top查看java占用的内存比较多

top - :: up  days, :,   user,  load average: 0.03, 0.05, 0.05
Tasks: total, running, sleeping, stopped, zombie
%Cpu(s): 0.0 us, 1.3 sy, 0.0 ni, 98.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : total, free, used, buff/cache
KiB Swap: total, free, used. avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
root .598g S 0.0 20.5 :01.18 jsvc
root .323g S 0.0 17.0 :32.59 jsvc
root .136g S 0.0 14.6 :06.62 jsvc
root S 0.0 9.2 :19.24 jsvc

可见每个占用了大概20%,还是比较高的,因为要部署新的服务,腾内存了

使用jstack查看一下进程的状态,其实也没什么用,不过我昨天刚学的java GC,就试用一下

jstack -F
Attaching to process ID , please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.111-b14
Deadlock Detection: No deadlocks found. Thread : (state = BLOCKED) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Interpreted frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Interpreted frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Interpreted frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame) Thread : (state = BLOCKED)
- sun.misc.Unsafe.park(boolean, long) @bci= (Compiled frame; information may be imprecise)
- java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=, line= (Compiled frame)
- java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=, line= (Interpreted frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.getTask() @bci=, line= (Compiled frame)
- java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=, line= (Interpreted frame)
- java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=, line= (Interpreted frame)
- java.lang.Thread.run() @bci=, line= (Interpreted frame)

后边不贴了,总之就是有大量的BLOCKED,这个程序说是bug导致的,下一个版本会修正,另外其他的进程实在IN_NATIVE状态,因为JAVA底层其实是C语言实现的,这个就是在执行C语言的调用,native

我竟然还以为是inactive,Naive

使用jstat分析一下gc,命令格式jstat -gc -t <PID>

jstat -gc -t
Timestamp S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT
484036.7 2048.0 2048.0 0.0 1296.0 694784.0 234952.5 1398272.0 259033.6 59136.0 57496.9 6400.0 6017.4 10.073 0.254 10.327

这里面S0C和S1C是两个survivor的容量,S0U和S1U是两个survivor已经使用的容量,EC和EU分别是新生代容量和已用容量,OC和OU是老年代的容量和已用,MC和MU是方法区的容量和使用大小,CCSC和CCSU是压缩类空间容量和使用大小,YGC是minor GC的次数,YGCT是minorGC的总计时间,FGC是major GC的次数,FGCT是major GC的时间,GCT是总共GC的占用时间。

其实这里还可以获取一下内存快照的,方法是

jmap -dump:format=b,file=heap.bin <pid>
file:保存路径及文件名
pid:进程编号(windows通过任务管理器查看,linux通过ps aux查看)

分析工具从http://www.eclipse.org/mat/下载,可惜我这里没有,所以说就算了吧

言归正传,用jmap分析下总的heap,heap就是堆,这里说下,堆和栈是有区别的,堆是存储变量,栈存储的是命令。堆是可以由应用程序来修改和申请空间,栈是由系统来管理的

root@localhost:~# jmap -heap
Attaching to process ID , please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.111-b14 using thread-local object allocation.
Parallel GC with thread(s) Heap Configuration:
MinHeapFreeRatio =
MaxHeapFreeRatio =
MaxHeapSize = (.0MB)
NewSize = (.5MB)
MaxNewSize = (.5MB)
OldSize = (.5MB)
NewRatio =
SurvivorRatio =
MetaspaceSize = (.796875MB)
CompressedClassSpaceSize = (.0MB)
MaxMetaspaceSize = MB
G1HeapRegionSize = (.0MB) Heap Usage:
PS Young Generation
Eden Space:
capacity = (.5MB)
used = (.6439056396484MB)
free = (.856094360351562MB)
96.33661100068511% used
From Space:
capacity = (.0MB)
used = (.001068115234375MB)
free = (.998931884765625MB)
50.05340576171875% used
To Space:
capacity = (.0MB)
used = (.0MB)
free = (.0MB)
0.0% used
PS Old Generation
capacity = (.5MB)
used = (.53402709960938MB)
free = (.9659729003906MB)
18.493887008393216% used

震惊!运维工程师用jmap分析jvm,竟然……

Eden看起来有点高了,但是其实这么说也是不公平的,Eden(伊甸园)区满了就会触发minorGC,把不活跃的对象清理掉,几次GC后还没有被清理掉的进入survivor,还能幸存的进入老年代,所以如果一个进程说Linux的哪一块内存没有去过,其实潜台词就是他老了(逃

不过Eden还是不能太小了,否则如果被活跃的对象占满了,GC不会处理这些对象,新的对象一直等着进不来,就会造成进程假死了,参考文献

http://www.cnblogs.com/jackchen001/p/6902909.html

或者温和一点,大量的对象放进老生代,导致频繁的full GC,full GC是要暂停程序的,并且会占用大量的CPU,导致性能下降

http://blog.csdn.net/hengyunabc/article/details/24924843

现在就比较简单了,使用java -XX就可以调整了

这里可以看到NewRatio是2,那么就是NewGeneration:OldGeneration = 1:2,new占了1/3的空间,old占了2/3,这里调整一下,把总体从原来的2G调整到1G就可以了,这样老年代空间和新生代空间都缩小了一半,YGC会频繁一点,但是YGC很快,不太会影响,只要老年区不被沾满就行,如果还不放心可以把新生代调大一点,SUN官方推荐新生代为整体的3/8。SurvivoRatio是连个Survivor区与Eden区的大小比值,8就是Eden:Survivor=8:2

java -Xmx1024m -Xmn374m

这样调整后感觉好多了

参考文献

http://www.cnblogs.com/redcreen/archive/2011/05/04/2037057.html

http://www.importnew.com/1993.html

jvm 内存调整的更多相关文章

  1. JVM内存调整

    JVM内存调整 先试着调整一下idea的 找到软件安装位置/bin/idea64.exe.vmoptions 给他直接整个起飞的,改成 -Xms512m -Xmx1500m 找到Java安装的位置/j ...

