java故障处理(内存100%，cpu100%，FullGC怎么办)

朴灿烈づ我的快乐病毒、 2022-01-23 15:33 331阅读 0赞

## 收藏的好文章 ##

<table> 
 <thead> 
  <tr> 
   <th>好文收藏</th> 
   <th>来源（公众号或者作者）</th> 
   <th>地址</th> 
   <th>日期</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>一些长时间GC停顿问题的排查及解决办法</td> 
   <td>占小狼</td> 
   <td>https://mp.weixin.qq.com/s/fP–JJnkTR92NWdZtdEgqQ</td> 
   <td>2019-3-25</td> 
  </tr> 
  <tr> 
   <td>系统运行缓慢，CPU 100%，以及Full GC次数过多问题的排查思路</td> 
   <td>芋道源码</td> 
   <td>https://mp.weixin.qq.com/s/_tWm2G57vLgomvpNNHKAMA</td> 
   <td>2019-3-1</td> 
  </tr> 
  <tr> 
   <td>分享一次 Java 内存泄漏的排查</td> 
   <td>Java基基</td> 
   <td>https://mp.weixin.qq.com/s/M02Qk5OQ13xRytTK97SaFw</td> 
   <td>2019-3-14</td> 
  </tr> 
  <tr> 
   <td>并发环境下HashMap引起full gc排查</td> 
   <td>李小武</td> 
   <td>http://blog.lichengwu.cn/java/2015/04/06/case-of-hashmap-in-concurrency/</td> 
   <td>2015-4-6</td> 
  </tr> 
  <tr> 
   <td>Metaspace 引起的 FullGC 问题排查过程及解决方案</td> 
   <td>程序猿DD</td> 
   <td>https://mp.weixin.qq.com/s/rkTDMFkvBDZzT2fUfOjV_Q</td> 
   <td>2019-6-14</td> 
  </tr> 
  <tr> 
   <td>从一起GC血案谈到反射原理</td> 
   <td>假笨说</td> 
   <td>https://mp.weixin.qq.com/s/5H6UHcP6kvR2X5hTj_SBjA?</td> 
   <td>2017-01-12</td> 
  </tr> 
  <tr> 
   <td>深入理解Java虚拟机：（十六） Java虚拟机的性能监控及诊断工具</td> 
   <td>老周聊架构</td> 
   <td>https://riemann.blog.csdn.net/article/details/104157865</td> 
   <td>2020-2-2</td> 
  </tr> 
 </tbody> 
</table>

## 一些常用命令 ##

### 1.查看自己服务的进程id （pid） ###

`ps -ef | grep java` 或者 `jps`

### 2.查看是否有full gc \*（5000ms打印一次，也可以去掉这个参数） ###

`jstat -gcutil （pid）5000`

S0     S1     E      O      M     CCS    YGC     YGCT    FGC    FGCT     GCT
      0.00 100.00  48.36  10.55  98.24  95.95     30    2.205     0    0.000    2.205
      0.00 100.00  70.42  10.55  98.24  95.95     30    2.205     0    0.000    2.205

### 3.查看堆内存使用状况 ###

`jmap -heap （pid）`

jmap -heap 59191
    Debugger attached successfully.
    Server compiler detected.
    JVM version is 25.45-b02
    
    using thread-local object allocation.
    Garbage-First (G1) GC with 2 thread(s)
    
    Heap Configuration:
       MinHeapFreeRatio         = 40
       MaxHeapFreeRatio         = 70
       MaxHeapSize              = 4194304000 (4000.0MB)
       NewSize                  = 1363144 (1.2999954223632812MB)
       MaxNewSize               = 2516582400 (2400.0MB)
       OldSize                  = 5452592 (5.1999969482421875MB)
       NewRatio                 = 2
       SurvivorRatio            = 8
       MetaspaceSize            = 21807104 (20.796875MB)
       CompressedClassSpaceSize = 1073741824 (1024.0MB)
       MaxMetaspaceSize         = 17592186044415 MB
       G1HeapRegionSize         = 1048576 (1.0MB)
    
    Heap Usage:
    G1 Heap:
       regions  = 4000
       capacity = 4194304000 (4000.0MB)
       used     = 556760056 (530.9677658081055MB)
       free     = 3637543944 (3469.0322341918945MB)
       13.274194145202637% used
    G1 Young Generation:
    Eden Space:
       regions  = 485
       capacity = 673185792 (642.0MB)
       used     = 508559360 (485.0MB)
       free     = 164626432 (157.0MB)
       75.54517133956386% used
    Survivor Space:
       regions  = 3
       capacity = 3145728 (3.0MB)
       used     = 3145728 (3.0MB)
       free     = 0 (0.0MB)
       100.0% used
    G1 Old Generation:
       regions  = 44
       capacity = 397410304 (379.0MB)
       used     = 45054968 (42.96776580810547MB)
       free     = 352355336 (336.03223419189453MB)
       11.337141374170308% used

### 4.现场保留 ###

保留histo内存快照;`jmap -histo (pid) > histo.log`  
JVM线程信息保存: `jstack (pid) > stack.log`  
保存jvm堆内存快照 `jmap -dump:live,format=b,file=heap.bin <pid>`