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https://issues.apache.org/jira/browse/GROOVY-10773?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17611648#comment-17611648
]
Val E commented on GROOVY-10773:
--------------------------------
Its retaining the *first hit* to the method actually. Here is a slightly
modified method signature, to provide how many items to return, and you can see
it retains 569 items in memory, the param of the first call to the method.
!image-2022-09-30-11-24-49-168.png|width=499,height=328!
{code:java}
class MemLeakItem3 {
String name = "I take up memory space"
Double value = Math.random();
}
class MemLeakContainer3 {
Map getItems(int size){
Map result =[:]
for(int i=0; i<size;i++){
MemLeakItem3 item = new MemLeakItem3()
result.put(item.value, item)
}
return result
}
}
10.times{
def container = new MemLeakContainer3()
container.getItems(569)
container.getItems(10000)
container.getItems(7000)
container = null
}
println "Execution paused check heap for MemLeakItem objects"
def input = System.in.newReader().readLine(){code}
> Groovy 4 memory leak due to presumptuous caching in
> org.codehaus.groovy.vmplugin.v8.CacheableCallSite
> -----------------------------------------------------------------------------------------------------
>
> Key: GROOVY-10773
> URL: https://issues.apache.org/jira/browse/GROOVY-10773
> Project: Groovy
> Issue Type: Bug
> Affects Versions: 4.0.5
> Environment: Java 1.8, 11, 14
> Groovy 4.0.4, 4.0.5
> Reporter: Val E
> Priority: Major
> Attachments: MemLeakContainer.groovy, MemLeakItem.groovy,
> MemLeakTest.zip, TestScript.groovy, build.gradle, heapdump.png,
> image-2022-09-29-13-21-57-256.png, image-2022-09-30-11-01-13-234.png,
> image-2022-09-30-11-05-57-860.png, image-2022-09-30-11-24-49-168.png,
> visualvm_mem_sampler.png
>
>
> It looks like method handles caching is creating memory leaks in Groovy 4,
> because in addition to the method handle it is also storing the results of
> the method execution in
> *_org.codehaus.groovy.vmplugin.v8.CacheableCallSite.latestHitMethodHandleWrapper_*
>
> These cached method handles are not subject to garbage collection. Since the
> cached handler is also storing the result of the method execution, which can
> be any arbitrary object, it will also prevent the object itself and any of
> its transitive properties from being garbage collected. In our case the
> method execution often produced very large maps which caused our prod servers
> to very quickly bog down and need restarts.
>
> I have tried this with Groovy 4.0.4 and 4.0.5, as well as Java 1.8, 11, and
> 14; all produced this memory leaks.
> However Groovy 3.0.5 did *NOT* produce this leak.
>
> I have attached a very simple Gradle project. It produces 5000 MemoryLeakItem
> objects. Nothing special about these objects themselves, just easy to find in
> VisualVM and heap dumps. A container object that does some basic dynamic
> method resolution via a methodMissing and a TestScript to run and pause
> execution, so a heap dump can be created or VisualVM inspected.
>
> To reproduce the leak:
> Run TestScript.groovy, and when it pauses for keyboard input, check VisualVM
> or a heap dump.
> !image-2022-09-29-13-21-57-256.png|width=471,height=421!
>
>
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