  2. 一次JVM内存调整

    单台服务器8G内存,2核 系统里装了redis, rocketmq, mysql, zookeeper, 还有20个左右的微服务,每个微服务的jvm 参数 -Xms128m -Xmx256m -Xmn ...

  3. JBoss - 调整JVM内存 -Xms512m -Xmx1024m

    $JBOSS-HOME/server/下有3个目录,all/default/minimal,它们是表示3种配置,全部的配置.默认配置.最小配置,我们在启动JBOSS服务时,可以指定 run –c al ...

  4. javaweb学习总结九(xml解析以及调整JVM内存大小)

    一:解析XML文件的两种方式 1:dom,document object model,文档对象模型. 2:sax,simple API for XML. 3:比较dom和sax解析XML文件的优缺点 ...

  5. Java SE之调整JVM内存笔记

    [文档整理系列]  Java SE之调整JVM内存笔记 一般JVM内存限制是64Mbyte Eclipse下 Run as configrationArguments选项:-Xmx80m [设置虚拟机 ...

  6. JVM内存限制和调整

    今天用java -jar执行一个jar文件提示内存不够,需要设置虚拟机的堆大小.以下是参考资料: 堆(Heap)和非堆(Non-heap)内存  按照官方的说法:“Java 虚拟机具有一个堆,堆是运行 ...

  7. 调整JVM内存大小

    首次运行公司项目,出现了内存溢出,具体出现java.lang.OutOfMemoryError: PermGen space和java.lang.OutOfMemoryError:GC overhea ...

  8. Java调整JVM内存大小——(八)

    JVM内存大小是有限的,有的时候程序过大时候会导致超出最大内存,产生下面异常: Exception in thread "main" java.lang.OutOfMemoryEr ...

  9. JVM内存管理------垃圾搜集器参数精解

    本文是GC相关的最后一篇,这次LZ只是罗列一下hotspot JVM中垃圾搜集器相关的重点参数,以及各个参数的解释.废话不多说,这就开始. 垃圾搜集器文章传送门 JVM内存管理------JAVA语言 ...

随机推荐

  1. codevs 5966 [SDOI2017]硬币游戏

    输入描述 Input Description 输入输出数据精度为1e-10 [题解] #include<cstdio> using namespace std; ; char s[N][N ...

  2. Linux系统内核main函数执行之前

    1.linux是一个操作系统在机器加电后,需要从硬件通过一个引导程序加载os kernel,那么在os kernel的main函数运行之前,都发生了什么呢? (1)引导BIOS(存储在ROM芯片中,R ...

  3. 【BZOJ3958】[WF2011]Mummy Madness 二分+扫描线+线段树

    [BZOJ3958][WF2011]Mummy Madness Description 在2011年ACM-ICPC World Finals上的一次游览中,你碰到了一个埃及古墓. 不幸的是,你打开了 ...

  4. 【BZOJ4196】[Noi2015]软件包管理器 树链剖分

    [Noi2015]软件包管理器 树链剖分 Description Linux用户和OSX用户一定对软件包管理器不会陌生.通过软件包管理器,你可以通过一行命令安装某一个软件包,然后软件包管理器会帮助你从 ...

  5. .net Asp AdRotator(广告控件)

    1.新建项目名称AdRotator 2.右键项目名称添加一个xml文件命名为AdRotator.xml <?xml version="1.0" encoding=" ...

  6. windows系统常用软件及配置介绍

    常用工具 ,,,, 开发工具 ,,, 快捷键 ... 等等 vvv 等等

  7. 【webpack】---模块打包机webpack基础使用---【巷子】

    001.什么是webpack? 作用有哪些? WebPack可以看做是模块打包机:它做的事情是,分析你的项目结构,找到JavaScript模块以及其它的一些浏览器不能直接运行的拓展语言(Scss,Ty ...

  8. Oracle下回滚rollback的使用

    oracle中可以设置一个回滚点进行回滚 设置回滚名称 savepoint pointa ; 进行回滚 rollback to pointa; 如果期间有删除的数据就回来了

  9. Faster R-CNN论文详解 - CSDN博客

    废话不多说,上车吧,少年 paper链接:Faster R-CNN: Towards Real-Time Object Detection with Region Proposal Networks ...

  10. P2750 贰五语言Two Five USACO5.5 记忆化搜索

    正解:记搜+逼近 解题报告: 神仙题预警,,, 我真滴觉得还是挺难的了,,, 大概说下思路趴QAQ 首先我们要知道逼近法是什么! 逼近法,有点像二分的思路,以这题为例举个eg 假如它给了个数字k.我们 ...