The slowest part of my application is to read the search hits from disk. I was hoping that using an SSD or RAMDirectory/MMapDirectory would speed that up. I read the JavaDoc for MMapDirectory but didn't really understand how that differs from RAMDirectory. Could someone please explain?
> Date: Wed, 18 Jul 2012 23:46:51 -0700 > Subject: Re: RAM or SSD... > From: vfunst...@gmail.com > To: java-user@lucene.apache.org > > I was referring to *RAMDirectory*. > > On Wed, Jul 18, 2012 at 11:04 PM, Lance Norskog <goks...@gmail.com> wrote: > >> You do not want to store 30 G of data in the JVM heap, no matter what > library does this. > > MMapDirectory does not store data in the JVM heap. It lets the > > operating system manage the disk buffer space. Even if the JVM says "I > > have 30G of memory space", it really does not. It only has address > > space allocated by the OS but no memory. > > > > On Wed, Jul 18, 2012 at 10:39 PM, Toke Eskildsen <t...@statsbiblioteket.dk> > wrote: > >> On Wed, 2012-07-18 at 17:50 +0200, Dragon Fly wrote: > >>> If I want to improve performance, which of the following is better and > why? > >>> > >>> 1. Buy a machine with a lot of RAM and use a RAMDirectory for the index. > >> > >> As others has pointed out, MMapDirectory should work better than > >> RAMDirectory. I am sure it will work fine with a relative small index > >> such as yours. However, it does not scale that well with index size. > >> > >>> 2. Put the index on a solid state drive. > >> > >> Why anyone buys computers without SSD's is a mystery to me. Use SSDs for > >> the small low-latency stuff and a secondary spinning drive for the large > >> slow stuff. Nowadays, a 30GB index (or 100GB for that matter) falls into > >> the small low-latency bucket. SSDs speeds up almost everything, saves > >> RAM and spares a lot of work hours optimizing I/O-speed. > >> > >> Regards, > >> Toke Eskildsen > >> > >> > >> --------------------------------------------------------------------- > >> To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > >> For additional commands, e-mail: java-user-h...@lucene.apache.org > >> > > > > > > > > -- > > Lance Norskog > > goks...@gmail.com > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > > For additional commands, e-mail: java-user-h...@lucene.apache.org > >