Thank you.
> From: dawid.we...@gmail.com > Date: Thu, 19 Jul 2012 13:34:26 +0200 > Subject: Re: RAM or SSD... > To: java-user@lucene.apache.org > > Read this: > http://blog.thetaphi.de/2012/07/use-lucenes-mmapdirectory-on-64bit.html > > Dawid > > On Thu, Jul 19, 2012 at 1:32 PM, Dragon Fly <dragon-fly...@hotmail.com> wrote: > > > > 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 > >> > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org >
