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From Tincu Gabriel <>
Subject Re: search performance
Date Mon, 02 Jun 2014 13:03:21 GMT
My bad, It's using the RamDirectory as a cache and a delegate directory
that you pass in the constructor to do the disk operations, limiting the
use of the RamDirectory to files that fit a certain size. So i guess the
underlying Directory implementation will be whatever you choose it to be.
I'd still try using a MMapDirectory and see if that improves performance.
Also, regarding the pagination, you said you're retrieving 1000 documents
at a time. Does that mean that if a query matches 10000 documents you want
all of them retrieved ?

On Mon, Jun 2, 2014 at 12:51 PM, Jamie <> wrote:

> I was under the impression that NRTCachingDirectory will instantiate an
> MMapDirectory if a 64 bit platform is detected? Is this not the case?
> On 2014/06/02, 2:09 PM, Tincu Gabriel wrote:
>> MMapDirectory will do the job for you. RamDirectory has a big warning in
>> the class description stating that the performance will get killed by an
>> index larger than a few hundred MB, and NRTCachingDirectory is a wrapper
>> for RamDirectory and suitable for low update rates. MMap will use the
>> system RAM to cache as much of the index it can and only hit disk when the
>> portion of the index you're trying to access isn't cached. I'd put my
>> money
>> on switching directory implementations and see what kind of performance
>> gains that brings to the table.

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