OOM 相关 VM参数

浅浅的花香味﹌ 2022-09-10 05:24 136阅读 0赞

# 一 点睛 #

> \-XX:+HeapDumpOnOutOfMemoryError内存出现 OOM 时生成 Heap 转储文件，与下面这个参数互斥
> 
> \-XX:+HeapDumpBeforeFullGC 出现 FullGC 时生成 Heap 转储文件，与上面这个参数互斥
> 
> \-XX:HeapDumpPath=<path> 指定 heap 转储文件的存储路径，默认当前目录
> 
> \-XX:OnOutOfMemoryError=<path> 指定一个可行性程序或脚本的路径，当发生 OOM 时执行脚本

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16][]

# 二 实战 #

**1 代码**

package chapter03;
    
    import java.util.ArrayList;
    import java.util.Random;
    
    /**
    * -Xms600m -Xmx600m -XX:SurvivorRatio=8
    * -XX:+HeapDumpOnOutOfMemoryError
    * -XX:+HeapDumpBeforeFullGC
    * -XX:HeapDumpPath=d:\HeapInstanceTest.hprof
    * 老年代：400m
    * 伊甸园：160m
    * s0:20m
    * s1:20m
    */
    public class HeapInstanceTest {
        byte[] buffer = new byte[new Random().nextInt(1024 * 1024)];
    
        public static void main(String[] args) {
            try {
                Thread.sleep(300);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            ArrayList<HeapInstanceTest> list = new ArrayList<>();
            while (true) {
                list.add(new HeapInstanceTest());
                try {
                    Thread.sleep(10);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

**2 当参数配置为 -Xms600m -Xmx600m -XX:HeapDumpPath=d:\\HeapInstanceTest.hprof -XX:+HeapDumpBeforeFullGC**

> Dumping heap to d:\\HeapInstanceTest.hprof ...
> 
> Heap dump file created \[444024614 bytes in 0.277 secs\]
> 
> Dumping heap to d:\\HeapInstanceTest.hprof.1 ...
> 
> Heap dump file created \[601407984 bytes in 0.381 secs\]
> 
> Dumping heap to d:\\HeapInstanceTest.hprof.2 ...
> 
> Heap dump file created \[599020322 bytes in 0.429 secs\]
> 
> Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
> 
> Dumping heap to d:\\HeapInstanceTest.hprof.3 ...
> 
> Heap dump file created \[598984886 bytes in 0.361 secs\]
> 
>     at chapter03.HeapInstanceTest.<init>(HeapInstanceTest.java:17)
> 
>     at chapter03.HeapInstanceTest.main(HeapInstanceTest.java:27)
> 
> Process finished with exit code 1

生成文件如下

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_15_color_FFFFFF_t_70_g_se_x_16][]

前3次是因为 FullGC 造成的，最后一次是因为 OOM造成的。

**3 当参数配置为 -Xms600m -Xmx600m -XX:HeapDumpPath=d:\\HeapInstanceTest.hprof -XX:+HeapDumpOnOutOfMemoryError**

> java.lang.OutOfMemoryError: Java heap space
> 
> Dumping heap to d:\\HeapInstanceTest.hprof ...
> 
> Heap dump file created \[577100327 bytes in 0.335 secs\]
> 
> Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
> 
>     at chapter03.HeapInstanceTest.<init>(HeapInstanceTest.java:17)
> 
>     at chapter03.HeapInstanceTest.main(HeapInstanceTest.java:27)

生成文件如下

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_16_color_FFFFFF_t_70_g_se_x_16][]

因为 OOM 生成 dump 文件。

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220829/00aaa0cf486248bf9d2bd3802df40fdb.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_15_color_FFFFFF_t_70_g_se_x_16]: /images/20220829/6f8815313fee470ead941fda519d3035.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_16_color_FFFFFF_t_70_g_se_x_16]: /images/20220829/ecc82efcc5af4fe2909c6d6db1438f9b.png