[jira] [Created] (JEXL-344) Don't fill stack trace for JexlExpression#Return (to improve performance)

["David Costanzo (Jira)" <ji...@apache.org>]

David Costanzo created JEXL-344:
-----------------------------------

             Summary: Don't fill stack trace for JexlExpression#Return (to improve performance)
                 Key: JEXL-344
                 URL: https://issues.apache.org/jira/browse/JEXL-344
             Project: Commons JEXL
          Issue Type: Improvement
    Affects Versions: 3.1
            Reporter: David Costanzo


In profiling my JEXL-enabled application, I observed that nearly 10% of the execution time is spend filling in the {{JexlExpression#Return}} class's stack.  As far as I can tell, the Return object's stack is not used by JEXL and so does not need to be present.

I read about an optimization technique where you override fillInStackTrace() to be a no-op when using exceptions for control flow.  As I understand it, this practice was codified into Java 7 with the "writableStackTrace" parameter to Throwable's ctor that lets you disable filling in the stack trace.

For Java 6 and below, this is as easy as adding this to the body of {{Return}}.
{code:java}
@Override
public Throwable fillInStackTrace()
{
    // Don't fill in the stack.  It's not needed for return values.
    return this;
}
{code}
In private testing, this has the expected effect: my application finishes in ~10% less time and all unit tests continue to pass.

 

There's a discussion of this on stack overflow:

[https://stackoverflow.com/questions/1836164/override-fillinstacktrace-for-control-flow-performance]

 

There's a better discussion in the answer given to:

[https://stackoverflow.com/questions/11434431/exception-without-stack-trace-in-java]

 



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