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From: "Alan D. Cabrera" <list@toolazydogs.com>
To: "Apache Directory Developers List" <dev@directory.apache.org>
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Subject: Re: DN storage : Table or Hash ? Some tests...
Date: Sat, 1 Mar 2008 10:03:49 -0800
References: <47C2BDF9.50609@gmail.com>


On Feb 25, 2008, at 5:09 AM, Emmanuel Lecharny wrote:

> Hi guys,
>
> I did some small tests in order to check if storing DN into a BTree  
> was slower than using an Hash. Assuming that we have enough memory  
> to cache data, I found that using a Hash does not bring any kind of  
> performance boost compared to using a BTree. Worst, it slow down the  
> wriate operation (twice slower ...).
>
> My small test was to store 500 000 DNs, using a 200 000 elements  
> cache, and searching for 500 000 random DNs from the created  
> structure.
>
> Some more insights :
> - if the cache is not big enough, performances are just incredibly  
> bad (disk accesses, a hell lot ...)
> - JDBM might be a little bit too light to support more than a few  
> hundred of thousands elements.

Very interesting.  Can you check in your stuff into a sandbox?


Regards,
Alan