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From "Sammy Yu" <temi...@gmail.com>
Subject Re: SOLR query times
Date Mon, 13 Oct 2008 19:51:10 GMT
Hi Grant,
   Thanks for your response.  I'm trying to simulate our production
environment's search traffic which has very low cache hit rate.
Turning off the caches can help us better understand query times and
the load of the slave's when distribution occurs with a small list of
pre-canned queries.

If the latency is caused by loading and caching of Lucene's segments,
is there a way to force Lucene's index to preload this?  This seems to
be the case in our production environment, when SOLR restarts the load
spikes and it takes a couple of hours before it settles down.

Also, are there general acceptable ways of doing scalability and
performance characterization?

Thanks,
Sammy.

On Sun, Oct 12, 2008 at 8:17 AM, Grant Ingersoll <gsingers@apache.org> wrote:
> This is pretty typical.  The first query is always more expensive, as Lucene
> lazily loads some pieces of the index into memory and you may see the
> FieldCache in action, depending on sorting, not to mention you are also
> seeing operating system caching take place.
>
> Is there some reason you don't want these or are you just trying to
> understand the why?
>
> -Grant
>
> On Oct 10, 2008, at 6:25 PM, Sammy Yu wrote:
>
>> Hi,
>>  I'm using SOLR 1.3 on a index with approximately 8 million
>> documents.  I would like to disable SOLR's cache so that it is easier
>> for me to test the scenario when there is a small likelihood of cache
>> hits.  I've disabled caching by commenting out the filterCache,
>> queryResultCache, and documentCache section in solrconfig.xml as
>> suggested by the Wiki.  It seems disabled because the admin interface
>> no longer shows any entries in the Cache section.
>>
>> However, it appears that there is still some sort caching taking
>> place.  The first time I make specific query it would take around 100
>> msec, subsequent queries would take around 15 msec.  Is there some
>> sort of caching happening at Lucene level?
>>
>> Thanks for your help,
>> Sammy Yu
>
> --------------------------
> Grant Ingersoll
> Lucene Boot Camp Training Nov. 3-4, 2008, ApacheCon US New Orleans.
> http://www.lucenebootcamp.com
>
>
> Lucene Helpful Hints:
> http://wiki.apache.org/lucene-java/BasicsOfPerformance
> http://wiki.apache.org/lucene-java/LuceneFAQ
>
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