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From Alex Karasulu <akaras...@apache.org>
Subject Re: Needed: LDAP expression evaluation optimization
Date Fri, 26 Jan 2007 01:55:27 GMT
Jan S. Rellermeyer wrote:
> Well, on the other hand, a cache is only of use if the requests are not
> totally random. Otherwise, you cache results that are never needed again.
> What Alex is describing sounds to me like a data index. I agree that this
> does not work for an unbounded set of properties. However, what might work
> is something like the index structures used in database technology. 
> What about a Hashtable (or better -Map) with B+-Trees as values. 

Yeah unfortunately you have to use BTrees here to properly advance on an 
*sorted* index and evaluate expressions like numeric comparisons 
(version > 3.0).  You cannot do this with a Hash unfortunately.

So the
> property name is the key, which means, all properties will fit into one
> table and providing that the properties have a reasonable distribution, the
> lookup of a property is in constant time. Each value is a B+-Tree, which
> allows you to have very efficient lookup of the complicated range
> structures, for instance, in the version property. Would something like this
> make sense ?

Yep perfectly.  Wanna work it with me in the sandbox? I may be able to 
get something going rapidly using jdbm.


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