我目前正在为客户的站点(
Java平台)使用Adobe Experience Manager(AEM也称为CQ).它使用OpenJDK：
java version "1.7.0_65" OpenJDK Runtime Environment (rhel-2.5.1.2.el6_5-x86_64 u65-b17) OpenJDK 64-Bit Server VM (build 24.65-b04,mixed mode)
它在Rackspace上运行,具有以下功能：
vcpu: 4 Memory: 16GB Guest OS: Red Hat Enterprise Linux 6 (64-bit)
由于它已经在生产中,我在应用程序方面的性能非常慢.就像这样,我启动应用程序,一切顺利,7到10天后,cpu使用率上升到400％(约4000用户/天击中该站点).该站点变得非常慢,从不会成为OOM异常.
由于我是Java内存管理的新手,我开始阅读有关它的工作原理,并发现了jstat和jmap等工具.当系统第二次被淹没时,我收到了堆堆,并将其挖出来.
所有这一切似乎都指向了org.slf4j.helpers.BasicMarkerFactory和org.slf4j.helpers.BasicMarker,当我用MAT eclipse分析它时,我看到保留大小最大的保留对象是：
org.slf4j.helpers.BasicMarkerFactory @ 0x6021a4f00 Shallow Size: 16 B Retained Size: 6.8 GB
和
当我运行泄漏嫌疑人报告时,我得到以下结果：
Description One instance of "org.slf4j.helpers.BasicMarkerFactory" loaded by "org.apache.felix.framework.BundleWiringImpl$BundleClassLoaderJava5 @ 0x60219a878" occupies 7,263,024,848 (96.71%) bytes. The memory is accumulated in one instance of "java.util.concurrent.ConcurrentHashMap$Segment[]" loaded by "<system class loader>". Keywords java.util.concurrent.ConcurrentHashMap$Segment[] org.apache.felix.framework.BundleWiringImpl$BundleClassLoaderJava5 @ 0x60219a878 org.slf4j.helpers.BasicMarkerFactory
和
Shortest Paths To the Accumulation Point
Class Name Shallow Heap Retained Heap
java.util.concurrent.ConcurrentHashMap$Segment[16] @ 0x6021a4f40 80 7,784
.
... segments java.util.concurrent.ConcurrentHashMap @ 0x6021a4f10 48 7,832
.
... markerMap org.slf4j.helpers.BasicMarkerFactory @ 0x6021a4f00 16 7,848
.
... markerFactory org.slf4j.impl.StaticMarkerBinder @ 0x6021d3970 16 16
.
... SINGLETON class org.slf4j.impl.StaticMarkerBinder @ 0x6021d38f8 8 24
.
... [328] java.lang.Object[640] @ 0x6021d2ee8 2,576 9,592
.
... elementData java.util.Vector @ 0x6021d0fe0 32 9,624
.
... classes org.apache.felix.framework.BundleWiringImpl$
BundleClassLoaderJava5 @ 0x6021c32e0 96 26,888
.
... <classloader> class ch.qos.logback.classic.Logger @
0x600be4310 16 16
. .
. ...<class> ch.qos.logback.classic.Logger @ 0x600282a78 48 48
.
... <Java Local> java.lang.Thread @ 0x60077b450
pool-9-thread-1 Thread 104 3,344
.
... <class> ch.qos.logback.classic.Logger @ 0x60025b850 48 48
.
... <class> ch.qos.logback.classic.Logger @ 0x604b0a708 48 48
.
... <class> ch.qos.logback.classic.Logger @ 0x604b0a6d8 48 48
.
... <class> ch.qos.logback.classic.Logger @ 0x6049debe0 48 48
.
... <class> ch.qos.logback.classic.Logger @ 0x604535228 48 48
.
