一次内存泄漏的排查
昨天,又有一位用户抱怨阳光牧场助手的内存占用过高 问用户拿到20来个帐号后,用助手加载,启动,得到一些GC的数据:
409.879: [Full GC 409.879: [Tenured: 349567K->349567K(349568K), 1.5796790 secs] 506815K->382998K(506816K), [Perm : 15879K->15879K(65536K)], 1.5797868 secs] [Times: user=1.55 sys=0.00, real=1.58 secs]
417.784: [Full GC 417.784: [Tenured: 349567K->349568K(349568K), 1.6968523 secs] 506815K->382777K(506816K), [Perm : 15880K->15878K(65536K)], 1.6969534 secs] [Times: user=1.68 sys=0.00, real=1.69 secs]
422.242: [Full GC 422.242: [Tenured: 349568K->349568K(349568K), 1.5697638 secs] 506815K->382844K(506816K), [Perm : 15879K->15879K(65536K)], 1.5698652 secs] [Times: user=1.56 sys=0.00, real=1.56 secs]
Heap
def new generation total 157248K, used 156479K [0x029e0000, 0x0d480000, 0x0d480000)
eden space 139776K, 100% used [0x029e0000, 0x0b260000, 0x0b260000)
from space 17472K, 95% used [0x0b260000, 0x0c2afda8, 0x0c370000)
to space 17472K, 0% used [0x0c370000, 0x0c370000, 0x0d480000)
tenured generation total 349568K, used 349568K [0x0d480000, 0x229e0000, 0x229e0000)
the space 349568K, 100% used [0x0d480000, 0x229e0000, 0x229e0000, 0x229e0000)
compacting perm gen total 65536K, used 16259K [0x229e0000, 0x269e0000, 0x2a9e0000)
the space 65536K, 24% used [0x229e0000, 0x239c0e98, 0x239c1000, 0x269e0000)
No shared spaces configured.
由于新生代应该会很快回收,故关注另外一块已经用完的空间tenured generation
tenured generation total 349568K, used 349568K [0x0d480000, 0x229e0000, 0x229e0000)
the space 349568K, 100% used [0x0d480000, 0x229e0000, 0x229e0000, 0x229e0000)
足足用掉了340M,怎么会这样呢? 最后几次都是FULL GC,故肯定是有对象一直被引用,而且用了很多内存. 用jmap把内存镜像抓下来
jmap -dump:format=b,file=heap.bin 1936
#1936是进程号pid
然后使用 Eclipse Memory Analyzer 打开heap.bin , 经过漫长的等待后 不跑任何分析,直接在Overview视图,点开Dominator Tree, 哇!!! 严重震惊了,数据如下:
Class Name | Shallow Heap | Retained Heap | Percentage
--------------------------------------------------------------------------------------------------------------
| | |
com.goojia.xiaonei.sunfarm.Config @ 0x144f8ea8 | 136 | 15,856,928 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x135aa160 | 136 | 15,856,880 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x1080dba8 | 136 | 15,856,872 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x13382830 | 136 | 15,856,872 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x1359cf10 | 136 | 15,856,872 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x107e8a28 | 136 | 15,856,864 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x117244d0 | 136 | 15,856,856 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x12413010 | 136 | 15,856,840 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x133913b0 | 136 | 15,856,840 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x140dc1c8 | 136 | 15,856,840 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x140d6c10 | 136 | 15,856,824 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x10152860 | 136 | 15,856,768 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x107ecc68 | 136 | 15,856,768 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x144f7050 | 136 | 15,856,736 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x1300c4d8 | 136 | 15,856,720 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x117267b8 | 136 | 15,856,712 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x107e8f20 | 136 | 15,856,696 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0xf8796a0 | 136 | 15,856,648 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0xf882128 | 136 | 15,856,576 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0xf87ea38 | 136 | 15,856,416 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0xf8bd308 | 136 | 15,856,416 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0xf87fb40 | 136 | 15,856,408 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0x140d7aa0 | 136 | 15,856,280 | 4.04%
com.goojia.xiaonei.sunfarm.Config @ 0xf8ac2a8 | 136 | 15,856,080 | 4.04%
com.goojia.xiaonei.sunfarm.Context @ 0x140d8970 | 120 | 1,105,208 | 0.28%
class com.goojia.sunfarm.TextAreaAppender @ 0x25095de8 System Class| 16 | 501,512 | 0.13%
class java.lang.Integer$IntegerCache @ 0x24e2cdb8 System Class | 8 | 401,032 | 0.10%
com.goojia.xiaonei.sunfarm.Context @ 0x140dc330 | 120 | 339,344 | 0.09%
com.goojia.xiaonei.sunfarm.Context @ 0x13391438 | 120 | 338,536 | 0.09%
