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From Emmanuel Lecharny <>
Subject DN storage : Table or Hash ? Some tests...
Date Mon, 25 Feb 2008 13:09:13 GMT
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.

cordialement, regards,
Emmanuel L├ęcharny

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