JVM可以在服务运行时实时修改生效的监控参数

环境：java version "1.8.0_131"

查看某个进程所有参数配置

[root@izbp1c /]# jps
15154 -- process information unavailable
24979 jar   -- 目标进程
17544 Jps
16573 Logstash
[root@izbp1c /]# java -XX:+PrintFlagsFinal 24979    -->  查看jvm所有当前服务使用的配置参数

所有参数中只有末尾以 {manageable} 标识的参数才是可以实时修改的参数，具体参数列表如下：

可动态配置的JVM参数

参数	参数类型	默认值	可修改标志
CMSAbortablePrecleanWaitMillis	intx	= 100	{manageable}
CMSTriggerInterval	intx	= -1	{manageable}
CMSWaitDuration	intx	= 2000	{manageable}
HeapDumpAfterFullGC	bool	= false	{manageable}
HeapDumpBeforeFullGC	bool	= false	{manageable}
HeapDumpOnOutOfMemoryError	bool	= false	{manageable}
HeapDumpPath	ccstr	=	{manageable}
MaxHeapFreeRatio	uintx	= 70	{manageable}
MinHeapFreeRatio	uintx	= 40	{manageable}
PrintClassHistogram	bool	= false	{manageable}
PrintClassHistogramAfterFullGC	bool	= false	{manageable}
PrintClassHistogramBeforeFullGC	bool	= false	{manageable}
PrintConcurrentLocks	bool	= false	{manageable}
PrintGC	bool	= false	{manageable}
PrintGCDateStamps	bool	= false	{manageable}
PrintGCDetails	bool	= false	{manageable}
PrintGCID	bool	= false	{manageable}
PrintGCTimeStamps	bool	= false	{manageable}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

修改方法：jinfo -flag  参数名=要设置参数值 ${ service PID }

如：

jinfo  -flag  +HeapDumpAfterFullGC  { java-pid }    --- 开启HeapDumpAfterFullGC 
jinfo  -flag  -HeapDumpAfterFullGC  { java-pid }     --- 关闭HeapDumpAfterFullGC 

jinfo -flag +HeapDumpBeforeFullGC  { java--pid }   --- 开启
jinfo -flag -HeapDumpBeforeFullGC  { java--pid }   --- 关闭

jinfo -flag HeapDumpPath=../heap.hprof  { java--pid }  ---指定dump快照路径