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基于Redis的分布式锁到底安全吗（上）？
网上有关Redis分布式锁的文章可谓多如牛毛了，不信的话你可以拿关键词“Redis 分布式锁”随便到哪个搜索引擎上去搜索一下就知道了。这些文章的思路大体相近，给出的实现算法也看似合乎逻辑，但当我们着手去实现它们的时候，却发现如果你越是仔细推敲，疑虑也就越来越多。 实际上，大概在一年以前，关于Redis分布式锁的安全性问题，在分布式系统专家 Martin Kleppmann 和Redis的作者...
View Article[Hadoop] Hadoop集群一般需要关注的几个重要指标
通用监控指标 对于每个RPC服务应该监控 RpcProcessingTimeAvgTime(PRC处理的平均时间) 通常hdfs在异常任务突发大量访问时，这个参数会突然变得很大，导致其他用户访问hdfs时，会感觉到卡顿，从而影响任务的执行时间 CallQueueLength(RPC Call队列的长度)...
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redis集群原理
redis是单线程，但是一般的作为缓存使用的话，redis足够了，因为它的读写速度太快了。 官方的一个简单测试： 测试完成了 50 个并发 执行 100000 个请求 。 设置和获取的值是一个256字节字符串。 结果: 读的速度是110000次/s,写的速度是81000次/s...
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架构|如何以1美元使用Netty、Akka和Cassandra将服务器性能提高到每小时处理1亿条消息
点击上方蓝色“ 网路冷眼” 可以订阅哦！ Thingsboard是一个用于数据收集，处理，可视化和设备管理的开源IoT平台。它通过工业标准IoT协议（MQTT，CoAP和HTTP）实现设备连接，并支持云和内部部署。...
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Really BigData, really small Cloud
I have decided to learn about data, Big Data, really Big Data in fact. It's going to be an adventure, and this is your invitation. The pretext I was at the GCP Next '16 conference in London towards the...
View ArticleClusters f**ked: Insecure Hadoop file systems wiped by miscreants
Administrators of Hadoop Distributed File System (HDFS) clusters have evidently not heeded warnings that surfaced last month about securing software with insecure default settings. Attacks on Hadoop...
View ArticleHortonworks: Hadoop Distributor Jumps 8% on Q4 Beat
By Tiernan Ray Softwaredistributor Hortonworks (HDP), which supports the Hadoop data mining program, this afternoon reported Q4 revenue that topped analysts’ expectations, and a smaller-than-expected...
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Learn to Add & Retrieve From a Collection using MongoDB & Java
In this chapter, we are going to use the MongoDB JDBC connection (created in the last article) in order to connect MongoDB database with JAVA. After successfully connecting MongoDB with JAVA, we are...
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Life after 1 year of using Neo4J
A year ago on one of my projects we got an idea that migrating to Neo4j would be great, cause we having data that would be ideal for graph. After that, our life changed forever. I think Neo4j is like...
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Adding #AzureSearch to #DocumentDB collections with a click of a button
Our customers love how easy it is to use Azure Search and DocumentDB together to meet business goals . Tight integration throughIndexers simplifies the task of indexing and searching in a variety of...
View ArticleRedis 3.2.7 发布，修复重要 bug
Redis 发布紧急升级版本 v3.2.7 。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。 新版本有两个重要的错误修复，其中第一个是关键： 1.显然Jemalloc...
View ArticleMongoDB 存储日志数据
线上运行的服务会产生大量的运行及访问日志，日志里会包含一些错误、警告、及用户行为等信息，通常服务会以文本的形式记录日志信息，这样可读性强，方便于日常定位问题，但当产生大量的日志之后，要想从大量日志里挖掘出有价值的内容，则需要对数据进行进一步的存储和分析。 本文以存储 web 服务的访问日志为例，介绍如何使用 MongoDB...
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The Problem with MongoDB
The Problem withMongoDB When building a web app (or any app) that needs to store data, one of the biggest decisions to make is what database to use. In the world of start-ups, where MVP’s and agile...
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MongoDB 数组查询
MongoDB在文档上支持数组，其次数组上可以实现嵌套，以及数组元素也可以文档。因此，对于文档上数组的操作，MongoDB提供很多种不同的方式，包括数组的查询，数组元素的添加删除等等。本文主要描述数组查询，供大家参考。 一、演示环境及数据 > db.version() 3.2.11 > db.users.insertMany( [ { _id: 1, name: "sue", age:...
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Differential dataflow status report
Differential dataflow progress report Back in July, I wrote a post about a differential dataflow roadmap : where I would like thing to go next based on current issues, and what sorts of problems we...
View ArticleUsing the command line to check redis health
In the forth entry of our series on redis we’ll have a look at its CLI tools. The central question for today: How can we check that redis is working as expected using the command line? redis-CLI basics...
View ArticleOn in-memory, key-value data stores. Ofer Bengal and Yiftach Shoolman
“While modernizing legacy applications used to be a key reason for deploying in-memory, key-value data stores, we see that this is changing. New applications particularly those that are highly...
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使用 Swift语言进行 Hadoop 数据流应用程序开发
本文详细源代码请参考 Github Perfect Examples 该项目展示了如何使用 Swift 语言开发 Hadoop 流处理应用程序。 该软件使用SPM进行编译和测试，本软件也是 Perfect 项目的一部分。本软件包可独立使用，因此使用时可以脱离PerfectLib等其他组件。 请确保您已经安装并激活了最新版本的 Swift 3.0 tool chain 工具链。...
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