Insurance Squared Inc. wrote:

> Make sure you don't have any empty or bad segments.   We had some 
> serious speed issues for a long time until we realized we had some 
> empty segments that had been generated as we tested.  Nutch would then 
> sit and spin on these bad segments for a few seconds on every search.  
> Simply deleting the bad segments took search times from >10 seconds to 
> fractions of a second.


how does one recognize bad (or empty) segments?

Thanks

Michael

>
> g.
>
>
> RP wrote:
>
>> I've got 500k urls indexed on an old 700mhz P3 clunker with only 
>> 384MB of RAM at my searches take sub-seconds....  Something is funny 
>> here.  I've got my JVM at 64MB for this as well, so be careful as it 
>> sounds like you just caused the box to thrash a bit with swapping.  
>> Set the JVM down to 128MB and see what happens....
>>
>> rp
>>
>> Sean Dean wrote:
>>
>>> It looks like you don't have enough RAM to maintain the quick speeds 
>>> you were seeing when the index was only around 3000 pages.
>>>  
>>> Nutch scales very well, but the hardware behind it must also. Using 
>>> quick calculations and common sense, if your total system RAM is 
>>> only 512MB and all of that is given to tomcat alone your looking at 
>>> a situation where other system applications and/or parts of Tomcat 
>>> are being executed out of swap memory. This will kill search speed.
>>>  
>>> My recommendation would be to get more RAM, another 512MB should 
>>> support a 1.5 million page index running at the speeds you 
>>> experienced during your 3000 page trials. If you can get even more, 
>>> then your only helping system (search) performance.
>>>
>>> Here are a few other tips, just in case you cant get any more RAM at 
>>> this time:
>>>  
>>> 1. Make sure your passing "-server" via JAVA_OPTS.
>>> 2. Disable all non-required system and user applications.
>>> 3. Download or install the newest stable kernel and recompile 
>>> without all the junk.
>>> 4. Reduce the size of your index.
>>>
>>>  
>>> ----- Original Message ----
>>> From: shrinivas patwardhan <[EMAIL PROTECTED]>
>>> To: [email protected]
>>> Sent: Friday, December 29, 2006 4:45:41 AM
>>> Subject: Re: search performance
>>>
>>>
>>> thank you Sean Dean for your quick reply ...
>>> well i am running nutch on ubuntu 5.01 and jdk1.5
>>> there are some apps running in the background but they dont take up 
>>> that
>>> much of memory .
>>> secondly i can understand about the first search .. but the other 
>>> searches
>>> following it also take time even getting the next 10 pages also 
>>> takes some
>>> time ..
>>> so looking at all the issues does it relate to my system on the 
>>> whole .. or
>>> have i got wrong some where in the indexing process ?
>>> i just followed the tutorial  for  nutch -0.7.2   under the section 
>>> whole
>>> web crawling .
>>> when i indexed just about 3000 pages (subset of that dmoz index) the 
>>> search
>>> results were quick ) but now after loading the index file for almost
>>> 1.5million pages it really dies up
>>> i use to get a java heap space error in tomcat ,so i fixed it by 
>>> setting the
>>>
>>> JAVA_OPTS  to Xmx512m
>>> i guess i have made my self very clear now . so wht do guys think 
>>> must be
>>> wrong ?
>>>
>>> Thanks
>>> Shrinivas
>>>   
>>
>>
>>
>


-- 
Michael Wechner
Wyona      -   Open Source Content Management   -    Apache Lenya
http://www.wyona.com                      http://lenya.apache.org
[EMAIL PROTECTED]                        [EMAIL PROTECTED]
+41 44 272 91 61


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