On 08.05.2016 07:22, Alain Stalder wrote:
GROOVY-7591 "Use of ClassValue causes major memory leak",
https://issues.apache.org/jira/browse/GROOVY-7591
introduced a new System Property groovy.use.shareclasses in
Groovy 2.4.5 and 2.4.6 which is "false" by default.
But this also caused follow-up issues with garbage collection
of "Groovy" classes, which go away if setting
groovy.use.shareclasses=true, which was also my experience.
GROOVY-7683 Memory leak when using Groovy as JSR-223 scripting language
GROOVY-7646 Classes generated by Eval() never collected from
Permgen/Metaspace
I think 2.4.7 will have an improved version here, that fixes the memory
problems for ClassValue and for not ClassValue. Because both versions
are supposed to be working, unless you fall over a JVM bug.
"Not to ClassValue" (default):
Don't do this if you parse many Groovy scripts or only load
many classes compiled from Groovy scripts - this will fill up
PermGen/Metaspace and blow up with an "OutOfMemoryError" and
you will see lots of MetaMethodIndex$Entry in heap dumps. (Right?)
"To ClassValue":
Personally, I have not observed any issues with this setting,
with Groovy 2.4.6 - under which circumstances would I have a
leak with groovy.use.shareclasses=true?
Can this be explained in a few sentences?
There has been some very recent conversation at GROOVY-7683 by
John Wagenleitner and Jochen Theodorou, so maybe there is a fix
for an upcoming version in preparation?
what did happen was, that the implementation for ClassValue caused some
refactorings on the old code, which produced a difficult to diagnose
memory leak in the old code, as well as the new code not always working.
The problem is that the code for ClassValue itself is still in flux..
just last week there had been for example discussions about replacing
the whole map used in ClassValue... with like 4 different versions to
choose from. Anyway... as there are still things in flux we got an
implementation that worked sometimes and under certain circumstances,
but not always. But I am positive those problems are fixed then in
2.4.7... it is also not that all Groovy versions are hit by this
problem. Any version before the ClassValue change for example is
unaffected. A general use classvalue or not, cannot be adviced really...
it depends on the version.
Any news on that which could already be communicated here?
I think we should work on getting a proper 2.4.7 out and then
communicate that people should upgrade
bye Jochen
