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From "Robert Engels" <>
Subject RE: Lucene vs. Ruby/Odeum
Date Wed, 01 Jun 2005 23:00:55 GMT
One more thing, his statement that "why returning 20 documents would perform
any better than returning all of them" (paraphrased), shows complete
ignorance of proper Lucene usage.


-----Original Message-----
From: Robert Engels []
Sent: Wednesday, June 01, 2005 5:52 PM
Subject: RE: Lucene vs. Ruby/Odeum

I read his complete article... he still doesn't have a clue.

The opening and closing of the IndexReader's is just creating garbage which
is distorting the memory consumption, and ruining the performance - it is
akin to starting it from the command-line to perform a search. As you state,
the Java memory consumption will continue to grow until it hits the Xmx
until it even attempts to purge, and even then it may not release the memory
back to the OS. Even small one-time use strings will eventually show huge
memory consumption until the runtime needs the memory.

It is my understanding in reviewing the Lucene code, is that Lucene caches
VERY LITTLE information in memory - seemingly just the skip table for terms,
and relies on the OS's disk cache for performance (other than the new
enhancements I posted that move a cache into the Lucene directory). Maybe
somebody has more information here?

Robert Engels

-----Original Message-----
From: Daniel Naber []
Sent: Wednesday, June 01, 2005 5:07 PM
Subject: Re: Lucene vs. Ruby/Odeum

On Tuesday 17 May 2005 04:41, Otis Gospodnetic wrote:


Here's a follow up:

Now the claim is that Lucene is faster than Ruby/Odeum but it takes 36
times more memory. However, I cannot find any information on how exactly
Lucene was started. It's no surprise that Java requires much memory and
doesn't clean up if it never comes close to the limit set with -Xmx.



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