<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[beichuanweibo的博客]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/beichuanweibo</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; beichuanweibo]]></copyright><item><title><![CDATA[maxMemory-totalMemory-freeMemory]]></title><link>https://blog.youkuaiyun.com/beichuanweibo/article/details/111573348</link><guid>https://blog.youkuaiyun.com/beichuanweibo/article/details/111573348</guid><author>beichuanweibo</author><pubDate>Wed, 23 Dec 2020 10:40:03 +0800</pubDate><description><![CDATA[Runtime r = Runtime.getRuntime();



long maxMemory= r.maxMemory();

long totalMemory= r.totalMemory();

long freeMemory = r.freeMemory();

// Xmx 最大值，，Xms 最小值，



maxMemory是java虚拟机从操作系统分配的最大内存值，单位是字节,

如果没有设置-Xmx，则最大值(默认)是64 * 1024*1024,也就是64M,如果设置了Xm...]]></description><category></category></item><item><title><![CDATA[redis 对象的空转时长]]></title><link>https://blog.youkuaiyun.com/beichuanweibo/article/details/111478811</link><guid>https://blog.youkuaiyun.com/beichuanweibo/article/details/111478811</guid><author>beichuanweibo</author><pubDate>Mon, 21 Dec 2020 17:04:54 +0800</pubDate><description><![CDATA[8.10 对象的空转时长
除了前面介绍过的type、encoding、ptr和refcount四个属性之外，redisObject结构包含的最后一个属性为lru属性，该属性记录了对象最后一次被命令程序访问的时间：
typedef struct redisObject {
  // ...
  unsigned lru:22;
  // ...
} robj;
OBJECT IDLETIME命令可以打印出给定键的空转时长，这一空转时长就是通过将当前时间减去键的值对象的lru时间计算得出的：
red...]]></description><category></category></item></channel></rss>