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From Dragon Fly <dragon-fly...@hotmail.com>
Subject RE: Loading an index into memory
Date Thu, 23 Jul 2009 16:38:32 GMT

Thank you both.

> Date: Thu, 23 Jul 2009 11:55:58 -0400
> Subject: Re: Loading an index into memory
> From: erickerickson@gmail.com
> To: java-user@lucene.apache.org
> 
> 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
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> > 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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