译文：HBase File Locality in HDFS
Hadoop中一个不明确的内容就是Block复制：它自动完成，通常不需要用户关心。HBase将数据保存到HDFS，并完全相信它的安全性。正是因为HDFS的Block复制对HBase来说是完全透明的，就产生了一个问题：HBase的效率会受到多大的影响？当我们开始写MapReduce作业访问HBase和Hadoop的时候，就难免会想到这个问题。尤为关键的是，当HBase中存储的数据很多的时候，它怎样使数...
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How to Change MongoDB Storage Engines Without Downtime
This blog is another in the series for the Percona Server for MongoDB 3.4 bundle release. Today’s blog post is about how to migrate between Percona Server for MongoDB storage engines without downtime....
View ArticleMongoDB 3.5.4 和 3.4.3rc0 发布，分布式文档存储数据库
MongoDB 3.5.4 和 3.4.3rc0 发布了。 3.5.4 部分更新如下： 改进 [ SERVER-2104 ] - covered index should support dotted fields [ SERVER-3181 ] - Add option to listDatabases to only get db names, not size info [...
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缓存那些事
作者：熊明辉，美团点评酒旅事业群酒店住宿研发团队B端商家业务平台负责人，主导构建商家业务平台系统，支撑美团点评酒店住宿业务的飞速发展需求。曾任职于联想集团、百度。 责编：钱曙光，关注架构和算法领域，寻求报道或者投稿请发邮件qianshg@csdn.net，另有「CSDN...
View Article.NET Core List, Queue, and Dictionary Data Structures backed by Couchbase
The addition of thesub-document API to Couchbase 4.5 has paved the way for efficient data structure support inCouchbase. In this blog post, I’m going to show a demo of three types of data structures...
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Redundancy does not imply fault tolerance: analysis of distributed storage...
Redundancy does not imply fault tolerance: analysis of distributed storage reactions to single errors and corruptions Ganesan et al., FAST 2017 It’s a tough life being the developer of a distributed...
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Getting Started with the Microsoft Concept Graph in Neo4j
ByCristina Escalante, COO of SilverLogic | March 8, 2017 Introduction What does the study of concepts (or categories, depending on your field of study) tell us about the human mind? A result of the...
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ScyllaDB raises $16 million to facilitate app building
ScyllaDB , an open-source NoSQL database that enables developers to easily build applications, announced today a new round of $16 million. The startup redesigned the open-source Apache Cassandra NoSQL...
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IDG Contributor Network: ScyllaDB another contender to the open source NoSQL...
The world of the database is one of those areas that sees lots of people obsessing over details that to outside observers would seem trivial. Graph, NoSQL, SQL, distributed―so many choices. So, when...
View ArticleA Look At Docker
A while ago I worked on a project that used this tech stack Akka HTTP : (actually we used Spray.IO but it is practically the same thing for the purpose of this article). For those that don’t know what...
View ArticleAmbari + HDP 升级 （Ambari 2.2.2 - 2.4.1 + HDP 2.4.2 - 2.5.0）
Ambari + HDP 升级 （Ambari 2.2.2 - 2.4.1 + HDP 2.4.2 - 2.5.0） 一、Ambari 升级 1.升级前准备 1.1确认版本 Be sure to review the Release Notes for this Ambari release for Known Issues and Behavioral Changes 1.2确认拥有root权限...
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Self-Service Open Data Science: Custom Anaconda Management Packs for...
As part of ourpartnershipwith Hortonworks, we’re excited to announce a new self-service feature of the Anaconda platform that can be used to generate custom Anaconda management packs for the...
View Articlearangochair a tool for listening to changes in ArangoDB
The ArangoDB team gave me an opportunity to write a tutorial about arangochair . Arangochair is the first attempt to listen for changes in the database and execute actions like pushing a document to...
View Articleoralce字符集 oralce oralce教程 oralce字符集 字符集设置
oralce字符集问题如下： 1、有个人的名字是王?，但是oralce11.2.0.4.0存成了‘王?’。 2、oralce字符集ZHS16GBK，通过oralce的local builder查看，这个字符集中没有这个“?”字 3、新建了一个数据库，字符集改完AL32UTF8， create table t(N varchar2(200)); select t.*, t.rowid from T...
View Article利用反射获取实体所有属性和方法 反射利用 实体属性 实体属性获取
利用反射获取实体所有属性和方法。 //实现思路: //1.获取实体的所有字段,遍历 //2.获取字段类型 //3.调用字段的get方法,set方法Field[] field = model.getClass().getDeclaredFields(); // 获取实体类的所有属性，返回Field数组try {for (int j = 0; j < field.length; j++) { //...
View Article服务器之如何更好的是使用开发缓存 服务器 开发缓存 开发缓存使用技巧
服务器之如何更好的是使用开发缓存。很多项目服务端最开始的性能瓶颈不出现在语言也不出现在框架，通常是出现在数据库上，具体表现为数据库慢查询、死锁、数据库连接数占满等。当遇到数据库读写频繁的业务，缓存是必不可少的了。但是缓存该怎么做才能使利用率更高，减少或避免脏读呢?本篇就以自己的经验来谈谈如何更好的使用缓存。 先说说自己的项目和经历。...
View Article应用ASP.Net在web中查询数据库 数据库 数据函数 数据库查询 website
将数据库中的数据查询出来，并打印在html页面上首先创建一个website，在web.config文件中写上连接字符串<connectionStrings><add name="constr" connectionString="Data Source=Graph;Initial Catalog=化学类一班;Integrated...
View ArticleKPIs For DBAs to Show Their CIOs
Last week I found this question about KPIs on #sqlhelp Anyone have any good KPI’s for DBA’s? Our director wants us to come up with some Key Performance Indicators. Any articles? #sqlhelp ― SS7...
View ArticleHigh-Availability with Redis Sentinels: Connecting to Redis Master/Slave Sets
Connecting to single, standalone Redis server is simple enough: simply point to the host, port and provide the authentication password, if any. Most Redis clients even provide support for some sort of...
View ArticleCouchDB is on Slack
CouchDB now has a Slack channel, where anyone interested in CouchDB can ask questions or get involved in the project. To join, you can sign up on our website . We are always looking to make it easier...
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