Performance Tuning

Weblogic Performance Tuning
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Generic JVM tuning tips:

        Generally, JVM performance is increased when the initial heap size (-Xms) is set equal to 
        maximum heap size (-Xmx). (Growing or shrinking the heap space is expensive as far as 
        performance goes, so setting them equal to each other prevents growing/shrinking, but also 
        assumes that you know what you're doing when you decided what that one value should be...)  

	The larger the heap, the longer a full garbage collection will take.  Remember, bigger 
        is not always better.  JVM tuning is a fine example of that.  There is a sweet spot between 
        too little and too much.

        Enable verbose GC and watch the log to see what size the heap settles to after a full GC.  
        If it consistently settles to greater than 80% of the heap size, then try increasing the 
        heap size by 10%-20%.  If it consistently settles to 20% or less of the heap size, 
        try shrinking the heap by 10%-20%.  

Generic JDBC Pool tuning tips:

	Set the BOTH the initial and maximum connection capacity settings to the maximum.  
	(There are two schools of thought on this.  Setting both to the max will prevent
        time and resources from being spent growing or shrinking the pool, but setting 
        both to max will make startup times longer and if the pool never shrinks,
        then resources are being tied up on these unnecessary connections) 

        Most importantly, remember that nothing is set in stone and there is no silver bullet 
        and that these are guidelines, not rules and you will encounter exceptions.