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From Cheng <zhoucheng2...@gmail.com>
Subject Re: Configure writer to write to FSDirectory?
Date Mon, 06 Feb 2012 15:55:31 GMT
My original question is if there exists a way to configure writer when to
writer to FSDirectory. I think there may be something in
the IndexWriterConfig that can helps.

On Mon, Feb 6, 2012 at 11:50 PM, Ian Lea <ian.lea@gmail.com> wrote:

> Well, yes.  What would you expect?  From the javadocs for
> IndexWriter.commit()
>
> Commits all pending changes (added & deleted documents, segment
> merges, added indexes, etc.) to the index, and syncs all referenced
> index files ... This may be a costly operation, so you should test the
> cost in your application and do it only when really necessary.
>
> If you are using NRTManager why do you care how long this takes?  How
> often are you calling it?  Why?
>
>
> --
> Ian.
>
>
> On Mon, Feb 6, 2012 at 3:45 PM, Cheng <zhoucheng2008@gmail.com> wrote:
> > Uwe, when I meant speed is slow, I didn't refer to instant visibility of
> > changes, but that the changes may be synchronized with FSDirectory when I
> > use writer.commit().
> >
> > When I use RAMDirectory, the writer.commit() seems much faster than using
> > NRTManager built upon FSDirectory. So, I am guessing the difference is
> the
> > index synchronization.
> >
> >
> >
> > On Mon, Feb 6, 2012 at 11:40 PM, Uwe Schindler <uwe@thetaphi.de> wrote:
> >
> >> Please review the following articles about NRT, absolutely instant
> updates
> >> that are visible as they are done are almost impossible (even with
> >> RAMDirectory):
> >>
> >> http://goo.gl/mzAHt
> >> http://goo.gl/5RoPx
> >> http://goo.gl/vSJ7x
> >>
> >> Uwe
> >>
> >> -----
> >> Uwe Schindler
> >> H.-H.-Meier-Allee 63, D-28213 Bremen
> >> http://www.thetaphi.de
> >> eMail: uwe@thetaphi.de
> >>
> >> > -----Original Message-----
> >> > From: Cheng [mailto:zhoucheng2008@gmail.com]
> >> > Sent: Monday, February 06, 2012 4:27 PM
> >> > To: java-user@lucene.apache.org
> >> > Subject: Re: Configure writer to write to FSDirectory?
> >> >
> >> > Ian,
> >> >
> >> > I encountered an issue that I need to frequently update the index. The
> >> > NRTManager seems not very helpful on this front as the speed is slower
> >> than
> >> > RAMDirectory is used.
> >> >
> >> > Any improvement advice?
> >> >
> >> >
> >> >
> >> > On Mon, Feb 6, 2012 at 10:24 PM, Cheng <zhoucheng2008@gmail.com>
> wrote:
> >> >
> >> > > That really helps! I will try it out.
> >> > >
> >> > > Thanks.
> >> > >
> >> > >
> >> > > On Mon, Feb 6, 2012 at 10:12 PM, Ian Lea <ian.lea@gmail.com>
wrote:
> >> > >
> >> > >> You would use NRTManagerReopenThread as a standalone thread, not
> >> > >> plugged into your Executor stuff.  It is a utility class which
you
> >> > >> don't have to use.  See the javadocs.
> >> > >>
> >> > >> But in your case I'd use it, to start with anyway.  Fire it up
with
> >> > >> suitable settings and forget about it, except to call close()
> >> > >> eventually. Once you've got things up and running you can tweak
> >> > >> things as much as you want but you appear to be having trouble
> >> > >> getting up and running.
> >> > >>
> >> > >> So ... somewhere in the initialisation code of your app, create
an
> >> > >> IndexWriter, NRTManager + ReopenThread and SearcherManager as
> >> > >> outlined before.  Then pass the NRTManager to any/all write methods
> >> > >> or threads and the SearcherManager instance to any/all search
> methods
> >> > >> or threads and you're done.  If you want to use threads that are
> part
> >> > >> of your ExecutorService, fine.  Just wrap it all together in
> whatever
> >> > >> combination of Thread or Runnable instances you want.
> >> > >>
> >> > >>
> >> > >> Does that help?
> >> > >>
> >> > >>
> >> > >> --
> >> > >> Ian.
> >> > >>
> >> > >>
> >> > >> > I don't understand this following portion:
> >> > >> >
> >> > >> > IndexWriter iw = new IndexWriter(whatever - some standard
disk
> >> > >> > index); NRTManager nrtm = new NRTManager(iw, null);
> >> > >> > NRTManagerReopenThread ropt = new NRTManagerReopenThread(nrtm,
> >> > >> > ...); ropt.setXxx(...); ....
