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http://opensource.atlassian.com/projects/hibernate/browse/HHH-3909?page=c...
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Ovidio Mallo commented on HHH-3909:
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I'm using the trunk version of Hibernate and the warning which is being output is in
InstrumentTest#runTest() which checks whether the classes in the
org.hibernate.test.instrument.domain package are instrumented. I will have a closer look
at why it doesn't work for me since I do also have CGLib and JavaAssist in the
classpath.
In any case, I guess you're right in that my patch is not really correct since
Class#getInterfaces() does only return the interfaces declared on the actual class but not
any interfaces implemented by superclasses as I was assuming. In that case, using
"instanceof" as I'm doing in my patch is obviously not the same thing.
In general, Class#getInterfaces() is probably the right thing since otherwise you might do
the dirty checking on a class which is not itself instrumented but only one of its
superclasses. So I guess you can discard my patch. I'm sorry for not having catched
this up earlier.
Improve Performance of FieldInterceptionHandler (and thus of
flushing)
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Key: HHH-3909
URL:
http://opensource.atlassian.com/projects/hibernate/browse/HHH-3909
Project: Hibernate Core
Issue Type: Improvement
Components: core
Affects Versions: 3.3.1
Reporter: Ovidio Mallo
Attachments: patch.txt
In the FieldInterceptionHelper class, the method Class#getInterfaces() is used in
conjunction with a subsequent loop over all interfaces of an entity class in order to
check whether a bytecode instrumentation interface of CGlib or Javassist is found. This is
done that way since CGlib and Javassist are both optional so they should only be accessed
at runtime if available on the classpath. Attached you can find a simple patch which only
once checks whether CGlib and/or Javassist is available and then uses the more performant
"instanceof" operator in order to check whether an entity has an interceptor.
The new code still guarantees that no CGlib or Javassist class is accessed if it is not on
the classpath.
The patch helps making the FieldInterceptionHelper methods more performant which can e.g.
be noticed during a session flush, especially if bytecode instrumentation is used. In
order to measure the performance impact of the patch I've written a simple program
which does the following:
1. insert 100 thousand entities into a simple table with 6 numeric attributes
2. do an initial flush on the session in order to execute all the insert statements
3. loop 300 times and do a flush on the session (only a dirty check is performed, no
database operation)
I've time the flushes under point 3 above with and without bytecode instrumentation
for the used entity. Here are the results:
USING BYTECODE INSTRUMENTATION
=============================
* SUN JVM 1.6.0_05:
- without patch: 25734ms
- with patch: 11015ms
* IBM JVM 1.4.2:
- without patch: 20672ms
- with patch: 11140ms
WITHOUT BYTECODE INSTRUMENTATION
================================
* SUN JVM 1.6.0_05:
- without patch: 73328ms
- with patch: 62015ms
* IBM JVM 1.4.2:
- without patch: 70344ms
- with patch: 61125ms
Using bytecode instrumentation, the performance improvement is about of a factor of
2-2.5. When not using bytecode instrumentation, the overall impact is of course less
relevant since the rest of the work done during flush is more expensive anyway. In any
case, IMHO the impact when using bytecode instrumentation is relevant.
The patch is very simple and only touches the FieldInterceptionHelper class.
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