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Posted to java-user@lucene.apache.org by "Kevin A. Burton" <bu...@newsmonster.org> on 2004/08/08 03:40:46 UTC

Benchmark of filesystem cache for index vs RAMDirectory... 

I'm not sure how Solaris or Windows perform but the Linux block cache 
will essentially use all avali memory to buffer the filesystem.

If one is using an FSDirectory to perform searches while the first 
search would be slow, remaining searches would be fast since Linux will 
now buffer the index in RAM.

The RAMDirectory has the advantage of pre-loading everything and can 
keep it in memory if the box is performing other operations.

In my benchmarks though RAMDirectory is slightly slower.  I assume this 
is because its Hashtable based even though it only needs to be 
synchronized in a few places.  IE searches should never be synchronized...

Would a HashMap implementation of RAMDirectory beat out a cached 
FSDirectory?

Kevin

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Re: Benchmark of filesystem cache for index vs RAMDirectory...

Posted by "Kevin A. Burton" <bu...@newsmonster.org>.
Daniel Naber wrote:

>On Sunday 08 August 2004 03:40, Kevin A. Burton wrote:
>
>  
>
>>Would a HashMap implementation of RAMDirectory beat out a cached
>>FSDirectory?
>>    
>>
>
>It's easy to test, so it's worth a try. Please try if the attached patch 
>makes any difference for you compared to the current implementation of 
>RAMDirectory.
>
>  
>
True... I was just thinking out loud... was being lazy.  Now I actually 
have to do the work to create the benchmark again... damn you ;)

Kevin

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Re: Benchmark of filesystem cache for index vs RAMDirectory...

Posted by Daniel Naber <da...@t-online.de>.
On Sunday 08 August 2004 03:40, Kevin A. Burton wrote:

> Would a HashMap implementation of RAMDirectory beat out a cached
> FSDirectory?

It's easy to test, so it's worth a try. Please try if the attached patch 
makes any difference for you compared to the current implementation of 
RAMDirectory.

Regards
 Daniel

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