java服务宕机原因查询

背景

在java服务项目上线之后经常会出现宕机的情况

常见原因

内存溢出

1.查到服务进程号

[root@wms ~]# ps -ef|grep java
root      6399  6069  0 08:57 pts/2    00:00:00 grep --color=auto java
root     25374     1  0 Oct17 ?        00:21:19 /usr/local/jdk/jre/bin/java -Djava.util.logging.config.file=/home/tomcat-wmsweb/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Xms3072m -Xmx3072m -Xss512K -XX:PermSize=256m -XX:MaxPermSize=512m -Djdk.tls.ephemeralDHKeySize=2048 -Djava.endorsed.dirs=/home/tomcat-wmsweb/endorsed -classpath /home/tomcat-wmsweb/bin/bootstrap.jar:/home/tomcat-wmsweb/bin/tomcat-juli.jar -Dcatalina.base=/home/tomcat-wmsweb -Dcatalina.home=/home/tomcat-wmsweb -Djava.io.tmpdir=/home/tomcat-wmsweb/temp org.apache.catalina.startup.Bootstrap start
root     25401     1  2 Oct17 ?        03:14:13 /usr/local/jdk/jre/bin/java -Djava.util.logging.config.file=/home/tomcat-wms/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Xms3000m -Xmx3000m -Xss512K -XX:PermSize=256m -XX:MaxPermSize=512m -XX:-UseGCOverheadLimit -Djdk.tls.ephemeralDHKeySize=2048 -Djava.endorsed.dirs=/home/tomcat-wms/endorsed -classpath /home/tomcat-wms/bin/bootstrap.jar:/home/tomcat-wms/bin/tomcat-juli.jar -Dcatalina.base=/home/tomcat-wms -Dcatalina.home=/home/tomcat-wms -Djava.io.tmpdir=/home/tomcat-wms/temp org.apache.catalina.startup.Bootstrap start
[root@wms ~]# 

2、查看内存使用情况

[root@wms ~]# jmap -heap 25401
Attaching to process ID 25401, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.211-b12

using thread-local object allocation.
Parallel GC with 4 thread(s)

Heap Configuration:
   MinHeapFreeRatio         = 0
   MaxHeapFreeRatio         = 100
   MaxHeapSize              = 3145728000 (3000.0MB)
   NewSize                  = 1048576000 (1000.0MB)
   MaxNewSize               = 1048576000 (1000.0MB)
   OldSize                  = 2097152000 (2000.0MB)
   NewRatio                 = 2
   SurvivorRatio            = 8
   MetaspaceSize            = 21807104 (20.796875MB)
   CompressedClassSpaceSize = 1073741824 (1024.0MB)
   MaxMetaspaceSize         = 17592186044415 MB
   G1HeapRegionSize         = 0 (0.0MB)

Heap Usage:
PS Young Generation
Eden Space:
   capacity = 607649792 (579.5MB)
   used     = 607649792 (579.5MB)
   free     = 0 (0.0MB)
   100.0% used
From Space:
   capacity = 213385216 (203.5MB)
   used     = 0 (0.0MB)
   free     = 213385216 (203.5MB)
   0.0% used
To Space:
   capacity = 201326592 (192.0MB)
   used     = 0 (0.0MB)
   free     = 201326592 (192.0MB)
   0.0% used
PS Old Generation
   capacity = 2097152000 (2000.0MB)
   used     = 2097149664 (1999.9977722167969MB)
   free     = 2336 (0.002227783203125MB)
   99.99988861083985% used

121339 interned Strings occupying 10592008 bytes.

发现 Eden Space 100.0% used
PS Old Generation 100.0% used
确认为内存溢出

接下来我们需要查看到底是那个大对象造成的这个问题
由于堆内对象信息太多，因此需要输出到问题中查看

[root@wms ~]# jmap -histo:live 25401 >aaa.log

查看大对象信息

[root@wms ~]# vim aaa.log

 num     #instances         #bytes  class name
----------------------------------------------
   1:      23798913      925276392  [C
   2:      23791642      570999408  java.lang.String
   3:        879806      201469128  [Ljava.lang.Object;
   4:        717239      189351096  com.demo.inventory.query.GetTaskCountQueryItem
   5:       5247003      125928072  java.lang.Double
   6:        932106       82025328  java.lang.reflect.Method
   7:       2144995       68639840  java.util.HashMap$Node
   8:       1457567       46642144  java.sql.Timestamp
   9:        725212       40611872  org.hibernate.engine.EntityEntry
  10:        725213       34810224  org.hibernate.engine.EntityKey
  11:        180443       26468992  [Ljava.util.HashMap$Node;
  12:        549431       26372688  org.aspectj.weaver.reflect.ShadowMatchImpl
  13:        655720       26228800  java.util.LinkedHashMap$Entry
  14:        239773       25712128  java.lang.Class
  15:        780484       24975488  org.apache.commons.collections.SequencedHashMap$Entry
  16:       1535589       24569424  java.lang.Integer
  17:        656230       20999360  java.util.concurrent.ConcurrentHashMap$Node
  18:        869529       20868696  java.util.ArrayList
  19:        822486       20851440  [Ljava.lang.String;
  20:         66016       19964336  [B
  21:        549431       17581792  org.aspectj.weaver.patterns.ExposedState
  22:        705540       15311776  [Z
  23:        549431       11702568  [Lorg.aspectj.weaver.ast.Var;
  24:        725212       11603392  org.hibernate.util.IdentityMap$IdentityKey
  25:        158941        8900696  java.util.LinkedHashMap
  26:        324828        7247936  [I
  27:        162778        6511120  java.lang.ref.SoftReference
  28:           476        6288080  [Ljava.util.concurrent.ConcurrentHashMap$Node;
  29:        110595        5308560  java.util.HashMap
  30:        155487        4975584  java.lang.ref.WeakReference
  31:         16090        3732880  com.demo.inventory.query.WmInvLotLocTraceIdQueryItem
  32:        163337        3313312  [Ljava.lang.Class;
  33:         41098        3287840  java.lang.reflect.Constructor
  34:         51249        3279936  org.hibernate.mapping.Column
  35:         81913        3276520  java.util.WeakHashMap$Entry
  36:         35571        3047840  [[Ljava.lang.String;
  37:         51247        2869832  org.hibernate.mapping.Property
  38:         51249        2459952  org.hibernate.mapping.SimpleValue
  39:         49720        1988800  org.hibernate.annotations.common.reflection.java.JavaXProperty
  40:         48352        1934080  org.hibernate.tuple.StandardProperty
  41:         78677        1888248  java.beans.MethodRef

由上可知com.demo.inventory.query.GetTaskCountQueryItem 导致内存过大，应优化处理。

本博文来源于：https://blog.csdn.net/weixin_43159039/article/details/102676161