MySQL has a number of global buffers, i.e. your SGA. There are also a number of per session/thread buffers that combined with other memory usage constitutes an unbounded PGA. One of the most common errors in mis-configured MySQL environments is the s…

There have been a few posts by Sheeri and Baron today on the MySQL sort_buffer_size variable. I wanted to add some more information about this buffer, what is impacted when it is changed, and what to do about it? The first thing you need to know is t…

Go 2 Draft Designs 28 August 2018 Yesterday, at our annual Go contributor summit, attendees got a sneak peek at preliminary drafts of possible designs for changes to error handling and generics. The development of Go 2 was announced last year and we…

CESSNA: 弹性边缘计算 本文为SIGCOMM 2018 Workshop (Mobile Edge Communications, MECOMM)论文. 笔者翻译了该论文.由于时间仓促,且笔者英文能力有限,错误之处在所难免:欢迎读者批评指正. 本文及翻译版本仅用于学习使用.如果有任何不当,请联系笔者删除. 本文包含5位共同作者,UC Berkeley的Yotam Harchol.Aisha Mushtaq和James McCauley,NYU和ICSI的Aurojit Panda以及UC…

说明   本文源码基于Openfire4.0.2.   Openfire的启动       Openfire的启动过程非常的简单,通过一个入口初始化lib目录下的openfire.jar包,并启动一个XMPPServer实例.   下面就是ServerStarter.start方法的代码片断:   Class containerClass = loader.loadClass("org.jivesoftware.openfire.XMPPServer"); containerClass…

同事在Toad里面执行SQL语句时,突然无线网络中断了,让我检查一下具体情况,如下所示(有些信息,用xxx替换,因为是在处理那些历史归档数据,使用的一个特殊用户,所以可以用下面SQL找到对应的会话信息): SQL> SELECT B.USERNAME     ,   2         B.SID          ,   3         B.SERIAL#      ,   4         LOGON_TIME     ,   5         A.OBJECT_ID   6   …

一大早就接到开发商的电话,说数据库的CPU使用率为100%,应用相应迟缓.急匆匆的赶到现场发现进行了基本的检查后发现是latch: cache buffers chains 作祟,处理过程还算顺利,当时忘了记录log,这里总结下处理思路,以便下次查看. 故障分析思路 查看等待事件,判断故障起因 SQL>select * from (select sid,event,p1,p2,p3,p1text,WAIT_TIME,SECONDS_IN_WAIT from v$session_wait wher…

http://en.wikipedia.org/wiki/Session_fixation In computer network security, session fixation attacks attempt to exploit the vulnerability of a system which allows one person to fixate (set) another person's session identifier (SID). Most session fixa…

Active Session History (ASH) Performed An Emergency Flush Messages In The Alert Log (文档 ID 1385872.1)   In this Document   Symptoms   Cause   Solution This document is being delivered to you via Oracle Support's Rapid Visibility (RaV) process and the…

tomcat集群时,原来通过HttpSessionListener实现类监听session的创建和销毁来统计在线人数的方法不再有效,因为不是每个人登陆都会在同一个tomcat服务器上,而在另一台tomcat上登陆的人的session是通过session复制创建的,而复制过程不会调用HttpSessionListener接口的方法,也一直没找着如何监听session复制的方法,所以就没法统计在线人了. 今天突然回想起tomcat下的manager应用上面就能看到session数和session的内…