> >> > >> > ropt.start();
> >> > >> >
> >> > >> > I have a java ExecutorServices instance running which take
care
> of
> >> > >> > my
> >> > >> own
> >> > >> > applications. I don't know how this NRTManagerReopenThread
works
> >> > >> > with my own ExecutorService instance.
> >> > >> >
> >> > >> > Can both work together? How can the NRTManagerReopenThread
> >> > instance
> >> > >> ropt be
> >> > >> > plugged into my own multithreading framework?
> >> > >> >
> >> > >> > On Mon, Feb 6, 2012 at 8:17 PM, Ian Lea <ian.lea@gmail.com>
> wrote:
> >> > >> >
> >> > >> >> If you can use NRTManager and SearcherManager things
should be
> >> > >> >> easy and blazingly fast rather than unbearably slow.
 The latter
> >> > >> >> phrase is not one often associated with lucene.
> >> > >> >>
> >> > >> >> IndexWriter iw = new IndexWriter(whatever - some standard
disk
> >> > >> >> index); NRTManager nrtm = new NRTManager(iw, null);
> >> > >> >> NRTManagerReopenThread ropt = new
> >> > NRTManagerReopenThread(nrtm,
> >> > >> >> ...); ropt.setXxx(...); ...
> >> > >> >> ropt.start();
> >> > >> >>
> >> > >> >> SearcherManager srchm = nrtm.getSearcherManager(b);
> >> > >> >>
> >> > >> >> Then add docs to your index via nrtm.addDocument(d),
update with
> >> > >> >> nrtm.updateDocument(...), and to search use
> >> > >> >>
> >> > >> >> IndexSearcher searcher = srchm.acquire(); try {  search
...
> >> > >> >> } finally {
> >> > >> >>  srchm.release(searcher);
> >> > >> >> }
> >> > >> >>
> >> > >> >> All thread safe so you don't have to worry about any
> complications
> >> > >> >> there.  And I bet it'll be blindingly fast.
> >> > >> >>
> >> > >> >> Don't forget to close() things down at the end.
> >> > >> >>
> >> > >> >>
> >> > >> >> --
> >> > >> >> Ian.
> >> > >> >>
> >> > >> >>
> >> > >> >>
> >> > >> >> On Mon, Feb 6, 2012 at 12:15 AM, Cheng <zhoucheng2008@gmail.com
> >
> >> > >> wrote:
> >> > >> >> > I was trying to, but don't know how to even I read
some of
> your
> >> > >> blogs.
> >> > >> >> >
> >> > >> >> > On Sun, Feb 5, 2012 at 10:22 PM, Michael McCandless
<
> >> > >> >> > lucene@mikemccandless.com> wrote:
> >> > >> >> >
> >> > >> >> >> Are you using near-real-time readers?
> >> > >> >> >>
> >> > >> >> >> (IndexReader.open(IndexWriter))
> >> > >> >> >>
> >> > >> >> >> Mike McCandless
> >> > >> >> >>
> >> > >> >> >> http://blog.mikemccandless.com
> >> > >> >> >>
> >> > >> >> >> On Sun, Feb 5, 2012 at 9:03 AM, Cheng <
> zhoucheng2008@gmail.com>
> >> > >> wrote:
> >> > >> >> >> > Hi Uwe,
> >> > >> >> >> >
> >> > >> >> >> > My challenge is that I need to update/modify
the indexes
> >> > >> frequently
> >> > >> >> while
> >> > >> >> >> > providing the search capability. I was
trying to use
> >> > >> >> >> > FSDirectory,
> >> > >> but
> >> > >> >> >> found
> >> > >> >> >> > out that the reading and writing from/to
FSDirectory is
> >> > >> >> >> > unbearably
> >> > >> >> slow.
> >> > >> >> >> So
> >> > >> >> >> > I now am trying the RAMDirectory, which
is fast.
> >> > >> >> >> >
> >> > >> >> >> > I don't know of  MMapDirectory, and wonder
if it is as fast
> >> > >> >> >> > as
> >> > >> >> >> RAMDirectory.
