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From Doug Cutting <>
Subject Re: [jira] Commented: (LUCENE-414) Java NIO patch against Lucene 1.9
Date Wed, 26 Oct 2005 21:51:16 GMT
Robert Engels wrote:
> The reason for using Nio and not IO is IO requires multiple file handles per file. There
are already numerous bugs/work-arounds in Lucene to limit the use of file handles (as this
is a OS limited resource), so I did not wish to further increase the number of file descriptors

Yes, but it appears to me that the submitted NioFile class opens a new 
file handle per channel.  So I don't see how this addresses that.

> Your statement that a raid system would be needed to exploit the added concurrency is
not exactly correct. By using multiple threads, even if the disk is busy handling a request,
the OS can combine the pending requests and perform more efficient reads to the disk subsystem
when it becomes available.

Perhaps.  It would be nice to see a benchmark demonstrating this.

> I also dispute the performance numbers cited. In my testing the 'user level' cache improved
performance of query operations nearly 100%. I will write a testcase to demonstrate the increased
performance. This testcase can be written independent of Lucene.

Can you provide your benchmark results?



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