com.goojia.xiaonei.sunfarm.Context @ 0x117245a0 | 120 | 337,376 | 0.09%
Total: 30 of 8,160 entries | | |
--------------------------------------------------------------------------------------------------------------
Config对象竟然占用了300多M,而且很准确的与帐号数一样,因为那是一一对应的.但,不对啊,怎么这么多呢? 打开一个Config看看
Class Name | Shallow Heap | Retained Heap | Percentage
------------------------------------------------------------------------------------------------
com.goojia.xiaonei.sunfarm.Config @ 0x144f8ea8 | 136 | 15,856,928 | 4.04%
|- com.goojia.xiaonei.sunfarm.DataMap @ 0x144f8fa8 | 56 | 15,854,760 | 4.04%
|- java.util.HashSet @ 0x17d01f50 | 16 | 560 | 0.00%
|- java.util.HashSet @ 0x17d01da8 | 16 | 424 | 0.00%
|- java.util.HashSet @ 0x17d02208 | 16 | 232 | 0.00%
|- java.lang.String[4] @ 0x17d02530 | 32 | 224 | 0.00%
|- java.util.HashSet @ 0x17d02180 | 16 | 136 | 0.00%
|- java.lang.String @ 0x179f3478 guanghuiyuan@qq.com| 24 | 80 | 0.00%
|- java.lang.String[1] @ 0x17d01d28 | 16 | 64 | 0.00%
|- java.lang.String[1] @ 0x17d01d68 | 16 | 64 | 0.00%
|- java.lang.String @ 0x179f34c8 qs828000 | 24 | 56 | 0.00%
|- java.lang.String[10] @ 0x17d02330 | 56 | 56 | 0.00%
|- java.lang.String @ 0x17d01d00 xn | 24 | 40 | 0.00%
|- java.lang.String @ 0x17d022e0 3 | 24 | 40 | 0.00%
|- java.lang.String @ 0x17d02308 30 | 24 | 40 | 0.00%
|- java.lang.String[1] @ 0x17d02610 | 16 | 16 | 0.00%
'- Total: 15 entries | | |
------------------------------------------------------------------------------------------------
哦? 是DataMap类的实例? 进行展开
Class Name | Shallow Heap | Retained Heap | Percentage
---------------------------------------------------------------------------------------------------
com.goojia.xiaonei.sunfarm.DataMap @ 0x144f8fa8 | 56 | 15,854,760 | 4.04%
|- net.sf.ezmorph.bean.MorphDynaBean @ 0x20b6f3f0 | 24 | 15,734,664 | 4.01%
|- java.util.HashMap @ 0x144f9108 | 40 | 31,912 | 0.01%
|- java.util.HashMap @ 0x144f9130 | 40 | 16,504 | 0.00%
|- java.util.HashMap @ 0x144f9068 | 40 | 10,464 | 0.00%
|- java.util.HashMap @ 0x144f90b8 | 40 | 6,432 | 0.00%
|- java.util.HashMap @ 0x144f9090 | 40 | 4,216 | 0.00%
|- java.util.HashMap @ 0x144f90e0 | 40 | 4,024 | 0.00%
|- java.text.DecimalFormat @ 0x144f8fe0 | 136 | 672 | 0.00%
|- java.lang.String @ 0x20d78370 shenqichinesecrabapple| 24 | 80 | 0.00%
|- java.lang.String @ 0x20d7cdd0 shenqiparadiseflower | 24 | 80 | 0.00%
|- java.lang.String @ 0x20d85b78 caomeilianrubaobing | 24 | 80 | 0.00%
|- java.lang.String @ 0x20d8c560 shenqiPutianBlackPig | 24 | 80 | 0.00%
|- java.lang.String @ 0x20d957d8 shengzhuanghuanxiong | 24 | 80 | 0.00%
|- java.lang.String @ 0x20d97370 shenqishuangfengluotuo| 24 | 80 | 0.00%
|- java.lang.String @ 0x20d75070 hongtouzhuomuniao | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d78470 shenqinigerseed | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d78568 wanshengjienangua | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d78950 gaojishengdanhong | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d7a518 tianshanxuelian | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d7b780 hongbailanmeigui | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d7d410 munaiyinan_farm | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d7d898 shenqima_ti_lian | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d80770 ziyezuojiangcao | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d822e8 shenqisweetviolet | 24 | 72 | 0.00%
|- java.lang.String @ 0x20d82790 chinesecrabapple | 24 | 72 | 0.00%
'- Total: 25 of 934 entries | | |
---------------------------------------------------------------------------------------------------
哦!!!!!!!! 原来是一个MorphDynaBean 的实例!! 但是DataMap不应该持有这个类的实例的啊,仅仅是初始化的时候,作为过程量传进入而已 稍微读了一下代码,发现这个DataMap类,发现对于这个实例变量有2个用途 1. 仅仅只是把bean赋值为一个实例变量:
this.bean = bean;
加载文件,转换为对象,赋值给实例变量,然后再另外一个方法中获取
public boolean initFromLocal() { loadDataFromLocal(); #这个方法仅仅在这里被调用,目的就是为this.bean赋值 if (null != this.bean) { initSeeds(bean); initBabies(bean); writeSeedReferenceFile(); return true; } else { return false; } }
显然,我轻微改动一下代码,这对象就不会被持有了! 具体改动,就是去掉实例变量,改为过程量!
就这样,内存就直接减下来了!! 哦也,搞定!Config对象占用的内存,从15M减到200K ,即减少98.7%! 仅仅几行代码的更改,使助手在相同内存占用的情况下,每100M内存,多运行20倍以上的帐号!! 故马上发布了助手的3.51版,哈哈!!
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