> >> > >> >> >> >
> >> > >> >> >> >
> >> > >> >> >> > On Sun, Feb 5, 2012 at 4:14 PM, Uwe Schindler
> >> > >> >> >> > <uwe@thetaphi.de>
> >> > >> >> wrote:
> >> > >> >> >> >
> >> > >> >> >> >> Hi Cheng,
> >> > >> >> >> >>
> >> > >> >> >> >> It seems that you use a RAMDirectory
for *caching*,
> >> > >> >> >> >> otherwise it
> >> > >> >> makes
> >> > >> >> >> no
> >> > >> >> >> >> sense to write changes back. In recent
Lucene versions,
> this
> >> > >> >> >> >> is
> >> > >> not a
> >> > >> >> >> good
> >> > >> >> >> >> idea, especially for large indexes
(RAMDirectory eats your
> >> > >> >> >> >> heap
> >> > >> >> space,
> >> > >> >> >> >> allocates millions of small byte[]
arrays,...). If you
> need
> >> > >> something
> >> > >> >> >> like
> >> > >> >> >> >> a
> >> > >> >> >> >> caching Directory and you are working
on a 64bit platform,
> >> > >> >> >> >> you
> >> > >> can
> >> > >> >> use
> >> > >> >> >> >> MMapDirectory (where the operating
system kernel manages
> the
> >> > >> >> read/write
> >> > >> >> >> >> between disk an memory). MMapDirectory
is returned by
> >> > >> >> >> >> default for
> >> > >> >> >> >> FSDirectory.open() on most 64 bit platforms.
The good
> thing:
> >> > >> >> >> >> the
> >> > >> >> >> "caching"
> >> > >> >> >> >> space is outside your JVM heap, so
does not slowdown the
> >> > >> >> >> >> garbage
> >> > >> >> >> collector.
> >> > >> >> >> >> So be sure to *not* allocate too much
heap space (-Xmx) to
> >> > >> >> >> >> your
> >> > >> >> search
> >> > >> >> >> app,
> >> > >> >> >> >> only the minimum needed to execute
it and leave the rest
> of
> >> > >> >> >> >> your
> >> > >> RAM
> >> > >> >> >> >> available for the OS kernel to manage
FS cache.
> >> > >> >> >> >>
> >> > >> >> >> >> Uwe
> >> > >> >> >> >>
> >> > >> >> >> >> -----
> >> > >> >> >> >> Uwe Schindler
> >> > >> >> >> >> H.-H.-Meier-Allee 63, D-28213 Bremen
> http://www.thetaphi.de
> >> > >> >> >> >> eMail: uwe@thetaphi.de
> >> > >> >> >> >>
> >> > >> >> >> >>
> >> > >> >> >> >> > -----Original Message-----
> >> > >> >> >> >> > From: Cheng [mailto:zhoucheng2008@gmail.com]
> >> > >> >> >> >> > Sent: Sunday, February 05, 2012
7:56 AM
> >> > >> >> >> >> > To: java-user@lucene.apache.org
> >> > >> >> >> >> > Subject: Configure writer to write
to FSDirectory?
> >> > >> >> >> >> >
> >> > >> >> >> >> > Hi,
> >> > >> >> >> >> >
> >> > >> >> >> >> > I build an RAMDirectory on a FSDirectory,
and would like
> >> the
> >> > >> writer
> >> > >> >> >> >> associated
> >> > >> >> >> >> > with the RAMDirectory to periodically
write to hard
> drive.
> >> > >> >> >> >> >
> >> > >> >> >> >> > Is this achievable?
> >> > >> >> >> >> >
> >> > >> >> >> >> > Thanks.
> >> > >> >> >> >>
> >> > >> >> >> >>
> >> > >> >> >> >>
> >> > >>
> ---------------------------------------------------------------------
> >> > >> >> >> >> To unsubscribe, e-mail:
> >> java-user-unsubscribe@lucene.apache.org
> >> > >> >> >> >> For additional commands, e-mail:
> >> > >> java-user-help@lucene.apache.org
> >> > >> >> >> >>
> >> > >> >> >> >>
> >> > >> >> >>
> >> > >> >> >>
> >> > >>
> ---------------------------------------------------------------------
> >> > >> >> >> To unsubscribe, e-mail:
> java-user-unsubscribe@lucene.apache.org
> >> > >> >> >> For additional commands, e-mail:
> >> java-user-help@lucene.apache.org
> >> > >> >> >>
> >> > >> >> >>
> >> > >> >>
> >> > >> >>
> >> ---------------------------------------------------------------------
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> >> > >> >> For additional commands, e-mail:
> java-user-help@lucene.apache.org
> >> > >> >>
> >> > >> >>
> >> > >>
> >> > >>
> ---------------------------------------------------------------------
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> >> > >> For additional commands, e-mail: java-user-help@lucene.apache.org
> >> > >>
> >> > >>
> >> > >
> >>
> >>
> >> ---------------------------------------------------------------------
> >> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> >> For additional commands, e-mail: java-user-help@lucene.apache.org
> >>
> >>
>
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>

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