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From David Spencer <>
Subject Re: Search Performance
Date Fri, 18 Feb 2005 19:00:18 GMT
Noone has mentioned JVM options yet.

[a] -server
[b] -XX:CompileThreshold=1000
[c] Raise the -Xms value if you haven't done so (-Xms...)

I think by default the VM runs with "-client" but -server makes more 
sense for web containers (Tomcat etc).
[b] tells the hotspot compiler to compile methods sooner - you can lower 
the 1000 to, say, '2' makes it compile methods after they've executed 2 
times - I had trouble once lowering this to 1 for some reason

Also, even though you're not supposed to need to do this, I've found it 
helpful to force gc() periodically e.g. every minute via this idiom:

public static long gc()
	long bef = mem();
	sleep( 100);
	sleep( 100);
	long aft= mem();
	return aft-bef;

Michael Celona wrote:

> What is single handedly the best way to improve search performance?  I have
> an index in the 2G range stored on the local file system of the searcher.
> Under a load test of 5 simultaneous users my average search time is ~4700
> ms.  Under a load test of 10 simultaneous users my average search time is
> ~10000 ms.    I have given the JVM 2G of memory and am a using a dual 3GHz
> Zeons.  Any ideas?  
> Michael

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