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From Daniel John Debrunner <...@apache.org>
Subject Re: Derbyall runtimes, 10.1, and Security Manager
Date Tue, 02 May 2006 01:02:37 GMT
Daniel John Debrunner wrote:

> Hmmm, it suprises me that the SecurityManager would have that much
> effect. I'll try running some tests and see what exactly is happening.

I did some testing of this today. There is a slowdown due the security
manager and it's not due to additional code in the test harness.

Disabling the security manager by either of:

 - forcing the noSecurityManager=true for every test
 - setting Xjava.security.manager instead of the real property

had similar speed-ups.

The overhead was suprisingly large from around 14-16mins to 12mins to
for a set of ~40 tests from derbylang. Some guesses are:

 - tests have a lot of compilation, leading to a lot of class loading
which may have a higher cost with a security manager
 - tests create & drop tables, indexes etc. which leads to files being
created and dropped, all requiring security manager checks
 - harness/derby startup reads a lot of system properties requiring
security checks
 - jvm setup with a security manager has a large overhead - would
disappaer if we ran all tests in the same jvm with junit
   (will test theory with nist suite)


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