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 <zhoucheng2...@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 <
> luc...@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 <zhoucheng2...@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 <u...@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: u...@thetaphi.de
>> >>
>> >>
>> >> > -----Original Message-----
>> >> > From: Cheng [mailto:zhoucheng2...@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.
>> >>
>> >>
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>> >>
>> >>
>>
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