Andrew Dalke: Weininger's Realization
[previous | next ] /home/ writings / diary / archive / 2016 / 12 /02/Weiningers_realization Weininger's Realization Dave Weininger passed away recently. He was very well known in the chemical...
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Redis源码剖析--源码结构解析
找工作那会儿，看了黄建宏老师的《Redis设计与实现》，对redis的部分实现有了一个简明的认识。在面试过程中，redis确实成为了面试官考核我的一个亮点，恰好以后的工作又与redis有着千丝万缕的联系，于是就想趁着毕业前的这段时间把redis的源代码研究一下，为以后的工作打个良好的基础。 Redis简介 redis全称REmote DIctionary Server，是一个由Salvatore...
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Redis源码剖析--动态字符串SDS
Redis没有使用C语言的字符串结构，而是自己设计了一个简单的动态字符串结构sds。它的特点是：可动态扩展内存、二进制安全和与传统的C语言字符串类型兼容。下面就从源码的角度来分析一下Redis中sds的实现。（sds的源码实现主要在sds.c和sds.h两个文件中） sds数据结构定义 在sds.h文件中，我们可以找到sds的数据结构定义如下： typedef char *sds;...
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常见性能优化策略的总结
本文要感谢我职级评定过程中的一位评委，他建议把之前所做的各种性能优化的案例和方案加以提炼、总结，以文档的形式沉淀下来，并在内部进行分享。力求达到如下效果： 1. 形成可实践、可借鉴、可参考的各种性能优化的方案以及选型考虑点，同时配合具体的真实案例，其他人遇到相似问题时，不用从零开始。 2....
View ArticleHouston User Group Visits - October 2016 (Videos)
I spent nearly a week in Texas, visiting four user groups and talking aboutCouchbase as much as possible. The second two days of the week I spent in Houston. Here are the videos: Houston.js Group - I...
View ArticleFriday Links 0.0.20 - MongoDB
This is based on an email I send my .NET team at work Happy Friday, I’ve been exploring MongoDB because we were supposed to be starting an engagement with a client that is pretty heavily invested in...
View ArticleJedis Sharding实现
随着业务的发展，当Redis单实例无法满足需求时，无可避免的要采用Redis集群方案。 目前普遍采用的Redis集群方案有： 客户端做Sharding； twenproxy； redis cluster Jedis...
View ArticleRedis 4.0-rc1 发布，超高性能 key-value 数据库
Redis 4.0-rc1 发布了，这是 4.0 的首个 RC 版。Redis 是一个高性能的key-value数据库。Redis 的出现，很大程度补偿了memcached这类keyvalue存储的不足，在部分场合可以对关系数据库起到很好的补充作用。它提供了python，Ruby，Erlang，php客户端，使用很方便。 以下是该版本发布值得关注的内容： Major features Redis...
View Articleredis 字符串
在 redis 中，字符串的基本结构如下，其中， len 表示字符串的长度， alloc 表示字符串的最大容量， flags 表示header的类型。 struct __attribute__ ((__packed__)) sdshdr8 { uint8_t len; /*
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redis 字典
redis字典和python的字典（java中的map）的性质是一样的，也被称为关联数组或映射，是一种保存键值对的数据结构。 redis字典使用哈希表作为底层实现，字典中的键不允许相同。 typedef struct dictht { dictEntry **table; // 哈希表 unsigned long size; // 哈希表大小 unsigned long sizemask; //...
View ArticleInstructions for the bigsql_support tool
Instructions for the bigsql_support tool As shown in Big SQL Log files Location and content , logs files that are useful for Big SQL problem determination are located in many directories and on many...
View ArticleArangoDB #FoxxChallenge
Starting today we launch the ArangoDB #FoxxChallenge and the winner will receive a brand new Amazon Echo . Use your knowledge about everyday needs in projects and create a Foxx service that could be...
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Scylla 1.4 on Compose - Optimizing connectivity
Compose is pleased to announce the availability of Scylla 1.4.2 on the Compose platform. This is the first update of the database since its arrival as a beta database on Compose. Compose databases are...
View ArticleThe innodb_system data file 'ibdata1' must be writeable
今天重启电脑后 mysql 又用不了了！ 然后查看了错误日志 ： $ sudo cat /usr/local/mysql/data/jh.local.err 2016-10-01T15:51:09.6NZ mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data...
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How Redis suits Centrifugo
In this post I want to share some details about Redis as one of the Centrifugo built-in engines. This is what “redis” means inRussia:) Maybe you know from project docs or from my first article here...
View ArticleCassandra经常被问到的问题（一）
1、为什么不可以设置listen_address为0.0.0.0（意思是监听所有地址）？ Cassandra是一个基于gossip协议的分布式系统，监听地址是用来告诉其它节点来访问的，告诉别的节点说“连接我任何地址都可以”，是一个糟糕的想法，如果集群中不同的节点使用了不同方式的地址，悲剧的事情就要发生了。...
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Elassandra: large scale multi-datacenter elasticsearch
I'm looking for a new challenge. Contact me at simon@nureality.ca if you're interested. Elassandra is a GitHub project that integrates Cassandra and Elasticsearch. Elassandra takes the advantages of...
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NoSQL .NET Core development using an local Azure DocumentDB Emulator
I was hanging out with Miguel de Icaza in New York a few weeks ago and he was sharing with me his ongoing love affair with a NoSQL Database called Azure DocumentDB. I've looked at it a few times over...
View Article第四周小练习
复制/etc/skel目录为/home/tuser1,要求/home/tuser1及其内部文件的属组和其它用户均没有任何访问权限 cp -r /etc/skel /home/tuser1chmod -R go= /home/tuser1 编辑/etc/group文件，添加组hadoop echo "hadoop600:" >> /etc/group...
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