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Posted to java-user@lucene.apache.org by Daniel Feinstein <da...@rawsugar.com> on 2006/03/09 13:57:52 UTC

Lucene performance question

Hi,
 
My lucene index is not big (about 150M). My computer has 2G RAM but for some reason when I'm trying to store my index
using org.apache.lucene.store.RAMDirectory it fails with java out of memory exception. Also sometimes for the same
search query time spent on search could raise in 10-20 times. For example:
 
Search one behavior: run one 90 msec, run two 1647 msec, run three 87 
Search two behavior: run one 2550 msec,  run two 178 msec,  run three 179 
Search three behavior: run one 113 msec,  run two 2744 msec, run three 112
 
Could somebody explain me the behavior above. Why when my computer has a lot of RAM lucene is not fully loaded to it?
Why I could not use RAMDirectory? Why search time is not stable?
 
Thanks,
Daniel

Re: Lucene performance question

Posted by DanielFeinstein <da...@topixa.com>.
I'm using the following java options:
JAVA_OPTS='-Xmx1524m -Xms1524m
-Djava.awt.headless=true'

--- Grant Ingersoll <gs...@syr.edu> wrote:

> What is your Java max heap size set to?  This is the
> -Xmx Java option.
> 
> Daniel Feinstein wrote:
> > Hi,
> >  
> > My lucene index is not big (about 150M). My
> computer has 2G RAM but for some reason when I'm
> trying to store my index
> > using org.apache.lucene.store.RAMDirectory it
> fails with java out of memory exception. Also
> sometimes for the same
> > search query time spent on search could raise in
> 10-20 times. For example:
> >  
> > Search one behavior: run one 90 msec, run two 1647
> msec, run three 87 
> > Search two behavior: run one 2550 msec,  run two
> 178 msec,  run three 179 
> > Search three behavior: run one 113 msec,  run two
> 2744 msec, run three 112
> >  
> > Could somebody explain me the behavior above. Why
> when my computer has a lot of RAM lucene is not
> fully loaded to it?
> > Why I could not use RAMDirectory? Why search time
> is not stable?
> >  
> > Thanks,
> > Daniel
> >
> >   
> 
> -- 
>
-------------------------------------------------------------------
> 
> Grant Ingersoll 
> Sr. Software Engineer 
> Center for Natural Language Processing 
> Syracuse University 
> School of Information Studies 
> 335 Hinds Hall 
> Syracuse, NY 13244 
> 
> http://www.cnlp.org 
> Voice:  315-443-5484 
> Fax: 315-443-6886 
> 
> 
>
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Re: Lucene performance question

Posted by Grant Ingersoll <gs...@syr.edu>.
What is your Java max heap size set to?  This is the -Xmx Java option.

Daniel Feinstein wrote:
> Hi,
>  
> My lucene index is not big (about 150M). My computer has 2G RAM but for some reason when I'm trying to store my index
> using org.apache.lucene.store.RAMDirectory it fails with java out of memory exception. Also sometimes for the same
> search query time spent on search could raise in 10-20 times. For example:
>  
> Search one behavior: run one 90 msec, run two 1647 msec, run three 87 
> Search two behavior: run one 2550 msec,  run two 178 msec,  run three 179 
> Search three behavior: run one 113 msec,  run two 2744 msec, run three 112
>  
> Could somebody explain me the behavior above. Why when my computer has a lot of RAM lucene is not fully loaded to it?
> Why I could not use RAMDirectory? Why search time is not stable?
>  
> Thanks,
> Daniel
>
>   

-- 
------------------------------------------------------------------- 
Grant Ingersoll 
Sr. Software Engineer 
Center for Natural Language Processing 
Syracuse University 
School of Information Studies 
335 Hinds Hall 
Syracuse, NY 13244 

http://www.cnlp.org 
Voice:  315-443-5484 
Fax: 315-443-6886 


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