNs, we may implement different 
optimizations.

* On the client, we don't really care to stroe the UP form. What we need 
is just to _validate_ the DN, keeping the initial String. Each time we 
need to parse the DN, we can do it. We can also implement the fail-fast 
parser (ASCII DN parser)
* On the server, that's another story. We absolutly need to deal with 
the DN/RDN/AttributeTypeAndValue structures, as we have a lot of 
controls on them. But the ASCII only parser can be used.

I guess we can quickly write the ASCII parser, and give it a try. If we 
gain a lot, then we have to switch to it in the server.


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



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