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From Cheng <zhoucheng2...@gmail.com>
Subject Re: Configure writer to write to FSDirectory?
Date Mon, 06 Feb 2012 15:49:56 GMT
I meant that when I use NRTManager and use commit(), the speed is slower
than when I use RAMDirectory.

In my case, NRTManager instance not only perform search but update/modify
indexes which should be visible to other threads. In RAMDirectory, the
commit() doesn't synchronize indexes with the FSDirectory. The slower speed
of using NRTManager built upon FSDirectory may be caused by the frequent
updates or modification of indexes.

That is my guess.

On Mon, Feb 6, 2012 at 11:41 PM, Ian Lea <ian.lea@gmail.com> wrote:

> What exactly do you mean by the "speed is slower"?  Time taken to
> update the index?  Time taken for updates to become visible in search
> results?  Time taken for searches to run on the IndexSearcher returned
> from SearcherManager?  Something else?
>
>
> --
> Ian.
>
>
> On Mon, Feb 6, 2012 at 3:27 PM, Cheng <zhoucheng2008@gmail.com> wrote:
> > 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
> >>> >> >>
> >>> >> >>
> >>> >>
> >>> >>
> ---------------------------------------------------------------------
> >>> >> 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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