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From "German Kondolf" <german.kond...@gmail.com>
Subject Re: RAMDirectory vs FSDirectory
Date Tue, 27 Nov 2007 15:09:38 GMT
There is a constructor in the RAMDirectory that already does that.
http://lucene.apache.org/java/2_2_0/api/org/apache/lucene/store/RAMDirectory.html

I don't think that worth modify the internal Lucene's code to achieve
a extra bit of performance...
What would you do on next version? Modify it again?

On Nov 27, 2007 11:36 AM, Haroldo Nascimento <haroldo.araras@gmail.com> wrote:
> You can serialize this object RAMDirectory em disk. When start the
> application , it read the file .ser and load the object in memory.
> The time of load of file .ser is much fast.
> You need change any classes of Lucece: Add the "implements Serialzable" in
> any classes.
>
>
>
>
> On Nov 27, 2007 4:28 AM, Chhabra, Kapil <kchhabra@akamai.com> wrote:
>
> > > one can improve search performance by using a RAMDirectory created
> > from an underlying FSDirectory using one of the parameterised
> > constructors. Is this correct?
> > Absolutly
> >
> > > Will a FSDirectory not automatically load the index into memory
> > provided enough RAM is available?
> > Not all index files are loaded in the RAM if you are using the
> > FSDirectory. Though at the same time, queries are cached.
> >
> > > Do I have to explicitly use a RAMDirectory?
> > If you want to load the comeplte index in the memory, yes. This increase
> > the performance a lot as it drastically reduces the number of disk IO.
> > Obviously at the cost of the RAM. If you have enough RAM available to
> > accommodate the complete index, you can go ahead with this.
> >
> > Regards,
> > kapilChhabra
> >
> > -----Original Message-----
> > From: Hardy Ferentschik [mailto:hardy@ferentschik.de]
> > Sent: Tuesday, November 27, 2007 12:25 PM
> > To: java-user@lucene.apache.org
> > Subject: RAMDirectory vs FSDirectory
> >
> > Hi there,
> >
> > I am using currently a FSDirectory to build my index. The reason for
> > using a file system based index is that a full index rebuild takes
> > around 30 minutes and I want to keep a persistent index.
> > In 'Lucene in Action' I've read that one can improve search performance
> > by using a RAMDirectory created from an underlying FSDirectory using one
> > of the parameterised constructors. Is this correct? Will a FSDirectory
> > not automatically load the index into memory provided enough RAM is
> > available?
> > Do I have to explicitly use a RAMDirectory?
> >
> > --Hardy
> >
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> >
> >
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> >
> >
>

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