My indexes are 500MB+. So it seems like that RAMDirectory is not good for that big a size.
My challenge, on the other side, is that I need to update the indexes very frequently. So, do you think MMapDirectory is the solution? Thanks. On Mon, Jun 4, 2012 at 10:30 PM, Jack Krupansky <j...@basetechnology.com>wrote: > From the javadoc for RAMDirectory: > > "Warning: This class is not intended to work with huge indexes. Everything > beyond several hundred megabytes will waste resources (GC cycles), because > it uses an internal buffer size of 1024 bytes, producing millions of > byte[1024] arrays. This class is optimized for small memory-resident > indexes. It also has bad concurrency on multithreaded environments. > > It is recommended to materialize large indexes on disk and use > MMapDirectory, which is a high-performance directory implementation working > directly on the file system cache of the operating system, so copying data > to Java heap space is not useful." > > -- Jack Krupansky > > -----Original Message----- From: Cheng > Sent: Monday, June 04, 2012 10:08 AM > To: java-user@lucene.apache.org > Subject: RAMDirectory unexpectedly slows > > > Hi, > > My apps need to read from and write to some big indexes frequently. So I > use RAMDirectory instead of FSDirectory, and give JVM about 2GB memory > size. > > I notice that the speed of reading and writing unexpectedly slows as the > size of the indexes increases. Since the usage of RAM is less than 20%, I > think by default the RAMDirectory doesn't take advantage of the memory I > assigned to JVM. > > What are the steps to improve the reading and writing speed of > RAMDirectory? > > Thanks! > Jeff > > ------------------------------**------------------------------**--------- > To unsubscribe, e-mail: > java-user-unsubscribe@lucene.**apache.org<java-user-unsubscr...@lucene.apache.org> > For additional commands, e-mail: > java-user-help@lucene.apache.**org<java-user-h...@lucene.apache.org> > >
