glassfish full gc每小时一次 [英] glassfish full gc once an hour

问题描述

我们在Glassfish应用程序中每小时看到一次完整的GC。从GC日志中提取：

  9.210：[Full GC 28311K-> 27979K（6422528K），0.3770238秒] 
 ... 
 3609.647：[Full GC 1186957K-> 597880K（6478208K），4.5102977 secs] 
 ... 
 7214.192：[Full GC 742184K-> 595596K（6469504K）， 4.3726625秒] 
 ... 
 10818.805：[Full GC 756228K-> 570803K（6455936K），4.8630472秒] 
  

只要Glassfish上涨，这种模式大致重复。其间的...是增量GC。时间似乎非常可疑 - 为什么我们会看到完整的GC每小时约一次？

JVM启动参数：

  -Xms6400m 
 -Xmx6400m 
 -XX：NewSize = 1024m 
 -XX：MaxNewSize = 1024m 
 -XX：PermSize = 256m 
 -XX：MaxPermSize = 1024m 
 -XX：+ UseParallelGC 
 -XX：+ UseParallelOldGC 
 -Xloggc：C：\glassfish3\glassfish\domains\domain1\ logs \gc\gc.log 
 -XX：+ AggressiveOpts 
 -Xss1024k 
 -XX：+ CMSClassUnloadingEnabled 
  

根据JVisualVM的说法，我们没有接近堆空间的地方。

Glassfish 3.1.2.2，Oracle JDK 1.6.0_45，Windows Server 2008

解决方案

我怀疑你的RMI正在触发Full清理。
$ b

http：// docs.oracle.com/javase/6/docs/technotes/guides/rmi/sunrmiproper ties.html

双方

sun.rmi.dgc .server.gcInterval

当需要确保无法访问的远程对象未及时导出并进行垃圾回收时，此属性的值表示最大时间间隔毫秒），Java RMI运行时将允许在本地堆的垃圾回收之间进行。

和

默认值为3600000毫秒（1小时）

sun.rmi.dgc.client.gcInterval

在需要确保DGC干净呼叫不可及远程引用时及时传送时尚，此属性的值表示Java RMI运行时在本地堆的垃圾回收之间允许的最大时间间隔（以毫秒为单位）。默认值为3600000毫秒（1小时）。

默认为每小时检查。

我会将这些设置为一天或一周，因为您认为您不需要这些。

I'm seeing a full GC about once an hour in our Glassfish application. Extract from the GC log:

9.210: [Full GC 28311K->27979K(6422528K), 0.3770238 secs]
...
3609.647: [Full GC 1186957K->597880K(6478208K), 4.5102977 secs]
...
7214.192: [Full GC 742184K->595596K(6469504K), 4.3726625 secs]
...
10818.805: [Full GC 756228K->570803K(6455936K), 4.8630472 secs]

And this pattern roughly repeats as long as Glassfish is up. The "..." in between are incremental GCs. The timing seems awfully suspicious- why would we be seeing full GC's about once an hour?

JVM startup parameters:

-Xms6400m
-Xmx6400m
-XX:NewSize=1024m
-XX:MaxNewSize=1024m
-XX:PermSize=256m
-XX:MaxPermSize=1024m
-XX:+UseParallelGC
-XX:+UseParallelOldGC
-Xloggc:C:\glassfish3\glassfish\domains\domain1\logs\gc\gc.log
-XX:+AggressiveOpts
-Xss1024k
-XX:+CMSClassUnloadingEnabled

According to JVisualVM, we're no where close to running out of heap space.

Glassfish 3.1.2.2, Oracle JDK 1.6.0_45, Windows Server 2008

解决方案

I suspect your RMI is triggering a Full clean up.

http://docs.oracle.com/javase/6/docs/technotes/guides/rmi/sunrmiproperties.html

both

sun.rmi.dgc.server.gcInterval

When it is necessary to ensure that unreachable remote objects are unexported and garbage collected in a timely fashion, the value of this property represents the maximum interval (in milliseconds) that the Java RMI runtime will allow between garbage collections of the local heap. The default value is 3600000 milliseconds (one hour).

and

sun.rmi.dgc.client.gcInterval

When it is necessary to ensure that DGC clean calls for unreachable remote references are delivered in a timely fashion, the value of this property represents the maximum interval (in milliseconds) that the Java RMI runtime will allow between garbage collections of the local heap. The default value is 3600000 milliseconds (one hour).

default to hourly checks.

I would set these to a day or a week for you believe you don't need these.

这篇关于glassfish full gc每小时一次的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！