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From Incze Lajos <>
Subject Re: Directory implementation using NIO (moved from Lucene User Li st)
Date Thu, 10 Jul 2003 21:18:25 GMT
On Thu, Jul 10, 2003 at 02:17:41PM -0400, Shah, Vineel wrote:
> On my system, I saw a speedup of 10x when I went from an FSDirectory to a RAMDirectory
(loaded the whole index into RAM.) This was also true in terms of scalability -- .1 searches/sec
went to 8 searches/sec under load (10 threads, no delay between requests.) The index was ~250,000
records in about
> 200mb on disk.
> The search was conducted by a JSP through a Lucene 1.3 dev release (I forget which one)
running under Tomcat. RedHat Linux 6.3 on an Intel machine (I didn't know the mhz, sorry.)
> vineel

That is another case. The ram directory is MUCH faster than the fs directory
because you spare billions of SYSTEM CALLS that are needed when accessing
the FS (even if it is buffered and resides in the memory). A system call is
very expensive.


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