[jira] [Created] (GROOVY-8388) Groovy MetaClass manager hangs up for 2 minutes every 30 minutes

["Shevek (JIRA)" <ji...@apache.org>]

Shevek created GROOVY-8388:
------------------------------

             Summary: Groovy MetaClass manager hangs up for 2 minutes every 30 minutes
                 Key: GROOVY-8388
                 URL: https://issues.apache.org/jira/browse/GROOVY-8388
             Project: Groovy
          Issue Type: Bug
    Affects Versions: 2.4.12
         Environment: Linux x86, OpenJDK8
            Reporter: Shevek


Groovy hangs on the host for over 2 minutes, at 30 minute intervals. Here is the stack:

```
        at java.util.concurrent.ConcurrentLinkedQueue.remove(ConcurrentLinkedQueue.java:490)
        at org.codehaus.groovy.util.ManagedConcurrentLinkedQueue$Element.finalizeReference(ManagedConcurrentLinkedQueue.java:117)
        at org.codehaus.groovy.util.ReferenceManager$CallBackedManager.removeStallEntries0(ReferenceManager.java:108)
        at org.codehaus.groovy.util.ReferenceManager$CallBackedManager.removeStallEntries(ReferenceManager.java:93)
        at org.codehaus.groovy.util.ReferenceManager$CallBackedManager.afterReferenceCreation(ReferenceManager.java:117)
        at org.codehaus.groovy.util.ReferenceManager$1.afterReferenceCreation(ReferenceManager.java:135)
        at org.codehaus.groovy.util.ManagedReference.<init>(ManagedReference.java:36)
        at org.codehaus.groovy.util.ManagedReference.<init>(ManagedReference.java:40)
        at org.codehaus.groovy.util.ManagedConcurrentLinkedQueue$Element.<init>(ManagedConcurrentLinkedQueue.java:112)
        at org.codehaus.groovy.util.ManagedConcurrentLinkedQueue.add(ManagedConcurrentLinkedQueue.java:62)
        at org.codehaus.groovy.reflection.ClassInfo$GlobalClassSet.add(ClassInfo.java:464)
        at org.codehaus.groovy.reflection.ClassInfo$1.computeValue(ClassInfo.java:84)
        at org.codehaus.groovy.reflection.ClassInfo$1.computeValue(ClassInfo.java:80)
        at org.codehaus.groovy.reflection.GroovyClassValuePreJava7$EntryWithValue.<init>(GroovyClassValuePreJava7.java:37)
        at org.codehaus.groovy.reflection.GroovyClassValuePreJava7$GroovyClassValuePreJava7Segment.createEntry(GroovyClassValuePreJava7.java:64)
        at org.codehaus.groovy.reflection.GroovyClassValuePreJava7$GroovyClassValuePreJava7Segment.createEntry(GroovyClassValuePreJava7.java:55)
        at org.codehaus.groovy.util.AbstractConcurrentMap$Segment.put(AbstractConcurrentMap.java:157)
        at org.codehaus.groovy.util.AbstractConcurrentMap$Segment.getOrPut(AbstractConcurrentMap.java:100)
        at org.codehaus.groovy.util.AbstractConcurrentMap.getOrPut(AbstractConcurrentMap.java:38)
        at org.codehaus.groovy.reflection.GroovyClassValuePreJava7.get(GroovyClassValuePreJava7.java:94)
        at org.codehaus.groovy.reflection.ClassInfo.getClassInfo(ClassInfo.java:143)
        at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.getMetaClass(MetaClassRegistryImpl.java:261)
        at org.codehaus.groovy.runtime.InvokerHelper.getMetaClass(InvokerHelper.java:883)
        at groovy.lang.GroovyObjectSupport.<init>(GroovyObjectSupport.java:34)
        at groovy.lang.Script.<init>(Script.java:42)
        at groovy.lang.Script.<init>(Script.java:39)
        at groovy.util.DelegatingScript.<init>(DelegatingScript.java:93)
        at hive-to-presto.<init>(hive-to-presto.groovy)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at org.codehaus.groovy.runtime.InvokerHelper.createScript(InvokerHelper.java:431)
        at groovy.lang.GroovyShell.parse(GroovyShell.java:700)
        at groovy.lang.GroovyShell.parse(GroovyShell.java:709)
[application code hereafter]
```

Stack captured by stack sampling at 10s intervals on a failing application; stack remains consistent for the 2 minute period.

I've noted on concurrency-interest that a couple of the j.u.c classes have slightly surprising (to us) complexity measures, partly because we're so used to j.u methods being very efficient; it's entirely possible that ConcurrentLinkedQueue.remove() takes linear time.

History: Sometime around groovy 2.4.7 - fixed in groovy 2.4.8 - there was a bug where groovy never released references to classes, and would crash the JVM with something like 'Out of compressed OOPS'. The fix for this apparently introduced a walk of a queue, which now hangs up the JVM instead of breaking it.

On groovy 2.4.7, the number of classes loaded before crash was about 238,000. We may be able to work around this by caching loaded classes, but that will impact the semantics of our application.



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