“Hard commits are about durability, soft commits are about visibility“  Transaction Logs 首先介绍下solrcloud的index流程. 1)update请求发送给任意节点(NodeA). 2)若该节点不是leader,将请求转发给leader. 3)leader将请求转发给所有副本节点(同一分片). 后面就是执行结果的响应(response),所有副本节点反馈给leader,leader再反馈给原接收到请求…

启动hadoop时,报错“mkdir: cannot create directory ‘/soft/hadoop-2.7.3/logs’: Permission denied” 注:/soft/hadoop-2.7.3为hadoop的安装目录,具体目录因人而异 原因:/soft目录的用户权限为root,需要修改为centos用户权限 注:centos为本机的用户名,具体用户名因人而异 解决办法: 1.切换到root用户 su root 2.递归修改/soft目录的用户权限 chown -R c…

关于 Solr Cloud Zookeeper 入门,介绍 原理 原封不动转自 http://wiki.apache.org/solr/SolrCloud/ ,文章的内存有些过时,但是了解原理. This page is outdated and you should read about SolrCloud at the Solr Reference Guide instead: https://cwiki.apache.org/confluence/display/solr/SolrClou…

http://www.onjava.com/pub/a/onjava/2001/05/30/optimization.htmlComparing the performance of LinkedLists and ArrayLists (and Vectors) (Page last updated May 2001, Added 2001-06-18, Author Jack Shirazi, Publisher OnJava). Tips: ArrayList is faster than…

Complete list of Microsoft SQL Server trace flags (585 trace flags) REMEMBER: Be extremely careful with trace flags, test in your test environment first. And consult professionals first if you are the slightest uncertain about the effects of your cha…

What is SolrCloud? (And how does it compare to master-slave?) SolrCloud is a set of new features and functionality added in Solr 4.0 to enable a new way of creating durable, highly available Solr clusters with commodity hardware. While similar in man…

原文地址:https://gist.github.com/maxivak/3e3ee1fca32f3949f052 Install Solr download and install Solr from http://lucene.apache.org/solr/. you can access Solr admin from your browser: http://localhost:8983/solr/ use the port number used in installation. M…

上一篇讲述了solr的安装启动过程,这一篇讲述如何导入数据到solr里. 一.准备数据 1.1 学生相关表 创建学生表.学生专业关联表.专业表.学生行业关联表.行业表.基础信息表,并创建一条小白的信息.由于navicat收费,所以这里利用HeidiSQL连接本地的MySql建立表. 1.2查询数据 查询出要导入solr的数据 二.添加jar包 2.1 添加mysql数据库驱动包 下载jar包,并放入到../solr-7.7.2/server/solr-webapp/webapp/WEB-INF/…

转载来自: http://www.infocool.net/kb/PHP/201607/168683.html a 函数 说明 abs 绝对值 acos 反余弦 acosh 反双曲余弦 addcslashes 以 C 语言风格使用反斜线转义字符串中的字符 addslashes 使用反斜线引用字符串 apache_child_terminate 在本次请求结束后终止 apache 子进程 apache_getenv 获取 Apache subprocess_env 变量 apache_get_mo…

There has been widespread characterization of one of the major distinctions between NoSQL and traditional DBMSs by saying that the former don’t care for ACID semantics or that transactions aren’t needed. This is an oversimplification to say the least…