Re: Cache use

2007-12-04 Thread Matthew Phillips
Thanks for the suggestion, Dennis. I decided to implement this as you 
described on my collection of about 400,000 documents, but I did not 
receive the results I expected.


Prior to putting the indexes on a tmpfs, I did a bit of benchmarking and 
found that it usually takes a little under two seconds for each facet 
query. After moving my indexes from disk to a tmpfs file system, I seem 
to get about the same result from facet queries: about two seconds.


Does anyone have any insight into this? Doesn't it seem odd that my 
response times are about the same? Thanks for the help.


Matt Phillips

Dennis Kubes wrote:
One way to do this if you are running on linux is to create a tempfs 
(which is ram) and then mount the filesystem in the ram.  Then your 
index acts normally to the application but is essentially served from 
Ram.  This is how we server the Nutch lucene indexes on our web search 
engine (www.visvo.com) which is ~100M pages.  Below is how you can 
achieve this, assuming your indexes are in /path/to/indexes:



mv /path/to/indexes /path/to/indexes.dist
mkdir /path/to/indexes
cd /path/to
mount -t tmpfs -o size=2684354560 none /path/to/indexes
rsync --progress -aptv indexes.dist/* indexes/
chown -R user:group indexes

This would of course be limited by the amount of RAM you have on the 
machine.  But with this approach most searches are sub-second.


Dennis Kubes

Evgeniy Strokin wrote:

Hello,...
we have 110M records index under Solr. Some queries takes a while, but 
we need sub-second results. I guess the only solution is cache 
(something else?)...
We use standard LRUCache. In docs it says (as far as I understood) 
that it loads view of index in to memory and next time works with 
memory instead of hard drive.
So, my question: hypothetically, we can have all index in memory if 
we'd have enough memory size, right? In this case the result should 
come up very fast. We have very rear updates. So I think this could be 
a solution.

How should I configure the cache to achieve such approach?
Thanks for any advise.
Gene


Re: Cache use

2007-12-06 Thread Matthew Phillips
No one has a suggestion? I must be missing something because as I  
understand it from Dennis' email, all of queries are very quick  
(cached type response times) whereas mine are not. I can clearly see  
time differences between queries that are cached (things that have  
been auto warmed) and queries that are not. This seems odd as my whole  
index is loaded on a tmpfs memory based file system. Thanks for the  
help.


Matt

On Dec 4, 2007, at 3:55 PM, Matthew Phillips wrote:

Thanks for the suggestion, Dennis. I decided to implement this as  
you described on my collection of about 400,000 documents, but I did  
not receive the results I expected.


Prior to putting the indexes on a tmpfs, I did a bit of benchmarking  
and found that it usually takes a little under two seconds for each  
facet query. After moving my indexes from disk to a tmpfs file  
system, I seem to get about the same result from facet queries:  
about two seconds.


Does anyone have any insight into this? Doesn't it seem odd that my  
response times are about the same? Thanks for the help.


Matt Phillips

Dennis Kubes wrote:
One way to do this if you are running on linux is to create a  
tempfs (which is ram) and then mount the filesystem in the ram.   
Then your index acts normally to the application but is essentially  
served from Ram.  This is how we server the Nutch lucene indexes on  
our web search engine (www.visvo.com) which is ~100M pages.  Below  
is how you can achieve this, assuming your indexes are in /path/to/ 
indexes:

mv /path/to/indexes /path/to/indexes.dist
mkdir /path/to/indexes
cd /path/to
mount -t tmpfs -o size=2684354560 none /path/to/indexes
rsync --progress -aptv indexes.dist/* indexes/
chown -R user:group indexes
This would of course be limited by the amount of RAM you have on  
the machine.  But with this approach most searches are sub-second.

Dennis Kubes
Evgeniy Strokin wrote:

Hello,...
we have 110M records index under Solr. Some queries takes a while,  
but we need sub-second results. I guess the only solution is cache  
(something else?)...
We use standard LRUCache. In docs it says (as far as I understood)  
that it loads view of index in to memory and next time works with  
memory instead of hard drive.
So, my question: hypothetically, we can have all index in memory  
if we'd have enough memory size, right? In this case the result  
should come up very fast. We have very rear updates. So I think  
this could be a solution.

How should I configure the cache to achieve such approach?
Thanks for any advise.
Gene