yang_net

1。 查询语句处理sql  ----解析器---> 关系代数表达式 ----查询优化器---> 查询执行计划 ----代码生成器---> 可执行代码。（关系代数解释了sql是如何计算的）2。 查询计算方法select        attrs, aggregatesfrom        relationswhere        conditiongroup by    group attr listhaving        group conditionorder by    or

Memcached初探手记Memcached是danga.com（运营LiveJournal的技术团队）开发的一套分布式内存对象缓存系统，目前全世界不少人使用这个缓存项目来构建自己大负载的网站，来分担数据库的压力。官方网址：http://memcached.org/Windows下的Memcached安装：1. 下载memcache的windows版(memcached-win32-1.4.4-54-g136cb6e.zip)，解压D:/work/memcached_win322.

Redis初探   Redis is an advanced key-value store. It is similar to memcached but the dataset is not volatile, and values can be strings, exactly like in memcached, but also lists, sets, and ordere

一、mysql在liunx下源码安装  1. 查看cent os版本以及linux内核版本：[root@localhost opt]# lsb_release -aLSB Version:    :core-3.1-ia32:core-3.1-noarch:graphics-3.1-ia32:graphics-3.1-noarchDistributor ID: CentOS

一、 hadoop安装 (本机单节点)1. Installing Software (or can adduser hadoop)$ sudo apt-get install ssh$ sudo apt-get install rsync2. Prepare to Start the Hadoop Clusterconf/hadoop-env.shexport

HBase Client总览1. affects concurrent readers and writers of that same row ==> atomic on a per-row basis2. RWCC : ReadWriteConsistencyControlread without wait for writeswrite wait for other