... <class> ch.qos.logback.classic.Logger @ 0x604124248 48 48
当我运行时：
$sudo -u aem jmap -histo PID num #instances #bytes class name ---------------------------------------------- 1: 11460084 950827248 [C 2: 10740160 257763840 java.lang.String 3: 7681495 245807840 java.util.concurrent.ConcurrentHashMap$HashEntry 4: 7563527 181524648 org.slf4j.helpers.BasicMarker 5: 217007 173568376 [I 6: 177602 158721184 [B 7: 60611 69739136 [Ljava.util.concurrent.ConcurrentHashMap$HashEntry; 8: 1147481 69348496 [Ljava.lang.Object; 9: 1797107 43130568 org.apache.jackrabbit.oak.plugins.segment.RecordId 10: 208912 33824544 <constMethodKlass> 11: 570143 31928008 org.mozilla.javascript.ast.Name 12: 22350 27643920 <constantPoolKlass> 13: 208912 26752544 <methodKlass> 14: 821217 26278944 java.util.UUID 15: 793800 25401600 java.util.HashMap$Entry 16: 532946 21317840 org.mozilla.javascript.Node 17: 792296 19015104 java.lang.Long 18: 191294 18335600 [Ljava.util.HashMap$Entry; 19: 22350 16133328 <instanceKlassKlass> 20: 173883 15855152 [Ljava.lang.String; 21: 635690 15256560 org.apache.sling.engine.impl.request.SlingRequestProgressTracker$TrackingEntry 22: 18509 14662848 <constantPoolCacheKlass> 23: 911112 14577792 java.lang.Integer 24: 255426 14303856 org.apache.jackrabbit.oak.plugins.segment.SegmentNodeBuilder 25: 519324 12463776 java.util.ArrayList 26: 254643 12222864 org.apache.jackrabbit.oak.core.SecureNodeBuilder 27: 137703 11016240 java.lang.reflect.Method 28: 312116 9987712 org.apache.jackrabbit.oak.plugins.segment.SegmentNodeState 29: 19236 9828448 [Lorg.apache.jackrabbit.oak.plugins.segment.SegmentId; 30: 242179 9687160 java.util.TreeMap$Entry 31: 197121 9461808 java.util.HashMap 32: 15041 9416328 <methodDataKlass> 33: 387927 9310248 org.apache.jackrabbit.oak.plugins.segment.MapRecord 34: 250049 8001568 org.apache.jackrabbit.oak.plugins.memory.MemoryNodeBuilder$UnconnectedHead 35: 248586 7954752 org.apache.jackrabbit.oak.core.MutableTree 36: 107865 7948112 [S 37: 191950 7678000 java.util.LinkedHashMap$Entry 38: 102212 6541568 org.mozilla.javascript.ast.PropertyGet 39: 37021 6515696 org.mozilla.javascript.ast.FunctionNode 40: 161905 6476200 org.mozilla.javascript.ScriptableObject$Slot ..... 8210: 1 16 org.slf4j.helpers.BasicMarkerFactory
我注意到：
4: 7563527 181524648 org.slf4j.helpers.BasicMarker
和
8210: 1 16 org.slf4j.helpers.BasicMarkerFactory
当我进入org.slf4j.helpers.BasicMarkerFacotry的文档时,我看到以下内容引起了我的注意：
detachMarker public boolean detachMarker(String name) Description copied from interface: IMarkerFactory Detach an existing marker. Note that after a marker is detached,there might still be "dangling" references to the detached marker. Specified by: detachMarker in interface IMarkerFactory Parameters: name - The name of the marker to detach Returns: whether the marker could be detached or not
尤其是：
Note that after a marker is detached,there might still be "dangling" references to the detached marker.
希望有人可以帮我找出我的问题的原因,因为我有点迷失在这里？
有人曾经看过这个吗？
>如何进一步解决这个问题？
>你同意org.slf4j.helpers.BasicMarker和org.slf4j.helpers.BasicMarkerFactory似乎是我的问题的根本原因吗？
>我的日志配置是可疑的？
这是一个缓慢的内存泄漏或性能调优问题(在我看来,似乎内存泄漏缓慢的一个多星期左右)？
欢迎任何建议.
提前致谢.
