Shulou(Shulou.com)06/03 Report--

[phenomenon]: after applying the updated version, one of the machines has a lot of restart phenomena.

[cause Analysis]:

Analyze the application log and find that there is OutOfMemoryError:PermGen space. This error indicates that the PermSize setting is too small and there is not enough memory.

[solution]:

Modify the JVM configuration on the

-XX:PermSize=128m

-XX:MaxPermSize=128m

Note: the Perm area of JVM is mainly used to store Class and Meta information. Class will be put into PermGen space when it is Loader. This area becomes the old generation. GC will not clean up the old area during the running of the main program. The default size is 64m. When the program needs to load more objects, more than 64m will report this part of memory overflow and need to increase memory allocation. Generally, 128m is enough.

There is also a direct report to java.lang.OutOfMemoryError, this situation is generally jvm maximum and minimum memory allocation configuration problems, the minimum memory allocation is too small, high GC frequency, reduce jvm performance, but the minimum memory can not infinitely increase, the minimum memory increases, the GC frequency is low, but its execution time will be longer. During the execution of GC, the java program does not handle other requests, so the minimum memory xms is the same as the maximum memory xmx setting. The xmn value is set to about 1 xmx 3. 0.

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