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From Erick Erickson <erickerick...@gmail.com>
Subject Re: Loading an index into memory
Date Thu, 23 Jul 2009 15:55:58 GMT
What are you trying to accomplish? I'd insure that my performance wasa
problem before doing anything. If you're thinking "it's in RAM so it
has to be faster" you might be surprised.....

So gather evidence that you have a problem before you jump to
providing a solution.

Erick

On Thu, Jul 23, 2009 at 9:47 AM, Uwe Schindler <uschindler@pangaea.de>wrote:

> The size is in bytes and the RAMDirectory stores the bytes in bytes, so
> size
> is equal. I would suggest to not copy the dir into a RAMdirectory. It is
> better to use MMapDirectory in this case, as it "swaps" the files into
> address space like a normal OS swap file. The OS kernel will automatically
> swap needed parts into physical RAM. In this case the Java Heap is not
> wasted and only needed parts are swapped into RAM.
>
> -----
> UWE SCHINDLER
> Webserver/Middleware Development
> PANGAEA - Publishing Network for Geoscientific and Environmental Data
> MARUM - University of Bremen
> Room 2500, Leobener Str., D-28359 Bremen
> Tel.: +49 421 218 65595
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> http://www.pangaea.de/
> E-mail: uschindler@pangaea.de
>
> > -----Original Message-----
> > From: Dragon Fly [mailto:dragon-fly999@hotmail.com]
> > Sent: Thursday, July 23, 2009 3:38 PM
> > To: java-user@lucene.apache.org
> > Subject: Loading an index into memory
> >
> >
> > Hi,
> >
> > I have a question regarding RAMDirectory.  I have a 5 GB index on disk
> and
> > it is opened like the following:
> >
> >   searcher = new IndexSearcher (new RAMDirectory (indexDirectory));
> >
> > Approximately how much memory is needed to load the index? 5GB of memory
> > or 10GB because of Unicode? Does the entire index get loaded into memory
> > or only parts of it? Thank you.
> >
> >
> > _________________________________________________________________
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> >
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>
>
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