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. > >> > >> > >> --------------------------------------------------------------------- > >> To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > >> For additional commands, e-mail: java-user-h...@lucene.apache.org > >> > >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org > >
